drivers/usb/usbip/stub_dev.c

   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 int stub_add_files(struct device *dev)
 110 {
 111         int err = 0;
 112
 113         err = device_create_file(dev, &dev_attr_usbip_status);
 114         if (err)
 115                 goto err_status;
 116
 117         err = device_create_file(dev, &dev_attr_usbip_sockfd);
 118         if (err)
 119                 goto err_sockfd;
 120
 121         err = device_create_file(dev, &dev_attr_usbip_debug);
 122         if (err)
 123                 goto err_debug;
 124
 125         return 0;
 126
 127 err_debug:
 128         device_remove_file(dev, &dev_attr_usbip_sockfd);
 129 err_sockfd:
 130         device_remove_file(dev, &dev_attr_usbip_status);
 131 err_status:
 132         return err;
 133 }
 134
 135 static void stub_remove_files(struct device *dev)
 136 {
 137         device_remove_file(dev, &dev_attr_usbip_status);
 138         device_remove_file(dev, &dev_attr_usbip_sockfd);
 139         device_remove_file(dev, &dev_attr_usbip_debug);
 140 }
 141
 142 static void stub_shutdown_connection(struct usbip_device *ud)
 143 {
 144         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 145
 146         /*
 147          * When removing an exported device, kernel panic sometimes occurred
 148          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 149          * sk_wait_data returned though stub_rx thread was already finished by
 150          * step 1?
 151          */
 152         if (ud->tcp_socket) {
 153                 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
 154                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 155         }
 156
 157         /* 1. stop threads */
 158         if (ud->tcp_rx) {
 159                 kthread_stop_put(ud->tcp_rx);
 160                 ud->tcp_rx = NULL;
 161         }
 162         if (ud->tcp_tx) {
 163                 kthread_stop_put(ud->tcp_tx);
 164                 ud->tcp_tx = NULL;
 165         }
 166
 167         /*
 168          * 2. close the socket
 169          *
 170          * tcp_socket is freed after threads are killed so that usbip_xmit does
 171          * not touch NULL socket.
 172          */
 173         if (ud->tcp_socket) {
 174                 sockfd_put(ud->tcp_socket);
 175                 ud->tcp_socket = NULL;
 176                 ud->sockfd = -1;
 177         }
 178
 179         /* 3. free used data */
 180         stub_device_cleanup_urbs(sdev);
 181
 182         /* 4. free stub_unlink */
 183         {
 184                 unsigned long flags;
 185                 struct stub_unlink *unlink, *tmp;
 186
 187                 spin_lock_irqsave(&sdev->priv_lock, flags);
 188                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 189                         list_del(&unlink->list);
 190                         kfree(unlink);
 191                 }
 192                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 193                                          list) {
 194                         list_del(&unlink->list);
 195                         kfree(unlink);
 196                 }
 197                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 198         }
 199 }
 200
 201 static void stub_device_reset(struct usbip_device *ud)
 202 {
 203         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 204         struct usb_device *udev = sdev->udev;
 205         int ret;
 206
 207         dev_dbg(&udev->dev, "device reset");
 208
 209         ret = usb_lock_device_for_reset(udev, NULL);
 210         if (ret < 0) {
 211                 dev_err(&udev->dev, "lock for reset\n");
 212                 spin_lock_irq(&ud->lock);
 213                 ud->status = SDEV_ST_ERROR;
 214                 spin_unlock_irq(&ud->lock);
 215                 return;
 216         }
 217
 218         /* try to reset the device */
 219         ret = usb_reset_device(udev);
 220         usb_unlock_device(udev);
 221
 222         spin_lock_irq(&ud->lock);
 223         if (ret) {
 224                 dev_err(&udev->dev, "device reset\n");
 225                 ud->status = SDEV_ST_ERROR;
 226         } else {
 227                 dev_info(&udev->dev, "device reset\n");
 228                 ud->status = SDEV_ST_AVAILABLE;
 229         }
 230         spin_unlock_irq(&ud->lock);
 231 }
 232
 233 static void stub_device_unusable(struct usbip_device *ud)
 234 {
 235         spin_lock_irq(&ud->lock);
 236         ud->status = SDEV_ST_ERROR;
 237         spin_unlock_irq(&ud->lock);
 238 }
 239
 240 /**
 241  * stub_device_alloc - allocate a new stub_device struct
 242  * @udev: usb_device of a new device
 243  *
 244  * Allocates and initializes a new stub_device struct.
 245  */
 246 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 247 {
 248         struct stub_device *sdev;
 249         int busnum = udev->bus->busnum;
 250         int devnum = udev->devnum;
 251
 252         dev_dbg(&udev->dev, "allocating stub device");
 253
 254         /* yes, it's a new device */
 255         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 256         if (!sdev)
 257                 return NULL;
 258
 259         sdev->udev = usb_get_dev(udev);
 260
 261         /*
 262          * devid is defined with devnum when this driver is first allocated.
 263          * devnum may change later if a device is reset. However, devid never
 264          * changes during a usbip connection.
 265          */
 266         sdev->devid             = (busnum << 16) | devnum;
 267         sdev->ud.side           = USBIP_STUB;
 268         sdev->ud.status         = SDEV_ST_AVAILABLE;
 269         spin_lock_init(&sdev->ud.lock);
 270         sdev->ud.tcp_socket     = NULL;
 271         sdev->ud.sockfd         = -1;
 272
 273         INIT_LIST_HEAD(&sdev->priv_init);
 274         INIT_LIST_HEAD(&sdev->priv_tx);
 275         INIT_LIST_HEAD(&sdev->priv_free);
 276         INIT_LIST_HEAD(&sdev->unlink_free);
 277         INIT_LIST_HEAD(&sdev->unlink_tx);
 278         spin_lock_init(&sdev->priv_lock);
 279
 280         init_waitqueue_head(&sdev->tx_waitq);
 281
 282         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 283         sdev->ud.eh_ops.reset    = stub_device_reset;
 284         sdev->ud.eh_ops.unusable = stub_device_unusable;
 285
 286         usbip_start_eh(&sdev->ud);
 287
 288         dev_dbg(&udev->dev, "register new device\n");
 289
 290         return sdev;
 291 }
 292
 293 static void stub_device_free(struct stub_device *sdev)
 294 {
 295         kfree(sdev);
 296 }
 297
 298 static int stub_probe(struct usb_device *udev)
 299 {
 300         struct stub_device *sdev = NULL;
 301         const char *udev_busid = dev_name(&udev->dev);
 302         struct bus_id_priv *busid_priv;
 303         int rc = 0;
 304         char save_status;
 305
 306         dev_dbg(&udev->dev, "Enter probe\n");
 307
 308         /* Not sure if this is our device. Allocate here to avoid
 309          * calling alloc while holding busid_table lock.
 310          */
 311         sdev = stub_device_alloc(udev);
 312         if (!sdev)
 313                 return -ENOMEM;
 314
 315         /* check we should claim or not by busid_table */
 316         busid_priv = get_busid_priv(udev_busid);
 317         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 318             (busid_priv->status == STUB_BUSID_OTHER)) {
 319                 dev_info(&udev->dev,
 320                         "%s is not in match_busid table... skip!\n",
 321                         udev_busid);
 322
 323                 /*
 324                  * Return value should be ENODEV or ENOXIO to continue trying
 325                  * other matched drivers by the driver core.
 326                  * See driver_probe_device() in driver/base/dd.c
 327                  */
 328                 rc = -ENODEV;
 329                 if (!busid_priv)
 330                         goto sdev_free;
 331
 332                 goto call_put_busid_priv;
 333         }
 334
 335         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 336                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 337                          udev_busid);
 338                 rc = -ENODEV;
 339                 goto call_put_busid_priv;
 340         }
 341
 342         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 343                 dev_dbg(&udev->dev,
 344                         "%s is attached on vhci_hcd... skip!\n",
 345                         udev_busid);
 346
 347                 rc = -ENODEV;
 348                 goto call_put_busid_priv;
 349         }
 350
 351
 352         dev_info(&udev->dev,
 353                 "usbip-host: register new device (bus %u dev %u)\n",
 354                 udev->bus->busnum, udev->devnum);
 355
 356         busid_priv->shutdown_busid = 0;
 357
 358         /* set private data to usb_device */
 359         dev_set_drvdata(&udev->dev, sdev);
 360
 361         busid_priv->sdev = sdev;
 362         busid_priv->udev = udev;
 363
 364         save_status = busid_priv->status;
 365         busid_priv->status = STUB_BUSID_ALLOC;
 366
 367         /* release the busid_lock */
 368         put_busid_priv(busid_priv);
 369
 370         /*
 371          * Claim this hub port.
 372          * It doesn't matter what value we pass as owner
 373          * (struct dev_state) as long as it is unique.
 374          */
 375         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 376                         (struct usb_dev_state *) udev);
 377         if (rc) {
 378                 dev_dbg(&udev->dev, "unable to claim port\n");
 379                 goto err_port;
 380         }
 381
 382         rc = stub_add_files(&udev->dev);
 383         if (rc) {
 384                 dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
 385                 goto err_files;
 386         }
 387
 388         return 0;
 389
 390 err_files:
 391         usb_hub_release_port(udev->parent, udev->portnum,
 392                              (struct usb_dev_state *) udev);
 393 err_port:
 394         dev_set_drvdata(&udev->dev, NULL);
 395         usb_put_dev(udev);
 396
 397         /* we already have busid_priv, just lock busid_lock */
 398         spin_lock(&busid_priv->busid_lock);
 399         busid_priv->sdev = NULL;
 400         busid_priv->status = save_status;
 401         spin_unlock(&busid_priv->busid_lock);
 402         /* lock is released - go to free */
 403         goto sdev_free;
 404
 405 call_put_busid_priv:
 406         /* release the busid_lock */
 407         put_busid_priv(busid_priv);
 408
 409 sdev_free:
 410         stub_device_free(sdev);
 411
 412         return rc;
 413 }
 414
 415 static void shutdown_busid(struct bus_id_priv *busid_priv)
 416 {
 417         usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 418
 419         /* wait for the stop of the event handler */
 420         usbip_stop_eh(&busid_priv->sdev->ud);
 421 }
 422
 423 /*
 424  * called in usb_disconnect() or usb_deregister()
 425  * but only if actconfig(active configuration) exists
 426  */
 427 static void stub_disconnect(struct usb_device *udev)
 428 {
 429         struct stub_device *sdev;
 430         const char *udev_busid = dev_name(&udev->dev);
 431         struct bus_id_priv *busid_priv;
 432         int rc;
 433
 434         dev_dbg(&udev->dev, "Enter disconnect\n");
 435
 436         busid_priv = get_busid_priv(udev_busid);
 437         if (!busid_priv) {
 438                 BUG();
 439                 return;
 440         }
 441
 442         sdev = dev_get_drvdata(&udev->dev);
 443
 444         /* get stub_device */
 445         if (!sdev) {
 446                 dev_err(&udev->dev, "could not get device");
 447                 /* release busid_lock */
 448                 put_busid_priv(busid_priv);
 449                 return;
 450         }
 451
 452         dev_set_drvdata(&udev->dev, NULL);
 453
 454         /* release busid_lock before call to remove device files */
 455         put_busid_priv(busid_priv);
 456
 457         /*
 458          * NOTE: rx/tx threads are invoked for each usb_device.
 459          */
 460         stub_remove_files(&udev->dev);
 461
 462         /* release port */
 463         rc = usb_hub_release_port(udev->parent, udev->portnum,
 464                                   (struct usb_dev_state *) udev);
 465         if (rc) {
 466                 dev_dbg(&udev->dev, "unable to release port\n");
 467                 return;
 468         }
 469
 470         /* If usb reset is called from event handler */
 471         if (usbip_in_eh(current))
 472                 return;
 473
 474         /* we already have busid_priv, just lock busid_lock */
 475         spin_lock(&busid_priv->busid_lock);
 476         if (!busid_priv->shutdown_busid)
 477                 busid_priv->shutdown_busid = 1;
 478         /* release busid_lock */
 479         spin_unlock(&busid_priv->busid_lock);
 480
 481         /* shutdown the current connection */
 482         shutdown_busid(busid_priv);
 483
 484         usb_put_dev(sdev->udev);
 485
 486         /* we already have busid_priv, just lock busid_lock */
 487         spin_lock(&busid_priv->busid_lock);
 488         /* free sdev */
 489         busid_priv->sdev = NULL;
 490         stub_device_free(sdev);
 491
 492         if (busid_priv->status == STUB_BUSID_ALLOC)
 493                 busid_priv->status = STUB_BUSID_ADDED;
 494         /* release busid_lock */
 495         spin_unlock(&busid_priv->busid_lock);
 496         return;
 497 }
 498
 499 #ifdef CONFIG_PM
 500
 501 /* These functions need usb_port_suspend and usb_port_resume,
 502  * which reside in drivers/usb/core/usb.h. Skip for now. */
 503
 504 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 505 {
 506         dev_dbg(&udev->dev, "stub_suspend\n");
 507
 508         return 0;
 509 }
 510
 511 static int stub_resume(struct usb_device *udev, pm_message_t message)
 512 {
 513         dev_dbg(&udev->dev, "stub_resume\n");
 514
 515         return 0;
 516 }
 517
 518 #endif  /* CONFIG_PM */
 519
 520 struct usb_device_driver stub_driver = {
 521         .name           = "usbip-host",
 522         .probe          = stub_probe,
 523         .disconnect     = stub_disconnect,
 524 #ifdef CONFIG_PM
 525         .suspend        = stub_suspend,
 526         .resume         = stub_resume,
 527 #endif
 528         .supports_autosuspend   =       0,
 529 };