root/drivers/usb/usbip/stub_dev.c

DEFINITIONS

1. usbip_status_show
2. usbip_sockfd_store
3. stub_shutdown_connection
4. stub_device_reset
5. stub_device_unusable
6. stub_device_alloc
7. stub_device_free
8. stub_probe
9. shutdown_busid
10. stub_disconnect
11. stub_suspend
12. stub_resume

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   4  */
   5 
   6 #include <linux/device.h>
   7 #include <linux/file.h>
   8 #include <linux/kthread.h>
   9 #include <linux/module.h>
  10 
  11 #include "usbip_common.h"
  12 #include "stub.h"
  13 
  14 /*
  15  * usbip_status shows the status of usbip-host as long as this driver is bound
  16  * to the target device.
  17  */
  18 static ssize_t usbip_status_show(struct device *dev,
  19                                  struct device_attribute *attr, char *buf)
  20 {
  21         struct stub_device *sdev = dev_get_drvdata(dev);
  22         int status;
  23 
  24         if (!sdev) {
  25                 dev_err(dev, "sdev is null\n");
  26                 return -ENODEV;
  27         }
  28 
  29         spin_lock_irq(&sdev->ud.lock);
  30         status = sdev->ud.status;
  31         spin_unlock_irq(&sdev->ud.lock);
  32 
  33         return snprintf(buf, PAGE_SIZE, "%d\n", status);
  34 }
  35 static DEVICE_ATTR_RO(usbip_status);
  36 
  37 /*
  38  * usbip_sockfd gets a socket descriptor of an established TCP connection that
  39  * is used to transfer usbip requests by kernel threads. -1 is a magic number
  40  * by which usbip connection is finished.
  41  */
  42 static ssize_t usbip_sockfd_store(struct device *dev, struct device_attribute *attr,
  43                             const char *buf, size_t count)
  44 {
  45         struct stub_device *sdev = dev_get_drvdata(dev);
  46         int sockfd = 0;
  47         struct socket *socket;
  48         int rv;
  49 
  50         if (!sdev) {
  51                 dev_err(dev, "sdev is null\n");
  52                 return -ENODEV;
  53         }
  54 
  55         rv = sscanf(buf, "%d", &sockfd);
  56         if (rv != 1)
  57                 return -EINVAL;
  58 
  59         if (sockfd != -1) {
  60                 int err;
  61 
  62                 dev_info(dev, "stub up\n");
  63 
  64                 spin_lock_irq(&sdev->ud.lock);
  65 
  66                 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
  67                         dev_err(dev, "not ready\n");
  68                         goto err;
  69                 }
  70 
  71                 socket = sockfd_lookup(sockfd, &err);
  72                 if (!socket)
  73                         goto err;
  74 
  75                 sdev->ud.tcp_socket = socket;
  76                 sdev->ud.sockfd = sockfd;
  77 
  78                 spin_unlock_irq(&sdev->ud.lock);
  79 
  80                 sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud,
  81                                                   "stub_rx");
  82                 sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud,
  83                                                   "stub_tx");
  84 
  85                 spin_lock_irq(&sdev->ud.lock);
  86                 sdev->ud.status = SDEV_ST_USED;
  87                 spin_unlock_irq(&sdev->ud.lock);
  88 
  89         } else {
  90                 dev_info(dev, "stub down\n");
  91 
  92                 spin_lock_irq(&sdev->ud.lock);
  93                 if (sdev->ud.status != SDEV_ST_USED)
  94                         goto err;
  95 
  96                 spin_unlock_irq(&sdev->ud.lock);
  97 
  98                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
  99         }
 100 
 101         return count;
 102 
 103 err:
 104         spin_unlock_irq(&sdev->ud.lock);
 105         return -EINVAL;
 106 }
 107 static DEVICE_ATTR_WO(usbip_sockfd);
 108 
 109 static struct attribute *usbip_attrs[] = {
 110         &dev_attr_usbip_status.attr,
 111         &dev_attr_usbip_sockfd.attr,
 112         &dev_attr_usbip_debug.attr,
 113         NULL,
 114 };
 115 ATTRIBUTE_GROUPS(usbip);
 116 
 117 static void stub_shutdown_connection(struct usbip_device *ud)
 118 {
 119         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 120 
 121         /*
 122          * When removing an exported device, kernel panic sometimes occurred
 123          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 124          * sk_wait_data returned though stub_rx thread was already finished by
 125          * step 1?
 126          */
 127         if (ud->tcp_socket) {
 128                 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
 129                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 130         }
 131 
 132         /* 1. stop threads */
 133         if (ud->tcp_rx) {
 134                 kthread_stop_put(ud->tcp_rx);
 135                 ud->tcp_rx = NULL;
 136         }
 137         if (ud->tcp_tx) {
 138                 kthread_stop_put(ud->tcp_tx);
 139                 ud->tcp_tx = NULL;
 140         }
 141 
 142         /*
 143          * 2. close the socket
 144          *
 145          * tcp_socket is freed after threads are killed so that usbip_xmit does
 146          * not touch NULL socket.
 147          */
 148         if (ud->tcp_socket) {
 149                 sockfd_put(ud->tcp_socket);
 150                 ud->tcp_socket = NULL;
 151                 ud->sockfd = -1;
 152         }
 153 
 154         /* 3. free used data */
 155         stub_device_cleanup_urbs(sdev);
 156 
 157         /* 4. free stub_unlink */
 158         {
 159                 unsigned long flags;
 160                 struct stub_unlink *unlink, *tmp;
 161 
 162                 spin_lock_irqsave(&sdev->priv_lock, flags);
 163                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 164                         list_del(&unlink->list);
 165                         kfree(unlink);
 166                 }
 167                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 168                                          list) {
 169                         list_del(&unlink->list);
 170                         kfree(unlink);
 171                 }
 172                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 173         }
 174 }
 175 
 176 static void stub_device_reset(struct usbip_device *ud)
 177 {
 178         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 179         struct usb_device *udev = sdev->udev;
 180         int ret;
 181 
 182         dev_dbg(&udev->dev, "device reset");
 183 
 184         ret = usb_lock_device_for_reset(udev, NULL);
 185         if (ret < 0) {
 186                 dev_err(&udev->dev, "lock for reset\n");
 187                 spin_lock_irq(&ud->lock);
 188                 ud->status = SDEV_ST_ERROR;
 189                 spin_unlock_irq(&ud->lock);
 190                 return;
 191         }
 192 
 193         /* try to reset the device */
 194         ret = usb_reset_device(udev);
 195         usb_unlock_device(udev);
 196 
 197         spin_lock_irq(&ud->lock);
 198         if (ret) {
 199                 dev_err(&udev->dev, "device reset\n");
 200                 ud->status = SDEV_ST_ERROR;
 201         } else {
 202                 dev_info(&udev->dev, "device reset\n");
 203                 ud->status = SDEV_ST_AVAILABLE;
 204         }
 205         spin_unlock_irq(&ud->lock);
 206 }
 207 
 208 static void stub_device_unusable(struct usbip_device *ud)
 209 {
 210         spin_lock_irq(&ud->lock);
 211         ud->status = SDEV_ST_ERROR;
 212         spin_unlock_irq(&ud->lock);
 213 }
 214 
 215 /**
 216  * stub_device_alloc - allocate a new stub_device struct
 217  * @udev: usb_device of a new device
 218  *
 219  * Allocates and initializes a new stub_device struct.
 220  */
 221 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 222 {
 223         struct stub_device *sdev;
 224         int busnum = udev->bus->busnum;
 225         int devnum = udev->devnum;
 226 
 227         dev_dbg(&udev->dev, "allocating stub device");
 228 
 229         /* yes, it's a new device */
 230         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 231         if (!sdev)
 232                 return NULL;
 233 
 234         sdev->udev = usb_get_dev(udev);
 235 
 236         /*
 237          * devid is defined with devnum when this driver is first allocated.
 238          * devnum may change later if a device is reset. However, devid never
 239          * changes during a usbip connection.
 240          */
 241         sdev->devid             = (busnum << 16) | devnum;
 242         sdev->ud.side           = USBIP_STUB;
 243         sdev->ud.status         = SDEV_ST_AVAILABLE;
 244         spin_lock_init(&sdev->ud.lock);
 245         sdev->ud.tcp_socket     = NULL;
 246         sdev->ud.sockfd         = -1;
 247 
 248         INIT_LIST_HEAD(&sdev->priv_init);
 249         INIT_LIST_HEAD(&sdev->priv_tx);
 250         INIT_LIST_HEAD(&sdev->priv_free);
 251         INIT_LIST_HEAD(&sdev->unlink_free);
 252         INIT_LIST_HEAD(&sdev->unlink_tx);
 253         spin_lock_init(&sdev->priv_lock);
 254 
 255         init_waitqueue_head(&sdev->tx_waitq);
 256 
 257         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 258         sdev->ud.eh_ops.reset    = stub_device_reset;
 259         sdev->ud.eh_ops.unusable = stub_device_unusable;
 260 
 261         usbip_start_eh(&sdev->ud);
 262 
 263         dev_dbg(&udev->dev, "register new device\n");
 264 
 265         return sdev;
 266 }
 267 
 268 static void stub_device_free(struct stub_device *sdev)
 269 {
 270         kfree(sdev);
 271 }
 272 
 273 static int stub_probe(struct usb_device *udev)
 274 {
 275         struct stub_device *sdev = NULL;
 276         const char *udev_busid = dev_name(&udev->dev);
 277         struct bus_id_priv *busid_priv;
 278         int rc = 0;
 279         char save_status;
 280 
 281         dev_dbg(&udev->dev, "Enter probe\n");
 282 
 283         /* Not sure if this is our device. Allocate here to avoid
 284          * calling alloc while holding busid_table lock.
 285          */
 286         sdev = stub_device_alloc(udev);
 287         if (!sdev)
 288                 return -ENOMEM;
 289 
 290         /* check we should claim or not by busid_table */
 291         busid_priv = get_busid_priv(udev_busid);
 292         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 293             (busid_priv->status == STUB_BUSID_OTHER)) {
 294                 dev_info(&udev->dev,
 295                         "%s is not in match_busid table... skip!\n",
 296                         udev_busid);
 297 
 298                 /*
 299                  * Return value should be ENODEV or ENOXIO to continue trying
 300                  * other matched drivers by the driver core.
 301                  * See driver_probe_device() in driver/base/dd.c
 302                  */
 303                 rc = -ENODEV;
 304                 if (!busid_priv)
 305                         goto sdev_free;
 306 
 307                 goto call_put_busid_priv;
 308         }
 309 
 310         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 311                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 312                          udev_busid);
 313                 rc = -ENODEV;
 314                 goto call_put_busid_priv;
 315         }
 316 
 317         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 318                 dev_dbg(&udev->dev,
 319                         "%s is attached on vhci_hcd... skip!\n",
 320                         udev_busid);
 321 
 322                 rc = -ENODEV;
 323                 goto call_put_busid_priv;
 324         }
 325 
 326 
 327         dev_info(&udev->dev,
 328                 "usbip-host: register new device (bus %u dev %u)\n",
 329                 udev->bus->busnum, udev->devnum);
 330 
 331         busid_priv->shutdown_busid = 0;
 332 
 333         /* set private data to usb_device */
 334         dev_set_drvdata(&udev->dev, sdev);
 335 
 336         busid_priv->sdev = sdev;
 337         busid_priv->udev = udev;
 338 
 339         save_status = busid_priv->status;
 340         busid_priv->status = STUB_BUSID_ALLOC;
 341 
 342         /* release the busid_lock */
 343         put_busid_priv(busid_priv);
 344 
 345         /*
 346          * Claim this hub port.
 347          * It doesn't matter what value we pass as owner
 348          * (struct dev_state) as long as it is unique.
 349          */
 350         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 351                         (struct usb_dev_state *) udev);
 352         if (rc) {
 353                 dev_dbg(&udev->dev, "unable to claim port\n");
 354                 goto err_port;
 355         }
 356 
 357         return 0;
 358 
 359 err_port:
 360         dev_set_drvdata(&udev->dev, NULL);
 361         usb_put_dev(udev);
 362 
 363         /* we already have busid_priv, just lock busid_lock */
 364         spin_lock(&busid_priv->busid_lock);
 365         busid_priv->sdev = NULL;
 366         busid_priv->status = save_status;
 367         spin_unlock(&busid_priv->busid_lock);
 368         /* lock is released - go to free */
 369         goto sdev_free;
 370 
 371 call_put_busid_priv:
 372         /* release the busid_lock */
 373         put_busid_priv(busid_priv);
 374 
 375 sdev_free:
 376         stub_device_free(sdev);
 377 
 378         return rc;
 379 }
 380 
 381 static void shutdown_busid(struct bus_id_priv *busid_priv)
 382 {
 383         usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 384 
 385         /* wait for the stop of the event handler */
 386         usbip_stop_eh(&busid_priv->sdev->ud);
 387 }
 388 
 389 /*
 390  * called in usb_disconnect() or usb_deregister()
 391  * but only if actconfig(active configuration) exists
 392  */
 393 static void stub_disconnect(struct usb_device *udev)
 394 {
 395         struct stub_device *sdev;
 396         const char *udev_busid = dev_name(&udev->dev);
 397         struct bus_id_priv *busid_priv;
 398         int rc;
 399 
 400         dev_dbg(&udev->dev, "Enter disconnect\n");
 401 
 402         busid_priv = get_busid_priv(udev_busid);
 403         if (!busid_priv) {
 404                 BUG();
 405                 return;
 406         }
 407 
 408         sdev = dev_get_drvdata(&udev->dev);
 409 
 410         /* get stub_device */
 411         if (!sdev) {
 412                 dev_err(&udev->dev, "could not get device");
 413                 /* release busid_lock */
 414                 put_busid_priv(busid_priv);
 415                 return;
 416         }
 417 
 418         dev_set_drvdata(&udev->dev, NULL);
 419 
 420         /* release busid_lock before call to remove device files */
 421         put_busid_priv(busid_priv);
 422 
 423         /*
 424          * NOTE: rx/tx threads are invoked for each usb_device.
 425          */
 426 
 427         /* release port */
 428         rc = usb_hub_release_port(udev->parent, udev->portnum,
 429                                   (struct usb_dev_state *) udev);
 430         if (rc) {
 431                 dev_dbg(&udev->dev, "unable to release port\n");
 432                 return;
 433         }
 434 
 435         /* If usb reset is called from event handler */
 436         if (usbip_in_eh(current))
 437                 return;
 438 
 439         /* we already have busid_priv, just lock busid_lock */
 440         spin_lock(&busid_priv->busid_lock);
 441         if (!busid_priv->shutdown_busid)
 442                 busid_priv->shutdown_busid = 1;
 443         /* release busid_lock */
 444         spin_unlock(&busid_priv->busid_lock);
 445 
 446         /* shutdown the current connection */
 447         shutdown_busid(busid_priv);
 448 
 449         usb_put_dev(sdev->udev);
 450 
 451         /* we already have busid_priv, just lock busid_lock */
 452         spin_lock(&busid_priv->busid_lock);
 453         /* free sdev */
 454         busid_priv->sdev = NULL;
 455         stub_device_free(sdev);
 456 
 457         if (busid_priv->status == STUB_BUSID_ALLOC)
 458                 busid_priv->status = STUB_BUSID_ADDED;
 459         /* release busid_lock */
 460         spin_unlock(&busid_priv->busid_lock);
 461         return;
 462 }
 463 
 464 #ifdef CONFIG_PM
 465 
 466 /* These functions need usb_port_suspend and usb_port_resume,
 467  * which reside in drivers/usb/core/usb.h. Skip for now. */
 468 
 469 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 470 {
 471         dev_dbg(&udev->dev, "stub_suspend\n");
 472 
 473         return 0;
 474 }
 475 
 476 static int stub_resume(struct usb_device *udev, pm_message_t message)
 477 {
 478         dev_dbg(&udev->dev, "stub_resume\n");
 479 
 480         return 0;
 481 }
 482 
 483 #endif  /* CONFIG_PM */
 484 
 485 struct usb_device_driver stub_driver = {
 486         .name           = "usbip-host",
 487         .probe          = stub_probe,
 488         .disconnect     = stub_disconnect,
 489 #ifdef CONFIG_PM
 490         .suspend        = stub_suspend,
 491         .resume         = stub_resume,
 492 #endif
 493         .supports_autosuspend   =       0,
 494         .dev_groups     = usbip_groups,
 495 };