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         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                 spin_lock_irq(&sdev->ud.lock);
 122                 if (sdev->ud.status != SDEV_ST_USED)
 123                         goto err;
 124
 125                 spin_unlock_irq(&sdev->ud.lock);
 126
 127                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
 128                 mutex_unlock(&sdev->ud.sysfs_lock);
 129         }
 130
 131         return count;
 132
 133 sock_err:
 134         sockfd_put(socket);
 135 err:
 136         spin_unlock_irq(&sdev->ud.lock);
 137 unlock_mutex:
 138         mutex_unlock(&sdev->ud.sysfs_lock);
 139         return -EINVAL;
 140 }
 141 static DEVICE_ATTR_WO(usbip_sockfd);
 142
 143 static struct attribute *usbip_attrs[] = {
 144         &dev_attr_usbip_status.attr,
 145         &dev_attr_usbip_sockfd.attr,
 146         &dev_attr_usbip_debug.attr,
 147         NULL,
 148 };
 149 ATTRIBUTE_GROUPS(usbip);
 150
 151 static void stub_shutdown_connection(struct usbip_device *ud)
 152 {
 153         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 154
 155         /*
 156          * When removing an exported device, kernel panic sometimes occurred
 157          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 158          * sk_wait_data returned though stub_rx thread was already finished by
 159          * step 1?
 160          */
 161         if (ud->tcp_socket) {
 162                 dev_dbg(&sdev->udev->dev, "shutdown sockfd %d\n", ud->sockfd);
 163                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 164         }
 165
 166         /* 1. stop threads */
 167         if (ud->tcp_rx) {
 168                 kthread_stop_put(ud->tcp_rx);
 169                 ud->tcp_rx = NULL;
 170         }
 171         if (ud->tcp_tx) {
 172                 kthread_stop_put(ud->tcp_tx);
 173                 ud->tcp_tx = NULL;
 174         }
 175
 176         /*
 177          * 2. close the socket
 178          *
 179          * tcp_socket is freed after threads are killed so that usbip_xmit does
 180          * not touch NULL socket.
 181          */
 182         if (ud->tcp_socket) {
 183                 sockfd_put(ud->tcp_socket);
 184                 ud->tcp_socket = NULL;
 185                 ud->sockfd = -1;
 186         }
 187
 188         /* 3. free used data */
 189         stub_device_cleanup_urbs(sdev);
 190
 191         /* 4. free stub_unlink */
 192         {
 193                 unsigned long flags;
 194                 struct stub_unlink *unlink, *tmp;
 195
 196                 spin_lock_irqsave(&sdev->priv_lock, flags);
 197                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 198                         list_del(&unlink->list);
 199                         kfree(unlink);
 200                 }
 201                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 202                                          list) {
 203                         list_del(&unlink->list);
 204                         kfree(unlink);
 205                 }
 206                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 207         }
 208 }
 209
 210 static void stub_device_reset(struct usbip_device *ud)
 211 {
 212         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 213         struct usb_device *udev = sdev->udev;
 214         int ret;
 215
 216         dev_dbg(&udev->dev, "device reset");
 217
 218         ret = usb_lock_device_for_reset(udev, NULL);
 219         if (ret < 0) {
 220                 dev_err(&udev->dev, "lock for reset\n");
 221                 spin_lock_irq(&ud->lock);
 222                 ud->status = SDEV_ST_ERROR;
 223                 spin_unlock_irq(&ud->lock);
 224                 return;
 225         }
 226
 227         /* try to reset the device */
 228         ret = usb_reset_device(udev);
 229         usb_unlock_device(udev);
 230
 231         spin_lock_irq(&ud->lock);
 232         if (ret) {
 233                 dev_err(&udev->dev, "device reset\n");
 234                 ud->status = SDEV_ST_ERROR;
 235         } else {
 236                 dev_info(&udev->dev, "device reset\n");
 237                 ud->status = SDEV_ST_AVAILABLE;
 238         }
 239         spin_unlock_irq(&ud->lock);
 240 }
 241
 242 static void stub_device_unusable(struct usbip_device *ud)
 243 {
 244         spin_lock_irq(&ud->lock);
 245         ud->status = SDEV_ST_ERROR;
 246         spin_unlock_irq(&ud->lock);
 247 }
 248
 249 /**
 250  * stub_device_alloc - allocate a new stub_device struct
 251  * @udev: usb_device of a new device
 252  *
 253  * Allocates and initializes a new stub_device struct.
 254  */
 255 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 256 {
 257         struct stub_device *sdev;
 258         int busnum = udev->bus->busnum;
 259         int devnum = udev->devnum;
 260
 261         dev_dbg(&udev->dev, "allocating stub device");
 262
 263         /* yes, it's a new device */
 264         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 265         if (!sdev)
 266                 return NULL;
 267
 268         sdev->udev = usb_get_dev(udev);
 269
 270         /*
 271          * devid is defined with devnum when this driver is first allocated.
 272          * devnum may change later if a device is reset. However, devid never
 273          * changes during a usbip connection.
 274          */
 275         sdev->devid             = (busnum << 16) | devnum;
 276         sdev->ud.side           = USBIP_STUB;
 277         sdev->ud.status         = SDEV_ST_AVAILABLE;
 278         spin_lock_init(&sdev->ud.lock);
 279         mutex_init(&sdev->ud.sysfs_lock);
 280         sdev->ud.tcp_socket     = NULL;
 281         sdev->ud.sockfd         = -1;
 282
 283         INIT_LIST_HEAD(&sdev->priv_init);
 284         INIT_LIST_HEAD(&sdev->priv_tx);
 285         INIT_LIST_HEAD(&sdev->priv_free);
 286         INIT_LIST_HEAD(&sdev->unlink_free);
 287         INIT_LIST_HEAD(&sdev->unlink_tx);
 288         spin_lock_init(&sdev->priv_lock);
 289
 290         init_waitqueue_head(&sdev->tx_waitq);
 291
 292         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 293         sdev->ud.eh_ops.reset    = stub_device_reset;
 294         sdev->ud.eh_ops.unusable = stub_device_unusable;
 295
 296         usbip_start_eh(&sdev->ud);
 297
 298         dev_dbg(&udev->dev, "register new device\n");
 299
 300         return sdev;
 301 }
 302
 303 static void stub_device_free(struct stub_device *sdev)
 304 {
 305         kfree(sdev);
 306 }
 307
 308 static int stub_probe(struct usb_device *udev)
 309 {
 310         struct stub_device *sdev = NULL;
 311         const char *udev_busid = dev_name(&udev->dev);
 312         struct bus_id_priv *busid_priv;
 313         int rc = 0;
 314         char save_status;
 315
 316         dev_dbg(&udev->dev, "Enter probe\n");
 317
 318         /* Not sure if this is our device. Allocate here to avoid
 319          * calling alloc while holding busid_table lock.
 320          */
 321         sdev = stub_device_alloc(udev);
 322         if (!sdev)
 323                 return -ENOMEM;
 324
 325         /* check we should claim or not by busid_table */
 326         busid_priv = get_busid_priv(udev_busid);
 327         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 328             (busid_priv->status == STUB_BUSID_OTHER)) {
 329                 dev_info(&udev->dev,
 330                         "%s is not in match_busid table... skip!\n",
 331                         udev_busid);
 332
 333                 /*
 334                  * Return value should be ENODEV or ENOXIO to continue trying
 335                  * other matched drivers by the driver core.
 336                  * See driver_probe_device() in driver/base/dd.c
 337                  */
 338                 rc = -ENODEV;
 339                 if (!busid_priv)
 340                         goto sdev_free;
 341
 342                 goto call_put_busid_priv;
 343         }
 344
 345         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 346                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 347                          udev_busid);
 348                 rc = -ENODEV;
 349                 goto call_put_busid_priv;
 350         }
 351
 352         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 353                 dev_dbg(&udev->dev,
 354                         "%s is attached on vhci_hcd... skip!\n",
 355                         udev_busid);
 356
 357                 rc = -ENODEV;
 358                 goto call_put_busid_priv;
 359         }
 360
 361
 362         dev_info(&udev->dev,
 363                 "usbip-host: register new device (bus %u dev %u)\n",
 364                 udev->bus->busnum, udev->devnum);
 365
 366         busid_priv->shutdown_busid = 0;
 367
 368         /* set private data to usb_device */
 369         dev_set_drvdata(&udev->dev, sdev);
 370
 371         busid_priv->sdev = sdev;
 372         busid_priv->udev = udev;
 373
 374         save_status = busid_priv->status;
 375         busid_priv->status = STUB_BUSID_ALLOC;
 376
 377         /* release the busid_lock */
 378         put_busid_priv(busid_priv);
 379
 380         /*
 381          * Claim this hub port.
 382          * It doesn't matter what value we pass as owner
 383          * (struct dev_state) as long as it is unique.
 384          */
 385         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 386                         (struct usb_dev_state *) udev);
 387         if (rc) {
 388                 dev_dbg(&udev->dev, "unable to claim port\n");
 389                 goto err_port;
 390         }
 391
 392         return 0;
 393
 394 err_port:
 395         dev_set_drvdata(&udev->dev, NULL);
 396         usb_put_dev(udev);
 397
 398         /* we already have busid_priv, just lock busid_lock */
 399         spin_lock(&busid_priv->busid_lock);
 400         busid_priv->sdev = NULL;
 401         busid_priv->status = save_status;
 402         spin_unlock(&busid_priv->busid_lock);
 403         /* lock is released - go to free */
 404         goto sdev_free;
 405
 406 call_put_busid_priv:
 407         /* release the busid_lock */
 408         put_busid_priv(busid_priv);
 409
 410 sdev_free:
 411         stub_device_free(sdev);
 412
 413         return rc;
 414 }
 415
 416 static void shutdown_busid(struct bus_id_priv *busid_priv)
 417 {
 418         usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 419
 420         /* wait for the stop of the event handler */
 421         usbip_stop_eh(&busid_priv->sdev->ud);
 422 }
 423
 424 /*
 425  * called in usb_disconnect() or usb_deregister()
 426  * but only if actconfig(active configuration) exists
 427  */
 428 static void stub_disconnect(struct usb_device *udev)
 429 {
 430         struct stub_device *sdev;
 431         const char *udev_busid = dev_name(&udev->dev);
 432         struct bus_id_priv *busid_priv;
 433         int rc;
 434
 435         dev_dbg(&udev->dev, "Enter disconnect\n");
 436
 437         busid_priv = get_busid_priv(udev_busid);
 438         if (!busid_priv) {
 439                 BUG();
 440                 return;
 441         }
 442
 443         sdev = dev_get_drvdata(&udev->dev);
 444
 445         /* get stub_device */
 446         if (!sdev) {
 447                 dev_err(&udev->dev, "could not get device");
 448                 /* release busid_lock */
 449                 put_busid_priv(busid_priv);
 450                 return;
 451         }
 452
 453         dev_set_drvdata(&udev->dev, NULL);
 454
 455         /* release busid_lock before call to remove device files */
 456         put_busid_priv(busid_priv);
 457
 458         /*
 459          * NOTE: rx/tx threads are invoked for each usb_device.
 460          */
 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         .dev_groups     = usbip_groups,
 530 };