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                 sdev->ud.sockfd = sockfd;
  91
  92                 spin_unlock_irq(&sdev->ud.lock);
  93
  94                 sdev->ud.tcp_rx = kthread_get_run(stub_rx_loop, &sdev->ud,
  95                                                   "stub_rx");
  96                 sdev->ud.tcp_tx = kthread_get_run(stub_tx_loop, &sdev->ud,
  97                                                   "stub_tx");
  98
  99                 spin_lock_irq(&sdev->ud.lock);
 100                 sdev->ud.status = SDEV_ST_USED;
 101                 spin_unlock_irq(&sdev->ud.lock);
 102
 103         } else {
 104                 dev_info(dev, "stub down\n");
 105
 106                 spin_lock_irq(&sdev->ud.lock);
 107                 if (sdev->ud.status != SDEV_ST_USED)
 108                         goto err;
 109
 110                 spin_unlock_irq(&sdev->ud.lock);
 111
 112                 usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
 113         }
 114
 115         return count;
 116
 117 err:
 118         spin_unlock_irq(&sdev->ud.lock);
 119         return -EINVAL;
 120 }
 121 static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd);
 122
 123 static int stub_add_files(struct device *dev)
 124 {
 125         int err = 0;
 126
 127         err = device_create_file(dev, &dev_attr_usbip_status);
 128         if (err)
 129                 goto err_status;
 130
 131         err = device_create_file(dev, &dev_attr_usbip_sockfd);
 132         if (err)
 133                 goto err_sockfd;
 134
 135         err = device_create_file(dev, &dev_attr_usbip_debug);
 136         if (err)
 137                 goto err_debug;
 138
 139         return 0;
 140
 141 err_debug:
 142         device_remove_file(dev, &dev_attr_usbip_sockfd);
 143 err_sockfd:
 144         device_remove_file(dev, &dev_attr_usbip_status);
 145 err_status:
 146         return err;
 147 }
 148
 149 static void stub_remove_files(struct device *dev)
 150 {
 151         device_remove_file(dev, &dev_attr_usbip_status);
 152         device_remove_file(dev, &dev_attr_usbip_sockfd);
 153         device_remove_file(dev, &dev_attr_usbip_debug);
 154 }
 155
 156 static void stub_shutdown_connection(struct usbip_device *ud)
 157 {
 158         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 159
 160         /*
 161          * When removing an exported device, kernel panic sometimes occurred
 162          * and then EIP was sk_wait_data of stub_rx thread. Is this because
 163          * sk_wait_data returned though stub_rx thread was already finished by
 164          * step 1?
 165          */
 166         if (ud->tcp_socket) {
 167                 dev_dbg(&sdev->udev->dev, "shutdown sockfd\n");
 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                 ud->sockfd = -1;
 191         }
 192
 193         /* 3. free used data */
 194         stub_device_cleanup_urbs(sdev);
 195
 196         /* 4. free stub_unlink */
 197         {
 198                 unsigned long flags;
 199                 struct stub_unlink *unlink, *tmp;
 200
 201                 spin_lock_irqsave(&sdev->priv_lock, flags);
 202                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 203                         list_del(&unlink->list);
 204                         kfree(unlink);
 205                 }
 206                 list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
 207                                          list) {
 208                         list_del(&unlink->list);
 209                         kfree(unlink);
 210                 }
 211                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 212         }
 213 }
 214
 215 static void stub_device_reset(struct usbip_device *ud)
 216 {
 217         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 218         struct usb_device *udev = sdev->udev;
 219         int ret;
 220
 221         dev_dbg(&udev->dev, "device reset");
 222
 223         ret = usb_lock_device_for_reset(udev, NULL);
 224         if (ret < 0) {
 225                 dev_err(&udev->dev, "lock for reset\n");
 226                 spin_lock_irq(&ud->lock);
 227                 ud->status = SDEV_ST_ERROR;
 228                 spin_unlock_irq(&ud->lock);
 229                 return;
 230         }
 231
 232         /* try to reset the device */
 233         ret = usb_reset_device(udev);
 234         usb_unlock_device(udev);
 235
 236         spin_lock_irq(&ud->lock);
 237         if (ret) {
 238                 dev_err(&udev->dev, "device reset\n");
 239                 ud->status = SDEV_ST_ERROR;
 240         } else {
 241                 dev_info(&udev->dev, "device reset\n");
 242                 ud->status = SDEV_ST_AVAILABLE;
 243         }
 244         spin_unlock_irq(&ud->lock);
 245 }
 246
 247 static void stub_device_unusable(struct usbip_device *ud)
 248 {
 249         spin_lock_irq(&ud->lock);
 250         ud->status = SDEV_ST_ERROR;
 251         spin_unlock_irq(&ud->lock);
 252 }
 253
 254 /**
 255  * stub_device_alloc - allocate a new stub_device struct
 256  * @udev: usb_device of a new device
 257  *
 258  * Allocates and initializes a new stub_device struct.
 259  */
 260 static struct stub_device *stub_device_alloc(struct usb_device *udev)
 261 {
 262         struct stub_device *sdev;
 263         int busnum = udev->bus->busnum;
 264         int devnum = udev->devnum;
 265
 266         dev_dbg(&udev->dev, "allocating stub device");
 267
 268         /* yes, it's a new device */
 269         sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
 270         if (!sdev)
 271                 return NULL;
 272
 273         sdev->udev = usb_get_dev(udev);
 274
 275         /*
 276          * devid is defined with devnum when this driver is first allocated.
 277          * devnum may change later if a device is reset. However, devid never
 278          * changes during a usbip connection.
 279          */
 280         sdev->devid             = (busnum << 16) | devnum;
 281         sdev->ud.side           = USBIP_STUB;
 282         sdev->ud.status         = SDEV_ST_AVAILABLE;
 283         spin_lock_init(&sdev->ud.lock);
 284         sdev->ud.tcp_socket     = NULL;
 285         sdev->ud.sockfd         = -1;
 286
 287         INIT_LIST_HEAD(&sdev->priv_init);
 288         INIT_LIST_HEAD(&sdev->priv_tx);
 289         INIT_LIST_HEAD(&sdev->priv_free);
 290         INIT_LIST_HEAD(&sdev->unlink_free);
 291         INIT_LIST_HEAD(&sdev->unlink_tx);
 292         spin_lock_init(&sdev->priv_lock);
 293
 294         init_waitqueue_head(&sdev->tx_waitq);
 295
 296         sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
 297         sdev->ud.eh_ops.reset    = stub_device_reset;
 298         sdev->ud.eh_ops.unusable = stub_device_unusable;
 299
 300         usbip_start_eh(&sdev->ud);
 301
 302         dev_dbg(&udev->dev, "register new device\n");
 303
 304         return sdev;
 305 }
 306
 307 static void stub_device_free(struct stub_device *sdev)
 308 {
 309         kfree(sdev);
 310 }
 311
 312 static int stub_probe(struct usb_device *udev)
 313 {
 314         struct stub_device *sdev = NULL;
 315         const char *udev_busid = dev_name(&udev->dev);
 316         struct bus_id_priv *busid_priv;
 317         int rc = 0;
 318
 319         dev_dbg(&udev->dev, "Enter probe\n");
 320
 321         /* check we should claim or not by busid_table */
 322         busid_priv = get_busid_priv(udev_busid);
 323         if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
 324             (busid_priv->status == STUB_BUSID_OTHER)) {
 325                 dev_info(&udev->dev,
 326                         "%s is not in match_busid table... skip!\n",
 327                         udev_busid);
 328
 329                 /*
 330                  * Return value should be ENODEV or ENOXIO to continue trying
 331                  * other matched drivers by the driver core.
 332                  * See driver_probe_device() in driver/base/dd.c
 333                  */
 334                 rc = -ENODEV;
 335                 goto call_put_busid_priv;
 336         }
 337
 338         if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
 339                 dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
 340                          udev_busid);
 341                 rc = -ENODEV;
 342                 goto call_put_busid_priv;
 343         }
 344
 345         if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
 346                 dev_dbg(&udev->dev,
 347                         "%s is attached on vhci_hcd... skip!\n",
 348                         udev_busid);
 349
 350                 rc = -ENODEV;
 351                 goto call_put_busid_priv;
 352         }
 353
 354         /* ok, this is my device */
 355         sdev = stub_device_alloc(udev);
 356         if (!sdev) {
 357                 rc = -ENOMEM;
 358                 goto call_put_busid_priv;
 359         }
 360
 361         dev_info(&udev->dev,
 362                 "usbip-host: register new device (bus %u dev %u)\n",
 363                 udev->bus->busnum, udev->devnum);
 364
 365         busid_priv->shutdown_busid = 0;
 366
 367         /* set private data to usb_device */
 368         dev_set_drvdata(&udev->dev, sdev);
 369         busid_priv->sdev = sdev;
 370         busid_priv->udev = udev;
 371
 372         /*
 373          * Claim this hub port.
 374          * It doesn't matter what value we pass as owner
 375          * (struct dev_state) as long as it is unique.
 376          */
 377         rc = usb_hub_claim_port(udev->parent, udev->portnum,
 378                         (struct usb_dev_state *) udev);
 379         if (rc) {
 380                 dev_dbg(&udev->dev, "unable to claim port\n");
 381                 goto err_port;
 382         }
 383
 384         rc = stub_add_files(&udev->dev);
 385         if (rc) {
 386                 dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
 387                 goto err_files;
 388         }
 389         busid_priv->status = STUB_BUSID_ALLOC;
 390
 391         rc = 0;
 392         goto call_put_busid_priv;
 393
 394 err_files:
 395         usb_hub_release_port(udev->parent, udev->portnum,
 396                              (struct usb_dev_state *) udev);
 397 err_port:
 398         dev_set_drvdata(&udev->dev, NULL);
 399         usb_put_dev(udev);
 400
 401         busid_priv->sdev = NULL;
 402         stub_device_free(sdev);
 403
 404 call_put_busid_priv:
 405         put_busid_priv(busid_priv);
 406         return rc;
 407 }
 408
 409 static void shutdown_busid(struct bus_id_priv *busid_priv)
 410 {
 411         if (busid_priv->sdev && !busid_priv->shutdown_busid) {
 412                 busid_priv->shutdown_busid = 1;
 413                 usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);
 414
 415                 /* wait for the stop of the event handler */
 416                 usbip_stop_eh(&busid_priv->sdev->ud);
 417         }
 418 }
 419
 420 /*
 421  * called in usb_disconnect() or usb_deregister()
 422  * but only if actconfig(active configuration) exists
 423  */
 424 static void stub_disconnect(struct usb_device *udev)
 425 {
 426         struct stub_device *sdev;
 427         const char *udev_busid = dev_name(&udev->dev);
 428         struct bus_id_priv *busid_priv;
 429         int rc;
 430
 431         dev_dbg(&udev->dev, "Enter disconnect\n");
 432
 433         busid_priv = get_busid_priv(udev_busid);
 434         if (!busid_priv) {
 435                 BUG();
 436                 return;
 437         }
 438
 439         sdev = dev_get_drvdata(&udev->dev);
 440
 441         /* get stub_device */
 442         if (!sdev) {
 443                 dev_err(&udev->dev, "could not get device");
 444                 goto call_put_busid_priv;
 445         }
 446
 447         dev_set_drvdata(&udev->dev, NULL);
 448
 449         /*
 450          * NOTE: rx/tx threads are invoked for each usb_device.
 451          */
 452         stub_remove_files(&udev->dev);
 453
 454         /* release port */
 455         rc = usb_hub_release_port(udev->parent, udev->portnum,
 456                                   (struct usb_dev_state *) udev);
 457         if (rc) {
 458                 dev_dbg(&udev->dev, "unable to release port\n");
 459                 goto call_put_busid_priv;
 460         }
 461
 462         /* If usb reset is called from event handler */
 463         if (usbip_in_eh(current))
 464                 goto call_put_busid_priv;
 465
 466         /* shutdown the current connection */
 467         shutdown_busid(busid_priv);
 468
 469         usb_put_dev(sdev->udev);
 470
 471         /* free sdev */
 472         busid_priv->sdev = NULL;
 473         stub_device_free(sdev);
 474
 475         if (busid_priv->status == STUB_BUSID_ALLOC)
 476                 busid_priv->status = STUB_BUSID_ADDED;
 477
 478 call_put_busid_priv:
 479         put_busid_priv(busid_priv);
 480 }
 481
 482 #ifdef CONFIG_PM
 483
 484 /* These functions need usb_port_suspend and usb_port_resume,
 485  * which reside in drivers/usb/core/usb.h. Skip for now. */
 486
 487 static int stub_suspend(struct usb_device *udev, pm_message_t message)
 488 {
 489         dev_dbg(&udev->dev, "stub_suspend\n");
 490
 491         return 0;
 492 }
 493
 494 static int stub_resume(struct usb_device *udev, pm_message_t message)
 495 {
 496         dev_dbg(&udev->dev, "stub_resume\n");
 497
 498         return 0;
 499 }
 500
 501 #endif  /* CONFIG_PM */
 502
 503 struct usb_device_driver stub_driver = {
 504         .name           = "usbip-host",
 505         .probe          = stub_probe,
 506         .disconnect     = stub_disconnect,
 507 #ifdef CONFIG_PM
 508         .suspend        = stub_suspend,
 509         .resume         = stub_resume,
 510 #endif
 511         .supports_autosuspend   =       0,
 512 };