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 sysfs_emit(buf, "%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         struct task_struct *tcp_rx = NULL;
  50         struct task_struct *tcp_tx = NULL;
  51
  52         if (!sdev) {
  53                 dev_err(dev, "sdev is null\n");
  54                 return -ENODEV;
  55         }
  56
  57         rv = sscanf(buf, "%d", &sockfd);
  58         if (rv != 1)
  59                 return -EINVAL;
  60
  61         if (sockfd != -1) {
  62                 int err;
  63
  64                 dev_info(dev, "stub up\n");
  65
  66                 mutex_lock(&sdev->ud.sysfs_lock);
  67                 spin_lock_irq(&sdev->ud.lock);
  68
  69                 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
  70                         dev_err(dev, "not ready\n");
  71                         goto err;
  72                 }
  73
  74                 socket = sockfd_lookup(sockfd, &err);
  75                 if (!socket) {
  76                         dev_err(dev, "failed to lookup sock");
  77                         goto err;
  78                 }
  79
  80                 if (socket->type != SOCK_STREAM) {
  81                         dev_err(dev, "Expecting SOCK_STREAM - found %d",
  82                                 socket->type);
  83                         goto sock_err;
  84                 }
  85
  86                 /* unlock and create threads and get tasks */
  87                 spin_unlock_irq(&sdev->ud.lock);
  88                 tcp_rx = kthread_create(stub_rx_loop, &sdev->ud, "stub_rx");
  89                 if (IS_ERR(tcp_rx)) {
  90                         sockfd_put(socket);
  91                         goto unlock_mutex;
  92                 }
  93                 tcp_tx = kthread_create(stub_tx_loop, &sdev->ud, "stub_tx");
  94                 if (IS_ERR(tcp_tx)) {
  95                         kthread_stop(tcp_rx);
  96                         sockfd_put(socket);
  97                         goto unlock_mutex;
  98                 }
  99
 100                 /* get task structs now */
 101                 get_task_struct(tcp_rx);
 102                 get_task_struct(tcp_tx);
 103
 104                 /* lock and update sdev->ud state */
 105                 spin_lock_irq(&sdev->ud.lock);
 106                 sdev->ud.tcp_socket = socket;
 107                 sdev->ud.sockfd = sockfd;
 108                 sdev->ud.tcp_rx = tcp_rx;
 109                 sdev->ud.tcp_tx = tcp_tx;
 110                 sdev->ud.status = SDEV_ST_USED;
 111                 spin_unlock_irq(&sdev->ud.lock);
 112
 113                 wake_up_process(sdev->ud.tcp_rx);
 114                 wake_up_process(sdev->ud.tcp_tx);
 115
 116                 mutex_unlock(&sdev->ud.sysfs_lock);
 117
 118         } else {
 119                 dev_info(dev, "stub down\n");
 120
 121                 mutex_lock(&sdev->ud.sysfs_lock);
 122
 123                 spin_lock_irq(&sdev->ud.lock);
 124                 if (sdev->ud.status != SDEV_ST_USED)
 125                         goto err;
 126
 127                 spin_unlock_irq(&sdev->ud.lock);
 128
 129                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
 130                 mutex_unlock(&sdev->ud.sysfs_lock);
 131         }
 132
 133         return count;
 134
 135 sock_err:
 136         sockfd_put(socket);
 137 err:
 138         spin_unlock_irq(&sdev->ud.lock);
 139 unlock_mutex:
 140         mutex_unlock(&sdev->ud.sysfs_lock);
 141         return -EINVAL;
 142 }
 143 static DEVICE_ATTR_WO(usbip_sockfd);
 144
 145 static struct attribute *usbip_attrs[] = {
 146         &dev_attr_usbip_status.attr,
 147         &dev_attr_usbip_sockfd.attr,
 148         &dev_attr_usbip_debug.attr,
 149         NULL,
 150 };
 151 ATTRIBUTE_GROUPS(usbip);
 152
 153 static void stub_shutdown_connection(struct usbip_device *ud)
 154 {
 155         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 156
 157         /*
 158          * When removing an exported device, kernel panic sometimes occurred
 159          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 160          * sk_wait_data returned though stub_rx thread was already finished by
 161          * step 1?
 162          */
 163         if (ud->tcp_socket) {
 164                 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
 165                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 166         }
 167
 168         /* 1. stop threads */
 169         if (ud->tcp_rx) {
 170                 kthread_stop_put(ud->tcp_rx);
 171                 ud->tcp_rx = NULL;
 172         }
 173         if (ud->tcp_tx) {
 174                 kthread_stop_put(ud->tcp_tx);
 175                 ud->tcp_tx = NULL;
 176         }
 177
 178         /*
 179          * 2. close the socket
 180          *
 181          * tcp_socket is freed after threads are killed so that usbip_xmit does
 182          * not touch NULL socket.
 183          */
 184         if (ud->tcp_socket) {
 185                 sockfd_put(ud->tcp_socket);
 186                 ud->tcp_socket = NULL;
 187                 ud->sockfd = -1;
 188         }
 189
 190         /* 3. free used data */
 191         stub_device_cleanup_urbs(sdev);
 192
 193         /* 4. free stub_unlink */
 194         {
 195                 unsigned long flags;
 196                 struct stub_unlink *unlink, *tmp;
 197
 198                 spin_lock_irqsave(&sdev->priv_lock, flags);
 199                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 200                         list_del(&unlink->list);
 201                         kfree(unlink);
 202                 }
 203                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 204                                          list) {
 205                         list_del(&unlink->list);
 206                         kfree(unlink);
 207                 }
 208                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 209         }
 210 }
 211
 212 static void stub_device_reset(struct usbip_device *ud)
 213 {
 214         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 215         struct usb_device *udev = sdev->udev;
 216         int ret;
 217
 218         dev_dbg(&udev->dev, "device reset");
 219
 220         ret = usb_lock_device_for_reset(udev, NULL);
 221         if (ret < 0) {
 222                 dev_err(&udev->dev, "lock for reset\n");
 223                 spin_lock_irq(&ud->lock);
 224                 ud->status = SDEV_ST_ERROR;
 225                 spin_unlock_irq(&ud->lock);
 226                 return;
 227         }
 228
 229         /* try to reset the device */
 230         ret = usb_reset_device(udev);
 231         usb_unlock_device(udev);
 232
 233         spin_lock_irq(&ud->lock);
 234         if (ret) {
 235                 dev_err(&udev->dev, "device reset\n");
 236                 ud->status = SDEV_ST_ERROR;
 237         } else {
 238                 dev_info(&udev->dev, "device reset\n");
 239                 ud->status = SDEV_ST_AVAILABLE;
 240         }
 241         spin_unlock_irq(&ud->lock);
 242 }
 243
 244 static void stub_device_unusable(struct usbip_device *ud)
 245 {
 246         spin_lock_irq(&ud->lock);
 247         ud->status = SDEV_ST_ERROR;
 248         spin_unlock_irq(&ud->lock);
 249 }
 250
 251 /**
 252  * stub_device_alloc - allocate a new stub_device struct
 253  * @udev: usb_device of a new device
 254  *
 255  * Allocates and initializes a new stub_device struct.
 256  */
 257 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 258 {
 259         struct stub_device *sdev;
 260         int busnum = udev->bus->busnum;
 261         int devnum = udev->devnum;
 262
 263         dev_dbg(&udev->dev, "allocating stub device");
 264
 265         /* yes, it's a new device */
 266         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 267         if (!sdev)
 268                 return NULL;
 269
 270         sdev->udev = usb_get_dev(udev);
 271
 272         /*
 273          * devid is defined with devnum when this driver is first allocated.
 274          * devnum may change later if a device is reset. However, devid never
 275          * changes during a usbip connection.
 276          */
 277         sdev->devid             = (busnum << 16) | devnum;
 278         sdev->ud.side           = USBIP_STUB;
 279         sdev->ud.status         = SDEV_ST_AVAILABLE;
 280         spin_lock_init(&sdev->ud.lock);
 281         mutex_init(&sdev->ud.sysfs_lock);
 282         sdev->ud.tcp_socket     = NULL;
 283         sdev->ud.sockfd         = -1;
 284
 285         INIT_LIST_HEAD(&sdev->priv_init);
 286         INIT_LIST_HEAD(&sdev->priv_tx);
 287         INIT_LIST_HEAD(&sdev->priv_free);
 288         INIT_LIST_HEAD(&sdev->unlink_free);
 289         INIT_LIST_HEAD(&sdev->unlink_tx);
 290         spin_lock_init(&sdev->priv_lock);
 291
 292         init_waitqueue_head(&sdev->tx_waitq);
 293
 294         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 295         sdev->ud.eh_ops.reset    = stub_device_reset;
 296         sdev->ud.eh_ops.unusable = stub_device_unusable;
 297
 298         usbip_start_eh(&sdev->ud);
 299
 300         dev_dbg(&udev->dev, "register new device\n");
 301
 302         return sdev;
 303 }
 304
 305 static void stub_device_free(struct stub_device *sdev)
 306 {
 307         kfree(sdev);
 308 }
 309
 310 static int stub_probe(struct usb_device *udev)
 311 {
 312         struct stub_device *sdev = NULL;
 313         const char *udev_busid = dev_name(&udev->dev);
 314         struct bus_id_priv *busid_priv;
 315         int rc = 0;
 316         char save_status;
 317
 318         dev_dbg(&udev->dev, "Enter probe\n");
 319
 320         /* Not sure if this is our device. Allocate here to avoid
 321          * calling alloc while holding busid_table lock.
 322          */
 323         sdev = stub_device_alloc(udev);
 324         if (!sdev)
 325                 return -ENOMEM;
 326
 327         /* check we should claim or not by busid_table */
 328         busid_priv = get_busid_priv(udev_busid);
 329         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 330             (busid_priv->status == STUB_BUSID_OTHER)) {
 331                 dev_info(&udev->dev,
 332                         "%s is not in match_busid table... skip!\n",
 333                         udev_busid);
 334
 335                 /*
 336                  * Return value should be ENODEV or ENOXIO to continue trying
 337                  * other matched drivers by the driver core.
 338                  * See driver_probe_device() in driver/base/dd.c
 339                  */
 340                 rc = -ENODEV;
 341                 if (!busid_priv)
 342                         goto sdev_free;
 343
 344                 goto call_put_busid_priv;
 345         }
 346
 347         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 348                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 349                          udev_busid);
 350                 rc = -ENODEV;
 351                 goto call_put_busid_priv;
 352         }
 353
 354         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 355                 dev_dbg(&udev->dev,
 356                         "%s is attached on vhci_hcd... skip!\n",
 357                         udev_busid);
 358
 359                 rc = -ENODEV;
 360                 goto call_put_busid_priv;
 361         }
 362
 363
 364         dev_info(&udev->dev,
 365                 "usbip-host: register new device (bus %u dev %u)\n",
 366                 udev->bus->busnum, udev->devnum);
 367
 368         busid_priv->shutdown_busid = 0;
 369
 370         /* set private data to usb_device */
 371         dev_set_drvdata(&udev->dev, sdev);
 372
 373         busid_priv->sdev = sdev;
 374         busid_priv->udev = udev;
 375
 376         save_status = busid_priv->status;
 377         busid_priv->status = STUB_BUSID_ALLOC;
 378
 379         /* release the busid_lock */
 380         put_busid_priv(busid_priv);
 381
 382         /*
 383          * Claim this hub port.
 384          * It doesn't matter what value we pass as owner
 385          * (struct dev_state) as long as it is unique.
 386          */
 387         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 388                         (struct usb_dev_state *) udev);
 389         if (rc) {
 390                 dev_dbg(&udev->dev, "unable to claim port\n");
 391                 goto err_port;
 392         }
 393
 394         return 0;
 395
 396 err_port:
 397         dev_set_drvdata(&udev->dev, NULL);
 398
 399         /* we already have busid_priv, just lock busid_lock */
 400         spin_lock(&busid_priv->busid_lock);
 401         busid_priv->sdev = NULL;
 402         busid_priv->status = save_status;
 403         spin_unlock(&busid_priv->busid_lock);
 404         /* lock is released - go to free */
 405         goto sdev_free;
 406
 407 call_put_busid_priv:
 408         /* release the busid_lock */
 409         put_busid_priv(busid_priv);
 410
 411 sdev_free:
 412         usb_put_dev(udev);
 413         stub_device_free(sdev);
 414
 415         return rc;
 416 }
 417
 418 static void shutdown_busid(struct bus_id_priv *busid_priv)
 419 {
 420         usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 421
 422         /* wait for the stop of the event handler */
 423         usbip_stop_eh(&busid_priv->sdev->ud);
 424 }
 425
 426 /*
 427  * called in usb_disconnect() or usb_deregister()
 428  * but only if actconfig(active configuration) exists
 429  */
 430 static void stub_disconnect(struct usb_device *udev)
 431 {
 432         struct stub_device *sdev;
 433         const char *udev_busid = dev_name(&udev->dev);
 434         struct bus_id_priv *busid_priv;
 435         int rc;
 436
 437         dev_dbg(&udev->dev, "Enter disconnect\n");
 438
 439         busid_priv = get_busid_priv(udev_busid);
 440         if (!busid_priv) {
 441                 BUG();
 442                 return;
 443         }
 444
 445         sdev = dev_get_drvdata(&udev->dev);
 446
 447         /* get stub_device */
 448         if (!sdev) {
 449                 dev_err(&udev->dev, "could not get device");
 450                 /* release busid_lock */
 451                 put_busid_priv(busid_priv);
 452                 return;
 453         }
 454
 455         dev_set_drvdata(&udev->dev, NULL);
 456
 457         /* release busid_lock before call to remove device files */
 458         put_busid_priv(busid_priv);
 459
 460         /*
 461          * NOTE: rx/tx threads are invoked for each usb_device.
 462          */
 463
 464         /* release port */
 465         rc = usb_hub_release_port(udev->parent, udev->portnum,
 466                                   (struct usb_dev_state *) udev);
 467         if (rc) {
 468                 dev_dbg(&udev->dev, "unable to release port\n");
 469                 return;
 470         }
 471
 472         /* If usb reset is called from event handler */
 473         if (usbip_in_eh(current))
 474                 return;
 475
 476         /* we already have busid_priv, just lock busid_lock */
 477         spin_lock(&busid_priv->busid_lock);
 478         if (!busid_priv->shutdown_busid)
 479                 busid_priv->shutdown_busid = 1;
 480         /* release busid_lock */
 481         spin_unlock(&busid_priv->busid_lock);
 482
 483         /* shutdown the current connection */
 484         shutdown_busid(busid_priv);
 485
 486         usb_put_dev(sdev->udev);
 487
 488         /* we already have busid_priv, just lock busid_lock */
 489         spin_lock(&busid_priv->busid_lock);
 490         /* free sdev */
 491         busid_priv->sdev = NULL;
 492         stub_device_free(sdev);
 493
 494         if (busid_priv->status == STUB_BUSID_ALLOC)
 495                 busid_priv->status = STUB_BUSID_ADDED;
 496         /* release busid_lock */
 497         spin_unlock(&busid_priv->busid_lock);
 498         return;
 499 }
 500
 501 #ifdef CONFIG_PM
 502
 503 /* These functions need usb_port_suspend and usb_port_resume,
 504  * which reside in drivers/usb/core/usb.h. Skip for now. */
 505
 506 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 507 {
 508         dev_dbg(&udev->dev, "stub_suspend\n");
 509
 510         return 0;
 511 }
 512
 513 static int stub_resume(struct usb_device *udev, pm_message_t message)
 514 {
 515         dev_dbg(&udev->dev, "stub_resume\n");
 516
 517         return 0;
 518 }
 519
 520 #endif  /* CONFIG_PM */
 521
 522 struct usb_device_driver stub_driver = {
 523         .name           = "usbip-host",
 524         .probe          = stub_probe,
 525         .disconnect     = stub_disconnect,
 526 #ifdef CONFIG_PM
 527         .suspend        = stub_suspend,
 528         .resume         = stub_resume,
 529 #endif
 530         .supports_autosuspend   =       0,
 531         .dev_groups     = usbip_groups,
 532 };