drivers/scsi/sg.c

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This source file includes following definitions.
sg_check_file_access
sg_allow_access
open_wait
sg_open
sg_release
sg_read
sg_new_read
sg_write
sg_new_write
sg_common_write
srp_done
max_sectors_bytes
sg_fill_request_table
sg_ioctl
sg_compat_ioctl
sg_poll
sg_fasync
sg_vma_fault
sg_mmap
sg_rq_end_io_usercontext
sg_rq_end_io
sg_alloc
sg_add_device
sg_device_destroy
sg_remove_device
init_sg
exit_sg
sg_start_req
sg_finish_rem_req
sg_build_sgat
sg_build_indirect
sg_remove_scat
sg_read_oxfer
sg_build_reserve
sg_link_reserve
sg_unlink_reserve
sg_get_rq_mark
sg_add_request
sg_remove_request
sg_add_sfp
sg_remove_sfp_usercontext
sg_remove_sfp
sg_idr_max_id
sg_last_dev
sg_lookup_dev
sg_get_dev
sg_proc_init
sg_proc_seq_show_int
sg_proc_single_open_adio
sg_proc_write_adio
sg_proc_single_open_dressz
sg_proc_write_dressz
sg_proc_seq_show_version
sg_proc_seq_show_devhdr
dev_seq_start
dev_seq_next
dev_seq_stop
sg_proc_seq_show_dev
sg_proc_seq_show_devstrs
sg_proc_debug_helper
sg_proc_seq_show_debug
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  History:
   4  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
   5  *           to allow user process control of SCSI devices.
   6  *  Development Sponsored by Killy Corp. NY NY
   7  *
   8  * Original driver (sg.c):
   9  *        Copyright (C) 1992 Lawrence Foard
  10  * Version 2 and 3 extensions to driver:
  11  *        Copyright (C) 1998 - 2014 Douglas Gilbert
  12  */
  13 
  14 static int sg_version_num = 30536;      /* 2 digits for each component */
  15 #define SG_VERSION_STR "3.5.36"
  16 
  17 /*
  18  *  D. P. Gilbert (dgilbert@interlog.com), notes:
  19  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
  20  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
  21  *        (otherwise the macros compile to empty statements).
  22  *
  23  */
  24 #include <linux/module.h>
  25 
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/ioctl.h>
  34 #include <linux/slab.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/init.h>
  37 #include <linux/poll.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/seq_file.h>
  42 #include <linux/blkdev.h>
  43 #include <linux/delay.h>
  44 #include <linux/blktrace_api.h>
  45 #include <linux/mutex.h>
  46 #include <linux/atomic.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/uio.h>
  49 #include <linux/cred.h> /* for sg_check_file_access() */
  50 
  51 #include "scsi.h"
  52 #include <scsi/scsi_dbg.h>
  53 #include <scsi/scsi_host.h>
  54 #include <scsi/scsi_driver.h>
  55 #include <scsi/scsi_ioctl.h>
  56 #include <scsi/sg.h>
  57 
  58 #include "scsi_logging.h"
  59 
  60 #ifdef CONFIG_SCSI_PROC_FS
  61 #include <linux/proc_fs.h>
  62 static char *sg_version_date = "20140603";
  63 
  64 static int sg_proc_init(void);
  65 #endif
  66 
  67 #define SG_ALLOW_DIO_DEF 0
  68 
  69 #define SG_MAX_DEVS 32768
  70 
  71 /* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
  72  * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
  73  * than 16 bytes are "variable length" whose length is a multiple of 4
  74  */
  75 #define SG_MAX_CDB_SIZE 252
  76 
  77 #define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
  78 
  79 int sg_big_buff = SG_DEF_RESERVED_SIZE;
  80 /* N.B. This variable is readable and writeable via
  81    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
  82    of this size (or less if there is not enough memory) will be reserved
  83    for use by this file descriptor. [Deprecated usage: this variable is also
  84    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
  85    the kernel (i.e. it is not a module).] */
  86 static int def_reserved_size = -1;      /* picks up init parameter */
  87 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
  88 
  89 static int scatter_elem_sz = SG_SCATTER_SZ;
  90 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
  91 
  92 #define SG_SECTOR_SZ 512
  93 
  94 static int sg_add_device(struct device *, struct class_interface *);
  95 static void sg_remove_device(struct device *, struct class_interface *);
  96 
  97 static DEFINE_IDR(sg_index_idr);
  98 static DEFINE_RWLOCK(sg_index_lock);    /* Also used to lock
  99                                                            file descriptor list for device */
 100 
 101 static struct class_interface sg_interface = {
 102         .add_dev        = sg_add_device,
 103         .remove_dev     = sg_remove_device,
 104 };
 105 
 106 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
 107         unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
 108         unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
 109         unsigned bufflen;       /* Size of (aggregate) data buffer */
 110         struct page **pages;
 111         int page_order;
 112         char dio_in_use;        /* 0->indirect IO (or mmap), 1->dio */
 113         unsigned char cmd_opcode; /* first byte of command */
 114 } Sg_scatter_hold;
 115 
 116 struct sg_device;               /* forward declarations */
 117 struct sg_fd;
 118 
 119 typedef struct sg_request {     /* SG_MAX_QUEUE requests outstanding per file */
 120         struct list_head entry; /* list entry */
 121         struct sg_fd *parentfp; /* NULL -> not in use */
 122         Sg_scatter_hold data;   /* hold buffer, perhaps scatter list */
 123         sg_io_hdr_t header;     /* scsi command+info, see <scsi/sg.h> */
 124         unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
 125         char res_used;          /* 1 -> using reserve buffer, 0 -> not ... */
 126         char orphan;            /* 1 -> drop on sight, 0 -> normal */
 127         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
 128         /* done protected by rq_list_lock */
 129         char done;              /* 0->before bh, 1->before read, 2->read */
 130         struct request *rq;
 131         struct bio *bio;
 132         struct execute_work ew;
 133 } Sg_request;
 134 
 135 typedef struct sg_fd {          /* holds the state of a file descriptor */
 136         struct list_head sfd_siblings;  /* protected by device's sfd_lock */
 137         struct sg_device *parentdp;     /* owning device */
 138         wait_queue_head_t read_wait;    /* queue read until command done */
 139         rwlock_t rq_list_lock;  /* protect access to list in req_arr */
 140         struct mutex f_mutex;   /* protect against changes in this fd */
 141         int timeout;            /* defaults to SG_DEFAULT_TIMEOUT      */
 142         int timeout_user;       /* defaults to SG_DEFAULT_TIMEOUT_USER */
 143         Sg_scatter_hold reserve;        /* buffer held for this file descriptor */
 144         struct list_head rq_list; /* head of request list */
 145         struct fasync_struct *async_qp; /* used by asynchronous notification */
 146         Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
 147         char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
 148         char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
 149         unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
 150         char keep_orphan;       /* 0 -> drop orphan (def), 1 -> keep for read() */
 151         char mmap_called;       /* 0 -> mmap() never called on this fd */
 152         char res_in_use;        /* 1 -> 'reserve' array in use */
 153         struct kref f_ref;
 154         struct execute_work ew;
 155 } Sg_fd;
 156 
 157 typedef struct sg_device { /* holds the state of each scsi generic device */
 158         struct scsi_device *device;
 159         wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
 160         struct mutex open_rel_lock;     /* held when in open() or release() */
 161         int sg_tablesize;       /* adapter's max scatter-gather table size */
 162         u32 index;              /* device index number */
 163         struct list_head sfds;
 164         rwlock_t sfd_lock;      /* protect access to sfd list */
 165         atomic_t detaching;     /* 0->device usable, 1->device detaching */
 166         bool exclude;           /* 1->open(O_EXCL) succeeded and is active */
 167         int open_cnt;           /* count of opens (perhaps < num(sfds) ) */
 168         char sgdebug;           /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
 169         struct gendisk *disk;
 170         struct cdev * cdev;     /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
 171         struct kref d_ref;
 172 } Sg_device;
 173 
 174 /* tasklet or soft irq callback */
 175 static void sg_rq_end_io(struct request *rq, blk_status_t status);
 176 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 177 static int sg_finish_rem_req(Sg_request * srp);
 178 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 179 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 180                            Sg_request * srp);
 181 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
 182                         const char __user *buf, size_t count, int blocking,
 183                         int read_only, int sg_io_owned, Sg_request **o_srp);
 184 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 185                            unsigned char *cmnd, int timeout, int blocking);
 186 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
 187 static void sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp);
 188 static void sg_build_reserve(Sg_fd * sfp, int req_size);
 189 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
 190 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
 191 static Sg_fd *sg_add_sfp(Sg_device * sdp);
 192 static void sg_remove_sfp(struct kref *);
 193 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
 194 static Sg_request *sg_add_request(Sg_fd * sfp);
 195 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 196 static Sg_device *sg_get_dev(int dev);
 197 static void sg_device_destroy(struct kref *kref);
 198 
 199 #define SZ_SG_HEADER sizeof(struct sg_header)
 200 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
 201 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
 202 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
 203 
 204 #define sg_printk(prefix, sdp, fmt, a...) \
 205         sdev_prefix_printk(prefix, (sdp)->device,               \
 206                            (sdp)->disk->disk_name, fmt, ##a)
 207 
 208 /*
 209  * The SCSI interfaces that use read() and write() as an asynchronous variant of
 210  * ioctl(..., SG_IO, ...) are fundamentally unsafe, since there are lots of ways
 211  * to trigger read() and write() calls from various contexts with elevated
 212  * privileges. This can lead to kernel memory corruption (e.g. if these
 213  * interfaces are called through splice()) and privilege escalation inside
 214  * userspace (e.g. if a process with access to such a device passes a file
 215  * descriptor to a SUID binary as stdin/stdout/stderr).
 216  *
 217  * This function provides protection for the legacy API by restricting the
 218  * calling context.
 219  */
 220 static int sg_check_file_access(struct file *filp, const char *caller)
 221 {
 222         if (filp->f_cred != current_real_cred()) {
 223                 pr_err_once("%s: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
 224                         caller, task_tgid_vnr(current), current->comm);
 225                 return -EPERM;
 226         }
 227         if (uaccess_kernel()) {
 228                 pr_err_once("%s: process %d (%s) called from kernel context, this is not allowed.\n",
 229                         caller, task_tgid_vnr(current), current->comm);
 230                 return -EACCES;
 231         }
 232         return 0;
 233 }
 234 
 235 static int sg_allow_access(struct file *filp, unsigned char *cmd)
 236 {
 237         struct sg_fd *sfp = filp->private_data;
 238 
 239         if (sfp->parentdp->device->type == TYPE_SCANNER)
 240                 return 0;
 241 
 242         return blk_verify_command(cmd, filp->f_mode);
 243 }
 244 
 245 static int
 246 open_wait(Sg_device *sdp, int flags)
 247 {
 248         int retval = 0;
 249 
 250         if (flags & O_EXCL) {
 251                 while (sdp->open_cnt > 0) {
 252                         mutex_unlock(&sdp->open_rel_lock);
 253                         retval = wait_event_interruptible(sdp->open_wait,
 254                                         (atomic_read(&sdp->detaching) ||
 255                                          !sdp->open_cnt));
 256                         mutex_lock(&sdp->open_rel_lock);
 257 
 258                         if (retval) /* -ERESTARTSYS */
 259                                 return retval;
 260                         if (atomic_read(&sdp->detaching))
 261                                 return -ENODEV;
 262                 }
 263         } else {
 264                 while (sdp->exclude) {
 265                         mutex_unlock(&sdp->open_rel_lock);
 266                         retval = wait_event_interruptible(sdp->open_wait,
 267                                         (atomic_read(&sdp->detaching) ||
 268                                          !sdp->exclude));
 269                         mutex_lock(&sdp->open_rel_lock);
 270 
 271                         if (retval) /* -ERESTARTSYS */
 272                                 return retval;
 273                         if (atomic_read(&sdp->detaching))
 274                                 return -ENODEV;
 275                 }
 276         }
 277 
 278         return retval;
 279 }
 280 
 281 /* Returns 0 on success, else a negated errno value */
 282 static int
 283 sg_open(struct inode *inode, struct file *filp)
 284 {
 285         int dev = iminor(inode);
 286         int flags = filp->f_flags;
 287         struct request_queue *q;
 288         Sg_device *sdp;
 289         Sg_fd *sfp;
 290         int retval;
 291 
 292         nonseekable_open(inode, filp);
 293         if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
 294                 return -EPERM; /* Can't lock it with read only access */
 295         sdp = sg_get_dev(dev);
 296         if (IS_ERR(sdp))
 297                 return PTR_ERR(sdp);
 298 
 299         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 300                                       "sg_open: flags=0x%x\n", flags));
 301 
 302         /* This driver's module count bumped by fops_get in <linux/fs.h> */
 303         /* Prevent the device driver from vanishing while we sleep */
 304         retval = scsi_device_get(sdp->device);
 305         if (retval)
 306                 goto sg_put;
 307 
 308         retval = scsi_autopm_get_device(sdp->device);
 309         if (retval)
 310                 goto sdp_put;
 311 
 312         /* scsi_block_when_processing_errors() may block so bypass
 313          * check if O_NONBLOCK. Permits SCSI commands to be issued
 314          * during error recovery. Tread carefully. */
 315         if (!((flags & O_NONBLOCK) ||
 316               scsi_block_when_processing_errors(sdp->device))) {
 317                 retval = -ENXIO;
 318                 /* we are in error recovery for this device */
 319                 goto error_out;
 320         }
 321 
 322         mutex_lock(&sdp->open_rel_lock);
 323         if (flags & O_NONBLOCK) {
 324                 if (flags & O_EXCL) {
 325                         if (sdp->open_cnt > 0) {
 326                                 retval = -EBUSY;
 327                                 goto error_mutex_locked;
 328                         }
 329                 } else {
 330                         if (sdp->exclude) {
 331                                 retval = -EBUSY;
 332                                 goto error_mutex_locked;
 333                         }
 334                 }
 335         } else {
 336                 retval = open_wait(sdp, flags);
 337                 if (retval) /* -ERESTARTSYS or -ENODEV */
 338                         goto error_mutex_locked;
 339         }
 340 
 341         /* N.B. at this point we are holding the open_rel_lock */
 342         if (flags & O_EXCL)
 343                 sdp->exclude = true;
 344 
 345         if (sdp->open_cnt < 1) {  /* no existing opens */
 346                 sdp->sgdebug = 0;
 347                 q = sdp->device->request_queue;
 348                 sdp->sg_tablesize = queue_max_segments(q);
 349         }
 350         sfp = sg_add_sfp(sdp);
 351         if (IS_ERR(sfp)) {
 352                 retval = PTR_ERR(sfp);
 353                 goto out_undo;
 354         }
 355 
 356         filp->private_data = sfp;
 357         sdp->open_cnt++;
 358         mutex_unlock(&sdp->open_rel_lock);
 359 
 360         retval = 0;
 361 sg_put:
 362         kref_put(&sdp->d_ref, sg_device_destroy);
 363         return retval;
 364 
 365 out_undo:
 366         if (flags & O_EXCL) {
 367                 sdp->exclude = false;   /* undo if error */
 368                 wake_up_interruptible(&sdp->open_wait);
 369         }
 370 error_mutex_locked:
 371         mutex_unlock(&sdp->open_rel_lock);
 372 error_out:
 373         scsi_autopm_put_device(sdp->device);
 374 sdp_put:
 375         scsi_device_put(sdp->device);
 376         goto sg_put;
 377 }
 378 
 379 /* Release resources associated with a successful sg_open()
 380  * Returns 0 on success, else a negated errno value */
 381 static int
 382 sg_release(struct inode *inode, struct file *filp)
 383 {
 384         Sg_device *sdp;
 385         Sg_fd *sfp;
 386 
 387         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 388                 return -ENXIO;
 389         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
 390 
 391         mutex_lock(&sdp->open_rel_lock);
 392         scsi_autopm_put_device(sdp->device);
 393         kref_put(&sfp->f_ref, sg_remove_sfp);
 394         sdp->open_cnt--;
 395 
 396         /* possibly many open()s waiting on exlude clearing, start many;
 397          * only open(O_EXCL)s wait on 0==open_cnt so only start one */
 398         if (sdp->exclude) {
 399                 sdp->exclude = false;
 400                 wake_up_interruptible_all(&sdp->open_wait);
 401         } else if (0 == sdp->open_cnt) {
 402                 wake_up_interruptible(&sdp->open_wait);
 403         }
 404         mutex_unlock(&sdp->open_rel_lock);
 405         return 0;
 406 }
 407 
 408 static ssize_t
 409 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
 410 {
 411         Sg_device *sdp;
 412         Sg_fd *sfp;
 413         Sg_request *srp;
 414         int req_pack_id = -1;
 415         sg_io_hdr_t *hp;
 416         struct sg_header *old_hdr = NULL;
 417         int retval = 0;
 418 
 419         /*
 420          * This could cause a response to be stranded. Close the associated
 421          * file descriptor to free up any resources being held.
 422          */
 423         retval = sg_check_file_access(filp, __func__);
 424         if (retval)
 425                 return retval;
 426 
 427         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 428                 return -ENXIO;
 429         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 430                                       "sg_read: count=%d\n", (int) count));
 431 
 432         if (!access_ok(buf, count))
 433                 return -EFAULT;
 434         if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
 435                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 436                 if (!old_hdr)
 437                         return -ENOMEM;
 438                 if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
 439                         retval = -EFAULT;
 440                         goto free_old_hdr;
 441                 }
 442                 if (old_hdr->reply_len < 0) {
 443                         if (count >= SZ_SG_IO_HDR) {
 444                                 sg_io_hdr_t *new_hdr;
 445                                 new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
 446                                 if (!new_hdr) {
 447                                         retval = -ENOMEM;
 448                                         goto free_old_hdr;
 449                                 }
 450                                 retval =__copy_from_user
 451                                     (new_hdr, buf, SZ_SG_IO_HDR);
 452                                 req_pack_id = new_hdr->pack_id;
 453                                 kfree(new_hdr);
 454                                 if (retval) {
 455                                         retval = -EFAULT;
 456                                         goto free_old_hdr;
 457                                 }
 458                         }
 459                 } else
 460                         req_pack_id = old_hdr->pack_id;
 461         }
 462         srp = sg_get_rq_mark(sfp, req_pack_id);
 463         if (!srp) {             /* now wait on packet to arrive */
 464                 if (atomic_read(&sdp->detaching)) {
 465                         retval = -ENODEV;
 466                         goto free_old_hdr;
 467                 }
 468                 if (filp->f_flags & O_NONBLOCK) {
 469                         retval = -EAGAIN;
 470                         goto free_old_hdr;
 471                 }
 472                 retval = wait_event_interruptible(sfp->read_wait,
 473                         (atomic_read(&sdp->detaching) ||
 474                         (srp = sg_get_rq_mark(sfp, req_pack_id))));
 475                 if (atomic_read(&sdp->detaching)) {
 476                         retval = -ENODEV;
 477                         goto free_old_hdr;
 478                 }
 479                 if (retval) {
 480                         /* -ERESTARTSYS as signal hit process */
 481                         goto free_old_hdr;
 482                 }
 483         }
 484         if (srp->header.interface_id != '\0') {
 485                 retval = sg_new_read(sfp, buf, count, srp);
 486                 goto free_old_hdr;
 487         }
 488 
 489         hp = &srp->header;
 490         if (old_hdr == NULL) {
 491                 old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
 492                 if (! old_hdr) {
 493                         retval = -ENOMEM;
 494                         goto free_old_hdr;
 495                 }
 496         }
 497         memset(old_hdr, 0, SZ_SG_HEADER);
 498         old_hdr->reply_len = (int) hp->timeout;
 499         old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
 500         old_hdr->pack_id = hp->pack_id;
 501         old_hdr->twelve_byte =
 502             ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
 503         old_hdr->target_status = hp->masked_status;
 504         old_hdr->host_status = hp->host_status;
 505         old_hdr->driver_status = hp->driver_status;
 506         if ((CHECK_CONDITION & hp->masked_status) ||
 507             (DRIVER_SENSE & hp->driver_status))
 508                 memcpy(old_hdr->sense_buffer, srp->sense_b,
 509                        sizeof (old_hdr->sense_buffer));
 510         switch (hp->host_status) {
 511         /* This setup of 'result' is for backward compatibility and is best
 512            ignored by the user who should use target, host + driver status */
 513         case DID_OK:
 514         case DID_PASSTHROUGH:
 515         case DID_SOFT_ERROR:
 516                 old_hdr->result = 0;
 517                 break;
 518         case DID_NO_CONNECT:
 519         case DID_BUS_BUSY:
 520         case DID_TIME_OUT:
 521                 old_hdr->result = EBUSY;
 522                 break;
 523         case DID_BAD_TARGET:
 524         case DID_ABORT:
 525         case DID_PARITY:
 526         case DID_RESET:
 527         case DID_BAD_INTR:
 528                 old_hdr->result = EIO;
 529                 break;
 530         case DID_ERROR:
 531                 old_hdr->result = (srp->sense_b[0] == 0 && 
 532                                   hp->masked_status == GOOD) ? 0 : EIO;
 533                 break;
 534         default:
 535                 old_hdr->result = EIO;
 536                 break;
 537         }
 538 
 539         /* Now copy the result back to the user buffer.  */
 540         if (count >= SZ_SG_HEADER) {
 541                 if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
 542                         retval = -EFAULT;
 543                         goto free_old_hdr;
 544                 }
 545                 buf += SZ_SG_HEADER;
 546                 if (count > old_hdr->reply_len)
 547                         count = old_hdr->reply_len;
 548                 if (count > SZ_SG_HEADER) {
 549                         if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
 550                                 retval = -EFAULT;
 551                                 goto free_old_hdr;
 552                         }
 553                 }
 554         } else
 555                 count = (old_hdr->result == 0) ? 0 : -EIO;
 556         sg_finish_rem_req(srp);
 557         sg_remove_request(sfp, srp);
 558         retval = count;
 559 free_old_hdr:
 560         kfree(old_hdr);
 561         return retval;
 562 }
 563 
 564 static ssize_t
 565 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
 566 {
 567         sg_io_hdr_t *hp = &srp->header;
 568         int err = 0, err2;
 569         int len;
 570 
 571         if (count < SZ_SG_IO_HDR) {
 572                 err = -EINVAL;
 573                 goto err_out;
 574         }
 575         hp->sb_len_wr = 0;
 576         if ((hp->mx_sb_len > 0) && hp->sbp) {
 577                 if ((CHECK_CONDITION & hp->masked_status) ||
 578                     (DRIVER_SENSE & hp->driver_status)) {
 579                         int sb_len = SCSI_SENSE_BUFFERSIZE;
 580                         sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
 581                         len = 8 + (int) srp->sense_b[7];        /* Additional sense length field */
 582                         len = (len > sb_len) ? sb_len : len;
 583                         if (copy_to_user(hp->sbp, srp->sense_b, len)) {
 584                                 err = -EFAULT;
 585                                 goto err_out;
 586                         }
 587                         hp->sb_len_wr = len;
 588                 }
 589         }
 590         if (hp->masked_status || hp->host_status || hp->driver_status)
 591                 hp->info |= SG_INFO_CHECK;
 592         if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
 593                 err = -EFAULT;
 594                 goto err_out;
 595         }
 596 err_out:
 597         err2 = sg_finish_rem_req(srp);
 598         sg_remove_request(sfp, srp);
 599         return err ? : err2 ? : count;
 600 }
 601 
 602 static ssize_t
 603 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 604 {
 605         int mxsize, cmd_size, k;
 606         int input_size, blocking;
 607         unsigned char opcode;
 608         Sg_device *sdp;
 609         Sg_fd *sfp;
 610         Sg_request *srp;
 611         struct sg_header old_hdr;
 612         sg_io_hdr_t *hp;
 613         unsigned char cmnd[SG_MAX_CDB_SIZE];
 614         int retval;
 615 
 616         retval = sg_check_file_access(filp, __func__);
 617         if (retval)
 618                 return retval;
 619 
 620         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 621                 return -ENXIO;
 622         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 623                                       "sg_write: count=%d\n", (int) count));
 624         if (atomic_read(&sdp->detaching))
 625                 return -ENODEV;
 626         if (!((filp->f_flags & O_NONBLOCK) ||
 627               scsi_block_when_processing_errors(sdp->device)))
 628                 return -ENXIO;
 629 
 630         if (!access_ok(buf, count))
 631                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 632         if (count < SZ_SG_HEADER)
 633                 return -EIO;
 634         if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
 635                 return -EFAULT;
 636         blocking = !(filp->f_flags & O_NONBLOCK);
 637         if (old_hdr.reply_len < 0)
 638                 return sg_new_write(sfp, filp, buf, count,
 639                                     blocking, 0, 0, NULL);
 640         if (count < (SZ_SG_HEADER + 6))
 641                 return -EIO;    /* The minimum scsi command length is 6 bytes. */
 642 
 643         if (!(srp = sg_add_request(sfp))) {
 644                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 645                                               "sg_write: queue full\n"));
 646                 return -EDOM;
 647         }
 648         buf += SZ_SG_HEADER;
 649         __get_user(opcode, buf);
 650         mutex_lock(&sfp->f_mutex);
 651         if (sfp->next_cmd_len > 0) {
 652                 cmd_size = sfp->next_cmd_len;
 653                 sfp->next_cmd_len = 0;  /* reset so only this write() effected */
 654         } else {
 655                 cmd_size = COMMAND_SIZE(opcode);        /* based on SCSI command group */
 656                 if ((opcode >= 0xc0) && old_hdr.twelve_byte)
 657                         cmd_size = 12;
 658         }
 659         mutex_unlock(&sfp->f_mutex);
 660         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
 661                 "sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
 662 /* Determine buffer size.  */
 663         input_size = count - cmd_size;
 664         mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
 665         mxsize -= SZ_SG_HEADER;
 666         input_size -= SZ_SG_HEADER;
 667         if (input_size < 0) {
 668                 sg_remove_request(sfp, srp);
 669                 return -EIO;    /* User did not pass enough bytes for this command. */
 670         }
 671         hp = &srp->header;
 672         hp->interface_id = '\0';        /* indicator of old interface tunnelled */
 673         hp->cmd_len = (unsigned char) cmd_size;
 674         hp->iovec_count = 0;
 675         hp->mx_sb_len = 0;
 676         if (input_size > 0)
 677                 hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
 678                     SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
 679         else
 680                 hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
 681         hp->dxfer_len = mxsize;
 682         if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
 683             (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
 684                 hp->dxferp = (char __user *)buf + cmd_size;
 685         else
 686                 hp->dxferp = NULL;
 687         hp->sbp = NULL;
 688         hp->timeout = old_hdr.reply_len;        /* structure abuse ... */
 689         hp->flags = input_size; /* structure abuse ... */
 690         hp->pack_id = old_hdr.pack_id;
 691         hp->usr_ptr = NULL;
 692         if (__copy_from_user(cmnd, buf, cmd_size)) {
 693                 sg_remove_request(sfp, srp);
 694                 return -EFAULT;
 695         }
 696         /*
 697          * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
 698          * but is is possible that the app intended SG_DXFER_TO_DEV, because there
 699          * is a non-zero input_size, so emit a warning.
 700          */
 701         if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
 702                 printk_ratelimited(KERN_WARNING
 703                                    "sg_write: data in/out %d/%d bytes "
 704                                    "for SCSI command 0x%x-- guessing "
 705                                    "data in;\n   program %s not setting "
 706                                    "count and/or reply_len properly\n",
 707                                    old_hdr.reply_len - (int)SZ_SG_HEADER,
 708                                    input_size, (unsigned int) cmnd[0],
 709                                    current->comm);
 710         }
 711         k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
 712         return (k < 0) ? k : count;
 713 }
 714 
 715 static ssize_t
 716 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 717                  size_t count, int blocking, int read_only, int sg_io_owned,
 718                  Sg_request **o_srp)
 719 {
 720         int k;
 721         Sg_request *srp;
 722         sg_io_hdr_t *hp;
 723         unsigned char cmnd[SG_MAX_CDB_SIZE];
 724         int timeout;
 725         unsigned long ul_timeout;
 726 
 727         if (count < SZ_SG_IO_HDR)
 728                 return -EINVAL;
 729         if (!access_ok(buf, count))
 730                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 731 
 732         sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
 733         if (!(srp = sg_add_request(sfp))) {
 734                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 735                                               "sg_new_write: queue full\n"));
 736                 return -EDOM;
 737         }
 738         srp->sg_io_owned = sg_io_owned;
 739         hp = &srp->header;
 740         if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
 741                 sg_remove_request(sfp, srp);
 742                 return -EFAULT;
 743         }
 744         if (hp->interface_id != 'S') {
 745                 sg_remove_request(sfp, srp);
 746                 return -ENOSYS;
 747         }
 748         if (hp->flags & SG_FLAG_MMAP_IO) {
 749                 if (hp->dxfer_len > sfp->reserve.bufflen) {
 750                         sg_remove_request(sfp, srp);
 751                         return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
 752                 }
 753                 if (hp->flags & SG_FLAG_DIRECT_IO) {
 754                         sg_remove_request(sfp, srp);
 755                         return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
 756                 }
 757                 if (sfp->res_in_use) {
 758                         sg_remove_request(sfp, srp);
 759                         return -EBUSY;  /* reserve buffer already being used */
 760                 }
 761         }
 762         ul_timeout = msecs_to_jiffies(srp->header.timeout);
 763         timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
 764         if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
 765                 sg_remove_request(sfp, srp);
 766                 return -EMSGSIZE;
 767         }
 768         if (!access_ok(hp->cmdp, hp->cmd_len)) {
 769                 sg_remove_request(sfp, srp);
 770                 return -EFAULT; /* protects following copy_from_user()s + get_user()s */
 771         }
 772         if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 773                 sg_remove_request(sfp, srp);
 774                 return -EFAULT;
 775         }
 776         if (read_only && sg_allow_access(file, cmnd)) {
 777                 sg_remove_request(sfp, srp);
 778                 return -EPERM;
 779         }
 780         k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
 781         if (k < 0)
 782                 return k;
 783         if (o_srp)
 784                 *o_srp = srp;
 785         return count;
 786 }
 787 
 788 static int
 789 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 790                 unsigned char *cmnd, int timeout, int blocking)
 791 {
 792         int k, at_head;
 793         Sg_device *sdp = sfp->parentdp;
 794         sg_io_hdr_t *hp = &srp->header;
 795 
 796         srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
 797         hp->status = 0;
 798         hp->masked_status = 0;
 799         hp->msg_status = 0;
 800         hp->info = 0;
 801         hp->host_status = 0;
 802         hp->driver_status = 0;
 803         hp->resid = 0;
 804         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
 805                         "sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
 806                         (int) cmnd[0], (int) hp->cmd_len));
 807 
 808         if (hp->dxfer_len >= SZ_256M) {
 809                 sg_remove_request(sfp, srp);
 810                 return -EINVAL;
 811         }
 812 
 813         k = sg_start_req(srp, cmnd);
 814         if (k) {
 815                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 816                         "sg_common_write: start_req err=%d\n", k));
 817                 sg_finish_rem_req(srp);
 818                 sg_remove_request(sfp, srp);
 819                 return k;       /* probably out of space --> ENOMEM */
 820         }
 821         if (atomic_read(&sdp->detaching)) {
 822                 if (srp->bio) {
 823                         scsi_req_free_cmd(scsi_req(srp->rq));
 824                         blk_put_request(srp->rq);
 825                         srp->rq = NULL;
 826                 }
 827 
 828                 sg_finish_rem_req(srp);
 829                 sg_remove_request(sfp, srp);
 830                 return -ENODEV;
 831         }
 832 
 833         hp->duration = jiffies_to_msecs(jiffies);
 834         if (hp->interface_id != '\0' && /* v3 (or later) interface */
 835             (SG_FLAG_Q_AT_TAIL & hp->flags))
 836                 at_head = 0;
 837         else
 838                 at_head = 1;
 839 
 840         srp->rq->timeout = timeout;
 841         kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
 842         blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
 843                               srp->rq, at_head, sg_rq_end_io);
 844         return 0;
 845 }
 846 
 847 static int srp_done(Sg_fd *sfp, Sg_request *srp)
 848 {
 849         unsigned long flags;
 850         int ret;
 851 
 852         read_lock_irqsave(&sfp->rq_list_lock, flags);
 853         ret = srp->done;
 854         read_unlock_irqrestore(&sfp->rq_list_lock, flags);
 855         return ret;
 856 }
 857 
 858 static int max_sectors_bytes(struct request_queue *q)
 859 {
 860         unsigned int max_sectors = queue_max_sectors(q);
 861 
 862         max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
 863 
 864         return max_sectors << 9;
 865 }
 866 
 867 static void
 868 sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
 869 {
 870         Sg_request *srp;
 871         int val;
 872         unsigned int ms;
 873 
 874         val = 0;
 875         list_for_each_entry(srp, &sfp->rq_list, entry) {
 876                 if (val >= SG_MAX_QUEUE)
 877                         break;
 878                 rinfo[val].req_state = srp->done + 1;
 879                 rinfo[val].problem =
 880                         srp->header.masked_status &
 881                         srp->header.host_status &
 882                         srp->header.driver_status;
 883                 if (srp->done)
 884                         rinfo[val].duration =
 885                                 srp->header.duration;
 886                 else {
 887                         ms = jiffies_to_msecs(jiffies);
 888                         rinfo[val].duration =
 889                                 (ms > srp->header.duration) ?
 890                                 (ms - srp->header.duration) : 0;
 891                 }
 892                 rinfo[val].orphan = srp->orphan;
 893                 rinfo[val].sg_io_owned = srp->sg_io_owned;
 894                 rinfo[val].pack_id = srp->header.pack_id;
 895                 rinfo[val].usr_ptr = srp->header.usr_ptr;
 896                 val++;
 897         }
 898 }
 899 
 900 static long
 901 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
 902 {
 903         void __user *p = (void __user *)arg;
 904         int __user *ip = p;
 905         int result, val, read_only;
 906         Sg_device *sdp;
 907         Sg_fd *sfp;
 908         Sg_request *srp;
 909         unsigned long iflags;
 910 
 911         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 912                 return -ENXIO;
 913 
 914         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 915                                    "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
 916         read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
 917 
 918         switch (cmd_in) {
 919         case SG_IO:
 920                 if (atomic_read(&sdp->detaching))
 921                         return -ENODEV;
 922                 if (!scsi_block_when_processing_errors(sdp->device))
 923                         return -ENXIO;
 924                 if (!access_ok(p, SZ_SG_IO_HDR))
 925                         return -EFAULT;
 926                 result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 927                                  1, read_only, 1, &srp);
 928                 if (result < 0)
 929                         return result;
 930                 result = wait_event_interruptible(sfp->read_wait,
 931                         (srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
 932                 if (atomic_read(&sdp->detaching))
 933                         return -ENODEV;
 934                 write_lock_irq(&sfp->rq_list_lock);
 935                 if (srp->done) {
 936                         srp->done = 2;
 937                         write_unlock_irq(&sfp->rq_list_lock);
 938                         result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
 939                         return (result < 0) ? result : 0;
 940                 }
 941                 srp->orphan = 1;
 942                 write_unlock_irq(&sfp->rq_list_lock);
 943                 return result;  /* -ERESTARTSYS because signal hit process */
 944         case SG_SET_TIMEOUT:
 945                 result = get_user(val, ip);
 946                 if (result)
 947                         return result;
 948                 if (val < 0)
 949                         return -EIO;
 950                 if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
 951                         val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
 952                                     INT_MAX);
 953                 sfp->timeout_user = val;
 954                 sfp->timeout = mult_frac(val, HZ, USER_HZ);
 955 
 956                 return 0;
 957         case SG_GET_TIMEOUT:    /* N.B. User receives timeout as return value */
 958                                 /* strange ..., for backward compatibility */
 959                 return sfp->timeout_user;
 960         case SG_SET_FORCE_LOW_DMA:
 961                 /*
 962                  * N.B. This ioctl never worked properly, but failed to
 963                  * return an error value. So returning '0' to keep compability
 964                  * with legacy applications.
 965                  */
 966                 return 0;
 967         case SG_GET_LOW_DMA:
 968                 return put_user((int) sdp->device->host->unchecked_isa_dma, ip);
 969         case SG_GET_SCSI_ID:
 970                 if (!access_ok(p, sizeof (sg_scsi_id_t)))
 971                         return -EFAULT;
 972                 else {
 973                         sg_scsi_id_t __user *sg_idp = p;
 974 
 975                         if (atomic_read(&sdp->detaching))
 976                                 return -ENODEV;
 977                         __put_user((int) sdp->device->host->host_no,
 978                                    &sg_idp->host_no);
 979                         __put_user((int) sdp->device->channel,
 980                                    &sg_idp->channel);
 981                         __put_user((int) sdp->device->id, &sg_idp->scsi_id);
 982                         __put_user((int) sdp->device->lun, &sg_idp->lun);
 983                         __put_user((int) sdp->device->type, &sg_idp->scsi_type);
 984                         __put_user((short) sdp->device->host->cmd_per_lun,
 985                                    &sg_idp->h_cmd_per_lun);
 986                         __put_user((short) sdp->device->queue_depth,
 987                                    &sg_idp->d_queue_depth);
 988                         __put_user(0, &sg_idp->unused[0]);
 989                         __put_user(0, &sg_idp->unused[1]);
 990                         return 0;
 991                 }
 992         case SG_SET_FORCE_PACK_ID:
 993                 result = get_user(val, ip);
 994                 if (result)
 995                         return result;
 996                 sfp->force_packid = val ? 1 : 0;
 997                 return 0;
 998         case SG_GET_PACK_ID:
 999                 if (!access_ok(ip, sizeof (int)))
1000                         return -EFAULT;
1001                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1002                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1003                         if ((1 == srp->done) && (!srp->sg_io_owned)) {
1004                                 read_unlock_irqrestore(&sfp->rq_list_lock,
1005                                                        iflags);
1006                                 __put_user(srp->header.pack_id, ip);
1007                                 return 0;
1008                         }
1009                 }
1010                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1011                 __put_user(-1, ip);
1012                 return 0;
1013         case SG_GET_NUM_WAITING:
1014                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1015                 val = 0;
1016                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1017                         if ((1 == srp->done) && (!srp->sg_io_owned))
1018                                 ++val;
1019                 }
1020                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1021                 return put_user(val, ip);
1022         case SG_GET_SG_TABLESIZE:
1023                 return put_user(sdp->sg_tablesize, ip);
1024         case SG_SET_RESERVED_SIZE:
1025                 result = get_user(val, ip);
1026                 if (result)
1027                         return result;
1028                 if (val < 0)
1029                         return -EINVAL;
1030                 val = min_t(int, val,
1031                             max_sectors_bytes(sdp->device->request_queue));
1032                 mutex_lock(&sfp->f_mutex);
1033                 if (val != sfp->reserve.bufflen) {
1034                         if (sfp->mmap_called ||
1035                             sfp->res_in_use) {
1036                                 mutex_unlock(&sfp->f_mutex);
1037                                 return -EBUSY;
1038                         }
1039 
1040                         sg_remove_scat(sfp, &sfp->reserve);
1041                         sg_build_reserve(sfp, val);
1042                 }
1043                 mutex_unlock(&sfp->f_mutex);
1044                 return 0;
1045         case SG_GET_RESERVED_SIZE:
1046                 val = min_t(int, sfp->reserve.bufflen,
1047                             max_sectors_bytes(sdp->device->request_queue));
1048                 return put_user(val, ip);
1049         case SG_SET_COMMAND_Q:
1050                 result = get_user(val, ip);
1051                 if (result)
1052                         return result;
1053                 sfp->cmd_q = val ? 1 : 0;
1054                 return 0;
1055         case SG_GET_COMMAND_Q:
1056                 return put_user((int) sfp->cmd_q, ip);
1057         case SG_SET_KEEP_ORPHAN:
1058                 result = get_user(val, ip);
1059                 if (result)
1060                         return result;
1061                 sfp->keep_orphan = val;
1062                 return 0;
1063         case SG_GET_KEEP_ORPHAN:
1064                 return put_user((int) sfp->keep_orphan, ip);
1065         case SG_NEXT_CMD_LEN:
1066                 result = get_user(val, ip);
1067                 if (result)
1068                         return result;
1069                 if (val > SG_MAX_CDB_SIZE)
1070                         return -ENOMEM;
1071                 sfp->next_cmd_len = (val > 0) ? val : 0;
1072                 return 0;
1073         case SG_GET_VERSION_NUM:
1074                 return put_user(sg_version_num, ip);
1075         case SG_GET_ACCESS_COUNT:
1076                 /* faked - we don't have a real access count anymore */
1077                 val = (sdp->device ? 1 : 0);
1078                 return put_user(val, ip);
1079         case SG_GET_REQUEST_TABLE:
1080                 if (!access_ok(p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
1081                         return -EFAULT;
1082                 else {
1083                         sg_req_info_t *rinfo;
1084 
1085                         rinfo = kcalloc(SG_MAX_QUEUE, SZ_SG_REQ_INFO,
1086                                         GFP_KERNEL);
1087                         if (!rinfo)
1088                                 return -ENOMEM;
1089                         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1090                         sg_fill_request_table(sfp, rinfo);
1091                         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1092                         result = __copy_to_user(p, rinfo,
1093                                                 SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1094                         result = result ? -EFAULT : 0;
1095                         kfree(rinfo);
1096                         return result;
1097                 }
1098         case SG_EMULATED_HOST:
1099                 if (atomic_read(&sdp->detaching))
1100                         return -ENODEV;
1101                 return put_user(sdp->device->host->hostt->emulated, ip);
1102         case SCSI_IOCTL_SEND_COMMAND:
1103                 if (atomic_read(&sdp->detaching))
1104                         return -ENODEV;
1105                 return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1106         case SG_SET_DEBUG:
1107                 result = get_user(val, ip);
1108                 if (result)
1109                         return result;
1110                 sdp->sgdebug = (char) val;
1111                 return 0;
1112         case BLKSECTGET:
1113                 return put_user(max_sectors_bytes(sdp->device->request_queue),
1114                                 ip);
1115         case BLKTRACESETUP:
1116                 return blk_trace_setup(sdp->device->request_queue,
1117                                        sdp->disk->disk_name,
1118                                        MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1119                                        NULL, p);
1120         case BLKTRACESTART:
1121                 return blk_trace_startstop(sdp->device->request_queue, 1);
1122         case BLKTRACESTOP:
1123                 return blk_trace_startstop(sdp->device->request_queue, 0);
1124         case BLKTRACETEARDOWN:
1125                 return blk_trace_remove(sdp->device->request_queue);
1126         case SCSI_IOCTL_GET_IDLUN:
1127         case SCSI_IOCTL_GET_BUS_NUMBER:
1128         case SCSI_IOCTL_PROBE_HOST:
1129         case SG_GET_TRANSFORM:
1130         case SG_SCSI_RESET:
1131                 if (atomic_read(&sdp->detaching))
1132                         return -ENODEV;
1133                 break;
1134         default:
1135                 if (read_only)
1136                         return -EPERM;  /* don't know so take safe approach */
1137                 break;
1138         }
1139 
1140         result = scsi_ioctl_block_when_processing_errors(sdp->device,
1141                         cmd_in, filp->f_flags & O_NDELAY);
1142         if (result)
1143                 return result;
1144         return scsi_ioctl(sdp->device, cmd_in, p);
1145 }
1146 
1147 #ifdef CONFIG_COMPAT
1148 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1149 {
1150         Sg_device *sdp;
1151         Sg_fd *sfp;
1152         struct scsi_device *sdev;
1153 
1154         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1155                 return -ENXIO;
1156 
1157         sdev = sdp->device;
1158         if (sdev->host->hostt->compat_ioctl) { 
1159                 int ret;
1160 
1161                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1162 
1163                 return ret;
1164         }
1165         
1166         return -ENOIOCTLCMD;
1167 }
1168 #endif
1169 
1170 static __poll_t
1171 sg_poll(struct file *filp, poll_table * wait)
1172 {
1173         __poll_t res = 0;
1174         Sg_device *sdp;
1175         Sg_fd *sfp;
1176         Sg_request *srp;
1177         int count = 0;
1178         unsigned long iflags;
1179 
1180         sfp = filp->private_data;
1181         if (!sfp)
1182                 return EPOLLERR;
1183         sdp = sfp->parentdp;
1184         if (!sdp)
1185                 return EPOLLERR;
1186         poll_wait(filp, &sfp->read_wait, wait);
1187         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1188         list_for_each_entry(srp, &sfp->rq_list, entry) {
1189                 /* if any read waiting, flag it */
1190                 if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1191                         res = EPOLLIN | EPOLLRDNORM;
1192                 ++count;
1193         }
1194         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1195 
1196         if (atomic_read(&sdp->detaching))
1197                 res |= EPOLLHUP;
1198         else if (!sfp->cmd_q) {
1199                 if (0 == count)
1200                         res |= EPOLLOUT | EPOLLWRNORM;
1201         } else if (count < SG_MAX_QUEUE)
1202                 res |= EPOLLOUT | EPOLLWRNORM;
1203         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1204                                       "sg_poll: res=0x%x\n", (__force u32) res));
1205         return res;
1206 }
1207 
1208 static int
1209 sg_fasync(int fd, struct file *filp, int mode)
1210 {
1211         Sg_device *sdp;
1212         Sg_fd *sfp;
1213 
1214         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1215                 return -ENXIO;
1216         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1217                                       "sg_fasync: mode=%d\n", mode));
1218 
1219         return fasync_helper(fd, filp, mode, &sfp->async_qp);
1220 }
1221 
1222 static vm_fault_t
1223 sg_vma_fault(struct vm_fault *vmf)
1224 {
1225         struct vm_area_struct *vma = vmf->vma;
1226         Sg_fd *sfp;
1227         unsigned long offset, len, sa;
1228         Sg_scatter_hold *rsv_schp;
1229         int k, length;
1230 
1231         if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1232                 return VM_FAULT_SIGBUS;
1233         rsv_schp = &sfp->reserve;
1234         offset = vmf->pgoff << PAGE_SHIFT;
1235         if (offset >= rsv_schp->bufflen)
1236                 return VM_FAULT_SIGBUS;
1237         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1238                                       "sg_vma_fault: offset=%lu, scatg=%d\n",
1239                                       offset, rsv_schp->k_use_sg));
1240         sa = vma->vm_start;
1241         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1242         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1243                 len = vma->vm_end - sa;
1244                 len = (len < length) ? len : length;
1245                 if (offset < len) {
1246                         struct page *page = nth_page(rsv_schp->pages[k],
1247                                                      offset >> PAGE_SHIFT);
1248                         get_page(page); /* increment page count */
1249                         vmf->page = page;
1250                         return 0; /* success */
1251                 }
1252                 sa += len;
1253                 offset -= len;
1254         }
1255 
1256         return VM_FAULT_SIGBUS;
1257 }
1258 
1259 static const struct vm_operations_struct sg_mmap_vm_ops = {
1260         .fault = sg_vma_fault,
1261 };
1262 
1263 static int
1264 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1265 {
1266         Sg_fd *sfp;
1267         unsigned long req_sz, len, sa;
1268         Sg_scatter_hold *rsv_schp;
1269         int k, length;
1270         int ret = 0;
1271 
1272         if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1273                 return -ENXIO;
1274         req_sz = vma->vm_end - vma->vm_start;
1275         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1276                                       "sg_mmap starting, vm_start=%p, len=%d\n",
1277                                       (void *) vma->vm_start, (int) req_sz));
1278         if (vma->vm_pgoff)
1279                 return -EINVAL; /* want no offset */
1280         rsv_schp = &sfp->reserve;
1281         mutex_lock(&sfp->f_mutex);
1282         if (req_sz > rsv_schp->bufflen) {
1283                 ret = -ENOMEM;  /* cannot map more than reserved buffer */
1284                 goto out;
1285         }
1286 
1287         sa = vma->vm_start;
1288         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1289         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1290                 len = vma->vm_end - sa;
1291                 len = (len < length) ? len : length;
1292                 sa += len;
1293         }
1294 
1295         sfp->mmap_called = 1;
1296         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1297         vma->vm_private_data = sfp;
1298         vma->vm_ops = &sg_mmap_vm_ops;
1299 out:
1300         mutex_unlock(&sfp->f_mutex);
1301         return ret;
1302 }
1303 
1304 static void
1305 sg_rq_end_io_usercontext(struct work_struct *work)
1306 {
1307         struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1308         struct sg_fd *sfp = srp->parentfp;
1309 
1310         sg_finish_rem_req(srp);
1311         sg_remove_request(sfp, srp);
1312         kref_put(&sfp->f_ref, sg_remove_sfp);
1313 }
1314 
1315 /*
1316  * This function is a "bottom half" handler that is called by the mid
1317  * level when a command is completed (or has failed).
1318  */
1319 static void
1320 sg_rq_end_io(struct request *rq, blk_status_t status)
1321 {
1322         struct sg_request *srp = rq->end_io_data;
1323         struct scsi_request *req = scsi_req(rq);
1324         Sg_device *sdp;
1325         Sg_fd *sfp;
1326         unsigned long iflags;
1327         unsigned int ms;
1328         char *sense;
1329         int result, resid, done = 1;
1330 
1331         if (WARN_ON(srp->done != 0))
1332                 return;
1333 
1334         sfp = srp->parentfp;
1335         if (WARN_ON(sfp == NULL))
1336                 return;
1337 
1338         sdp = sfp->parentdp;
1339         if (unlikely(atomic_read(&sdp->detaching)))
1340                 pr_info("%s: device detaching\n", __func__);
1341 
1342         sense = req->sense;
1343         result = req->result;
1344         resid = req->resid_len;
1345 
1346         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1347                                       "sg_cmd_done: pack_id=%d, res=0x%x\n",
1348                                       srp->header.pack_id, result));
1349         srp->header.resid = resid;
1350         ms = jiffies_to_msecs(jiffies);
1351         srp->header.duration = (ms > srp->header.duration) ?
1352                                 (ms - srp->header.duration) : 0;
1353         if (0 != result) {
1354                 struct scsi_sense_hdr sshdr;
1355 
1356                 srp->header.status = 0xff & result;
1357                 srp->header.masked_status = status_byte(result);
1358                 srp->header.msg_status = msg_byte(result);
1359                 srp->header.host_status = host_byte(result);
1360                 srp->header.driver_status = driver_byte(result);
1361                 if ((sdp->sgdebug > 0) &&
1362                     ((CHECK_CONDITION == srp->header.masked_status) ||
1363                      (COMMAND_TERMINATED == srp->header.masked_status)))
1364                         __scsi_print_sense(sdp->device, __func__, sense,
1365                                            SCSI_SENSE_BUFFERSIZE);
1366 
1367                 /* Following if statement is a patch supplied by Eric Youngdale */
1368                 if (driver_byte(result) != 0
1369                     && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1370                     && !scsi_sense_is_deferred(&sshdr)
1371                     && sshdr.sense_key == UNIT_ATTENTION
1372                     && sdp->device->removable) {
1373                         /* Detected possible disc change. Set the bit - this */
1374                         /* may be used if there are filesystems using this device */
1375                         sdp->device->changed = 1;
1376                 }
1377         }
1378 
1379         if (req->sense_len)
1380                 memcpy(srp->sense_b, req->sense, SCSI_SENSE_BUFFERSIZE);
1381 
1382         /* Rely on write phase to clean out srp status values, so no "else" */
1383 
1384         /*
1385          * Free the request as soon as it is complete so that its resources
1386          * can be reused without waiting for userspace to read() the
1387          * result.  But keep the associated bio (if any) around until
1388          * blk_rq_unmap_user() can be called from user context.
1389          */
1390         srp->rq = NULL;
1391         scsi_req_free_cmd(scsi_req(rq));
1392         blk_put_request(rq);
1393 
1394         write_lock_irqsave(&sfp->rq_list_lock, iflags);
1395         if (unlikely(srp->orphan)) {
1396                 if (sfp->keep_orphan)
1397                         srp->sg_io_owned = 0;
1398                 else
1399                         done = 0;
1400         }
1401         srp->done = done;
1402         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1403 
1404         if (likely(done)) {
1405                 /* Now wake up any sg_read() that is waiting for this
1406                  * packet.
1407                  */
1408                 wake_up_interruptible(&sfp->read_wait);
1409                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1410                 kref_put(&sfp->f_ref, sg_remove_sfp);
1411         } else {
1412                 INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1413                 schedule_work(&srp->ew.work);
1414         }
1415 }
1416 
1417 static const struct file_operations sg_fops = {
1418         .owner = THIS_MODULE,
1419         .read = sg_read,
1420         .write = sg_write,
1421         .poll = sg_poll,
1422         .unlocked_ioctl = sg_ioctl,
1423 #ifdef CONFIG_COMPAT
1424         .compat_ioctl = sg_compat_ioctl,
1425 #endif
1426         .open = sg_open,
1427         .mmap = sg_mmap,
1428         .release = sg_release,
1429         .fasync = sg_fasync,
1430         .llseek = no_llseek,
1431 };
1432 
1433 static struct class *sg_sysfs_class;
1434 
1435 static int sg_sysfs_valid = 0;
1436 
1437 static Sg_device *
1438 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1439 {
1440         struct request_queue *q = scsidp->request_queue;
1441         Sg_device *sdp;
1442         unsigned long iflags;
1443         int error;
1444         u32 k;
1445 
1446         sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1447         if (!sdp) {
1448                 sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1449                             "failure\n", __func__);
1450                 return ERR_PTR(-ENOMEM);
1451         }
1452 
1453         idr_preload(GFP_KERNEL);
1454         write_lock_irqsave(&sg_index_lock, iflags);
1455 
1456         error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1457         if (error < 0) {
1458                 if (error == -ENOSPC) {
1459                         sdev_printk(KERN_WARNING, scsidp,
1460                                     "Unable to attach sg device type=%d, minor number exceeds %d\n",
1461                                     scsidp->type, SG_MAX_DEVS - 1);
1462                         error = -ENODEV;
1463                 } else {
1464                         sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1465                                     "allocation Sg_device failure: %d\n",
1466                                     __func__, error);
1467                 }
1468                 goto out_unlock;
1469         }
1470         k = error;
1471 
1472         SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1473                                         "sg_alloc: dev=%d \n", k));
1474         sprintf(disk->disk_name, "sg%d", k);
1475         disk->first_minor = k;
1476         sdp->disk = disk;
1477         sdp->device = scsidp;
1478         mutex_init(&sdp->open_rel_lock);
1479         INIT_LIST_HEAD(&sdp->sfds);
1480         init_waitqueue_head(&sdp->open_wait);
1481         atomic_set(&sdp->detaching, 0);
1482         rwlock_init(&sdp->sfd_lock);
1483         sdp->sg_tablesize = queue_max_segments(q);
1484         sdp->index = k;
1485         kref_init(&sdp->d_ref);
1486         error = 0;
1487 
1488 out_unlock:
1489         write_unlock_irqrestore(&sg_index_lock, iflags);
1490         idr_preload_end();
1491 
1492         if (error) {
1493                 kfree(sdp);
1494                 return ERR_PTR(error);
1495         }
1496         return sdp;
1497 }
1498 
1499 static int
1500 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1501 {
1502         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1503         struct gendisk *disk;
1504         Sg_device *sdp = NULL;
1505         struct cdev * cdev = NULL;
1506         int error;
1507         unsigned long iflags;
1508 
1509         disk = alloc_disk(1);
1510         if (!disk) {
1511                 pr_warn("%s: alloc_disk failed\n", __func__);
1512                 return -ENOMEM;
1513         }
1514         disk->major = SCSI_GENERIC_MAJOR;
1515 
1516         error = -ENOMEM;
1517         cdev = cdev_alloc();
1518         if (!cdev) {
1519                 pr_warn("%s: cdev_alloc failed\n", __func__);
1520                 goto out;
1521         }
1522         cdev->owner = THIS_MODULE;
1523         cdev->ops = &sg_fops;
1524 
1525         sdp = sg_alloc(disk, scsidp);
1526         if (IS_ERR(sdp)) {
1527                 pr_warn("%s: sg_alloc failed\n", __func__);
1528                 error = PTR_ERR(sdp);
1529                 goto out;
1530         }
1531 
1532         error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1533         if (error)
1534                 goto cdev_add_err;
1535 
1536         sdp->cdev = cdev;
1537         if (sg_sysfs_valid) {
1538                 struct device *sg_class_member;
1539 
1540                 sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1541                                                 MKDEV(SCSI_GENERIC_MAJOR,
1542                                                       sdp->index),
1543                                                 sdp, "%s", disk->disk_name);
1544                 if (IS_ERR(sg_class_member)) {
1545                         pr_err("%s: device_create failed\n", __func__);
1546                         error = PTR_ERR(sg_class_member);
1547                         goto cdev_add_err;
1548                 }
1549                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1550                                           &sg_class_member->kobj, "generic");
1551                 if (error)
1552                         pr_err("%s: unable to make symlink 'generic' back "
1553                                "to sg%d\n", __func__, sdp->index);
1554         } else
1555                 pr_warn("%s: sg_sys Invalid\n", __func__);
1556 
1557         sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1558                     "type %d\n", sdp->index, scsidp->type);
1559 
1560         dev_set_drvdata(cl_dev, sdp);
1561 
1562         return 0;
1563 
1564 cdev_add_err:
1565         write_lock_irqsave(&sg_index_lock, iflags);
1566         idr_remove(&sg_index_idr, sdp->index);
1567         write_unlock_irqrestore(&sg_index_lock, iflags);
1568         kfree(sdp);
1569 
1570 out:
1571         put_disk(disk);
1572         if (cdev)
1573                 cdev_del(cdev);
1574         return error;
1575 }
1576 
1577 static void
1578 sg_device_destroy(struct kref *kref)
1579 {
1580         struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1581         unsigned long flags;
1582 
1583         /* CAUTION!  Note that the device can still be found via idr_find()
1584          * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1585          * any other cleanup.
1586          */
1587 
1588         write_lock_irqsave(&sg_index_lock, flags);
1589         idr_remove(&sg_index_idr, sdp->index);
1590         write_unlock_irqrestore(&sg_index_lock, flags);
1591 
1592         SCSI_LOG_TIMEOUT(3,
1593                 sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1594 
1595         put_disk(sdp->disk);
1596         kfree(sdp);
1597 }
1598 
1599 static void
1600 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1601 {
1602         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1603         Sg_device *sdp = dev_get_drvdata(cl_dev);
1604         unsigned long iflags;
1605         Sg_fd *sfp;
1606         int val;
1607 
1608         if (!sdp)
1609                 return;
1610         /* want sdp->detaching non-zero as soon as possible */
1611         val = atomic_inc_return(&sdp->detaching);
1612         if (val > 1)
1613                 return; /* only want to do following once per device */
1614 
1615         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1616                                       "%s\n", __func__));
1617 
1618         read_lock_irqsave(&sdp->sfd_lock, iflags);
1619         list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1620                 wake_up_interruptible_all(&sfp->read_wait);
1621                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1622         }
1623         wake_up_interruptible_all(&sdp->open_wait);
1624         read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1625 
1626         sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1627         device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1628         cdev_del(sdp->cdev);
1629         sdp->cdev = NULL;
1630 
1631         kref_put(&sdp->d_ref, sg_device_destroy);
1632 }
1633 
1634 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1635 module_param_named(def_reserved_size, def_reserved_size, int,
1636                    S_IRUGO | S_IWUSR);
1637 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1638 
1639 MODULE_AUTHOR("Douglas Gilbert");
1640 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1641 MODULE_LICENSE("GPL");
1642 MODULE_VERSION(SG_VERSION_STR);
1643 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1644 
1645 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1646                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1647 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1648 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1649 
1650 static int __init
1651 init_sg(void)
1652 {
1653         int rc;
1654 
1655         if (scatter_elem_sz < PAGE_SIZE) {
1656                 scatter_elem_sz = PAGE_SIZE;
1657                 scatter_elem_sz_prev = scatter_elem_sz;
1658         }
1659         if (def_reserved_size >= 0)
1660                 sg_big_buff = def_reserved_size;
1661         else
1662                 def_reserved_size = sg_big_buff;
1663 
1664         rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), 
1665                                     SG_MAX_DEVS, "sg");
1666         if (rc)
1667                 return rc;
1668         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1669         if ( IS_ERR(sg_sysfs_class) ) {
1670                 rc = PTR_ERR(sg_sysfs_class);
1671                 goto err_out;
1672         }
1673         sg_sysfs_valid = 1;
1674         rc = scsi_register_interface(&sg_interface);
1675         if (0 == rc) {
1676 #ifdef CONFIG_SCSI_PROC_FS
1677                 sg_proc_init();
1678 #endif                          /* CONFIG_SCSI_PROC_FS */
1679                 return 0;
1680         }
1681         class_destroy(sg_sysfs_class);
1682 err_out:
1683         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1684         return rc;
1685 }
1686 
1687 static void __exit
1688 exit_sg(void)
1689 {
1690 #ifdef CONFIG_SCSI_PROC_FS
1691         remove_proc_subtree("scsi/sg", NULL);
1692 #endif                          /* CONFIG_SCSI_PROC_FS */
1693         scsi_unregister_interface(&sg_interface);
1694         class_destroy(sg_sysfs_class);
1695         sg_sysfs_valid = 0;
1696         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1697                                  SG_MAX_DEVS);
1698         idr_destroy(&sg_index_idr);
1699 }
1700 
1701 static int
1702 sg_start_req(Sg_request *srp, unsigned char *cmd)
1703 {
1704         int res;
1705         struct request *rq;
1706         struct scsi_request *req;
1707         Sg_fd *sfp = srp->parentfp;
1708         sg_io_hdr_t *hp = &srp->header;
1709         int dxfer_len = (int) hp->dxfer_len;
1710         int dxfer_dir = hp->dxfer_direction;
1711         unsigned int iov_count = hp->iovec_count;
1712         Sg_scatter_hold *req_schp = &srp->data;
1713         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1714         struct request_queue *q = sfp->parentdp->device->request_queue;
1715         struct rq_map_data *md, map_data;
1716         int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1717         unsigned char *long_cmdp = NULL;
1718 
1719         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1720                                       "sg_start_req: dxfer_len=%d\n",
1721                                       dxfer_len));
1722 
1723         if (hp->cmd_len > BLK_MAX_CDB) {
1724                 long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1725                 if (!long_cmdp)
1726                         return -ENOMEM;
1727         }
1728 
1729         /*
1730          * NOTE
1731          *
1732          * With scsi-mq enabled, there are a fixed number of preallocated
1733          * requests equal in number to shost->can_queue.  If all of the
1734          * preallocated requests are already in use, then blk_get_request()
1735          * will sleep until an active command completes, freeing up a request.
1736          * Although waiting in an asynchronous interface is less than ideal, we
1737          * do not want to use BLK_MQ_REQ_NOWAIT here because userspace might
1738          * not expect an EWOULDBLOCK from this condition.
1739          */
1740         rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1741                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
1742         if (IS_ERR(rq)) {
1743                 kfree(long_cmdp);
1744                 return PTR_ERR(rq);
1745         }
1746         req = scsi_req(rq);
1747 
1748         if (hp->cmd_len > BLK_MAX_CDB)
1749                 req->cmd = long_cmdp;
1750         memcpy(req->cmd, cmd, hp->cmd_len);
1751         req->cmd_len = hp->cmd_len;
1752 
1753         srp->rq = rq;
1754         rq->end_io_data = srp;
1755         req->retries = SG_DEFAULT_RETRIES;
1756 
1757         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1758                 return 0;
1759 
1760         if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1761             dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1762             !sfp->parentdp->device->host->unchecked_isa_dma &&
1763             blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1764                 md = NULL;
1765         else
1766                 md = &map_data;
1767 
1768         if (md) {
1769                 mutex_lock(&sfp->f_mutex);
1770                 if (dxfer_len <= rsv_schp->bufflen &&
1771                     !sfp->res_in_use) {
1772                         sfp->res_in_use = 1;
1773                         sg_link_reserve(sfp, srp, dxfer_len);
1774                 } else if (hp->flags & SG_FLAG_MMAP_IO) {
1775                         res = -EBUSY; /* sfp->res_in_use == 1 */
1776                         if (dxfer_len > rsv_schp->bufflen)
1777                                 res = -ENOMEM;
1778                         mutex_unlock(&sfp->f_mutex);
1779                         return res;
1780                 } else {
1781                         res = sg_build_indirect(req_schp, sfp, dxfer_len);
1782                         if (res) {
1783                                 mutex_unlock(&sfp->f_mutex);
1784                                 return res;
1785                         }
1786                 }
1787                 mutex_unlock(&sfp->f_mutex);
1788 
1789                 md->pages = req_schp->pages;
1790                 md->page_order = req_schp->page_order;
1791                 md->nr_entries = req_schp->k_use_sg;
1792                 md->offset = 0;
1793                 md->null_mapped = hp->dxferp ? 0 : 1;
1794                 if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1795                         md->from_user = 1;
1796                 else
1797                         md->from_user = 0;
1798         }
1799 
1800         if (iov_count) {
1801                 struct iovec *iov = NULL;
1802                 struct iov_iter i;
1803 
1804                 res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
1805                 if (res < 0)
1806                         return res;
1807 
1808                 iov_iter_truncate(&i, hp->dxfer_len);
1809                 if (!iov_iter_count(&i)) {
1810                         kfree(iov);
1811                         return -EINVAL;
1812                 }
1813 
1814                 res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1815                 kfree(iov);
1816         } else
1817                 res = blk_rq_map_user(q, rq, md, hp->dxferp,
1818                                       hp->dxfer_len, GFP_ATOMIC);
1819 
1820         if (!res) {
1821                 srp->bio = rq->bio;
1822 
1823                 if (!md) {
1824                         req_schp->dio_in_use = 1;
1825                         hp->info |= SG_INFO_DIRECT_IO;
1826                 }
1827         }
1828         return res;
1829 }
1830 
1831 static int
1832 sg_finish_rem_req(Sg_request *srp)
1833 {
1834         int ret = 0;
1835 
1836         Sg_fd *sfp = srp->parentfp;
1837         Sg_scatter_hold *req_schp = &srp->data;
1838 
1839         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1840                                       "sg_finish_rem_req: res_used=%d\n",
1841                                       (int) srp->res_used));
1842         if (srp->bio)
1843                 ret = blk_rq_unmap_user(srp->bio);
1844 
1845         if (srp->rq) {
1846                 scsi_req_free_cmd(scsi_req(srp->rq));
1847                 blk_put_request(srp->rq);
1848         }
1849 
1850         if (srp->res_used)
1851                 sg_unlink_reserve(sfp, srp);
1852         else
1853                 sg_remove_scat(sfp, req_schp);
1854 
1855         return ret;
1856 }
1857 
1858 static int
1859 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1860 {
1861         int sg_bufflen = tablesize * sizeof(struct page *);
1862         gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1863 
1864         schp->pages = kzalloc(sg_bufflen, gfp_flags);
1865         if (!schp->pages)
1866                 return -ENOMEM;
1867         schp->sglist_len = sg_bufflen;
1868         return tablesize;       /* number of scat_gath elements allocated */
1869 }
1870 
1871 static int
1872 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1873 {
1874         int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1875         int sg_tablesize = sfp->parentdp->sg_tablesize;
1876         int blk_size = buff_size, order;
1877         gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN | __GFP_ZERO;
1878         struct sg_device *sdp = sfp->parentdp;
1879 
1880         if (blk_size < 0)
1881                 return -EFAULT;
1882         if (0 == blk_size)
1883                 ++blk_size;     /* don't know why */
1884         /* round request up to next highest SG_SECTOR_SZ byte boundary */
1885         blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1886         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1887                 "sg_build_indirect: buff_size=%d, blk_size=%d\n",
1888                 buff_size, blk_size));
1889 
1890         /* N.B. ret_sz carried into this block ... */
1891         mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1892         if (mx_sc_elems < 0)
1893                 return mx_sc_elems;     /* most likely -ENOMEM */
1894 
1895         num = scatter_elem_sz;
1896         if (unlikely(num != scatter_elem_sz_prev)) {
1897                 if (num < PAGE_SIZE) {
1898                         scatter_elem_sz = PAGE_SIZE;
1899                         scatter_elem_sz_prev = PAGE_SIZE;
1900                 } else
1901                         scatter_elem_sz_prev = num;
1902         }
1903 
1904         if (sdp->device->host->unchecked_isa_dma)
1905                 gfp_mask |= GFP_DMA;
1906 
1907         order = get_order(num);
1908 retry:
1909         ret_sz = 1 << (PAGE_SHIFT + order);
1910 
1911         for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1912              k++, rem_sz -= ret_sz) {
1913 
1914                 num = (rem_sz > scatter_elem_sz_prev) ?
1915                         scatter_elem_sz_prev : rem_sz;
1916 
1917                 schp->pages[k] = alloc_pages(gfp_mask, order);
1918                 if (!schp->pages[k])
1919                         goto out;
1920 
1921                 if (num == scatter_elem_sz_prev) {
1922                         if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1923                                 scatter_elem_sz = ret_sz;
1924                                 scatter_elem_sz_prev = ret_sz;
1925                         }
1926                 }
1927 
1928                 SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1929                                  "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1930                                  k, num, ret_sz));
1931         }               /* end of for loop */
1932 
1933         schp->page_order = order;
1934         schp->k_use_sg = k;
1935         SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1936                          "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1937                          k, rem_sz));
1938 
1939         schp->bufflen = blk_size;
1940         if (rem_sz > 0) /* must have failed */
1941                 return -ENOMEM;
1942         return 0;
1943 out:
1944         for (i = 0; i < k; i++)
1945                 __free_pages(schp->pages[i], order);
1946 
1947         if (--order >= 0)
1948                 goto retry;
1949 
1950         return -ENOMEM;
1951 }
1952 
1953 static void
1954 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1955 {
1956         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1957                          "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1958         if (schp->pages && schp->sglist_len > 0) {
1959                 if (!schp->dio_in_use) {
1960                         int k;
1961 
1962                         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1963                                 SCSI_LOG_TIMEOUT(5,
1964                                         sg_printk(KERN_INFO, sfp->parentdp,
1965                                         "sg_remove_scat: k=%d, pg=0x%p\n",
1966                                         k, schp->pages[k]));
1967                                 __free_pages(schp->pages[k], schp->page_order);
1968                         }
1969 
1970                         kfree(schp->pages);
1971                 }
1972         }
1973         memset(schp, 0, sizeof (*schp));
1974 }
1975 
1976 static int
1977 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1978 {
1979         Sg_scatter_hold *schp = &srp->data;
1980         int k, num;
1981 
1982         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1983                          "sg_read_oxfer: num_read_xfer=%d\n",
1984                          num_read_xfer));
1985         if ((!outp) || (num_read_xfer <= 0))
1986                 return 0;
1987 
1988         num = 1 << (PAGE_SHIFT + schp->page_order);
1989         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1990                 if (num > num_read_xfer) {
1991                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1992                                            num_read_xfer))
1993                                 return -EFAULT;
1994                         break;
1995                 } else {
1996                         if (__copy_to_user(outp, page_address(schp->pages[k]),
1997                                            num))
1998                                 return -EFAULT;
1999                         num_read_xfer -= num;
2000                         if (num_read_xfer <= 0)
2001                                 break;
2002                         outp += num;
2003                 }
2004         }
2005 
2006         return 0;
2007 }
2008 
2009 static void
2010 sg_build_reserve(Sg_fd * sfp, int req_size)
2011 {
2012         Sg_scatter_hold *schp = &sfp->reserve;
2013 
2014         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2015                          "sg_build_reserve: req_size=%d\n", req_size));
2016         do {
2017                 if (req_size < PAGE_SIZE)
2018                         req_size = PAGE_SIZE;
2019                 if (0 == sg_build_indirect(schp, sfp, req_size))
2020                         return;
2021                 else
2022                         sg_remove_scat(sfp, schp);
2023                 req_size >>= 1; /* divide by 2 */
2024         } while (req_size > (PAGE_SIZE / 2));
2025 }
2026 
2027 static void
2028 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2029 {
2030         Sg_scatter_hold *req_schp = &srp->data;
2031         Sg_scatter_hold *rsv_schp = &sfp->reserve;
2032         int k, num, rem;
2033 
2034         srp->res_used = 1;
2035         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2036                          "sg_link_reserve: size=%d\n", size));
2037         rem = size;
2038 
2039         num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2040         for (k = 0; k < rsv_schp->k_use_sg; k++) {
2041                 if (rem <= num) {
2042                         req_schp->k_use_sg = k + 1;
2043                         req_schp->sglist_len = rsv_schp->sglist_len;
2044                         req_schp->pages = rsv_schp->pages;
2045 
2046                         req_schp->bufflen = size;
2047                         req_schp->page_order = rsv_schp->page_order;
2048                         break;
2049                 } else
2050                         rem -= num;
2051         }
2052 
2053         if (k >= rsv_schp->k_use_sg)
2054                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2055                                  "sg_link_reserve: BAD size\n"));
2056 }
2057 
2058 static void
2059 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2060 {
2061         Sg_scatter_hold *req_schp = &srp->data;
2062 
2063         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2064                                       "sg_unlink_reserve: req->k_use_sg=%d\n",
2065                                       (int) req_schp->k_use_sg));
2066         req_schp->k_use_sg = 0;
2067         req_schp->bufflen = 0;
2068         req_schp->pages = NULL;
2069         req_schp->page_order = 0;
2070         req_schp->sglist_len = 0;
2071         srp->res_used = 0;
2072         /* Called without mutex lock to avoid deadlock */
2073         sfp->res_in_use = 0;
2074 }
2075 
2076 static Sg_request *
2077 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2078 {
2079         Sg_request *resp;
2080         unsigned long iflags;
2081 
2082         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2083         list_for_each_entry(resp, &sfp->rq_list, entry) {
2084                 /* look for requests that are ready + not SG_IO owned */
2085                 if ((1 == resp->done) && (!resp->sg_io_owned) &&
2086                     ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2087                         resp->done = 2; /* guard against other readers */
2088                         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2089                         return resp;
2090                 }
2091         }
2092         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2093         return NULL;
2094 }
2095 
2096 /* always adds to end of list */
2097 static Sg_request *
2098 sg_add_request(Sg_fd * sfp)
2099 {
2100         int k;
2101         unsigned long iflags;
2102         Sg_request *rp = sfp->req_arr;
2103 
2104         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2105         if (!list_empty(&sfp->rq_list)) {
2106                 if (!sfp->cmd_q)
2107                         goto out_unlock;
2108 
2109                 for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2110                         if (!rp->parentfp)
2111                                 break;
2112                 }
2113                 if (k >= SG_MAX_QUEUE)
2114                         goto out_unlock;
2115         }
2116         memset(rp, 0, sizeof (Sg_request));
2117         rp->parentfp = sfp;
2118         rp->header.duration = jiffies_to_msecs(jiffies);
2119         list_add_tail(&rp->entry, &sfp->rq_list);
2120         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2121         return rp;
2122 out_unlock:
2123         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2124         return NULL;
2125 }
2126 
2127 /* Return of 1 for found; 0 for not found */
2128 static int
2129 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2130 {
2131         unsigned long iflags;
2132         int res = 0;
2133 
2134         if (!sfp || !srp || list_empty(&sfp->rq_list))
2135                 return res;
2136         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2137         if (!list_empty(&srp->entry)) {
2138                 list_del(&srp->entry);
2139                 srp->parentfp = NULL;
2140                 res = 1;
2141         }
2142         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2143         return res;
2144 }
2145 
2146 static Sg_fd *
2147 sg_add_sfp(Sg_device * sdp)
2148 {
2149         Sg_fd *sfp;
2150         unsigned long iflags;
2151         int bufflen;
2152 
2153         sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2154         if (!sfp)
2155                 return ERR_PTR(-ENOMEM);
2156 
2157         init_waitqueue_head(&sfp->read_wait);
2158         rwlock_init(&sfp->rq_list_lock);
2159         INIT_LIST_HEAD(&sfp->rq_list);
2160         kref_init(&sfp->f_ref);
2161         mutex_init(&sfp->f_mutex);
2162         sfp->timeout = SG_DEFAULT_TIMEOUT;
2163         sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2164         sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2165         sfp->cmd_q = SG_DEF_COMMAND_Q;
2166         sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2167         sfp->parentdp = sdp;
2168         write_lock_irqsave(&sdp->sfd_lock, iflags);
2169         if (atomic_read(&sdp->detaching)) {
2170                 write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2171                 kfree(sfp);
2172                 return ERR_PTR(-ENODEV);
2173         }
2174         list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2175         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2176         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2177                                       "sg_add_sfp: sfp=0x%p\n", sfp));
2178         if (unlikely(sg_big_buff != def_reserved_size))
2179                 sg_big_buff = def_reserved_size;
2180 
2181         bufflen = min_t(int, sg_big_buff,
2182                         max_sectors_bytes(sdp->device->request_queue));
2183         sg_build_reserve(sfp, bufflen);
2184         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2185                                       "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2186                                       sfp->reserve.bufflen,
2187                                       sfp->reserve.k_use_sg));
2188 
2189         kref_get(&sdp->d_ref);
2190         __module_get(THIS_MODULE);
2191         return sfp;
2192 }
2193 
2194 static void
2195 sg_remove_sfp_usercontext(struct work_struct *work)
2196 {
2197         struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2198         struct sg_device *sdp = sfp->parentdp;
2199         Sg_request *srp;
2200         unsigned long iflags;
2201 
2202         /* Cleanup any responses which were never read(). */
2203         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2204         while (!list_empty(&sfp->rq_list)) {
2205                 srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
2206                 sg_finish_rem_req(srp);
2207                 list_del(&srp->entry);
2208                 srp->parentfp = NULL;
2209         }
2210         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2211 
2212         if (sfp->reserve.bufflen > 0) {
2213                 SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2214                                 "sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2215                                 (int) sfp->reserve.bufflen,
2216                                 (int) sfp->reserve.k_use_sg));
2217                 sg_remove_scat(sfp, &sfp->reserve);
2218         }
2219 
2220         SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2221                         "sg_remove_sfp: sfp=0x%p\n", sfp));
2222         kfree(sfp);
2223 
2224         scsi_device_put(sdp->device);
2225         kref_put(&sdp->d_ref, sg_device_destroy);
2226         module_put(THIS_MODULE);
2227 }
2228 
2229 static void
2230 sg_remove_sfp(struct kref *kref)
2231 {
2232         struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2233         struct sg_device *sdp = sfp->parentdp;
2234         unsigned long iflags;
2235 
2236         write_lock_irqsave(&sdp->sfd_lock, iflags);
2237         list_del(&sfp->sfd_siblings);
2238         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2239 
2240         INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2241         schedule_work(&sfp->ew.work);
2242 }
2243 
2244 #ifdef CONFIG_SCSI_PROC_FS
2245 static int
2246 sg_idr_max_id(int id, void *p, void *data)
2247 {
2248         int *k = data;
2249 
2250         if (*k < id)
2251                 *k = id;
2252 
2253         return 0;
2254 }
2255 
2256 static int
2257 sg_last_dev(void)
2258 {
2259         int k = -1;
2260         unsigned long iflags;
2261 
2262         read_lock_irqsave(&sg_index_lock, iflags);
2263         idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2264         read_unlock_irqrestore(&sg_index_lock, iflags);
2265         return k + 1;           /* origin 1 */
2266 }
2267 #endif
2268 
2269 /* must be called with sg_index_lock held */
2270 static Sg_device *sg_lookup_dev(int dev)
2271 {
2272         return idr_find(&sg_index_idr, dev);
2273 }
2274 
2275 static Sg_device *
2276 sg_get_dev(int dev)
2277 {
2278         struct sg_device *sdp;
2279         unsigned long flags;
2280 
2281         read_lock_irqsave(&sg_index_lock, flags);
2282         sdp = sg_lookup_dev(dev);
2283         if (!sdp)
2284                 sdp = ERR_PTR(-ENXIO);
2285         else if (atomic_read(&sdp->detaching)) {
2286                 /* If sdp->detaching, then the refcount may already be 0, in
2287                  * which case it would be a bug to do kref_get().
2288                  */
2289                 sdp = ERR_PTR(-ENODEV);
2290         } else
2291                 kref_get(&sdp->d_ref);
2292         read_unlock_irqrestore(&sg_index_lock, flags);
2293 
2294         return sdp;
2295 }
2296 
2297 #ifdef CONFIG_SCSI_PROC_FS
2298 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2299 
2300 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2301 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2302                                   size_t count, loff_t *off);
2303 static const struct file_operations adio_fops = {
2304         .owner = THIS_MODULE,
2305         .open = sg_proc_single_open_adio,
2306         .read = seq_read,
2307         .llseek = seq_lseek,
2308         .write = sg_proc_write_adio,
2309         .release = single_release,
2310 };
2311 
2312 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2313 static ssize_t sg_proc_write_dressz(struct file *filp, 
2314                 const char __user *buffer, size_t count, loff_t *off);
2315 static const struct file_operations dressz_fops = {
2316         .owner = THIS_MODULE,
2317         .open = sg_proc_single_open_dressz,
2318         .read = seq_read,
2319         .llseek = seq_lseek,
2320         .write = sg_proc_write_dressz,
2321         .release = single_release,
2322 };
2323 
2324 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2325 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2326 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2327 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2328 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2329 static void dev_seq_stop(struct seq_file *s, void *v);
2330 static const struct seq_operations dev_seq_ops = {
2331         .start = dev_seq_start,
2332         .next  = dev_seq_next,
2333         .stop  = dev_seq_stop,
2334         .show  = sg_proc_seq_show_dev,
2335 };
2336 
2337 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2338 static const struct seq_operations devstrs_seq_ops = {
2339         .start = dev_seq_start,
2340         .next  = dev_seq_next,
2341         .stop  = dev_seq_stop,
2342         .show  = sg_proc_seq_show_devstrs,
2343 };
2344 
2345 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2346 static const struct seq_operations debug_seq_ops = {
2347         .start = dev_seq_start,
2348         .next  = dev_seq_next,
2349         .stop  = dev_seq_stop,
2350         .show  = sg_proc_seq_show_debug,
2351 };
2352 
2353 static int
2354 sg_proc_init(void)
2355 {
2356         struct proc_dir_entry *p;
2357 
2358         p = proc_mkdir("scsi/sg", NULL);
2359         if (!p)
2360                 return 1;
2361 
2362         proc_create("allow_dio", S_IRUGO | S_IWUSR, p, &adio_fops);
2363         proc_create_seq("debug", S_IRUGO, p, &debug_seq_ops);
2364         proc_create("def_reserved_size", S_IRUGO | S_IWUSR, p, &dressz_fops);
2365         proc_create_single("device_hdr", S_IRUGO, p, sg_proc_seq_show_devhdr);
2366         proc_create_seq("devices", S_IRUGO, p, &dev_seq_ops);
2367         proc_create_seq("device_strs", S_IRUGO, p, &devstrs_seq_ops);
2368         proc_create_single("version", S_IRUGO, p, sg_proc_seq_show_version);
2369         return 0;
2370 }
2371 
2372 
2373 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2374 {
2375         seq_printf(s, "%d\n", *((int *)s->private));
2376         return 0;
2377 }
2378 
2379 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2380 {
2381         return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2382 }
2383 
2384 static ssize_t 
2385 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2386                    size_t count, loff_t *off)
2387 {
2388         int err;
2389         unsigned long num;
2390 
2391         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2392                 return -EACCES;
2393         err = kstrtoul_from_user(buffer, count, 0, &num);
2394         if (err)
2395                 return err;
2396         sg_allow_dio = num ? 1 : 0;
2397         return count;
2398 }
2399 
2400 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2401 {
2402         return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2403 }
2404 
2405 static ssize_t 
2406 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2407                      size_t count, loff_t *off)
2408 {
2409         int err;
2410         unsigned long k = ULONG_MAX;
2411 
2412         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2413                 return -EACCES;
2414 
2415         err = kstrtoul_from_user(buffer, count, 0, &k);
2416         if (err)
2417                 return err;
2418         if (k <= 1048576) {     /* limit "big buff" to 1 MB */
2419                 sg_big_buff = k;
2420                 return count;
2421         }
2422         return -ERANGE;
2423 }
2424 
2425 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2426 {
2427         seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2428                    sg_version_date);
2429         return 0;
2430 }
2431 
2432 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2433 {
2434         seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2435         return 0;
2436 }
2437 
2438 struct sg_proc_deviter {
2439         loff_t  index;
2440         size_t  max;
2441 };
2442 
2443 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2444 {
2445         struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2446 
2447         s->private = it;
2448         if (! it)
2449                 return NULL;
2450 
2451         it->index = *pos;
2452         it->max = sg_last_dev();
2453         if (it->index >= it->max)
2454                 return NULL;
2455         return it;
2456 }
2457 
2458 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2459 {
2460         struct sg_proc_deviter * it = s->private;
2461 
2462         *pos = ++it->index;
2463         return (it->index < it->max) ? it : NULL;
2464 }
2465 
2466 static void dev_seq_stop(struct seq_file *s, void *v)
2467 {
2468         kfree(s->private);
2469 }
2470 
2471 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2472 {
2473         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2474         Sg_device *sdp;
2475         struct scsi_device *scsidp;
2476         unsigned long iflags;
2477 
2478         read_lock_irqsave(&sg_index_lock, iflags);
2479         sdp = it ? sg_lookup_dev(it->index) : NULL;
2480         if ((NULL == sdp) || (NULL == sdp->device) ||
2481             (atomic_read(&sdp->detaching)))
2482                 seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2483         else {
2484                 scsidp = sdp->device;
2485                 seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2486                               scsidp->host->host_no, scsidp->channel,
2487                               scsidp->id, scsidp->lun, (int) scsidp->type,
2488                               1,
2489                               (int) scsidp->queue_depth,
2490                               (int) atomic_read(&scsidp->device_busy),
2491                               (int) scsi_device_online(scsidp));
2492         }
2493         read_unlock_irqrestore(&sg_index_lock, iflags);
2494         return 0;
2495 }
2496 
2497 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2498 {
2499         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2500         Sg_device *sdp;
2501         struct scsi_device *scsidp;
2502         unsigned long iflags;
2503 
2504         read_lock_irqsave(&sg_index_lock, iflags);
2505         sdp = it ? sg_lookup_dev(it->index) : NULL;
2506         scsidp = sdp ? sdp->device : NULL;
2507         if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2508                 seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2509                            scsidp->vendor, scsidp->model, scsidp->rev);
2510         else
2511                 seq_puts(s, "<no active device>\n");
2512         read_unlock_irqrestore(&sg_index_lock, iflags);
2513         return 0;
2514 }
2515 
2516 /* must be called while holding sg_index_lock */
2517 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2518 {
2519         int k, new_interface, blen, usg;
2520         Sg_request *srp;
2521         Sg_fd *fp;
2522         const sg_io_hdr_t *hp;
2523         const char * cp;
2524         unsigned int ms;
2525 
2526         k = 0;
2527         list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2528                 k++;
2529                 read_lock(&fp->rq_list_lock); /* irqs already disabled */
2530                 seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2531                            "(res)sgat=%d low_dma=%d\n", k,
2532                            jiffies_to_msecs(fp->timeout),
2533                            fp->reserve.bufflen,
2534                            (int) fp->reserve.k_use_sg,
2535                            (int) sdp->device->host->unchecked_isa_dma);
2536                 seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2537                            (int) fp->cmd_q, (int) fp->force_packid,
2538                            (int) fp->keep_orphan);
2539                 list_for_each_entry(srp, &fp->rq_list, entry) {
2540                         hp = &srp->header;
2541                         new_interface = (hp->interface_id == '\0') ? 0 : 1;
2542                         if (srp->res_used) {
2543                                 if (new_interface &&
2544                                     (SG_FLAG_MMAP_IO & hp->flags))
2545                                         cp = "     mmap>> ";
2546                                 else
2547                                         cp = "     rb>> ";
2548                         } else {
2549                                 if (SG_INFO_DIRECT_IO_MASK & hp->info)
2550                                         cp = "     dio>> ";
2551                                 else
2552                                         cp = "     ";
2553                         }
2554                         seq_puts(s, cp);
2555                         blen = srp->data.bufflen;
2556                         usg = srp->data.k_use_sg;
2557                         seq_puts(s, srp->done ?
2558                                  ((1 == srp->done) ?  "rcv:" : "fin:")
2559                                   : "act:");
2560                         seq_printf(s, " id=%d blen=%d",
2561                                    srp->header.pack_id, blen);
2562                         if (srp->done)
2563                                 seq_printf(s, " dur=%d", hp->duration);
2564                         else {
2565                                 ms = jiffies_to_msecs(jiffies);
2566                                 seq_printf(s, " t_o/elap=%d/%d",
2567                                         (new_interface ? hp->timeout :
2568                                                   jiffies_to_msecs(fp->timeout)),
2569                                         (ms > hp->duration ? ms - hp->duration : 0));
2570                         }
2571                         seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2572                                    (int) srp->data.cmd_opcode);
2573                 }
2574                 if (list_empty(&fp->rq_list))
2575                         seq_puts(s, "     No requests active\n");
2576                 read_unlock(&fp->rq_list_lock);
2577         }
2578 }
2579 
2580 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2581 {
2582         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2583         Sg_device *sdp;
2584         unsigned long iflags;
2585 
2586         if (it && (0 == it->index))
2587                 seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2588                            (int)it->max, sg_big_buff);
2589 
2590         read_lock_irqsave(&sg_index_lock, iflags);
2591         sdp = it ? sg_lookup_dev(it->index) : NULL;
2592         if (NULL == sdp)
2593                 goto skip;
2594         read_lock(&sdp->sfd_lock);
2595         if (!list_empty(&sdp->sfds)) {
2596                 seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2597                 if (atomic_read(&sdp->detaching))
2598                         seq_puts(s, "detaching pending close ");
2599                 else if (sdp->device) {
2600                         struct scsi_device *scsidp = sdp->device;
2601 
2602                         seq_printf(s, "%d:%d:%d:%llu   em=%d",
2603                                    scsidp->host->host_no,
2604                                    scsidp->channel, scsidp->id,
2605                                    scsidp->lun,
2606                                    scsidp->host->hostt->emulated);
2607                 }
2608                 seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2609                            sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2610                 sg_proc_debug_helper(s, sdp);
2611         }
2612         read_unlock(&sdp->sfd_lock);
2613 skip:
2614         read_unlock_irqrestore(&sg_index_lock, iflags);
2615         return 0;
2616 }
2617 
2618 #endif                          /* CONFIG_SCSI_PROC_FS */
2619 
2620 module_init(init_sg);
2621 module_exit(exit_sg);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/scsi/sg.c

DEFINITIONS
