drivers/usb/usbip/stub_dev.c

   1 /*
   2  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   3  *
   4  * This is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17  * USA.
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/file.h>
  22 #include <linux/kthread.h>
  23 #include <linux/module.h>
  24
  25 #include "usbip_common.h"
  26 #include "stub.h"
  27
  28 /*
  29  * usbip_status shows the status of usbip-host as long as this driver is bound
  30  * to the target device.
  31  */
  32 static ssize_t usbip_status_show(struct device *dev,
  33                                  struct device_attribute *attr, char *buf)
  34 {
  35         struct stub_device *sdev = dev_get_drvdata(dev);
  36         int status;
  37
  38         if (!sdev) {
  39                 dev_err(dev, "sdev is null\n");
  40                 return -ENODEV;
  41         }
  42
  43         spin_lock_irq(&sdev->ud.lock);
  44         status = sdev->ud.status;
  45         spin_unlock_irq(&sdev->ud.lock);
  46
  47         return snprintf(buf, PAGE_SIZE, "%d\n", status);
  48 }
  49 static DEVICE_ATTR_RO(usbip_status);
  50
  51 /*
  52  * usbip_sockfd gets a socket descriptor of an established TCP connection that
  53  * is used to transfer usbip requests by kernel threads. -1 is a magic number
  54  * by which usbip connection is finished.
  55  */
  56 static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr,
  57                             const char *buf, size_t count)
  58 {
  59         struct stub_device *sdev = dev_get_drvdata(dev);
  60         int sockfd = 0;
  61         struct socket *socket;
  62         int rv;
  63
  64         if (!sdev) {
  65                 dev_err(dev, "sdev is null\n");
  66                 return -ENODEV;
  67         }
  68
  69         rv = sscanf(buf, "%d", &sockfd);
  70         if (rv != 1)
  71                 return -EINVAL;
  72
  73         if (sockfd != -1) {
  74                 int err;
  75
  76                 dev_info(dev, "stub up\n");
  77
  78                 spin_lock_irq(&sdev->ud.lock);
  79
  80                 if (sdev->ud.status != SDEV_ST_AVAILABLE) {
  81                         dev_err(dev, "not ready\n");
  82                         goto err;
  83                 }
  84
  85                 socket = sockfd_lookup(sockfd, &err);
  86                 if (!socket)
  87                         goto err;
  88
  89                 sdev->ud.tcp_socket = socket;
  90
  91                 spin_unlock_irq(&sdev->ud.lock);
  92
  93                 sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud,
  94                                                   "stub_rx");
  95                 sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud,
  96                                                   "stub_tx");
  97
  98                 spin_lock_irq(&sdev->ud.lock);
  99                 sdev->ud.status = SDEV_ST_USED;
 100                 spin_unlock_irq(&sdev->ud.lock);
 101
 102         } else {
 103                 dev_info(dev, "stub down\n");
 104
 105                 spin_lock_irq(&sdev->ud.lock);
 106                 if (sdev->ud.status != SDEV_ST_USED)
 107                         goto err;
 108
 109                 spin_unlock_irq(&sdev->ud.lock);
 110
 111                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
 112         }
 113
 114         return count;
 115
 116 err:
 117         spin_unlock_irq(&sdev->ud.lock);
 118         return -EINVAL;
 119 }
 120 static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd);
 121
 122 static int stub_add_files(struct device *dev)
 123 {
 124         int err = 0;
 125
 126         err = device_create_file(dev, &dev_attr_usbip_status);
 127         if (err)
 128                 goto err_status;
 129
 130         err = device_create_file(dev, &dev_attr_usbip_sockfd);
 131         if (err)
 132                 goto err_sockfd;
 133
 134         err = device_create_file(dev, &dev_attr_usbip_debug);
 135         if (err)
 136                 goto err_debug;
 137
 138         return 0;
 139
 140 err_debug:
 141         device_remove_file(dev, &dev_attr_usbip_sockfd);
 142 err_sockfd:
 143         device_remove_file(dev, &dev_attr_usbip_status);
 144 err_status:
 145         return err;
 146 }
 147
 148 static void stub_remove_files(struct device *dev)
 149 {
 150         device_remove_file(dev, &dev_attr_usbip_status);
 151         device_remove_file(dev, &dev_attr_usbip_sockfd);
 152         device_remove_file(dev, &dev_attr_usbip_debug);
 153 }
 154
 155 static void stub_shutdown_connection(struct usbip_device *ud)
 156 {
 157         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 158
 159         /*
 160          * When removing an exported device, kernel panic sometimes occurred
 161          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 162          * sk_wait_data returned though stub_rx thread was already finished by
 163          * step 1?
 164          */
 165         if (ud->tcp_socket) {
 166                 dev_dbg(&sdev->udev->dev, "shutdown tcp_socket %p\n",
 167                         ud->tcp_socket);
 168                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
 169         }
 170
 171         /* 1. stop threads */
 172         if (ud->tcp_rx) {
 173                 kthread_stop_put(ud->tcp_rx);
 174                 ud->tcp_rx = NULL;
 175         }
 176         if (ud->tcp_tx) {
 177                 kthread_stop_put(ud->tcp_tx);
 178                 ud->tcp_tx = NULL;
 179         }
 180
 181         /*
 182          * 2. close the socket
 183          *
 184          * tcp_socket is freed after threads are killed so that usbip_xmit does
 185          * not touch NULL socket.
 186          */
 187         if (ud->tcp_socket) {
 188                 sockfd_put(ud->tcp_socket);
 189                 ud->tcp_socket = NULL;
 190         }
 191
 192         /* 3. free used data */
 193         stub_device_cleanup_urbs(sdev);
 194
 195         /* 4. free stub_unlink */
 196         {
 197                 unsigned long flags;
 198                 struct stub_unlink *unlink, *tmp;
 199
 200                 spin_lock_irqsave(&sdev->priv_lock, flags);
 201                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 202                         list_del(&unlink->list);
 203                         kfree(unlink);
 204                 }
 205                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 206                                          list) {
 207                         list_del(&unlink->list);
 208                         kfree(unlink);
 209                 }
 210                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 211         }
 212 }
 213
 214 static void stub_device_reset(struct usbip_device *ud)
 215 {
 216         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 217         struct usb_device *udev = sdev->udev;
 218         int ret;
 219
 220         dev_dbg(&udev->dev, "device reset");
 221
 222         ret = usb_lock_device_for_reset(udev, NULL);
 223         if (ret < 0) {
 224                 dev_err(&udev->dev, "lock for reset\n");
 225                 spin_lock_irq(&ud->lock);
 226                 ud->status = SDEV_ST_ERROR;
 227                 spin_unlock_irq(&ud->lock);
 228                 return;
 229         }
 230
 231         /* try to reset the device */
 232         ret = usb_reset_device(udev);
 233         usb_unlock_device(udev);
 234
 235         spin_lock_irq(&ud->lock);
 236         if (ret) {
 237                 dev_err(&udev->dev, "device reset\n");
 238                 ud->status = SDEV_ST_ERROR;
 239         } else {
 240                 dev_info(&udev->dev, "device reset\n");
 241                 ud->status = SDEV_ST_AVAILABLE;
 242         }
 243         spin_unlock_irq(&ud->lock);
 244 }
 245
 246 static void stub_device_unusable(struct usbip_device *ud)
 247 {
 248         spin_lock_irq(&ud->lock);
 249         ud->status = SDEV_ST_ERROR;
 250         spin_unlock_irq(&ud->lock);
 251 }
 252
 253 /**
 254  * stub_device_alloc - allocate a new stub_device struct
 255  * @udev: usb_device of a new device
 256  *
 257  * Allocates and initializes a new stub_device struct.
 258  */
 259 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 260 {
 261         struct stub_device *sdev;
 262         int busnum = udev->bus->busnum;
 263         int devnum = udev->devnum;
 264
 265         dev_dbg(&udev->dev, "allocating stub device");
 266
 267         /* yes, it's a new device */
 268         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 269         if (!sdev)
 270                 return NULL;
 271
 272         sdev->udev = usb_get_dev(udev);
 273
 274         /*
 275          * devid is defined with devnum when this driver is first allocated.
 276          * devnum may change later if a device is reset. However, devid never
 277          * changes during a usbip connection.
 278          */
 279         sdev->devid             = (busnum << 16) | devnum;
 280         sdev->ud.side           = USBIP_STUB;
 281         sdev->ud.status         = SDEV_ST_AVAILABLE;
 282         spin_lock_init(&sdev->ud.lock);
 283         sdev->ud.tcp_socket     = NULL;
 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;
 316
 317         dev_dbg(&udev->dev, "Enter\n");
 318
 319         /* check we should claim or not by busid_table */
 320         busid_priv = get_busid_priv(udev_busid);
 321         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 322             (busid_priv->status == STUB_BUSID_OTHER)) {
 323                 dev_info(&udev->dev,
 324                         "%s is not in match_busid table... skip!\n",
 325                         udev_busid);
 326
 327                 /*
 328                  * Return value should be ENODEV or ENOXIO to continue trying
 329                  * other matched drivers by the driver core.
 330                  * See driver_probe_device() in driver/base/dd.c
 331                  */
 332                 return -ENODEV;
 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                 return -ENODEV;
 339         }
 340
 341         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 342                 dev_dbg(&udev->dev,
 343                         "%s is attached on vhci_hcd... skip!\n",
 344                         udev_busid);
 345
 346                 return -ENODEV;
 347         }
 348
 349         /* ok, this is my device */
 350         sdev = stub_device_alloc(udev);
 351         if (!sdev)
 352                 return -ENOMEM;
 353
 354         dev_info(&udev->dev,
 355                 "usbip-host: register new device (bus %u dev %u)\n",
 356                 udev->bus->busnum, udev->devnum);
 357
 358         busid_priv->shutdown_busid = 0;
 359
 360         /* set private data to usb_device */
 361         dev_set_drvdata(&udev->dev, sdev);
 362         busid_priv->sdev = sdev;
 363         busid_priv->udev = udev;
 364
 365         /*
 366          * Claim this hub port.
 367          * It doesn't matter what value we pass as owner
 368          * (struct dev_state) as long as it is unique.
 369          */
 370         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 371                         (struct usb_dev_state *) udev);
 372         if (rc) {
 373                 dev_dbg(&udev->dev, "unable to claim port\n");
 374                 goto err_port;
 375         }
 376
 377         rc = stub_add_files(&udev->dev);
 378         if (rc) {
 379                 dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
 380                 goto err_files;
 381         }
 382         busid_priv->status = STUB_BUSID_ALLOC;
 383
 384         return 0;
 385 err_files:
 386         usb_hub_release_port(udev->parent, udev->portnum,
 387                              (struct usb_dev_state *) udev);
 388 err_port:
 389         dev_set_drvdata(&udev->dev, NULL);
 390         usb_put_dev(udev);
 391
 392         busid_priv->sdev = NULL;
 393         stub_device_free(sdev);
 394         return rc;
 395 }
 396
 397 static void shutdown_busid(struct bus_id_priv *busid_priv)
 398 {
 399         if (busid_priv->sdev && !busid_priv->shutdown_busid) {
 400                 busid_priv->shutdown_busid = 1;
 401                 usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 402
 403                 /* wait for the stop of the event handler */
 404                 usbip_stop_eh(&busid_priv->sdev->ud);
 405         }
 406 }
 407
 408 /*
 409  * called in usb_disconnect() or usb_deregister()
 410  * but only if actconfig(active configuration) exists
 411  */
 412 static void stub_disconnect(struct usb_device *udev)
 413 {
 414         struct stub_device *sdev;
 415         const char *udev_busid = dev_name(&udev->dev);
 416         struct bus_id_priv *busid_priv;
 417         int rc;
 418
 419         dev_dbg(&udev->dev, "Enter\n");
 420
 421         busid_priv = get_busid_priv(udev_busid);
 422         if (!busid_priv) {
 423                 BUG();
 424                 return;
 425         }
 426
 427         sdev = dev_get_drvdata(&udev->dev);
 428
 429         /* get stub_device */
 430         if (!sdev) {
 431                 dev_err(&udev->dev, "could not get device");
 432                 return;
 433         }
 434
 435         dev_set_drvdata(&udev->dev, NULL);
 436
 437         /*
 438          * NOTE: rx/tx threads are invoked for each usb_device.
 439          */
 440         stub_remove_files(&udev->dev);
 441
 442         /* release port */
 443         rc = usb_hub_release_port(udev->parent, udev->portnum,
 444                                   (struct usb_dev_state *) udev);
 445         if (rc) {
 446                 dev_dbg(&udev->dev, "unable to release port\n");
 447                 return;
 448         }
 449
 450         /* If usb reset is called from event handler */
 451         if (usbip_in_eh(current))
 452                 return;
 453
 454         /* shutdown the current connection */
 455         shutdown_busid(busid_priv);
 456
 457         usb_put_dev(sdev->udev);
 458
 459         /* free sdev */
 460         busid_priv->sdev = NULL;
 461         stub_device_free(sdev);
 462
 463         if (busid_priv->status == STUB_BUSID_ALLOC) {
 464                 busid_priv->status = STUB_BUSID_ADDED;
 465         } else {
 466                 busid_priv->status = STUB_BUSID_OTHER;
 467                 del_match_busid((char *)udev_busid);
 468         }
 469 }
 470
 471 #ifdef CONFIG_PM
 472
 473 /* These functions need usb_port_suspend and usb_port_resume,
 474  * which reside in drivers/usb/core/usb.h. Skip for now. */
 475
 476 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 477 {
 478         dev_dbg(&udev->dev, "stub_suspend\n");
 479
 480         return 0;
 481 }
 482
 483 static int stub_resume(struct usb_device *udev, pm_message_t message)
 484 {
 485         dev_dbg(&udev->dev, "stub_resume\n");
 486
 487         return 0;
 488 }
 489
 490 #endif  /* CONFIG_PM */
 491
 492 struct usb_device_driver stub_driver = {
 493         .name           = "usbip-host",
 494         .probe          = stub_probe,
 495         .disconnect     = stub_disconnect,
 496 #ifdef CONFIG_PM
 497         .suspend        = stub_suspend,
 498         .resume         = stub_resume,
 499 #endif
 500         .supports_autosuspend   =       0,
 501 };