root/drivers/usb/gadget/function/f_fs.c

DEFINITIONS

1. ffs_func_from_usb
2. ffs_setup_state_clear_cancelled
3. ffs_ep0_complete
4. __ffs_ep0_queue_wait
5. __ffs_ep0_stall
6. ffs_ep0_write
7. __ffs_ep0_read_events
8. ffs_ep0_read
9. ffs_ep0_open
10. ffs_ep0_release
11. ffs_ep0_ioctl
12. ffs_ep0_poll
13. ffs_epfile_io_complete
14. ffs_copy_to_iter
15. ffs_build_sg_list
16. ffs_alloc_buffer
17. ffs_free_buffer
18. ffs_user_copy_worker
19. ffs_epfile_async_io_complete
20. __ffs_epfile_read_buffer_free
21. __ffs_epfile_read_buffered
22. __ffs_epfile_read_data
23. ffs_epfile_io
24. ffs_epfile_open
25. ffs_aio_cancel
26. ffs_epfile_write_iter
27. ffs_epfile_read_iter
28. ffs_epfile_release
29. ffs_epfile_ioctl
30. ffs_epfile_compat_ioctl
31. ffs_sb_make_inode
32. ffs_sb_create_file
33. ffs_sb_fill
34. ffs_fs_parse_param
35. ffs_fs_get_tree
36. ffs_fs_free_fc
37. ffs_fs_init_fs_context
38. ffs_fs_kill_sb
39. functionfs_init
40. functionfs_cleanup
41. ffs_data_get
42. ffs_data_opened
43. ffs_data_put
44. ffs_data_closed
45. ffs_data_new
46. ffs_data_clear
47. ffs_data_reset
48. functionfs_bind
49. functionfs_unbind
50. ffs_epfiles_create
51. ffs_epfiles_destroy
52. ffs_func_eps_disable
53. ffs_func_eps_enable
54. ffs_do_single_desc
55. ffs_do_descs
56. __ffs_data_do_entity
57. __ffs_do_os_desc_header
58. ffs_do_single_os_desc
59. ffs_do_os_descs
60. __ffs_data_do_os_desc
61. __ffs_data_got_descs
62. __ffs_data_got_strings
63. __ffs_event_add
64. ffs_event_add
65. ffs_ep_addr2idx
66. __ffs_func_bind_do_descs
67. __ffs_func_bind_do_nums
68. __ffs_func_bind_do_os_desc
69. ffs_do_functionfs_bind
70. _ffs_func_bind
71. ffs_func_bind
72. ffs_reset_work
73. ffs_func_set_alt
74. ffs_func_disable
75. ffs_func_setup
76. ffs_func_req_match
77. ffs_func_suspend
78. ffs_func_resume
79. ffs_func_revmap_ep
80. ffs_func_revmap_intf
81. _ffs_do_find_dev
82. _ffs_get_single_dev
83. _ffs_find_dev
84. to_ffs_opts
85. ffs_attr_release
86. ffs_free_inst
87. ffs_set_inst_name
88. ffs_alloc_inst
89. ffs_free
90. ffs_func_unbind
91. ffs_alloc
92. _ffs_alloc_dev
93. ffs_name_dev
94. ffs_single_dev
95. _ffs_free_dev
96. ffs_acquire_dev
97. ffs_release_dev
98. ffs_ready
99. ffs_closed
100. ffs_mutex_lock
101. ffs_prepare_buffer

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_fs.c -- user mode file system API for USB composite function controllers
   4  *
   5  * Copyright (C) 2010 Samsung Electronics
   6  * Author: Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * Based on inode.c (GadgetFS) which was:
   9  * Copyright (C) 2003-2004 David Brownell
  10  * Copyright (C) 2003 Agilent Technologies
  11  */
  12 
  13 
  14 /* #define DEBUG */
  15 /* #define VERBOSE_DEBUG */
  16 
  17 #include <linux/blkdev.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/export.h>
  20 #include <linux/fs_parser.h>
  21 #include <linux/hid.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/sched/signal.h>
  26 #include <linux/uio.h>
  27 #include <linux/vmalloc.h>
  28 #include <asm/unaligned.h>
  29 
  30 #include <linux/usb/ccid.h>
  31 #include <linux/usb/composite.h>
  32 #include <linux/usb/functionfs.h>
  33 
  34 #include <linux/aio.h>
  35 #include <linux/mmu_context.h>
  36 #include <linux/poll.h>
  37 #include <linux/eventfd.h>
  38 
  39 #include "u_fs.h"
  40 #include "u_f.h"
  41 #include "u_os_desc.h"
  42 #include "configfs.h"
  43 
  44 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  45 
  46 /* Reference counter handling */
  47 static void ffs_data_get(struct ffs_data *ffs);
  48 static void ffs_data_put(struct ffs_data *ffs);
  49 /* Creates new ffs_data object. */
  50 static struct ffs_data *__must_check ffs_data_new(const char *dev_name)
  51         __attribute__((malloc));
  52 
  53 /* Opened counter handling. */
  54 static void ffs_data_opened(struct ffs_data *ffs);
  55 static void ffs_data_closed(struct ffs_data *ffs);
  56 
  57 /* Called with ffs->mutex held; take over ownership of data. */
  58 static int __must_check
  59 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  60 static int __must_check
  61 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  62 
  63 
  64 /* The function structure ***************************************************/
  65 
  66 struct ffs_ep;
  67 
  68 struct ffs_function {
  69         struct usb_configuration        *conf;
  70         struct usb_gadget               *gadget;
  71         struct ffs_data                 *ffs;
  72 
  73         struct ffs_ep                   *eps;
  74         u8                              eps_revmap[16];
  75         short                           *interfaces_nums;
  76 
  77         struct usb_function             function;
  78 };
  79 
  80 
  81 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  82 {
  83         return container_of(f, struct ffs_function, function);
  84 }
  85 
  86 
  87 static inline enum ffs_setup_state
  88 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  89 {
  90         return (enum ffs_setup_state)
  91                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  92 }
  93 
  94 
  95 static void ffs_func_eps_disable(struct ffs_function *func);
  96 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  97 
  98 static int ffs_func_bind(struct usb_configuration *,
  99                          struct usb_function *);
 100 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
 101 static void ffs_func_disable(struct usb_function *);
 102 static int ffs_func_setup(struct usb_function *,
 103                           const struct usb_ctrlrequest *);
 104 static bool ffs_func_req_match(struct usb_function *,
 105                                const struct usb_ctrlrequest *,
 106                                bool config0);
 107 static void ffs_func_suspend(struct usb_function *);
 108 static void ffs_func_resume(struct usb_function *);
 109 
 110 
 111 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 112 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 113 
 114 
 115 /* The endpoints structures *************************************************/
 116 
 117 struct ffs_ep {
 118         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 119         struct usb_request              *req;   /* P: epfile->mutex */
 120 
 121         /* [0]: full speed, [1]: high speed, [2]: super speed */
 122         struct usb_endpoint_descriptor  *descs[3];
 123 
 124         u8                              num;
 125 
 126         int                             status; /* P: epfile->mutex */
 127 };
 128 
 129 struct ffs_epfile {
 130         /* Protects ep->ep and ep->req. */
 131         struct mutex                    mutex;
 132 
 133         struct ffs_data                 *ffs;
 134         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 135 
 136         struct dentry                   *dentry;
 137 
 138         /*
 139          * Buffer for holding data from partial reads which may happen since
 140          * we’re rounding user read requests to a multiple of a max packet size.
 141          *
 142          * The pointer is initialised with NULL value and may be set by
 143          * __ffs_epfile_read_data function to point to a temporary buffer.
 144          *
 145          * In normal operation, calls to __ffs_epfile_read_buffered will consume
 146          * data from said buffer and eventually free it.  Importantly, while the
 147          * function is using the buffer, it sets the pointer to NULL.  This is
 148          * all right since __ffs_epfile_read_data and __ffs_epfile_read_buffered
 149          * can never run concurrently (they are synchronised by epfile->mutex)
 150          * so the latter will not assign a new value to the pointer.
 151          *
 152          * Meanwhile ffs_func_eps_disable frees the buffer (if the pointer is
 153          * valid) and sets the pointer to READ_BUFFER_DROP value.  This special
 154          * value is crux of the synchronisation between ffs_func_eps_disable and
 155          * __ffs_epfile_read_data.
 156          *
 157          * Once __ffs_epfile_read_data is about to finish it will try to set the
 158          * pointer back to its old value (as described above), but seeing as the
 159          * pointer is not-NULL (namely READ_BUFFER_DROP) it will instead free
 160          * the buffer.
 161          *
 162          * == State transitions ==
 163          *
 164          * • ptr == NULL:  (initial state)
 165          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP
 166          *   ◦ __ffs_epfile_read_buffered:    nop
 167          *   ◦ __ffs_epfile_read_data allocates temp buffer: go to ptr == buf
 168          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 169          * • ptr == DROP:
 170          *   ◦ __ffs_epfile_read_buffer_free: nop
 171          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL
 172          *   ◦ __ffs_epfile_read_data allocates temp buffer: free buf, nop
 173          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 174          * • ptr == buf:
 175          *   ◦ __ffs_epfile_read_buffer_free: free buf, go to ptr == DROP
 176          *   ◦ __ffs_epfile_read_buffered:    go to ptr == NULL and reading
 177          *   ◦ __ffs_epfile_read_data:        n/a, __ffs_epfile_read_buffered
 178          *                                    is always called first
 179          *   ◦ reading finishes:              n/a, not in ‘and reading’ state
 180          * • ptr == NULL and reading:
 181          *   ◦ __ffs_epfile_read_buffer_free: go to ptr == DROP and reading
 182          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 183          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 184          *   ◦ reading finishes and …
 185          *     … all data read:               free buf, go to ptr == NULL
 186          *     … otherwise:                   go to ptr == buf and reading
 187          * • ptr == DROP and reading:
 188          *   ◦ __ffs_epfile_read_buffer_free: nop
 189          *   ◦ __ffs_epfile_read_buffered:    n/a, mutex is held
 190          *   ◦ __ffs_epfile_read_data:        n/a, mutex is held
 191          *   ◦ reading finishes:              free buf, go to ptr == DROP
 192          */
 193         struct ffs_buffer               *read_buffer;
 194 #define READ_BUFFER_DROP ((struct ffs_buffer *)ERR_PTR(-ESHUTDOWN))
 195 
 196         char                            name[5];
 197 
 198         unsigned char                   in;     /* P: ffs->eps_lock */
 199         unsigned char                   isoc;   /* P: ffs->eps_lock */
 200 
 201         unsigned char                   _pad;
 202 };
 203 
 204 struct ffs_buffer {
 205         size_t length;
 206         char *data;
 207         char storage[];
 208 };
 209 
 210 /*  ffs_io_data structure ***************************************************/
 211 
 212 struct ffs_io_data {
 213         bool aio;
 214         bool read;
 215 
 216         struct kiocb *kiocb;
 217         struct iov_iter data;
 218         const void *to_free;
 219         char *buf;
 220 
 221         struct mm_struct *mm;
 222         struct work_struct work;
 223 
 224         struct usb_ep *ep;
 225         struct usb_request *req;
 226         struct sg_table sgt;
 227         bool use_sg;
 228 
 229         struct ffs_data *ffs;
 230 };
 231 
 232 struct ffs_desc_helper {
 233         struct ffs_data *ffs;
 234         unsigned interfaces_count;
 235         unsigned eps_count;
 236 };
 237 
 238 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 239 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 240 
 241 static struct dentry *
 242 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 243                    const struct file_operations *fops);
 244 
 245 /* Devices management *******************************************************/
 246 
 247 DEFINE_MUTEX(ffs_lock);
 248 EXPORT_SYMBOL_GPL(ffs_lock);
 249 
 250 static struct ffs_dev *_ffs_find_dev(const char *name);
 251 static struct ffs_dev *_ffs_alloc_dev(void);
 252 static void _ffs_free_dev(struct ffs_dev *dev);
 253 static void *ffs_acquire_dev(const char *dev_name);
 254 static void ffs_release_dev(struct ffs_data *ffs_data);
 255 static int ffs_ready(struct ffs_data *ffs);
 256 static void ffs_closed(struct ffs_data *ffs);
 257 
 258 /* Misc helper functions ****************************************************/
 259 
 260 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 261         __attribute__((warn_unused_result, nonnull));
 262 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 263         __attribute__((warn_unused_result, nonnull));
 264 
 265 
 266 /* Control file aka ep0 *****************************************************/
 267 
 268 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ffs_data *ffs = req->context;
 271 
 272         complete(&ffs->ep0req_completion);
 273 }
 274 
 275 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 276         __releases(&ffs->ev.waitq.lock)
 277 {
 278         struct usb_request *req = ffs->ep0req;
 279         int ret;
 280 
 281         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 282 
 283         spin_unlock_irq(&ffs->ev.waitq.lock);
 284 
 285         req->buf      = data;
 286         req->length   = len;
 287 
 288         /*
 289          * UDC layer requires to provide a buffer even for ZLP, but should
 290          * not use it at all. Let's provide some poisoned pointer to catch
 291          * possible bug in the driver.
 292          */
 293         if (req->buf == NULL)
 294                 req->buf = (void *)0xDEADBABE;
 295 
 296         reinit_completion(&ffs->ep0req_completion);
 297 
 298         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 299         if (unlikely(ret < 0))
 300                 return ret;
 301 
 302         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 303         if (unlikely(ret)) {
 304                 usb_ep_dequeue(ffs->gadget->ep0, req);
 305                 return -EINTR;
 306         }
 307 
 308         ffs->setup_state = FFS_NO_SETUP;
 309         return req->status ? req->status : req->actual;
 310 }
 311 
 312 static int __ffs_ep0_stall(struct ffs_data *ffs)
 313 {
 314         if (ffs->ev.can_stall) {
 315                 pr_vdebug("ep0 stall\n");
 316                 usb_ep_set_halt(ffs->gadget->ep0);
 317                 ffs->setup_state = FFS_NO_SETUP;
 318                 return -EL2HLT;
 319         } else {
 320                 pr_debug("bogus ep0 stall!\n");
 321                 return -ESRCH;
 322         }
 323 }
 324 
 325 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 326                              size_t len, loff_t *ptr)
 327 {
 328         struct ffs_data *ffs = file->private_data;
 329         ssize_t ret;
 330         char *data;
 331 
 332         ENTER();
 333 
 334         /* Fast check if setup was canceled */
 335         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 336                 return -EIDRM;
 337 
 338         /* Acquire mutex */
 339         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 340         if (unlikely(ret < 0))
 341                 return ret;
 342 
 343         /* Check state */
 344         switch (ffs->state) {
 345         case FFS_READ_DESCRIPTORS:
 346         case FFS_READ_STRINGS:
 347                 /* Copy data */
 348                 if (unlikely(len < 16)) {
 349                         ret = -EINVAL;
 350                         break;
 351                 }
 352 
 353                 data = ffs_prepare_buffer(buf, len);
 354                 if (IS_ERR(data)) {
 355                         ret = PTR_ERR(data);
 356                         break;
 357                 }
 358 
 359                 /* Handle data */
 360                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 361                         pr_info("read descriptors\n");
 362                         ret = __ffs_data_got_descs(ffs, data, len);
 363                         if (unlikely(ret < 0))
 364                                 break;
 365 
 366                         ffs->state = FFS_READ_STRINGS;
 367                         ret = len;
 368                 } else {
 369                         pr_info("read strings\n");
 370                         ret = __ffs_data_got_strings(ffs, data, len);
 371                         if (unlikely(ret < 0))
 372                                 break;
 373 
 374                         ret = ffs_epfiles_create(ffs);
 375                         if (unlikely(ret)) {
 376                                 ffs->state = FFS_CLOSING;
 377                                 break;
 378                         }
 379 
 380                         ffs->state = FFS_ACTIVE;
 381                         mutex_unlock(&ffs->mutex);
 382 
 383                         ret = ffs_ready(ffs);
 384                         if (unlikely(ret < 0)) {
 385                                 ffs->state = FFS_CLOSING;
 386                                 return ret;
 387                         }
 388 
 389                         return len;
 390                 }
 391                 break;
 392 
 393         case FFS_ACTIVE:
 394                 data = NULL;
 395                 /*
 396                  * We're called from user space, we can use _irq
 397                  * rather then _irqsave
 398                  */
 399                 spin_lock_irq(&ffs->ev.waitq.lock);
 400                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 401                 case FFS_SETUP_CANCELLED:
 402                         ret = -EIDRM;
 403                         goto done_spin;
 404 
 405                 case FFS_NO_SETUP:
 406                         ret = -ESRCH;
 407                         goto done_spin;
 408 
 409                 case FFS_SETUP_PENDING:
 410                         break;
 411                 }
 412 
 413                 /* FFS_SETUP_PENDING */
 414                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 415                         spin_unlock_irq(&ffs->ev.waitq.lock);
 416                         ret = __ffs_ep0_stall(ffs);
 417                         break;
 418                 }
 419 
 420                 /* FFS_SETUP_PENDING and not stall */
 421                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 422 
 423                 spin_unlock_irq(&ffs->ev.waitq.lock);
 424 
 425                 data = ffs_prepare_buffer(buf, len);
 426                 if (IS_ERR(data)) {
 427                         ret = PTR_ERR(data);
 428                         break;
 429                 }
 430 
 431                 spin_lock_irq(&ffs->ev.waitq.lock);
 432 
 433                 /*
 434                  * We are guaranteed to be still in FFS_ACTIVE state
 435                  * but the state of setup could have changed from
 436                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 437                  * to check for that.  If that happened we copied data
 438                  * from user space in vain but it's unlikely.
 439                  *
 440                  * For sure we are not in FFS_NO_SETUP since this is
 441                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 442                  * transition can be performed and it's protected by
 443                  * mutex.
 444                  */
 445                 if (ffs_setup_state_clear_cancelled(ffs) ==
 446                     FFS_SETUP_CANCELLED) {
 447                         ret = -EIDRM;
 448 done_spin:
 449                         spin_unlock_irq(&ffs->ev.waitq.lock);
 450                 } else {
 451                         /* unlocks spinlock */
 452                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 453                 }
 454                 kfree(data);
 455                 break;
 456 
 457         default:
 458                 ret = -EBADFD;
 459                 break;
 460         }
 461 
 462         mutex_unlock(&ffs->mutex);
 463         return ret;
 464 }
 465 
 466 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 467 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 468                                      size_t n)
 469         __releases(&ffs->ev.waitq.lock)
 470 {
 471         /*
 472          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 473          * size of ffs->ev.types array (which is four) so that's how much space
 474          * we reserve.
 475          */
 476         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 477         const size_t size = n * sizeof *events;
 478         unsigned i = 0;
 479 
 480         memset(events, 0, size);
 481 
 482         do {
 483                 events[i].type = ffs->ev.types[i];
 484                 if (events[i].type == FUNCTIONFS_SETUP) {
 485                         events[i].u.setup = ffs->ev.setup;
 486                         ffs->setup_state = FFS_SETUP_PENDING;
 487                 }
 488         } while (++i < n);
 489 
 490         ffs->ev.count -= n;
 491         if (ffs->ev.count)
 492                 memmove(ffs->ev.types, ffs->ev.types + n,
 493                         ffs->ev.count * sizeof *ffs->ev.types);
 494 
 495         spin_unlock_irq(&ffs->ev.waitq.lock);
 496         mutex_unlock(&ffs->mutex);
 497 
 498         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 499 }
 500 
 501 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 502                             size_t len, loff_t *ptr)
 503 {
 504         struct ffs_data *ffs = file->private_data;
 505         char *data = NULL;
 506         size_t n;
 507         int ret;
 508 
 509         ENTER();
 510 
 511         /* Fast check if setup was canceled */
 512         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 513                 return -EIDRM;
 514 
 515         /* Acquire mutex */
 516         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 517         if (unlikely(ret < 0))
 518                 return ret;
 519 
 520         /* Check state */
 521         if (ffs->state != FFS_ACTIVE) {
 522                 ret = -EBADFD;
 523                 goto done_mutex;
 524         }
 525 
 526         /*
 527          * We're called from user space, we can use _irq rather then
 528          * _irqsave
 529          */
 530         spin_lock_irq(&ffs->ev.waitq.lock);
 531 
 532         switch (ffs_setup_state_clear_cancelled(ffs)) {
 533         case FFS_SETUP_CANCELLED:
 534                 ret = -EIDRM;
 535                 break;
 536 
 537         case FFS_NO_SETUP:
 538                 n = len / sizeof(struct usb_functionfs_event);
 539                 if (unlikely(!n)) {
 540                         ret = -EINVAL;
 541                         break;
 542                 }
 543 
 544                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 545                         ret = -EAGAIN;
 546                         break;
 547                 }
 548 
 549                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 550                                                         ffs->ev.count)) {
 551                         ret = -EINTR;
 552                         break;
 553                 }
 554 
 555                 /* unlocks spinlock */
 556                 return __ffs_ep0_read_events(ffs, buf,
 557                                              min(n, (size_t)ffs->ev.count));
 558 
 559         case FFS_SETUP_PENDING:
 560                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 561                         spin_unlock_irq(&ffs->ev.waitq.lock);
 562                         ret = __ffs_ep0_stall(ffs);
 563                         goto done_mutex;
 564                 }
 565 
 566                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 567 
 568                 spin_unlock_irq(&ffs->ev.waitq.lock);
 569 
 570                 if (likely(len)) {
 571                         data = kmalloc(len, GFP_KERNEL);
 572                         if (unlikely(!data)) {
 573                                 ret = -ENOMEM;
 574                                 goto done_mutex;
 575                         }
 576                 }
 577 
 578                 spin_lock_irq(&ffs->ev.waitq.lock);
 579 
 580                 /* See ffs_ep0_write() */
 581                 if (ffs_setup_state_clear_cancelled(ffs) ==
 582                     FFS_SETUP_CANCELLED) {
 583                         ret = -EIDRM;
 584                         break;
 585                 }
 586 
 587                 /* unlocks spinlock */
 588                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 589                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 590                         ret = -EFAULT;
 591                 goto done_mutex;
 592 
 593         default:
 594                 ret = -EBADFD;
 595                 break;
 596         }
 597 
 598         spin_unlock_irq(&ffs->ev.waitq.lock);
 599 done_mutex:
 600         mutex_unlock(&ffs->mutex);
 601         kfree(data);
 602         return ret;
 603 }
 604 
 605 static int ffs_ep0_open(struct inode *inode, struct file *file)
 606 {
 607         struct ffs_data *ffs = inode->i_private;
 608 
 609         ENTER();
 610 
 611         if (unlikely(ffs->state == FFS_CLOSING))
 612                 return -EBUSY;
 613 
 614         file->private_data = ffs;
 615         ffs_data_opened(ffs);
 616 
 617         return 0;
 618 }
 619 
 620 static int ffs_ep0_release(struct inode *inode, struct file *file)
 621 {
 622         struct ffs_data *ffs = file->private_data;
 623 
 624         ENTER();
 625 
 626         ffs_data_closed(ffs);
 627 
 628         return 0;
 629 }
 630 
 631 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 632 {
 633         struct ffs_data *ffs = file->private_data;
 634         struct usb_gadget *gadget = ffs->gadget;
 635         long ret;
 636 
 637         ENTER();
 638 
 639         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 640                 struct ffs_function *func = ffs->func;
 641                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 642         } else if (gadget && gadget->ops->ioctl) {
 643                 ret = gadget->ops->ioctl(gadget, code, value);
 644         } else {
 645                 ret = -ENOTTY;
 646         }
 647 
 648         return ret;
 649 }
 650 
 651 static __poll_t ffs_ep0_poll(struct file *file, poll_table *wait)
 652 {
 653         struct ffs_data *ffs = file->private_data;
 654         __poll_t mask = EPOLLWRNORM;
 655         int ret;
 656 
 657         poll_wait(file, &ffs->ev.waitq, wait);
 658 
 659         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 660         if (unlikely(ret < 0))
 661                 return mask;
 662 
 663         switch (ffs->state) {
 664         case FFS_READ_DESCRIPTORS:
 665         case FFS_READ_STRINGS:
 666                 mask |= EPOLLOUT;
 667                 break;
 668 
 669         case FFS_ACTIVE:
 670                 switch (ffs->setup_state) {
 671                 case FFS_NO_SETUP:
 672                         if (ffs->ev.count)
 673                                 mask |= EPOLLIN;
 674                         break;
 675 
 676                 case FFS_SETUP_PENDING:
 677                 case FFS_SETUP_CANCELLED:
 678                         mask |= (EPOLLIN | EPOLLOUT);
 679                         break;
 680                 }
 681         case FFS_CLOSING:
 682                 break;
 683         case FFS_DEACTIVATED:
 684                 break;
 685         }
 686 
 687         mutex_unlock(&ffs->mutex);
 688 
 689         return mask;
 690 }
 691 
 692 static const struct file_operations ffs_ep0_operations = {
 693         .llseek =       no_llseek,
 694 
 695         .open =         ffs_ep0_open,
 696         .write =        ffs_ep0_write,
 697         .read =         ffs_ep0_read,
 698         .release =      ffs_ep0_release,
 699         .unlocked_ioctl =       ffs_ep0_ioctl,
 700         .poll =         ffs_ep0_poll,
 701 };
 702 
 703 
 704 /* "Normal" endpoints operations ********************************************/
 705 
 706 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 707 {
 708         ENTER();
 709         if (likely(req->context)) {
 710                 struct ffs_ep *ep = _ep->driver_data;
 711                 ep->status = req->status ? req->status : req->actual;
 712                 complete(req->context);
 713         }
 714 }
 715 
 716 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 717 {
 718         ssize_t ret = copy_to_iter(data, data_len, iter);
 719         if (likely(ret == data_len))
 720                 return ret;
 721 
 722         if (unlikely(iov_iter_count(iter)))
 723                 return -EFAULT;
 724 
 725         /*
 726          * Dear user space developer!
 727          *
 728          * TL;DR: To stop getting below error message in your kernel log, change
 729          * user space code using functionfs to align read buffers to a max
 730          * packet size.
 731          *
 732          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 733          * packet size.  When unaligned buffer is passed to functionfs, it
 734          * internally uses a larger, aligned buffer so that such UDCs are happy.
 735          *
 736          * Unfortunately, this means that host may send more data than was
 737          * requested in read(2) system call.  f_fs doesn’t know what to do with
 738          * that excess data so it simply drops it.
 739          *
 740          * Was the buffer aligned in the first place, no such problem would
 741          * happen.
 742          *
 743          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 744          * by splitting a request into multiple parts.  This splitting may still
 745          * be a problem though so it’s likely best to align the buffer
 746          * regardless of it being AIO or not..
 747          *
 748          * This only affects OUT endpoints, i.e. reading data with a read(2),
 749          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 750          * affected.
 751          */
 752         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 753                "Align read buffer size to max packet size to avoid the problem.\n",
 754                data_len, ret);
 755 
 756         return ret;
 757 }
 758 
 759 /*
 760  * allocate a virtually contiguous buffer and create a scatterlist describing it
 761  * @sg_table    - pointer to a place to be filled with sg_table contents
 762  * @size        - required buffer size
 763  */
 764 static void *ffs_build_sg_list(struct sg_table *sgt, size_t sz)
 765 {
 766         struct page **pages;
 767         void *vaddr, *ptr;
 768         unsigned int n_pages;
 769         int i;
 770 
 771         vaddr = vmalloc(sz);
 772         if (!vaddr)
 773                 return NULL;
 774 
 775         n_pages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
 776         pages = kvmalloc_array(n_pages, sizeof(struct page *), GFP_KERNEL);
 777         if (!pages) {
 778                 vfree(vaddr);
 779 
 780                 return NULL;
 781         }
 782         for (i = 0, ptr = vaddr; i < n_pages; ++i, ptr += PAGE_SIZE)
 783                 pages[i] = vmalloc_to_page(ptr);
 784 
 785         if (sg_alloc_table_from_pages(sgt, pages, n_pages, 0, sz, GFP_KERNEL)) {
 786                 kvfree(pages);
 787                 vfree(vaddr);
 788 
 789                 return NULL;
 790         }
 791         kvfree(pages);
 792 
 793         return vaddr;
 794 }
 795 
 796 static inline void *ffs_alloc_buffer(struct ffs_io_data *io_data,
 797         size_t data_len)
 798 {
 799         if (io_data->use_sg)
 800                 return ffs_build_sg_list(&io_data->sgt, data_len);
 801 
 802         return kmalloc(data_len, GFP_KERNEL);
 803 }
 804 
 805 static inline void ffs_free_buffer(struct ffs_io_data *io_data)
 806 {
 807         if (!io_data->buf)
 808                 return;
 809 
 810         if (io_data->use_sg) {
 811                 sg_free_table(&io_data->sgt);
 812                 vfree(io_data->buf);
 813         } else {
 814                 kfree(io_data->buf);
 815         }
 816 }
 817 
 818 static void ffs_user_copy_worker(struct work_struct *work)
 819 {
 820         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 821                                                    work);
 822         int ret = io_data->req->status ? io_data->req->status :
 823                                          io_data->req->actual;
 824         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 825 
 826         if (io_data->read && ret > 0) {
 827                 mm_segment_t oldfs = get_fs();
 828 
 829                 set_fs(USER_DS);
 830                 use_mm(io_data->mm);
 831                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 832                 unuse_mm(io_data->mm);
 833                 set_fs(oldfs);
 834         }
 835 
 836         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 837 
 838         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 839                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 840 
 841         usb_ep_free_request(io_data->ep, io_data->req);
 842 
 843         if (io_data->read)
 844                 kfree(io_data->to_free);
 845         ffs_free_buffer(io_data);
 846         kfree(io_data);
 847 }
 848 
 849 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 850                                          struct usb_request *req)
 851 {
 852         struct ffs_io_data *io_data = req->context;
 853         struct ffs_data *ffs = io_data->ffs;
 854 
 855         ENTER();
 856 
 857         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 858         queue_work(ffs->io_completion_wq, &io_data->work);
 859 }
 860 
 861 static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
 862 {
 863         /*
 864          * See comment in struct ffs_epfile for full read_buffer pointer
 865          * synchronisation story.
 866          */
 867         struct ffs_buffer *buf = xchg(&epfile->read_buffer, READ_BUFFER_DROP);
 868         if (buf && buf != READ_BUFFER_DROP)
 869                 kfree(buf);
 870 }
 871 
 872 /* Assumes epfile->mutex is held. */
 873 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 874                                           struct iov_iter *iter)
 875 {
 876         /*
 877          * Null out epfile->read_buffer so ffs_func_eps_disable does not free
 878          * the buffer while we are using it.  See comment in struct ffs_epfile
 879          * for full read_buffer pointer synchronisation story.
 880          */
 881         struct ffs_buffer *buf = xchg(&epfile->read_buffer, NULL);
 882         ssize_t ret;
 883         if (!buf || buf == READ_BUFFER_DROP)
 884                 return 0;
 885 
 886         ret = copy_to_iter(buf->data, buf->length, iter);
 887         if (buf->length == ret) {
 888                 kfree(buf);
 889                 return ret;
 890         }
 891 
 892         if (unlikely(iov_iter_count(iter))) {
 893                 ret = -EFAULT;
 894         } else {
 895                 buf->length -= ret;
 896                 buf->data += ret;
 897         }
 898 
 899         if (cmpxchg(&epfile->read_buffer, NULL, buf))
 900                 kfree(buf);
 901 
 902         return ret;
 903 }
 904 
 905 /* Assumes epfile->mutex is held. */
 906 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 907                                       void *data, int data_len,
 908                                       struct iov_iter *iter)
 909 {
 910         struct ffs_buffer *buf;
 911 
 912         ssize_t ret = copy_to_iter(data, data_len, iter);
 913         if (likely(data_len == ret))
 914                 return ret;
 915 
 916         if (unlikely(iov_iter_count(iter)))
 917                 return -EFAULT;
 918 
 919         /* See ffs_copy_to_iter for more context. */
 920         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 921                 data_len, ret);
 922 
 923         data_len -= ret;
 924         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 925         if (!buf)
 926                 return -ENOMEM;
 927         buf->length = data_len;
 928         buf->data = buf->storage;
 929         memcpy(buf->storage, data + ret, data_len);
 930 
 931         /*
 932          * At this point read_buffer is NULL or READ_BUFFER_DROP (if
 933          * ffs_func_eps_disable has been called in the meanwhile).  See comment
 934          * in struct ffs_epfile for full read_buffer pointer synchronisation
 935          * story.
 936          */
 937         if (unlikely(cmpxchg(&epfile->read_buffer, NULL, buf)))
 938                 kfree(buf);
 939 
 940         return ret;
 941 }
 942 
 943 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 944 {
 945         struct ffs_epfile *epfile = file->private_data;
 946         struct usb_request *req;
 947         struct ffs_ep *ep;
 948         char *data = NULL;
 949         ssize_t ret, data_len = -EINVAL;
 950         int halt;
 951 
 952         /* Are we still active? */
 953         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 954                 return -ENODEV;
 955 
 956         /* Wait for endpoint to be enabled */
 957         ep = epfile->ep;
 958         if (!ep) {
 959                 if (file->f_flags & O_NONBLOCK)
 960                         return -EAGAIN;
 961 
 962                 ret = wait_event_interruptible(
 963                                 epfile->ffs->wait, (ep = epfile->ep));
 964                 if (ret)
 965                         return -EINTR;
 966         }
 967 
 968         /* Do we halt? */
 969         halt = (!io_data->read == !epfile->in);
 970         if (halt && epfile->isoc)
 971                 return -EINVAL;
 972 
 973         /* We will be using request and read_buffer */
 974         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 975         if (unlikely(ret))
 976                 goto error;
 977 
 978         /* Allocate & copy */
 979         if (!halt) {
 980                 struct usb_gadget *gadget;
 981 
 982                 /*
 983                  * Do we have buffered data from previous partial read?  Check
 984                  * that for synchronous case only because we do not have
 985                  * facility to ‘wake up’ a pending asynchronous read and push
 986                  * buffered data to it which we would need to make things behave
 987                  * consistently.
 988                  */
 989                 if (!io_data->aio && io_data->read) {
 990                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 991                         if (ret)
 992                                 goto error_mutex;
 993                 }
 994 
 995                 /*
 996                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 997                  * before the waiting completes, so do not assign to 'gadget'
 998                  * earlier
 999                  */
1000                 gadget = epfile->ffs->gadget;
1001 
1002                 spin_lock_irq(&epfile->ffs->eps_lock);
1003                 /* In the meantime, endpoint got disabled or changed. */
1004                 if (epfile->ep != ep) {
1005                         ret = -ESHUTDOWN;
1006                         goto error_lock;
1007                 }
1008                 data_len = iov_iter_count(&io_data->data);
1009                 /*
1010                  * Controller may require buffer size to be aligned to
1011                  * maxpacketsize of an out endpoint.
1012                  */
1013                 if (io_data->read)
1014                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
1015 
1016                 io_data->use_sg = gadget->sg_supported && data_len > PAGE_SIZE;
1017                 spin_unlock_irq(&epfile->ffs->eps_lock);
1018 
1019                 data = ffs_alloc_buffer(io_data, data_len);
1020                 if (unlikely(!data)) {
1021                         ret = -ENOMEM;
1022                         goto error_mutex;
1023                 }
1024                 if (!io_data->read &&
1025                     !copy_from_iter_full(data, data_len, &io_data->data)) {
1026                         ret = -EFAULT;
1027                         goto error_mutex;
1028                 }
1029         }
1030 
1031         spin_lock_irq(&epfile->ffs->eps_lock);
1032 
1033         if (epfile->ep != ep) {
1034                 /* In the meantime, endpoint got disabled or changed. */
1035                 ret = -ESHUTDOWN;
1036         } else if (halt) {
1037                 ret = usb_ep_set_halt(ep->ep);
1038                 if (!ret)
1039                         ret = -EBADMSG;
1040         } else if (unlikely(data_len == -EINVAL)) {
1041                 /*
1042                  * Sanity Check: even though data_len can't be used
1043                  * uninitialized at the time I write this comment, some
1044                  * compilers complain about this situation.
1045                  * In order to keep the code clean from warnings, data_len is
1046                  * being initialized to -EINVAL during its declaration, which
1047                  * means we can't rely on compiler anymore to warn no future
1048                  * changes won't result in data_len being used uninitialized.
1049                  * For such reason, we're adding this redundant sanity check
1050                  * here.
1051                  */
1052                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
1053                 ret = -EINVAL;
1054         } else if (!io_data->aio) {
1055                 DECLARE_COMPLETION_ONSTACK(done);
1056                 bool interrupted = false;
1057 
1058                 req = ep->req;
1059                 if (io_data->use_sg) {
1060                         req->buf = NULL;
1061                         req->sg = io_data->sgt.sgl;
1062                         req->num_sgs = io_data->sgt.nents;
1063                 } else {
1064                         req->buf = data;
1065                         req->num_sgs = 0;
1066                 }
1067                 req->length = data_len;
1068 
1069                 io_data->buf = data;
1070 
1071                 req->context  = &done;
1072                 req->complete = ffs_epfile_io_complete;
1073 
1074                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1075                 if (unlikely(ret < 0))
1076                         goto error_lock;
1077 
1078                 spin_unlock_irq(&epfile->ffs->eps_lock);
1079 
1080                 if (unlikely(wait_for_completion_interruptible(&done))) {
1081                         /*
1082                          * To avoid race condition with ffs_epfile_io_complete,
1083                          * dequeue the request first then check
1084                          * status. usb_ep_dequeue API should guarantee no race
1085                          * condition with req->complete callback.
1086                          */
1087                         usb_ep_dequeue(ep->ep, req);
1088                         wait_for_completion(&done);
1089                         interrupted = ep->status < 0;
1090                 }
1091 
1092                 if (interrupted)
1093                         ret = -EINTR;
1094                 else if (io_data->read && ep->status > 0)
1095                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
1096                                                      &io_data->data);
1097                 else
1098                         ret = ep->status;
1099                 goto error_mutex;
1100         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
1101                 ret = -ENOMEM;
1102         } else {
1103                 if (io_data->use_sg) {
1104                         req->buf = NULL;
1105                         req->sg = io_data->sgt.sgl;
1106                         req->num_sgs = io_data->sgt.nents;
1107                 } else {
1108                         req->buf = data;
1109                         req->num_sgs = 0;
1110                 }
1111                 req->length = data_len;
1112 
1113                 io_data->buf = data;
1114                 io_data->ep = ep->ep;
1115                 io_data->req = req;
1116                 io_data->ffs = epfile->ffs;
1117 
1118                 req->context  = io_data;
1119                 req->complete = ffs_epfile_async_io_complete;
1120 
1121                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
1122                 if (unlikely(ret)) {
1123                         io_data->req = NULL;
1124                         usb_ep_free_request(ep->ep, req);
1125                         goto error_lock;
1126                 }
1127 
1128                 ret = -EIOCBQUEUED;
1129                 /*
1130                  * Do not kfree the buffer in this function.  It will be freed
1131                  * by ffs_user_copy_worker.
1132                  */
1133                 data = NULL;
1134         }
1135 
1136 error_lock:
1137         spin_unlock_irq(&epfile->ffs->eps_lock);
1138 error_mutex:
1139         mutex_unlock(&epfile->mutex);
1140 error:
1141         if (ret != -EIOCBQUEUED) /* don't free if there is iocb queued */
1142                 ffs_free_buffer(io_data);
1143         return ret;
1144 }
1145 
1146 static int
1147 ffs_epfile_open(struct inode *inode, struct file *file)
1148 {
1149         struct ffs_epfile *epfile = inode->i_private;
1150 
1151         ENTER();
1152 
1153         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1154                 return -ENODEV;
1155 
1156         file->private_data = epfile;
1157         ffs_data_opened(epfile->ffs);
1158 
1159         return 0;
1160 }
1161 
1162 static int ffs_aio_cancel(struct kiocb *kiocb)
1163 {
1164         struct ffs_io_data *io_data = kiocb->private;
1165         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
1166         unsigned long flags;
1167         int value;
1168 
1169         ENTER();
1170 
1171         spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
1172 
1173         if (likely(io_data && io_data->ep && io_data->req))
1174                 value = usb_ep_dequeue(io_data->ep, io_data->req);
1175         else
1176                 value = -EINVAL;
1177 
1178         spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
1179 
1180         return value;
1181 }
1182 
1183 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1184 {
1185         struct ffs_io_data io_data, *p = &io_data;
1186         ssize_t res;
1187 
1188         ENTER();
1189 
1190         if (!is_sync_kiocb(kiocb)) {
1191                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1192                 if (unlikely(!p))
1193                         return -ENOMEM;
1194                 p->aio = true;
1195         } else {
1196                 memset(p, 0, sizeof(*p));
1197                 p->aio = false;
1198         }
1199 
1200         p->read = false;
1201         p->kiocb = kiocb;
1202         p->data = *from;
1203         p->mm = current->mm;
1204 
1205         kiocb->private = p;
1206 
1207         if (p->aio)
1208                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1209 
1210         res = ffs_epfile_io(kiocb->ki_filp, p);
1211         if (res == -EIOCBQUEUED)
1212                 return res;
1213         if (p->aio)
1214                 kfree(p);
1215         else
1216                 *from = p->data;
1217         return res;
1218 }
1219 
1220 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1221 {
1222         struct ffs_io_data io_data, *p = &io_data;
1223         ssize_t res;
1224 
1225         ENTER();
1226 
1227         if (!is_sync_kiocb(kiocb)) {
1228                 p = kzalloc(sizeof(io_data), GFP_KERNEL);
1229                 if (unlikely(!p))
1230                         return -ENOMEM;
1231                 p->aio = true;
1232         } else {
1233                 memset(p, 0, sizeof(*p));
1234                 p->aio = false;
1235         }
1236 
1237         p->read = true;
1238         p->kiocb = kiocb;
1239         if (p->aio) {
1240                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1241                 if (!p->to_free) {
1242                         kfree(p);
1243                         return -ENOMEM;
1244                 }
1245         } else {
1246                 p->data = *to;
1247                 p->to_free = NULL;
1248         }
1249         p->mm = current->mm;
1250 
1251         kiocb->private = p;
1252 
1253         if (p->aio)
1254                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1255 
1256         res = ffs_epfile_io(kiocb->ki_filp, p);
1257         if (res == -EIOCBQUEUED)
1258                 return res;
1259 
1260         if (p->aio) {
1261                 kfree(p->to_free);
1262                 kfree(p);
1263         } else {
1264                 *to = p->data;
1265         }
1266         return res;
1267 }
1268 
1269 static int
1270 ffs_epfile_release(struct inode *inode, struct file *file)
1271 {
1272         struct ffs_epfile *epfile = inode->i_private;
1273 
1274         ENTER();
1275 
1276         __ffs_epfile_read_buffer_free(epfile);
1277         ffs_data_closed(epfile->ffs);
1278 
1279         return 0;
1280 }
1281 
1282 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1283                              unsigned long value)
1284 {
1285         struct ffs_epfile *epfile = file->private_data;
1286         struct ffs_ep *ep;
1287         int ret;
1288 
1289         ENTER();
1290 
1291         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1292                 return -ENODEV;
1293 
1294         /* Wait for endpoint to be enabled */
1295         ep = epfile->ep;
1296         if (!ep) {
1297                 if (file->f_flags & O_NONBLOCK)
1298                         return -EAGAIN;
1299 
1300                 ret = wait_event_interruptible(
1301                                 epfile->ffs->wait, (ep = epfile->ep));
1302                 if (ret)
1303                         return -EINTR;
1304         }
1305 
1306         spin_lock_irq(&epfile->ffs->eps_lock);
1307 
1308         /* In the meantime, endpoint got disabled or changed. */
1309         if (epfile->ep != ep) {
1310                 spin_unlock_irq(&epfile->ffs->eps_lock);
1311                 return -ESHUTDOWN;
1312         }
1313 
1314         switch (code) {
1315         case FUNCTIONFS_FIFO_STATUS:
1316                 ret = usb_ep_fifo_status(epfile->ep->ep);
1317                 break;
1318         case FUNCTIONFS_FIFO_FLUSH:
1319                 usb_ep_fifo_flush(epfile->ep->ep);
1320                 ret = 0;
1321                 break;
1322         case FUNCTIONFS_CLEAR_HALT:
1323                 ret = usb_ep_clear_halt(epfile->ep->ep);
1324                 break;
1325         case FUNCTIONFS_ENDPOINT_REVMAP:
1326                 ret = epfile->ep->num;
1327                 break;
1328         case FUNCTIONFS_ENDPOINT_DESC:
1329         {
1330                 int desc_idx;
1331                 struct usb_endpoint_descriptor *desc;
1332 
1333                 switch (epfile->ffs->gadget->speed) {
1334                 case USB_SPEED_SUPER:
1335                         desc_idx = 2;
1336                         break;
1337                 case USB_SPEED_HIGH:
1338                         desc_idx = 1;
1339                         break;
1340                 default:
1341                         desc_idx = 0;
1342                 }
1343                 desc = epfile->ep->descs[desc_idx];
1344 
1345                 spin_unlock_irq(&epfile->ffs->eps_lock);
1346                 ret = copy_to_user((void __user *)value, desc, desc->bLength);
1347                 if (ret)
1348                         ret = -EFAULT;
1349                 return ret;
1350         }
1351         default:
1352                 ret = -ENOTTY;
1353         }
1354         spin_unlock_irq(&epfile->ffs->eps_lock);
1355 
1356         return ret;
1357 }
1358 
1359 #ifdef CONFIG_COMPAT
1360 static long ffs_epfile_compat_ioctl(struct file *file, unsigned code,
1361                 unsigned long value)
1362 {
1363         return ffs_epfile_ioctl(file, code, value);
1364 }
1365 #endif
1366 
1367 static const struct file_operations ffs_epfile_operations = {
1368         .llseek =       no_llseek,
1369 
1370         .open =         ffs_epfile_open,
1371         .write_iter =   ffs_epfile_write_iter,
1372         .read_iter =    ffs_epfile_read_iter,
1373         .release =      ffs_epfile_release,
1374         .unlocked_ioctl =       ffs_epfile_ioctl,
1375 #ifdef CONFIG_COMPAT
1376         .compat_ioctl = ffs_epfile_compat_ioctl,
1377 #endif
1378 };
1379 
1380 
1381 /* File system and super block operations ***********************************/
1382 
1383 /*
1384  * Mounting the file system creates a controller file, used first for
1385  * function configuration then later for event monitoring.
1386  */
1387 
1388 static struct inode *__must_check
1389 ffs_sb_make_inode(struct super_block *sb, void *data,
1390                   const struct file_operations *fops,
1391                   const struct inode_operations *iops,
1392                   struct ffs_file_perms *perms)
1393 {
1394         struct inode *inode;
1395 
1396         ENTER();
1397 
1398         inode = new_inode(sb);
1399 
1400         if (likely(inode)) {
1401                 struct timespec64 ts = current_time(inode);
1402 
1403                 inode->i_ino     = get_next_ino();
1404                 inode->i_mode    = perms->mode;
1405                 inode->i_uid     = perms->uid;
1406                 inode->i_gid     = perms->gid;
1407                 inode->i_atime   = ts;
1408                 inode->i_mtime   = ts;
1409                 inode->i_ctime   = ts;
1410                 inode->i_private = data;
1411                 if (fops)
1412                         inode->i_fop = fops;
1413                 if (iops)
1414                         inode->i_op  = iops;
1415         }
1416 
1417         return inode;
1418 }
1419 
1420 /* Create "regular" file */
1421 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1422                                         const char *name, void *data,
1423                                         const struct file_operations *fops)
1424 {
1425         struct ffs_data *ffs = sb->s_fs_info;
1426         struct dentry   *dentry;
1427         struct inode    *inode;
1428 
1429         ENTER();
1430 
1431         dentry = d_alloc_name(sb->s_root, name);
1432         if (unlikely(!dentry))
1433                 return NULL;
1434 
1435         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1436         if (unlikely(!inode)) {
1437                 dput(dentry);
1438                 return NULL;
1439         }
1440 
1441         d_add(dentry, inode);
1442         return dentry;
1443 }
1444 
1445 /* Super block */
1446 static const struct super_operations ffs_sb_operations = {
1447         .statfs =       simple_statfs,
1448         .drop_inode =   generic_delete_inode,
1449 };
1450 
1451 struct ffs_sb_fill_data {
1452         struct ffs_file_perms perms;
1453         umode_t root_mode;
1454         const char *dev_name;
1455         bool no_disconnect;
1456         struct ffs_data *ffs_data;
1457 };
1458 
1459 static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
1460 {
1461         struct ffs_sb_fill_data *data = fc->fs_private;
1462         struct inode    *inode;
1463         struct ffs_data *ffs = data->ffs_data;
1464 
1465         ENTER();
1466 
1467         ffs->sb              = sb;
1468         data->ffs_data       = NULL;
1469         sb->s_fs_info        = ffs;
1470         sb->s_blocksize      = PAGE_SIZE;
1471         sb->s_blocksize_bits = PAGE_SHIFT;
1472         sb->s_magic          = FUNCTIONFS_MAGIC;
1473         sb->s_op             = &ffs_sb_operations;
1474         sb->s_time_gran      = 1;
1475 
1476         /* Root inode */
1477         data->perms.mode = data->root_mode;
1478         inode = ffs_sb_make_inode(sb, NULL,
1479                                   &simple_dir_operations,
1480                                   &simple_dir_inode_operations,
1481                                   &data->perms);
1482         sb->s_root = d_make_root(inode);
1483         if (unlikely(!sb->s_root))
1484                 return -ENOMEM;
1485 
1486         /* EP0 file */
1487         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1488                                          &ffs_ep0_operations)))
1489                 return -ENOMEM;
1490 
1491         return 0;
1492 }
1493 
1494 enum {
1495         Opt_no_disconnect,
1496         Opt_rmode,
1497         Opt_fmode,
1498         Opt_mode,
1499         Opt_uid,
1500         Opt_gid,
1501 };
1502 
1503 static const struct fs_parameter_spec ffs_fs_param_specs[] = {
1504         fsparam_bool    ("no_disconnect",       Opt_no_disconnect),
1505         fsparam_u32     ("rmode",               Opt_rmode),
1506         fsparam_u32     ("fmode",               Opt_fmode),
1507         fsparam_u32     ("mode",                Opt_mode),
1508         fsparam_u32     ("uid",                 Opt_uid),
1509         fsparam_u32     ("gid",                 Opt_gid),
1510         {}
1511 };
1512 
1513 static const struct fs_parameter_description ffs_fs_fs_parameters = {
1514         .name           = "kAFS",
1515         .specs          = ffs_fs_param_specs,
1516 };
1517 
1518 static int ffs_fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1519 {
1520         struct ffs_sb_fill_data *data = fc->fs_private;
1521         struct fs_parse_result result;
1522         int opt;
1523 
1524         ENTER();
1525 
1526         opt = fs_parse(fc, &ffs_fs_fs_parameters, param, &result);
1527         if (opt < 0)
1528                 return opt;
1529 
1530         switch (opt) {
1531         case Opt_no_disconnect:
1532                 data->no_disconnect = result.boolean;
1533                 break;
1534         case Opt_rmode:
1535                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1536                 break;
1537         case Opt_fmode:
1538                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1539                 break;
1540         case Opt_mode:
1541                 data->root_mode  = (result.uint_32 & 0555) | S_IFDIR;
1542                 data->perms.mode = (result.uint_32 & 0666) | S_IFREG;
1543                 break;
1544 
1545         case Opt_uid:
1546                 data->perms.uid = make_kuid(current_user_ns(), result.uint_32);
1547                 if (!uid_valid(data->perms.uid))
1548                         goto unmapped_value;
1549                 break;
1550         case Opt_gid:
1551                 data->perms.gid = make_kgid(current_user_ns(), result.uint_32);
1552                 if (!gid_valid(data->perms.gid))
1553                         goto unmapped_value;
1554                 break;
1555 
1556         default:
1557                 return -ENOPARAM;
1558         }
1559 
1560         return 0;
1561 
1562 unmapped_value:
1563         return invalf(fc, "%s: unmapped value: %u", param->key, result.uint_32);
1564 }
1565 
1566 /*
1567  * Set up the superblock for a mount.
1568  */
1569 static int ffs_fs_get_tree(struct fs_context *fc)
1570 {
1571         struct ffs_sb_fill_data *ctx = fc->fs_private;
1572         void *ffs_dev;
1573         struct ffs_data *ffs;
1574 
1575         ENTER();
1576 
1577         if (!fc->source)
1578                 return invalf(fc, "No source specified");
1579 
1580         ffs = ffs_data_new(fc->source);
1581         if (unlikely(!ffs))
1582                 return -ENOMEM;
1583         ffs->file_perms = ctx->perms;
1584         ffs->no_disconnect = ctx->no_disconnect;
1585 
1586         ffs->dev_name = kstrdup(fc->source, GFP_KERNEL);
1587         if (unlikely(!ffs->dev_name)) {
1588                 ffs_data_put(ffs);
1589                 return -ENOMEM;
1590         }
1591 
1592         ffs_dev = ffs_acquire_dev(ffs->dev_name);
1593         if (IS_ERR(ffs_dev)) {
1594                 ffs_data_put(ffs);
1595                 return PTR_ERR(ffs_dev);
1596         }
1597 
1598         ffs->private_data = ffs_dev;
1599         ctx->ffs_data = ffs;
1600         return get_tree_nodev(fc, ffs_sb_fill);
1601 }
1602 
1603 static void ffs_fs_free_fc(struct fs_context *fc)
1604 {
1605         struct ffs_sb_fill_data *ctx = fc->fs_private;
1606 
1607         if (ctx) {
1608                 if (ctx->ffs_data) {
1609                         ffs_release_dev(ctx->ffs_data);
1610                         ffs_data_put(ctx->ffs_data);
1611                 }
1612 
1613                 kfree(ctx);
1614         }
1615 }
1616 
1617 static const struct fs_context_operations ffs_fs_context_ops = {
1618         .free           = ffs_fs_free_fc,
1619         .parse_param    = ffs_fs_parse_param,
1620         .get_tree       = ffs_fs_get_tree,
1621 };
1622 
1623 static int ffs_fs_init_fs_context(struct fs_context *fc)
1624 {
1625         struct ffs_sb_fill_data *ctx;
1626 
1627         ctx = kzalloc(sizeof(struct ffs_sb_fill_data), GFP_KERNEL);
1628         if (!ctx)
1629                 return -ENOMEM;
1630 
1631         ctx->perms.mode = S_IFREG | 0600;
1632         ctx->perms.uid = GLOBAL_ROOT_UID;
1633         ctx->perms.gid = GLOBAL_ROOT_GID;
1634         ctx->root_mode = S_IFDIR | 0500;
1635         ctx->no_disconnect = false;
1636 
1637         fc->fs_private = ctx;
1638         fc->ops = &ffs_fs_context_ops;
1639         return 0;
1640 }
1641 
1642 static void
1643 ffs_fs_kill_sb(struct super_block *sb)
1644 {
1645         ENTER();
1646 
1647         kill_litter_super(sb);
1648         if (sb->s_fs_info) {
1649                 ffs_release_dev(sb->s_fs_info);
1650                 ffs_data_closed(sb->s_fs_info);
1651         }
1652 }
1653 
1654 static struct file_system_type ffs_fs_type = {
1655         .owner          = THIS_MODULE,
1656         .name           = "functionfs",
1657         .init_fs_context = ffs_fs_init_fs_context,
1658         .parameters     = &ffs_fs_fs_parameters,
1659         .kill_sb        = ffs_fs_kill_sb,
1660 };
1661 MODULE_ALIAS_FS("functionfs");
1662 
1663 
1664 /* Driver's main init/cleanup functions *************************************/
1665 
1666 static int functionfs_init(void)
1667 {
1668         int ret;
1669 
1670         ENTER();
1671 
1672         ret = register_filesystem(&ffs_fs_type);
1673         if (likely(!ret))
1674                 pr_info("file system registered\n");
1675         else
1676                 pr_err("failed registering file system (%d)\n", ret);
1677 
1678         return ret;
1679 }
1680 
1681 static void functionfs_cleanup(void)
1682 {
1683         ENTER();
1684 
1685         pr_info("unloading\n");
1686         unregister_filesystem(&ffs_fs_type);
1687 }
1688 
1689 
1690 /* ffs_data and ffs_function construction and destruction code **************/
1691 
1692 static void ffs_data_clear(struct ffs_data *ffs);
1693 static void ffs_data_reset(struct ffs_data *ffs);
1694 
1695 static void ffs_data_get(struct ffs_data *ffs)
1696 {
1697         ENTER();
1698 
1699         refcount_inc(&ffs->ref);
1700 }
1701 
1702 static void ffs_data_opened(struct ffs_data *ffs)
1703 {
1704         ENTER();
1705 
1706         refcount_inc(&ffs->ref);
1707         if (atomic_add_return(1, &ffs->opened) == 1 &&
1708                         ffs->state == FFS_DEACTIVATED) {
1709                 ffs->state = FFS_CLOSING;
1710                 ffs_data_reset(ffs);
1711         }
1712 }
1713 
1714 static void ffs_data_put(struct ffs_data *ffs)
1715 {
1716         ENTER();
1717 
1718         if (unlikely(refcount_dec_and_test(&ffs->ref))) {
1719                 pr_info("%s(): freeing\n", __func__);
1720                 ffs_data_clear(ffs);
1721                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1722                        waitqueue_active(&ffs->ep0req_completion.wait) ||
1723                        waitqueue_active(&ffs->wait));
1724                 destroy_workqueue(ffs->io_completion_wq);
1725                 kfree(ffs->dev_name);
1726                 kfree(ffs);
1727         }
1728 }
1729 
1730 static void ffs_data_closed(struct ffs_data *ffs)
1731 {
1732         ENTER();
1733 
1734         if (atomic_dec_and_test(&ffs->opened)) {
1735                 if (ffs->no_disconnect) {
1736                         ffs->state = FFS_DEACTIVATED;
1737                         if (ffs->epfiles) {
1738                                 ffs_epfiles_destroy(ffs->epfiles,
1739                                                    ffs->eps_count);
1740                                 ffs->epfiles = NULL;
1741                         }
1742                         if (ffs->setup_state == FFS_SETUP_PENDING)
1743                                 __ffs_ep0_stall(ffs);
1744                 } else {
1745                         ffs->state = FFS_CLOSING;
1746                         ffs_data_reset(ffs);
1747                 }
1748         }
1749         if (atomic_read(&ffs->opened) < 0) {
1750                 ffs->state = FFS_CLOSING;
1751                 ffs_data_reset(ffs);
1752         }
1753 
1754         ffs_data_put(ffs);
1755 }
1756 
1757 static struct ffs_data *ffs_data_new(const char *dev_name)
1758 {
1759         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1760         if (unlikely(!ffs))
1761                 return NULL;
1762 
1763         ENTER();
1764 
1765         ffs->io_completion_wq = alloc_ordered_workqueue("%s", 0, dev_name);
1766         if (!ffs->io_completion_wq) {
1767                 kfree(ffs);
1768                 return NULL;
1769         }
1770 
1771         refcount_set(&ffs->ref, 1);
1772         atomic_set(&ffs->opened, 0);
1773         ffs->state = FFS_READ_DESCRIPTORS;
1774         mutex_init(&ffs->mutex);
1775         spin_lock_init(&ffs->eps_lock);
1776         init_waitqueue_head(&ffs->ev.waitq);
1777         init_waitqueue_head(&ffs->wait);
1778         init_completion(&ffs->ep0req_completion);
1779 
1780         /* XXX REVISIT need to update it in some places, or do we? */
1781         ffs->ev.can_stall = 1;
1782 
1783         return ffs;
1784 }
1785 
1786 static void ffs_data_clear(struct ffs_data *ffs)
1787 {
1788         ENTER();
1789 
1790         ffs_closed(ffs);
1791 
1792         BUG_ON(ffs->gadget);
1793 
1794         if (ffs->epfiles)
1795                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1796 
1797         if (ffs->ffs_eventfd)
1798                 eventfd_ctx_put(ffs->ffs_eventfd);
1799 
1800         kfree(ffs->raw_descs_data);
1801         kfree(ffs->raw_strings);
1802         kfree(ffs->stringtabs);
1803 }
1804 
1805 static void ffs_data_reset(struct ffs_data *ffs)
1806 {
1807         ENTER();
1808 
1809         ffs_data_clear(ffs);
1810 
1811         ffs->epfiles = NULL;
1812         ffs->raw_descs_data = NULL;
1813         ffs->raw_descs = NULL;
1814         ffs->raw_strings = NULL;
1815         ffs->stringtabs = NULL;
1816 
1817         ffs->raw_descs_length = 0;
1818         ffs->fs_descs_count = 0;
1819         ffs->hs_descs_count = 0;
1820         ffs->ss_descs_count = 0;
1821 
1822         ffs->strings_count = 0;
1823         ffs->interfaces_count = 0;
1824         ffs->eps_count = 0;
1825 
1826         ffs->ev.count = 0;
1827 
1828         ffs->state = FFS_READ_DESCRIPTORS;
1829         ffs->setup_state = FFS_NO_SETUP;
1830         ffs->flags = 0;
1831 
1832         ffs->ms_os_descs_ext_prop_count = 0;
1833         ffs->ms_os_descs_ext_prop_name_len = 0;
1834         ffs->ms_os_descs_ext_prop_data_len = 0;
1835 }
1836 
1837 
1838 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1839 {
1840         struct usb_gadget_strings **lang;
1841         int first_id;
1842 
1843         ENTER();
1844 
1845         if (WARN_ON(ffs->state != FFS_ACTIVE
1846                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1847                 return -EBADFD;
1848 
1849         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1850         if (unlikely(first_id < 0))
1851                 return first_id;
1852 
1853         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1854         if (unlikely(!ffs->ep0req))
1855                 return -ENOMEM;
1856         ffs->ep0req->complete = ffs_ep0_complete;
1857         ffs->ep0req->context = ffs;
1858 
1859         lang = ffs->stringtabs;
1860         if (lang) {
1861                 for (; *lang; ++lang) {
1862                         struct usb_string *str = (*lang)->strings;
1863                         int id = first_id;
1864                         for (; str->s; ++id, ++str)
1865                                 str->id = id;
1866                 }
1867         }
1868 
1869         ffs->gadget = cdev->gadget;
1870         ffs_data_get(ffs);
1871         return 0;
1872 }
1873 
1874 static void functionfs_unbind(struct ffs_data *ffs)
1875 {
1876         ENTER();
1877 
1878         if (!WARN_ON(!ffs->gadget)) {
1879                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1880                 ffs->ep0req = NULL;
1881                 ffs->gadget = NULL;
1882                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1883                 ffs_data_put(ffs);
1884         }
1885 }
1886 
1887 static int ffs_epfiles_create(struct ffs_data *ffs)
1888 {
1889         struct ffs_epfile *epfile, *epfiles;
1890         unsigned i, count;
1891 
1892         ENTER();
1893 
1894         count = ffs->eps_count;
1895         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1896         if (!epfiles)
1897                 return -ENOMEM;
1898 
1899         epfile = epfiles;
1900         for (i = 1; i <= count; ++i, ++epfile) {
1901                 epfile->ffs = ffs;
1902                 mutex_init(&epfile->mutex);
1903                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1904                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1905                 else
1906                         sprintf(epfile->name, "ep%u", i);
1907                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1908                                                  epfile,
1909                                                  &ffs_epfile_operations);
1910                 if (unlikely(!epfile->dentry)) {
1911                         ffs_epfiles_destroy(epfiles, i - 1);
1912                         return -ENOMEM;
1913                 }
1914         }
1915 
1916         ffs->epfiles = epfiles;
1917         return 0;
1918 }
1919 
1920 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1921 {
1922         struct ffs_epfile *epfile = epfiles;
1923 
1924         ENTER();
1925 
1926         for (; count; --count, ++epfile) {
1927                 BUG_ON(mutex_is_locked(&epfile->mutex));
1928                 if (epfile->dentry) {
1929                         d_delete(epfile->dentry);
1930                         dput(epfile->dentry);
1931                         epfile->dentry = NULL;
1932                 }
1933         }
1934 
1935         kfree(epfiles);
1936 }
1937 
1938 static void ffs_func_eps_disable(struct ffs_function *func)
1939 {
1940         struct ffs_ep *ep         = func->eps;
1941         struct ffs_epfile *epfile = func->ffs->epfiles;
1942         unsigned count            = func->ffs->eps_count;
1943         unsigned long flags;
1944 
1945         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1946         while (count--) {
1947                 /* pending requests get nuked */
1948                 if (likely(ep->ep))
1949                         usb_ep_disable(ep->ep);
1950                 ++ep;
1951 
1952                 if (epfile) {
1953                         epfile->ep = NULL;
1954                         __ffs_epfile_read_buffer_free(epfile);
1955                         ++epfile;
1956                 }
1957         }
1958         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1959 }
1960 
1961 static int ffs_func_eps_enable(struct ffs_function *func)
1962 {
1963         struct ffs_data *ffs      = func->ffs;
1964         struct ffs_ep *ep         = func->eps;
1965         struct ffs_epfile *epfile = ffs->epfiles;
1966         unsigned count            = ffs->eps_count;
1967         unsigned long flags;
1968         int ret = 0;
1969 
1970         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1971         while(count--) {
1972                 ep->ep->driver_data = ep;
1973 
1974                 ret = config_ep_by_speed(func->gadget, &func->function, ep->ep);
1975                 if (ret) {
1976                         pr_err("%s: config_ep_by_speed(%s) returned %d\n",
1977                                         __func__, ep->ep->name, ret);
1978                         break;
1979                 }
1980 
1981                 ret = usb_ep_enable(ep->ep);
1982                 if (likely(!ret)) {
1983                         epfile->ep = ep;
1984                         epfile->in = usb_endpoint_dir_in(ep->ep->desc);
1985                         epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
1986                 } else {
1987                         break;
1988                 }
1989 
1990                 ++ep;
1991                 ++epfile;
1992         }
1993 
1994         wake_up_interruptible(&ffs->wait);
1995         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1996 
1997         return ret;
1998 }
1999 
2000 
2001 /* Parsing and building descriptors and strings *****************************/
2002 
2003 /*
2004  * This validates if data pointed by data is a valid USB descriptor as
2005  * well as record how many interfaces, endpoints and strings are
2006  * required by given configuration.  Returns address after the
2007  * descriptor or NULL if data is invalid.
2008  */
2009 
2010 enum ffs_entity_type {
2011         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
2012 };
2013 
2014 enum ffs_os_desc_type {
2015         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
2016 };
2017 
2018 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
2019                                    u8 *valuep,
2020                                    struct usb_descriptor_header *desc,
2021                                    void *priv);
2022 
2023 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
2024                                     struct usb_os_desc_header *h, void *data,
2025                                     unsigned len, void *priv);
2026 
2027 static int __must_check ffs_do_single_desc(char *data, unsigned len,
2028                                            ffs_entity_callback entity,
2029                                            void *priv, int *current_class)
2030 {
2031         struct usb_descriptor_header *_ds = (void *)data;
2032         u8 length;
2033         int ret;
2034 
2035         ENTER();
2036 
2037         /* At least two bytes are required: length and type */
2038         if (len < 2) {
2039                 pr_vdebug("descriptor too short\n");
2040                 return -EINVAL;
2041         }
2042 
2043         /* If we have at least as many bytes as the descriptor takes? */
2044         length = _ds->bLength;
2045         if (len < length) {
2046                 pr_vdebug("descriptor longer then available data\n");
2047                 return -EINVAL;
2048         }
2049 
2050 #define __entity_check_INTERFACE(val)  1
2051 #define __entity_check_STRING(val)     (val)
2052 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
2053 #define __entity(type, val) do {                                        \
2054                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
2055                 if (unlikely(!__entity_check_ ##type(val))) {           \
2056                         pr_vdebug("invalid entity's value\n");          \
2057                         return -EINVAL;                                 \
2058                 }                                                       \
2059                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
2060                 if (unlikely(ret < 0)) {                                \
2061                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
2062                                  (val), ret);                           \
2063                         return ret;                                     \
2064                 }                                                       \
2065         } while (0)
2066 
2067         /* Parse descriptor depending on type. */
2068         switch (_ds->bDescriptorType) {
2069         case USB_DT_DEVICE:
2070         case USB_DT_CONFIG:
2071         case USB_DT_STRING:
2072         case USB_DT_DEVICE_QUALIFIER:
2073                 /* function can't have any of those */
2074                 pr_vdebug("descriptor reserved for gadget: %d\n",
2075                       _ds->bDescriptorType);
2076                 return -EINVAL;
2077 
2078         case USB_DT_INTERFACE: {
2079                 struct usb_interface_descriptor *ds = (void *)_ds;
2080                 pr_vdebug("interface descriptor\n");
2081                 if (length != sizeof *ds)
2082                         goto inv_length;
2083 
2084                 __entity(INTERFACE, ds->bInterfaceNumber);
2085                 if (ds->iInterface)
2086                         __entity(STRING, ds->iInterface);
2087                 *current_class = ds->bInterfaceClass;
2088         }
2089                 break;
2090 
2091         case USB_DT_ENDPOINT: {
2092                 struct usb_endpoint_descriptor *ds = (void *)_ds;
2093                 pr_vdebug("endpoint descriptor\n");
2094                 if (length != USB_DT_ENDPOINT_SIZE &&
2095                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
2096                         goto inv_length;
2097                 __entity(ENDPOINT, ds->bEndpointAddress);
2098         }
2099                 break;
2100 
2101         case USB_TYPE_CLASS | 0x01:
2102                 if (*current_class == USB_INTERFACE_CLASS_HID) {
2103                         pr_vdebug("hid descriptor\n");
2104                         if (length != sizeof(struct hid_descriptor))
2105                                 goto inv_length;
2106                         break;
2107                 } else if (*current_class == USB_INTERFACE_CLASS_CCID) {
2108                         pr_vdebug("ccid descriptor\n");
2109                         if (length != sizeof(struct ccid_descriptor))
2110                                 goto inv_length;
2111                         break;
2112                 } else {
2113                         pr_vdebug("unknown descriptor: %d for class %d\n",
2114                               _ds->bDescriptorType, *current_class);
2115                         return -EINVAL;
2116                 }
2117 
2118         case USB_DT_OTG:
2119                 if (length != sizeof(struct usb_otg_descriptor))
2120                         goto inv_length;
2121                 break;
2122 
2123         case USB_DT_INTERFACE_ASSOCIATION: {
2124                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
2125                 pr_vdebug("interface association descriptor\n");
2126                 if (length != sizeof *ds)
2127                         goto inv_length;
2128                 if (ds->iFunction)
2129                         __entity(STRING, ds->iFunction);
2130         }
2131                 break;
2132 
2133         case USB_DT_SS_ENDPOINT_COMP:
2134                 pr_vdebug("EP SS companion descriptor\n");
2135                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
2136                         goto inv_length;
2137                 break;
2138 
2139         case USB_DT_OTHER_SPEED_CONFIG:
2140         case USB_DT_INTERFACE_POWER:
2141         case USB_DT_DEBUG:
2142         case USB_DT_SECURITY:
2143         case USB_DT_CS_RADIO_CONTROL:
2144                 /* TODO */
2145                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
2146                 return -EINVAL;
2147 
2148         default:
2149                 /* We should never be here */
2150                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
2151                 return -EINVAL;
2152 
2153 inv_length:
2154                 pr_vdebug("invalid length: %d (descriptor %d)\n",
2155                           _ds->bLength, _ds->bDescriptorType);
2156                 return -EINVAL;
2157         }
2158 
2159 #undef __entity
2160 #undef __entity_check_DESCRIPTOR
2161 #undef __entity_check_INTERFACE
2162 #undef __entity_check_STRING
2163 #undef __entity_check_ENDPOINT
2164 
2165         return length;
2166 }
2167 
2168 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
2169                                      ffs_entity_callback entity, void *priv)
2170 {
2171         const unsigned _len = len;
2172         unsigned long num = 0;
2173         int current_class = -1;
2174 
2175         ENTER();
2176 
2177         for (;;) {
2178                 int ret;
2179 
2180                 if (num == count)
2181                         data = NULL;
2182 
2183                 /* Record "descriptor" entity */
2184                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
2185                 if (unlikely(ret < 0)) {
2186                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
2187                                  num, ret);
2188                         return ret;
2189                 }
2190 
2191                 if (!data)
2192                         return _len - len;
2193 
2194                 ret = ffs_do_single_desc(data, len, entity, priv,
2195                         &current_class);
2196                 if (unlikely(ret < 0)) {
2197                         pr_debug("%s returns %d\n", __func__, ret);
2198                         return ret;
2199                 }
2200 
2201                 len -= ret;
2202                 data += ret;
2203                 ++num;
2204         }
2205 }
2206 
2207 static int __ffs_data_do_entity(enum ffs_entity_type type,
2208                                 u8 *valuep, struct usb_descriptor_header *desc,
2209                                 void *priv)
2210 {
2211         struct ffs_desc_helper *helper = priv;
2212         struct usb_endpoint_descriptor *d;
2213 
2214         ENTER();
2215 
2216         switch (type) {
2217         case FFS_DESCRIPTOR:
2218                 break;
2219 
2220         case FFS_INTERFACE:
2221                 /*
2222                  * Interfaces are indexed from zero so if we
2223                  * encountered interface "n" then there are at least
2224                  * "n+1" interfaces.
2225                  */
2226                 if (*valuep >= helper->interfaces_count)
2227                         helper->interfaces_count = *valuep + 1;
2228                 break;
2229 
2230         case FFS_STRING:
2231                 /*
2232                  * Strings are indexed from 1 (0 is reserved
2233                  * for languages list)
2234                  */
2235                 if (*valuep > helper->ffs->strings_count)
2236                         helper->ffs->strings_count = *valuep;
2237                 break;
2238 
2239         case FFS_ENDPOINT:
2240                 d = (void *)desc;
2241                 helper->eps_count++;
2242                 if (helper->eps_count >= FFS_MAX_EPS_COUNT)
2243                         return -EINVAL;
2244                 /* Check if descriptors for any speed were already parsed */
2245                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2246                         helper->ffs->eps_addrmap[helper->eps_count] =
2247                                 d->bEndpointAddress;
2248                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2249                                 d->bEndpointAddress)
2250                         return -EINVAL;
2251                 break;
2252         }
2253 
2254         return 0;
2255 }
2256 
2257 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2258                                    struct usb_os_desc_header *desc)
2259 {
2260         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2261         u16 w_index = le16_to_cpu(desc->wIndex);
2262 
2263         if (bcd_version != 1) {
2264                 pr_vdebug("unsupported os descriptors version: %d",
2265                           bcd_version);
2266                 return -EINVAL;
2267         }
2268         switch (w_index) {
2269         case 0x4:
2270                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2271                 break;
2272         case 0x5:
2273                 *next_type = FFS_OS_DESC_EXT_PROP;
2274                 break;
2275         default:
2276                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2277                 return -EINVAL;
2278         }
2279 
2280         return sizeof(*desc);
2281 }
2282 
2283 /*
2284  * Process all extended compatibility/extended property descriptors
2285  * of a feature descriptor
2286  */
2287 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2288                                               enum ffs_os_desc_type type,
2289                                               u16 feature_count,
2290                                               ffs_os_desc_callback entity,
2291                                               void *priv,
2292                                               struct usb_os_desc_header *h)
2293 {
2294         int ret;
2295         const unsigned _len = len;
2296 
2297         ENTER();
2298 
2299         /* loop over all ext compat/ext prop descriptors */
2300         while (feature_count--) {
2301                 ret = entity(type, h, data, len, priv);
2302                 if (unlikely(ret < 0)) {
2303                         pr_debug("bad OS descriptor, type: %d\n", type);
2304                         return ret;
2305                 }
2306                 data += ret;
2307                 len -= ret;
2308         }
2309         return _len - len;
2310 }
2311 
2312 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2313 static int __must_check ffs_do_os_descs(unsigned count,
2314                                         char *data, unsigned len,
2315                                         ffs_os_desc_callback entity, void *priv)
2316 {
2317         const unsigned _len = len;
2318         unsigned long num = 0;
2319 
2320         ENTER();
2321 
2322         for (num = 0; num < count; ++num) {
2323                 int ret;
2324                 enum ffs_os_desc_type type;
2325                 u16 feature_count;
2326                 struct usb_os_desc_header *desc = (void *)data;
2327 
2328                 if (len < sizeof(*desc))
2329                         return -EINVAL;
2330 
2331                 /*
2332                  * Record "descriptor" entity.
2333                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2334                  * Move the data pointer to the beginning of extended
2335                  * compatibilities proper or extended properties proper
2336                  * portions of the data
2337                  */
2338                 if (le32_to_cpu(desc->dwLength) > len)
2339                         return -EINVAL;
2340 
2341                 ret = __ffs_do_os_desc_header(&type, desc);
2342                 if (unlikely(ret < 0)) {
2343                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2344                                  num, ret);
2345                         return ret;
2346                 }
2347                 /*
2348                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2349                  */
2350                 feature_count = le16_to_cpu(desc->wCount);
2351                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2352                     (feature_count > 255 || desc->Reserved))
2353                                 return -EINVAL;
2354                 len -= ret;
2355                 data += ret;
2356 
2357                 /*
2358                  * Process all function/property descriptors
2359                  * of this Feature Descriptor
2360                  */
2361                 ret = ffs_do_single_os_desc(data, len, type,
2362                                             feature_count, entity, priv, desc);
2363                 if (unlikely(ret < 0)) {
2364                         pr_debug("%s returns %d\n", __func__, ret);
2365                         return ret;
2366                 }
2367 
2368                 len -= ret;
2369                 data += ret;
2370         }
2371         return _len - len;
2372 }
2373 
2374 /**
2375  * Validate contents of the buffer from userspace related to OS descriptors.
2376  */
2377 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2378                                  struct usb_os_desc_header *h, void *data,
2379                                  unsigned len, void *priv)
2380 {
2381         struct ffs_data *ffs = priv;
2382         u8 length;
2383 
2384         ENTER();
2385 
2386         switch (type) {
2387         case FFS_OS_DESC_EXT_COMPAT: {
2388                 struct usb_ext_compat_desc *d = data;
2389                 int i;
2390 
2391                 if (len < sizeof(*d) ||
2392                     d->bFirstInterfaceNumber >= ffs->interfaces_count)
2393                         return -EINVAL;
2394                 if (d->Reserved1 != 1) {
2395                         /*
2396                          * According to the spec, Reserved1 must be set to 1
2397                          * but older kernels incorrectly rejected non-zero
2398                          * values.  We fix it here to avoid returning EINVAL
2399                          * in response to values we used to accept.
2400                          */
2401                         pr_debug("usb_ext_compat_desc::Reserved1 forced to 1\n");
2402                         d->Reserved1 = 1;
2403                 }
2404                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2405                         if (d->Reserved2[i])
2406                                 return -EINVAL;
2407 
2408                 length = sizeof(struct usb_ext_compat_desc);
2409         }
2410                 break;
2411         case FFS_OS_DESC_EXT_PROP: {
2412                 struct usb_ext_prop_desc *d = data;
2413                 u32 type, pdl;
2414                 u16 pnl;
2415 
2416                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2417                         return -EINVAL;
2418                 length = le32_to_cpu(d->dwSize);
2419                 if (len < length)
2420                         return -EINVAL;
2421                 type = le32_to_cpu(d->dwPropertyDataType);
2422                 if (type < USB_EXT_PROP_UNICODE ||
2423                     type > USB_EXT_PROP_UNICODE_MULTI) {
2424                         pr_vdebug("unsupported os descriptor property type: %d",
2425                                   type);
2426                         return -EINVAL;
2427                 }
2428                 pnl = le16_to_cpu(d->wPropertyNameLength);
2429                 if (length < 14 + pnl) {
2430                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2431                                   length, pnl, type);
2432                         return -EINVAL;
2433                 }
2434                 pdl = le32_to_cpu(*(__le32 *)((u8 *)data + 10 + pnl));
2435                 if (length != 14 + pnl + pdl) {
2436                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2437                                   length, pnl, pdl, type);
2438                         return -EINVAL;
2439                 }
2440                 ++ffs->ms_os_descs_ext_prop_count;
2441                 /* property name reported to the host as "WCHAR"s */
2442                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2443                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2444         }
2445                 break;
2446         default:
2447                 pr_vdebug("unknown descriptor: %d\n", type);
2448                 return -EINVAL;
2449         }
2450         return length;
2451 }
2452 
2453 static int __ffs_data_got_descs(struct ffs_data *ffs,
2454                                 char *const _data, size_t len)
2455 {
2456         char *data = _data, *raw_descs;
2457         unsigned os_descs_count = 0, counts[3], flags;
2458         int ret = -EINVAL, i;
2459         struct ffs_desc_helper helper;
2460 
2461         ENTER();
2462 
2463         if (get_unaligned_le32(data + 4) != len)
2464                 goto error;
2465 
2466         switch (get_unaligned_le32(data)) {
2467         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2468                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2469                 data += 8;
2470                 len  -= 8;
2471                 break;
2472         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2473                 flags = get_unaligned_le32(data + 8);
2474                 ffs->user_flags = flags;
2475                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2476                               FUNCTIONFS_HAS_HS_DESC |
2477                               FUNCTIONFS_HAS_SS_DESC |
2478                               FUNCTIONFS_HAS_MS_OS_DESC |
2479                               FUNCTIONFS_VIRTUAL_ADDR |
2480                               FUNCTIONFS_EVENTFD |
2481                               FUNCTIONFS_ALL_CTRL_RECIP |
2482                               FUNCTIONFS_CONFIG0_SETUP)) {
2483                         ret = -ENOSYS;
2484                         goto error;
2485                 }
2486                 data += 12;
2487                 len  -= 12;
2488                 break;
2489         default:
2490                 goto error;
2491         }
2492 
2493         if (flags & FUNCTIONFS_EVENTFD) {
2494                 if (len < 4)
2495                         goto error;
2496                 ffs->ffs_eventfd =
2497                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2498                 if (IS_ERR(ffs->ffs_eventfd)) {
2499                         ret = PTR_ERR(ffs->ffs_eventfd);
2500                         ffs->ffs_eventfd = NULL;
2501                         goto error;
2502                 }
2503                 data += 4;
2504                 len  -= 4;
2505         }
2506 
2507         /* Read fs_count, hs_count and ss_count (if present) */
2508         for (i = 0; i < 3; ++i) {
2509                 if (!(flags & (1 << i))) {
2510                         counts[i] = 0;
2511                 } else if (len < 4) {
2512                         goto error;
2513                 } else {
2514                         counts[i] = get_unaligned_le32(data);
2515                         data += 4;
2516                         len  -= 4;
2517                 }
2518         }
2519         if (flags & (1 << i)) {
2520                 if (len < 4) {
2521                         goto error;
2522                 }
2523                 os_descs_count = get_unaligned_le32(data);
2524                 data += 4;
2525                 len -= 4;
2526         };
2527 
2528         /* Read descriptors */
2529         raw_descs = data;
2530         helper.ffs = ffs;
2531         for (i = 0; i < 3; ++i) {
2532                 if (!counts[i])
2533                         continue;
2534                 helper.interfaces_count = 0;
2535                 helper.eps_count = 0;
2536                 ret = ffs_do_descs(counts[i], data, len,
2537                                    __ffs_data_do_entity, &helper);
2538                 if (ret < 0)
2539                         goto error;
2540                 if (!ffs->eps_count && !ffs->interfaces_count) {
2541                         ffs->eps_count = helper.eps_count;
2542                         ffs->interfaces_count = helper.interfaces_count;
2543                 } else {
2544                         if (ffs->eps_count != helper.eps_count) {
2545                                 ret = -EINVAL;
2546                                 goto error;
2547                         }
2548                         if (ffs->interfaces_count != helper.interfaces_count) {
2549                                 ret = -EINVAL;
2550                                 goto error;
2551                         }
2552                 }
2553                 data += ret;
2554                 len  -= ret;
2555         }
2556         if (os_descs_count) {
2557                 ret = ffs_do_os_descs(os_descs_count, data, len,
2558                                       __ffs_data_do_os_desc, ffs);
2559                 if (ret < 0)
2560                         goto error;
2561                 data += ret;
2562                 len -= ret;
2563         }
2564 
2565         if (raw_descs == data || len) {
2566                 ret = -EINVAL;
2567                 goto error;
2568         }
2569 
2570         ffs->raw_descs_data     = _data;
2571         ffs->raw_descs          = raw_descs;
2572         ffs->raw_descs_length   = data - raw_descs;
2573         ffs->fs_descs_count     = counts[0];
2574         ffs->hs_descs_count     = counts[1];
2575         ffs->ss_descs_count     = counts[2];
2576         ffs->ms_os_descs_count  = os_descs_count;
2577 
2578         return 0;
2579 
2580 error:
2581         kfree(_data);
2582         return ret;
2583 }
2584 
2585 static int __ffs_data_got_strings(struct ffs_data *ffs,
2586                                   char *const _data, size_t len)
2587 {
2588         u32 str_count, needed_count, lang_count;
2589         struct usb_gadget_strings **stringtabs, *t;
2590         const char *data = _data;
2591         struct usb_string *s;
2592 
2593         ENTER();
2594 
2595         if (unlikely(len < 16 ||
2596                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2597                      get_unaligned_le32(data + 4) != len))
2598                 goto error;
2599         str_count  = get_unaligned_le32(data + 8);
2600         lang_count = get_unaligned_le32(data + 12);
2601 
2602         /* if one is zero the other must be zero */
2603         if (unlikely(!str_count != !lang_count))
2604                 goto error;
2605 
2606         /* Do we have at least as many strings as descriptors need? */
2607         needed_count = ffs->strings_count;
2608         if (unlikely(str_count < needed_count))
2609                 goto error;
2610 
2611         /*
2612          * If we don't need any strings just return and free all
2613          * memory.
2614          */
2615         if (!needed_count) {
2616                 kfree(_data);
2617                 return 0;
2618         }
2619 
2620         /* Allocate everything in one chunk so there's less maintenance. */
2621         {
2622                 unsigned i = 0;
2623                 vla_group(d);
2624                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2625                         lang_count + 1);
2626                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2627                 vla_item(d, struct usb_string, strings,
2628                         lang_count*(needed_count+1));
2629 
2630                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2631 
2632                 if (unlikely(!vlabuf)) {
2633                         kfree(_data);
2634                         return -ENOMEM;
2635                 }
2636 
2637                 /* Initialize the VLA pointers */
2638                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2639                 t = vla_ptr(vlabuf, d, stringtab);
2640                 i = lang_count;
2641                 do {
2642                         *stringtabs++ = t++;
2643                 } while (--i);
2644                 *stringtabs = NULL;
2645 
2646                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2647                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2648                 t = vla_ptr(vlabuf, d, stringtab);
2649                 s = vla_ptr(vlabuf, d, strings);
2650         }
2651 
2652         /* For each language */
2653         data += 16;
2654         len -= 16;
2655 
2656         do { /* lang_count > 0 so we can use do-while */
2657                 unsigned needed = needed_count;
2658 
2659                 if (unlikely(len < 3))
2660                         goto error_free;
2661                 t->language = get_unaligned_le16(data);
2662                 t->strings  = s;
2663                 ++t;
2664 
2665                 data += 2;
2666                 len -= 2;
2667 
2668                 /* For each string */
2669                 do { /* str_count > 0 so we can use do-while */
2670                         size_t length = strnlen(data, len);
2671 
2672                         if (unlikely(length == len))
2673                                 goto error_free;
2674 
2675                         /*
2676                          * User may provide more strings then we need,
2677                          * if that's the case we simply ignore the
2678                          * rest
2679                          */
2680                         if (likely(needed)) {
2681                                 /*
2682                                  * s->id will be set while adding
2683                                  * function to configuration so for
2684                                  * now just leave garbage here.
2685                                  */
2686                                 s->s = data;
2687                                 --needed;
2688                                 ++s;
2689                         }
2690 
2691                         data += length + 1;
2692                         len -= length + 1;
2693                 } while (--str_count);
2694 
2695                 s->id = 0;   /* terminator */
2696                 s->s = NULL;
2697                 ++s;
2698 
2699         } while (--lang_count);
2700 
2701         /* Some garbage left? */
2702         if (unlikely(len))
2703                 goto error_free;
2704 
2705         /* Done! */
2706         ffs->stringtabs = stringtabs;
2707         ffs->raw_strings = _data;
2708 
2709         return 0;
2710 
2711 error_free:
2712         kfree(stringtabs);
2713 error:
2714         kfree(_data);
2715         return -EINVAL;
2716 }
2717 
2718 
2719 /* Events handling and management *******************************************/
2720 
2721 static void __ffs_event_add(struct ffs_data *ffs,
2722                             enum usb_functionfs_event_type type)
2723 {
2724         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2725         int neg = 0;
2726 
2727         /*
2728          * Abort any unhandled setup
2729          *
2730          * We do not need to worry about some cmpxchg() changing value
2731          * of ffs->setup_state without holding the lock because when
2732          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2733          * the source does nothing.
2734          */
2735         if (ffs->setup_state == FFS_SETUP_PENDING)
2736                 ffs->setup_state = FFS_SETUP_CANCELLED;
2737 
2738         /*
2739          * Logic of this function guarantees that there are at most four pending
2740          * evens on ffs->ev.types queue.  This is important because the queue
2741          * has space for four elements only and __ffs_ep0_read_events function
2742          * depends on that limit as well.  If more event types are added, those
2743          * limits have to be revisited or guaranteed to still hold.
2744          */
2745         switch (type) {
2746         case FUNCTIONFS_RESUME:
2747                 rem_type2 = FUNCTIONFS_SUSPEND;
2748                 /* FALL THROUGH */
2749         case FUNCTIONFS_SUSPEND:
2750         case FUNCTIONFS_SETUP:
2751                 rem_type1 = type;
2752                 /* Discard all similar events */
2753                 break;
2754 
2755         case FUNCTIONFS_BIND:
2756         case FUNCTIONFS_UNBIND:
2757         case FUNCTIONFS_DISABLE:
2758         case FUNCTIONFS_ENABLE:
2759                 /* Discard everything other then power management. */
2760                 rem_type1 = FUNCTIONFS_SUSPEND;
2761                 rem_type2 = FUNCTIONFS_RESUME;
2762                 neg = 1;
2763                 break;
2764 
2765         default:
2766                 WARN(1, "%d: unknown event, this should not happen\n", type);
2767                 return;
2768         }
2769 
2770         {
2771                 u8 *ev  = ffs->ev.types, *out = ev;
2772                 unsigned n = ffs->ev.count;
2773                 for (; n; --n, ++ev)
2774                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2775                                 *out++ = *ev;
2776                         else
2777                                 pr_vdebug("purging event %d\n", *ev);
2778                 ffs->ev.count = out - ffs->ev.types;
2779         }
2780 
2781         pr_vdebug("adding event %d\n", type);
2782         ffs->ev.types[ffs->ev.count++] = type;
2783         wake_up_locked(&ffs->ev.waitq);
2784         if (ffs->ffs_eventfd)
2785                 eventfd_signal(ffs->ffs_eventfd, 1);
2786 }
2787 
2788 static void ffs_event_add(struct ffs_data *ffs,
2789                           enum usb_functionfs_event_type type)
2790 {
2791         unsigned long flags;
2792         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2793         __ffs_event_add(ffs, type);
2794         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2795 }
2796 
2797 /* Bind/unbind USB function hooks *******************************************/
2798 
2799 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2800 {
2801         int i;
2802 
2803         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2804                 if (ffs->eps_addrmap[i] == endpoint_address)
2805                         return i;
2806         return -ENOENT;
2807 }
2808 
2809 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2810                                     struct usb_descriptor_header *desc,
2811                                     void *priv)
2812 {
2813         struct usb_endpoint_descriptor *ds = (void *)desc;
2814         struct ffs_function *func = priv;
2815         struct ffs_ep *ffs_ep;
2816         unsigned ep_desc_id;
2817         int idx;
2818         static const char *speed_names[] = { "full", "high", "super" };
2819 
2820         if (type != FFS_DESCRIPTOR)
2821                 return 0;
2822 
2823         /*
2824          * If ss_descriptors is not NULL, we are reading super speed
2825          * descriptors; if hs_descriptors is not NULL, we are reading high
2826          * speed descriptors; otherwise, we are reading full speed
2827          * descriptors.
2828          */
2829         if (func->function.ss_descriptors) {
2830                 ep_desc_id = 2;
2831                 func->function.ss_descriptors[(long)valuep] = desc;
2832         } else if (func->function.hs_descriptors) {
2833                 ep_desc_id = 1;
2834                 func->function.hs_descriptors[(long)valuep] = desc;
2835         } else {
2836                 ep_desc_id = 0;
2837                 func->function.fs_descriptors[(long)valuep]    = desc;
2838         }
2839 
2840         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2841                 return 0;
2842 
2843         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2844         if (idx < 0)
2845                 return idx;
2846 
2847         ffs_ep = func->eps + idx;
2848 
2849         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2850                 pr_err("two %sspeed descriptors for EP %d\n",
2851                           speed_names[ep_desc_id],
2852                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2853                 return -EINVAL;
2854         }
2855         ffs_ep->descs[ep_desc_id] = ds;
2856 
2857         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2858         if (ffs_ep->ep) {
2859                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2860                 if (!ds->wMaxPacketSize)
2861                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2862         } else {
2863                 struct usb_request *req;
2864                 struct usb_ep *ep;
2865                 u8 bEndpointAddress;
2866                 u16 wMaxPacketSize;
2867 
2868                 /*
2869                  * We back up bEndpointAddress because autoconfig overwrites
2870                  * it with physical endpoint address.
2871                  */
2872                 bEndpointAddress = ds->bEndpointAddress;
2873                 /*
2874                  * We back up wMaxPacketSize because autoconfig treats
2875                  * endpoint descriptors as if they were full speed.
2876                  */
2877                 wMaxPacketSize = ds->wMaxPacketSize;
2878                 pr_vdebug("autoconfig\n");
2879                 ep = usb_ep_autoconfig(func->gadget, ds);
2880                 if (unlikely(!ep))
2881                         return -ENOTSUPP;
2882                 ep->driver_data = func->eps + idx;
2883 
2884                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2885                 if (unlikely(!req))
2886                         return -ENOMEM;
2887 
2888                 ffs_ep->ep  = ep;
2889                 ffs_ep->req = req;
2890                 func->eps_revmap[ds->bEndpointAddress &
2891                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2892                 /*
2893                  * If we use virtual address mapping, we restore
2894                  * original bEndpointAddress value.
2895                  */
2896                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2897                         ds->bEndpointAddress = bEndpointAddress;
2898                 /*
2899                  * Restore wMaxPacketSize which was potentially
2900                  * overwritten by autoconfig.
2901                  */
2902                 ds->wMaxPacketSize = wMaxPacketSize;
2903         }
2904         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2905 
2906         return 0;
2907 }
2908 
2909 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2910                                    struct usb_descriptor_header *desc,
2911                                    void *priv)
2912 {
2913         struct ffs_function *func = priv;
2914         unsigned idx;
2915         u8 newValue;
2916 
2917         switch (type) {
2918         default:
2919         case FFS_DESCRIPTOR:
2920                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2921                 return 0;
2922 
2923         case FFS_INTERFACE:
2924                 idx = *valuep;
2925                 if (func->interfaces_nums[idx] < 0) {
2926                         int id = usb_interface_id(func->conf, &func->function);
2927                         if (unlikely(id < 0))
2928                                 return id;
2929                         func->interfaces_nums[idx] = id;
2930                 }
2931                 newValue = func->interfaces_nums[idx];
2932                 break;
2933 
2934         case FFS_STRING:
2935                 /* String' IDs are allocated when fsf_data is bound to cdev */
2936                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2937                 break;
2938 
2939         case FFS_ENDPOINT:
2940                 /*
2941                  * USB_DT_ENDPOINT are handled in
2942                  * __ffs_func_bind_do_descs().
2943                  */
2944                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2945                         return 0;
2946 
2947                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2948                 if (unlikely(!func->eps[idx].ep))
2949                         return -EINVAL;
2950 
2951                 {
2952                         struct usb_endpoint_descriptor **descs;
2953                         descs = func->eps[idx].descs;
2954                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2955                 }
2956                 break;
2957         }
2958 
2959         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2960         *valuep = newValue;
2961         return 0;
2962 }
2963 
2964 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2965                                       struct usb_os_desc_header *h, void *data,
2966                                       unsigned len, void *priv)
2967 {
2968         struct ffs_function *func = priv;
2969         u8 length = 0;
2970 
2971         switch (type) {
2972         case FFS_OS_DESC_EXT_COMPAT: {
2973                 struct usb_ext_compat_desc *desc = data;
2974                 struct usb_os_desc_table *t;
2975 
2976                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2977                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2978                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2979                        ARRAY_SIZE(desc->CompatibleID) +
2980                        ARRAY_SIZE(desc->SubCompatibleID));
2981                 length = sizeof(*desc);
2982         }
2983                 break;
2984         case FFS_OS_DESC_EXT_PROP: {
2985                 struct usb_ext_prop_desc *desc = data;
2986                 struct usb_os_desc_table *t;
2987                 struct usb_os_desc_ext_prop *ext_prop;
2988                 char *ext_prop_name;
2989                 char *ext_prop_data;
2990 
2991                 t = &func->function.os_desc_table[h->interface];
2992                 t->if_id = func->interfaces_nums[h->interface];
2993 
2994                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2995                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2996 
2997                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2998                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2999                 ext_prop->data_len = le32_to_cpu(*(__le32 *)
3000                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
3001                 length = ext_prop->name_len + ext_prop->data_len + 14;
3002 
3003                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
3004                 func->ffs->ms_os_descs_ext_prop_name_avail +=
3005                         ext_prop->name_len;
3006 
3007                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
3008                 func->ffs->ms_os_descs_ext_prop_data_avail +=
3009                         ext_prop->data_len;
3010                 memcpy(ext_prop_data,
3011                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
3012                        ext_prop->data_len);
3013                 /* unicode data reported to the host as "WCHAR"s */
3014                 switch (ext_prop->type) {
3015                 case USB_EXT_PROP_UNICODE:
3016                 case USB_EXT_PROP_UNICODE_ENV:
3017                 case USB_EXT_PROP_UNICODE_LINK:
3018                 case USB_EXT_PROP_UNICODE_MULTI:
3019                         ext_prop->data_len *= 2;
3020                         break;
3021                 }
3022                 ext_prop->data = ext_prop_data;
3023 
3024                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
3025                        ext_prop->name_len);
3026                 /* property name reported to the host as "WCHAR"s */
3027                 ext_prop->name_len *= 2;
3028                 ext_prop->name = ext_prop_name;
3029 
3030                 t->os_desc->ext_prop_len +=
3031                         ext_prop->name_len + ext_prop->data_len + 14;
3032                 ++t->os_desc->ext_prop_count;
3033                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
3034         }
3035                 break;
3036         default:
3037                 pr_vdebug("unknown descriptor: %d\n", type);
3038         }
3039 
3040         return length;
3041 }
3042 
3043 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
3044                                                 struct usb_configuration *c)
3045 {
3046         struct ffs_function *func = ffs_func_from_usb(f);
3047         struct f_fs_opts *ffs_opts =
3048                 container_of(f->fi, struct f_fs_opts, func_inst);
3049         int ret;
3050 
3051         ENTER();
3052 
3053         /*
3054          * Legacy gadget triggers binding in functionfs_ready_callback,
3055          * which already uses locking; taking the same lock here would
3056          * cause a deadlock.
3057          *
3058          * Configfs-enabled gadgets however do need ffs_dev_lock.
3059          */
3060         if (!ffs_opts->no_configfs)
3061                 ffs_dev_lock();
3062         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
3063         func->ffs = ffs_opts->dev->ffs_data;
3064         if (!ffs_opts->no_configfs)
3065                 ffs_dev_unlock();
3066         if (ret)
3067                 return ERR_PTR(ret);
3068 
3069         func->conf = c;
3070         func->gadget = c->cdev->gadget;
3071 
3072         /*
3073          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
3074          * configurations are bound in sequence with list_for_each_entry,
3075          * in each configuration its functions are bound in sequence
3076          * with list_for_each_entry, so we assume no race condition
3077          * with regard to ffs_opts->bound access
3078          */
3079         if (!ffs_opts->refcnt) {
3080                 ret = functionfs_bind(func->ffs, c->cdev);
3081                 if (ret)
3082                         return ERR_PTR(ret);
3083         }
3084         ffs_opts->refcnt++;
3085         func->function.strings = func->ffs->stringtabs;
3086 
3087         return ffs_opts;
3088 }
3089 
3090 static int _ffs_func_bind(struct usb_configuration *c,
3091                           struct usb_function *f)
3092 {
3093         struct ffs_function *func = ffs_func_from_usb(f);
3094         struct ffs_data *ffs = func->ffs;
3095 
3096         const int full = !!func->ffs->fs_descs_count;
3097         const int high = !!func->ffs->hs_descs_count;
3098         const int super = !!func->ffs->ss_descs_count;
3099 
3100         int fs_len, hs_len, ss_len, ret, i;
3101         struct ffs_ep *eps_ptr;
3102 
3103         /* Make it a single chunk, less management later on */
3104         vla_group(d);
3105         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
3106         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
3107                 full ? ffs->fs_descs_count + 1 : 0);
3108         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
3109                 high ? ffs->hs_descs_count + 1 : 0);
3110         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
3111                 super ? ffs->ss_descs_count + 1 : 0);
3112         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
3113         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
3114                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3115         vla_item_with_sz(d, char[16], ext_compat,
3116                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3117         vla_item_with_sz(d, struct usb_os_desc, os_desc,
3118                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
3119         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
3120                          ffs->ms_os_descs_ext_prop_count);
3121         vla_item_with_sz(d, char, ext_prop_name,
3122                          ffs->ms_os_descs_ext_prop_name_len);
3123         vla_item_with_sz(d, char, ext_prop_data,
3124                          ffs->ms_os_descs_ext_prop_data_len);
3125         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
3126         char *vlabuf;
3127 
3128         ENTER();
3129 
3130         /* Has descriptors only for speeds gadget does not support */
3131         if (unlikely(!(full | high | super)))
3132                 return -ENOTSUPP;
3133 
3134         /* Allocate a single chunk, less management later on */
3135         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
3136         if (unlikely(!vlabuf))
3137                 return -ENOMEM;
3138 
3139         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
3140         ffs->ms_os_descs_ext_prop_name_avail =
3141                 vla_ptr(vlabuf, d, ext_prop_name);
3142         ffs->ms_os_descs_ext_prop_data_avail =
3143                 vla_ptr(vlabuf, d, ext_prop_data);
3144 
3145         /* Copy descriptors  */
3146         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
3147                ffs->raw_descs_length);
3148 
3149         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
3150         eps_ptr = vla_ptr(vlabuf, d, eps);
3151         for (i = 0; i < ffs->eps_count; i++)
3152                 eps_ptr[i].num = -1;
3153 
3154         /* Save pointers
3155          * d_eps == vlabuf, func->eps used to kfree vlabuf later
3156         */
3157         func->eps             = vla_ptr(vlabuf, d, eps);
3158         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
3159 
3160         /*
3161          * Go through all the endpoint descriptors and allocate
3162          * endpoints first, so that later we can rewrite the endpoint
3163          * numbers without worrying that it may be described later on.
3164          */
3165         if (likely(full)) {
3166                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
3167                 fs_len = ffs_do_descs(ffs->fs_descs_count,
3168                                       vla_ptr(vlabuf, d, raw_descs),
3169                                       d_raw_descs__sz,
3170                                       __ffs_func_bind_do_descs, func);
3171                 if (unlikely(fs_len < 0)) {
3172                         ret = fs_len;
3173                         goto error;
3174                 }
3175         } else {
3176                 fs_len = 0;
3177         }
3178 
3179         if (likely(high)) {
3180                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
3181                 hs_len = ffs_do_descs(ffs->hs_descs_count,
3182                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
3183                                       d_raw_descs__sz - fs_len,
3184                                       __ffs_func_bind_do_descs, func);
3185                 if (unlikely(hs_len < 0)) {
3186                         ret = hs_len;
3187                         goto error;
3188                 }
3189         } else {
3190                 hs_len = 0;
3191         }
3192 
3193         if (likely(super)) {
3194                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
3195                 ss_len = ffs_do_descs(ffs->ss_descs_count,
3196                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
3197                                 d_raw_descs__sz - fs_len - hs_len,
3198                                 __ffs_func_bind_do_descs, func);
3199                 if (unlikely(ss_len < 0)) {
3200                         ret = ss_len;
3201                         goto error;
3202                 }
3203         } else {
3204                 ss_len = 0;
3205         }
3206 
3207         /*
3208          * Now handle interface numbers allocation and interface and
3209          * endpoint numbers rewriting.  We can do that in one go
3210          * now.
3211          */
3212         ret = ffs_do_descs(ffs->fs_descs_count +
3213                            (high ? ffs->hs_descs_count : 0) +
3214                            (super ? ffs->ss_descs_count : 0),
3215                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
3216                            __ffs_func_bind_do_nums, func);
3217         if (unlikely(ret < 0))
3218                 goto error;
3219 
3220         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
3221         if (c->cdev->use_os_string) {
3222                 for (i = 0; i < ffs->interfaces_count; ++i) {
3223                         struct usb_os_desc *desc;
3224 
3225                         desc = func->function.os_desc_table[i].os_desc =
3226                                 vla_ptr(vlabuf, d, os_desc) +
3227                                 i * sizeof(struct usb_os_desc);
3228                         desc->ext_compat_id =
3229                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
3230                         INIT_LIST_HEAD(&desc->ext_prop);
3231                 }
3232                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
3233                                       vla_ptr(vlabuf, d, raw_descs) +
3234                                       fs_len + hs_len + ss_len,
3235                                       d_raw_descs__sz - fs_len - hs_len -
3236                                       ss_len,
3237                                       __ffs_func_bind_do_os_desc, func);
3238                 if (unlikely(ret < 0))
3239                         goto error;
3240         }
3241         func->function.os_desc_n =
3242                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
3243 
3244         /* And we're done */
3245         ffs_event_add(ffs, FUNCTIONFS_BIND);
3246         return 0;
3247 
3248 error:
3249         /* XXX Do we need to release all claimed endpoints here? */
3250         return ret;
3251 }
3252 
3253 static int ffs_func_bind(struct usb_configuration *c,
3254                          struct usb_function *f)
3255 {
3256         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3257         struct ffs_function *func = ffs_func_from_usb(f);
3258         int ret;
3259 
3260         if (IS_ERR(ffs_opts))
3261                 return PTR_ERR(ffs_opts);
3262 
3263         ret = _ffs_func_bind(c, f);
3264         if (ret && !--ffs_opts->refcnt)
3265                 functionfs_unbind(func->ffs);
3266 
3267         return ret;
3268 }
3269 
3270 
3271 /* Other USB function hooks *************************************************/
3272 
3273 static void ffs_reset_work(struct work_struct *work)
3274 {
3275         struct ffs_data *ffs = container_of(work,
3276                 struct ffs_data, reset_work);
3277         ffs_data_reset(ffs);
3278 }
3279 
3280 static int ffs_func_set_alt(struct usb_function *f,
3281                             unsigned interface, unsigned alt)
3282 {
3283         struct ffs_function *func = ffs_func_from_usb(f);
3284         struct ffs_data *ffs = func->ffs;
3285         int ret = 0, intf;
3286 
3287         if (alt != (unsigned)-1) {
3288                 intf = ffs_func_revmap_intf(func, interface);
3289                 if (unlikely(intf < 0))
3290                         return intf;
3291         }
3292 
3293         if (ffs->func)
3294                 ffs_func_eps_disable(ffs->func);
3295 
3296         if (ffs->state == FFS_DEACTIVATED) {
3297                 ffs->state = FFS_CLOSING;
3298                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3299                 schedule_work(&ffs->reset_work);
3300                 return -ENODEV;
3301         }
3302 
3303         if (ffs->state != FFS_ACTIVE)
3304                 return -ENODEV;
3305 
3306         if (alt == (unsigned)-1) {
3307                 ffs->func = NULL;
3308                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3309                 return 0;
3310         }
3311 
3312         ffs->func = func;
3313         ret = ffs_func_eps_enable(func);
3314         if (likely(ret >= 0))
3315                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3316         return ret;
3317 }
3318 
3319 static void ffs_func_disable(struct usb_function *f)
3320 {
3321         ffs_func_set_alt(f, 0, (unsigned)-1);
3322 }
3323 
3324 static int ffs_func_setup(struct usb_function *f,
3325                           const struct usb_ctrlrequest *creq)
3326 {
3327         struct ffs_function *func = ffs_func_from_usb(f);
3328         struct ffs_data *ffs = func->ffs;
3329         unsigned long flags;
3330         int ret;
3331 
3332         ENTER();
3333 
3334         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3335         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3336         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3337         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3338         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3339 
3340         /*
3341          * Most requests directed to interface go through here
3342          * (notable exceptions are set/get interface) so we need to
3343          * handle them.  All other either handled by composite or
3344          * passed to usb_configuration->setup() (if one is set).  No
3345          * matter, we will handle requests directed to endpoint here
3346          * as well (as it's straightforward).  Other request recipient
3347          * types are only handled when the user flag FUNCTIONFS_ALL_CTRL_RECIP
3348          * is being used.
3349          */
3350         if (ffs->state != FFS_ACTIVE)
3351                 return -ENODEV;
3352 
3353         switch (creq->bRequestType & USB_RECIP_MASK) {
3354         case USB_RECIP_INTERFACE:
3355                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3356                 if (unlikely(ret < 0))
3357                         return ret;
3358                 break;
3359 
3360         case USB_RECIP_ENDPOINT:
3361                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3362                 if (unlikely(ret < 0))
3363                         return ret;
3364                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3365                         ret = func->ffs->eps_addrmap[ret];
3366                 break;
3367 
3368         default:
3369                 if (func->ffs->user_flags & FUNCTIONFS_ALL_CTRL_RECIP)
3370                         ret = le16_to_cpu(creq->wIndex);
3371                 else
3372                         return -EOPNOTSUPP;
3373         }
3374 
3375         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3376         ffs->ev.setup = *creq;
3377         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3378         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3379         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3380 
3381         return creq->wLength == 0 ? USB_GADGET_DELAYED_STATUS : 0;
3382 }
3383 
3384 static bool ffs_func_req_match(struct usb_function *f,
3385                                const struct usb_ctrlrequest *creq,
3386                                bool config0)
3387 {
3388         struct ffs_function *func = ffs_func_from_usb(f);
3389 
3390         if (config0 && !(func->ffs->user_flags & FUNCTIONFS_CONFIG0_SETUP))
3391                 return false;
3392 
3393         switch (creq->bRequestType & USB_RECIP_MASK) {
3394         case USB_RECIP_INTERFACE:
3395                 return (ffs_func_revmap_intf(func,
3396                                              le16_to_cpu(creq->wIndex)) >= 0);
3397         case USB_RECIP_ENDPOINT:
3398                 return (ffs_func_revmap_ep(func,
3399                                            le16_to_cpu(creq->wIndex)) >= 0);
3400         default:
3401                 return (bool) (func->ffs->user_flags &
3402                                FUNCTIONFS_ALL_CTRL_RECIP);
3403         }
3404 }
3405 
3406 static void ffs_func_suspend(struct usb_function *f)
3407 {
3408         ENTER();
3409         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3410 }
3411 
3412 static void ffs_func_resume(struct usb_function *f)
3413 {
3414         ENTER();
3415         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3416 }
3417 
3418 
3419 /* Endpoint and interface numbers reverse mapping ***************************/
3420 
3421 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3422 {
3423         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3424         return num ? num : -EDOM;
3425 }
3426 
3427 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3428 {
3429         short *nums = func->interfaces_nums;
3430         unsigned count = func->ffs->interfaces_count;
3431 
3432         for (; count; --count, ++nums) {
3433                 if (*nums >= 0 && *nums == intf)
3434                         return nums - func->interfaces_nums;
3435         }
3436 
3437         return -EDOM;
3438 }
3439 
3440 
3441 /* Devices management *******************************************************/
3442 
3443 static LIST_HEAD(ffs_devices);
3444 
3445 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3446 {
3447         struct ffs_dev *dev;
3448 
3449         if (!name)
3450                 return NULL;
3451 
3452         list_for_each_entry(dev, &ffs_devices, entry) {
3453                 if (strcmp(dev->name, name) == 0)
3454                         return dev;
3455         }
3456 
3457         return NULL;
3458 }
3459 
3460 /*
3461  * ffs_lock must be taken by the caller of this function
3462  */
3463 static struct ffs_dev *_ffs_get_single_dev(void)
3464 {
3465         struct ffs_dev *dev;
3466 
3467         if (list_is_singular(&ffs_devices)) {
3468                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3469                 if (dev->single)
3470                         return dev;
3471         }
3472 
3473         return NULL;
3474 }
3475 
3476 /*
3477  * ffs_lock must be taken by the caller of this function
3478  */
3479 static struct ffs_dev *_ffs_find_dev(const char *name)
3480 {
3481         struct ffs_dev *dev;
3482 
3483         dev = _ffs_get_single_dev();
3484         if (dev)
3485                 return dev;
3486 
3487         return _ffs_do_find_dev(name);
3488 }
3489 
3490 /* Configfs support *********************************************************/
3491 
3492 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3493 {
3494         return container_of(to_config_group(item), struct f_fs_opts,
3495                             func_inst.group);
3496 }
3497 
3498 static void ffs_attr_release(struct config_item *item)
3499 {
3500         struct f_fs_opts *opts = to_ffs_opts(item);
3501 
3502         usb_put_function_instance(&opts->func_inst);
3503 }
3504 
3505 static struct configfs_item_operations ffs_item_ops = {
3506         .release        = ffs_attr_release,
3507 };
3508 
3509 static const struct config_item_type ffs_func_type = {
3510         .ct_item_ops    = &ffs_item_ops,
3511         .ct_owner       = THIS_MODULE,
3512 };
3513 
3514 
3515 /* Function registration interface ******************************************/
3516 
3517 static void ffs_free_inst(struct usb_function_instance *f)
3518 {
3519         struct f_fs_opts *opts;
3520 
3521         opts = to_f_fs_opts(f);
3522         ffs_dev_lock();
3523         _ffs_free_dev(opts->dev);
3524         ffs_dev_unlock();
3525         kfree(opts);
3526 }
3527 
3528 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3529 {
3530         if (strlen(name) >= FIELD_SIZEOF(struct ffs_dev, name))
3531                 return -ENAMETOOLONG;
3532         return ffs_name_dev(to_f_fs_opts(fi)->dev, name);
3533 }
3534 
3535 static struct usb_function_instance *ffs_alloc_inst(void)
3536 {
3537         struct f_fs_opts *opts;
3538         struct ffs_dev *dev;
3539 
3540         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3541         if (!opts)
3542                 return ERR_PTR(-ENOMEM);
3543 
3544         opts->func_inst.set_inst_name = ffs_set_inst_name;
3545         opts->func_inst.free_func_inst = ffs_free_inst;
3546         ffs_dev_lock();
3547         dev = _ffs_alloc_dev();
3548         ffs_dev_unlock();
3549         if (IS_ERR(dev)) {
3550                 kfree(opts);
3551                 return ERR_CAST(dev);
3552         }
3553         opts->dev = dev;
3554         dev->opts = opts;
3555 
3556         config_group_init_type_name(&opts->func_inst.group, "",
3557                                     &ffs_func_type);
3558         return &opts->func_inst;
3559 }
3560 
3561 static void ffs_free(struct usb_function *f)
3562 {
3563         kfree(ffs_func_from_usb(f));
3564 }
3565 
3566 static void ffs_func_unbind(struct usb_configuration *c,
3567                             struct usb_function *f)
3568 {
3569         struct ffs_function *func = ffs_func_from_usb(f);
3570         struct ffs_data *ffs = func->ffs;
3571         struct f_fs_opts *opts =
3572                 container_of(f->fi, struct f_fs_opts, func_inst);
3573         struct ffs_ep *ep = func->eps;
3574         unsigned count = ffs->eps_count;
3575         unsigned long flags;
3576 
3577         ENTER();
3578         if (ffs->func == func) {
3579                 ffs_func_eps_disable(func);
3580                 ffs->func = NULL;
3581         }
3582 
3583         if (!--opts->refcnt)
3584                 functionfs_unbind(ffs);
3585 
3586         /* cleanup after autoconfig */
3587         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3588         while (count--) {
3589                 if (ep->ep && ep->req)
3590                         usb_ep_free_request(ep->ep, ep->req);
3591                 ep->req = NULL;
3592                 ++ep;
3593         }
3594         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3595         kfree(func->eps);
3596         func->eps = NULL;
3597         /*
3598          * eps, descriptors and interfaces_nums are allocated in the
3599          * same chunk so only one free is required.
3600          */
3601         func->function.fs_descriptors = NULL;
3602         func->function.hs_descriptors = NULL;
3603         func->function.ss_descriptors = NULL;
3604         func->interfaces_nums = NULL;
3605 
3606         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3607 }
3608 
3609 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3610 {
3611         struct ffs_function *func;
3612 
3613         ENTER();
3614 
3615         func = kzalloc(sizeof(*func), GFP_KERNEL);
3616         if (unlikely(!func))
3617                 return ERR_PTR(-ENOMEM);
3618 
3619         func->function.name    = "Function FS Gadget";
3620 
3621         func->function.bind    = ffs_func_bind;
3622         func->function.unbind  = ffs_func_unbind;
3623         func->function.set_alt = ffs_func_set_alt;
3624         func->function.disable = ffs_func_disable;
3625         func->function.setup   = ffs_func_setup;
3626         func->function.req_match = ffs_func_req_match;
3627         func->function.suspend = ffs_func_suspend;
3628         func->function.resume  = ffs_func_resume;
3629         func->function.free_func = ffs_free;
3630 
3631         return &func->function;
3632 }
3633 
3634 /*
3635  * ffs_lock must be taken by the caller of this function
3636  */
3637 static struct ffs_dev *_ffs_alloc_dev(void)
3638 {
3639         struct ffs_dev *dev;
3640         int ret;
3641 
3642         if (_ffs_get_single_dev())
3643                         return ERR_PTR(-EBUSY);
3644 
3645         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3646         if (!dev)
3647                 return ERR_PTR(-ENOMEM);
3648 
3649         if (list_empty(&ffs_devices)) {
3650                 ret = functionfs_init();
3651                 if (ret) {
3652                         kfree(dev);
3653                         return ERR_PTR(ret);
3654                 }
3655         }
3656 
3657         list_add(&dev->entry, &ffs_devices);
3658 
3659         return dev;
3660 }
3661 
3662 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3663 {
3664         struct ffs_dev *existing;
3665         int ret = 0;
3666 
3667         ffs_dev_lock();
3668 
3669         existing = _ffs_do_find_dev(name);
3670         if (!existing)
3671                 strlcpy(dev->name, name, ARRAY_SIZE(dev->name));
3672         else if (existing != dev)
3673                 ret = -EBUSY;
3674 
3675         ffs_dev_unlock();
3676 
3677         return ret;
3678 }
3679 EXPORT_SYMBOL_GPL(ffs_name_dev);
3680 
3681 int ffs_single_dev(struct ffs_dev *dev)
3682 {
3683         int ret;
3684 
3685         ret = 0;
3686         ffs_dev_lock();
3687 
3688         if (!list_is_singular(&ffs_devices))
3689                 ret = -EBUSY;
3690         else
3691                 dev->single = true;
3692 
3693         ffs_dev_unlock();
3694         return ret;
3695 }
3696 EXPORT_SYMBOL_GPL(ffs_single_dev);
3697 
3698 /*
3699  * ffs_lock must be taken by the caller of this function
3700  */
3701 static void _ffs_free_dev(struct ffs_dev *dev)
3702 {
3703         list_del(&dev->entry);
3704 
3705         /* Clear the private_data pointer to stop incorrect dev access */
3706         if (dev->ffs_data)
3707                 dev->ffs_data->private_data = NULL;
3708 
3709         kfree(dev);
3710         if (list_empty(&ffs_devices))
3711                 functionfs_cleanup();
3712 }
3713 
3714 static void *ffs_acquire_dev(const char *dev_name)
3715 {
3716         struct ffs_dev *ffs_dev;
3717 
3718         ENTER();
3719         ffs_dev_lock();
3720 
3721         ffs_dev = _ffs_find_dev(dev_name);
3722         if (!ffs_dev)
3723                 ffs_dev = ERR_PTR(-ENOENT);
3724         else if (ffs_dev->mounted)
3725                 ffs_dev = ERR_PTR(-EBUSY);
3726         else if (ffs_dev->ffs_acquire_dev_callback &&
3727             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3728                 ffs_dev = ERR_PTR(-ENOENT);
3729         else
3730                 ffs_dev->mounted = true;
3731 
3732         ffs_dev_unlock();
3733         return ffs_dev;
3734 }
3735 
3736 static void ffs_release_dev(struct ffs_data *ffs_data)
3737 {
3738         struct ffs_dev *ffs_dev;
3739 
3740         ENTER();
3741         ffs_dev_lock();
3742 
3743         ffs_dev = ffs_data->private_data;
3744         if (ffs_dev) {
3745                 ffs_dev->mounted = false;
3746 
3747                 if (ffs_dev->ffs_release_dev_callback)
3748                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3749         }
3750 
3751         ffs_dev_unlock();
3752 }
3753 
3754 static int ffs_ready(struct ffs_data *ffs)
3755 {
3756         struct ffs_dev *ffs_obj;
3757         int ret = 0;
3758 
3759         ENTER();
3760         ffs_dev_lock();
3761 
3762         ffs_obj = ffs->private_data;
3763         if (!ffs_obj) {
3764                 ret = -EINVAL;
3765                 goto done;
3766         }
3767         if (WARN_ON(ffs_obj->desc_ready)) {
3768                 ret = -EBUSY;
3769                 goto done;
3770         }
3771 
3772         ffs_obj->desc_ready = true;
3773         ffs_obj->ffs_data = ffs;
3774 
3775         if (ffs_obj->ffs_ready_callback) {
3776                 ret = ffs_obj->ffs_ready_callback(ffs);
3777                 if (ret)
3778                         goto done;
3779         }
3780 
3781         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3782 done:
3783         ffs_dev_unlock();
3784         return ret;
3785 }
3786 
3787 static void ffs_closed(struct ffs_data *ffs)
3788 {
3789         struct ffs_dev *ffs_obj;
3790         struct f_fs_opts *opts;
3791         struct config_item *ci;
3792 
3793         ENTER();
3794         ffs_dev_lock();
3795 
3796         ffs_obj = ffs->private_data;
3797         if (!ffs_obj)
3798                 goto done;
3799 
3800         ffs_obj->desc_ready = false;
3801         ffs_obj->ffs_data = NULL;
3802 
3803         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3804             ffs_obj->ffs_closed_callback)
3805                 ffs_obj->ffs_closed_callback(ffs);
3806 
3807         if (ffs_obj->opts)
3808                 opts = ffs_obj->opts;
3809         else
3810                 goto done;
3811 
3812         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3813             || !kref_read(&opts->func_inst.group.cg_item.ci_kref))
3814                 goto done;
3815 
3816         ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
3817         ffs_dev_unlock();
3818 
3819         if (test_bit(FFS_FL_BOUND, &ffs->flags))
3820                 unregister_gadget_item(ci);
3821         return;
3822 done:
3823         ffs_dev_unlock();
3824 }
3825 
3826 /* Misc helper functions ****************************************************/
3827 
3828 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3829 {
3830         return nonblock
3831                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3832                 : mutex_lock_interruptible(mutex);
3833 }
3834 
3835 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3836 {
3837         char *data;
3838 
3839         if (unlikely(!len))
3840                 return NULL;
3841 
3842         data = kmalloc(len, GFP_KERNEL);
3843         if (unlikely(!data))
3844                 return ERR_PTR(-ENOMEM);
3845 
3846         if (unlikely(copy_from_user(data, buf, len))) {
3847                 kfree(data);
3848                 return ERR_PTR(-EFAULT);
3849         }
3850 
3851         pr_vdebug("Buffer from user space:\n");
3852         ffs_dump_mem("", data, len);
3853 
3854         return data;
3855 }
3856 
3857 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3858 MODULE_LICENSE("GPL");
3859 MODULE_AUTHOR("Michal Nazarewicz");