drivers/usb/usbip/stub_rx.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 <asm/byteorder.h>
  21 #include <linux/kthread.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/hcd.h>
  24 #include <linux/scatterlist.h>
  25
  26 #include "usbip_common.h"
  27 #include "stub.h"
  28
  29 static int is_clear_halt_cmd(struct urb *urb)
  30 {
  31         struct usb_ctrlrequest *req;
  32
  33         req = (struct usb_ctrlrequest *) urb->setup_packet;
  34
  35          return (req->bRequest == USB_REQ_CLEAR_FEATURE) &&
  36                  (req->bRequestType == USB_RECIP_ENDPOINT) &&
  37                  (req->wValue == USB_ENDPOINT_HALT);
  38 }
  39
  40 static int is_set_interface_cmd(struct urb *urb)
  41 {
  42         struct usb_ctrlrequest *req;
  43
  44         req = (struct usb_ctrlrequest *) urb->setup_packet;
  45
  46         return (req->bRequest == USB_REQ_SET_INTERFACE) &&
  47                 (req->bRequestType == USB_RECIP_INTERFACE);
  48 }
  49
  50 static int is_set_configuration_cmd(struct urb *urb)
  51 {
  52         struct usb_ctrlrequest *req;
  53
  54         req = (struct usb_ctrlrequest *) urb->setup_packet;
  55
  56         return (req->bRequest == USB_REQ_SET_CONFIGURATION) &&
  57                 (req->bRequestType == USB_RECIP_DEVICE);
  58 }
  59
  60 static int is_reset_device_cmd(struct urb *urb)
  61 {
  62         struct usb_ctrlrequest *req;
  63         __u16 value;
  64         __u16 index;
  65
  66         req = (struct usb_ctrlrequest *) urb->setup_packet;
  67         value = le16_to_cpu(req->wValue);
  68         index = le16_to_cpu(req->wIndex);
  69
  70         if ((req->bRequest == USB_REQ_SET_FEATURE) &&
  71             (req->bRequestType == USB_RT_PORT) &&
  72             (value == USB_PORT_FEAT_RESET)) {
  73                 usbip_dbg_stub_rx("reset_device_cmd, port %u\n", index);
  74                 return 1;
  75         } else
  76                 return 0;
  77 }
  78
  79 static int tweak_clear_halt_cmd(struct urb *urb)
  80 {
  81         struct usb_ctrlrequest *req;
  82         int target_endp;
  83         int target_dir;
  84         int target_pipe;
  85         int ret;
  86
  87         req = (struct usb_ctrlrequest *) urb->setup_packet;
  88
  89         /*
  90          * The stalled endpoint is specified in the wIndex value. The endpoint
  91          * of the urb is the target of this clear_halt request (i.e., control
  92          * endpoint).
  93          */
  94         target_endp = le16_to_cpu(req->wIndex) & 0x000f;
  95
  96         /* the stalled endpoint direction is IN or OUT?. USB_DIR_IN is 0x80.  */
  97         target_dir = le16_to_cpu(req->wIndex) & 0x0080;
  98
  99         if (target_dir)
 100                 target_pipe = usb_rcvctrlpipe(urb->dev, target_endp);
 101         else
 102                 target_pipe = usb_sndctrlpipe(urb->dev, target_endp);
 103
 104         ret = usb_clear_halt(urb->dev, target_pipe);
 105         if (ret < 0)
 106                 dev_err(&urb->dev->dev,
 107                         "usb_clear_halt error: devnum %d endp %d ret %d\n",
 108                         urb->dev->devnum, target_endp, ret);
 109         else
 110                 dev_info(&urb->dev->dev,
 111                          "usb_clear_halt done: devnum %d endp %d\n",
 112                          urb->dev->devnum, target_endp);
 113
 114         return ret;
 115 }
 116
 117 static int tweak_set_interface_cmd(struct urb *urb)
 118 {
 119         struct usb_ctrlrequest *req;
 120         __u16 alternate;
 121         __u16 interface;
 122         int ret;
 123
 124         req = (struct usb_ctrlrequest *) urb->setup_packet;
 125         alternate = le16_to_cpu(req->wValue);
 126         interface = le16_to_cpu(req->wIndex);
 127
 128         usbip_dbg_stub_rx("set_interface: inf %u alt %u\n",
 129                           interface, alternate);
 130
 131         ret = usb_set_interface(urb->dev, interface, alternate);
 132         if (ret < 0)
 133                 dev_err(&urb->dev->dev,
 134                         "usb_set_interface error: inf %u alt %u ret %d\n",
 135                         interface, alternate, ret);
 136         else
 137                 dev_info(&urb->dev->dev,
 138                         "usb_set_interface done: inf %u alt %u\n",
 139                         interface, alternate);
 140
 141         return ret;
 142 }
 143
 144 static int tweak_set_configuration_cmd(struct urb *urb)
 145 {
 146         struct stub_priv *priv = (struct stub_priv *) urb->context;
 147         struct stub_device *sdev = priv->sdev;
 148         struct usb_ctrlrequest *req;
 149         __u16 config;
 150         int err;
 151
 152         req = (struct usb_ctrlrequest *) urb->setup_packet;
 153         config = le16_to_cpu(req->wValue);
 154
 155         err = usb_set_configuration(sdev->udev, config);
 156         if (err && err != -ENODEV)
 157                 dev_err(&sdev->udev->dev, "can't set config #%d, error %d\n",
 158                         config, err);
 159         return 0;
 160 }
 161
 162 static int tweak_reset_device_cmd(struct urb *urb)
 163 {
 164         struct stub_priv *priv = (struct stub_priv *) urb->context;
 165         struct stub_device *sdev = priv->sdev;
 166
 167         dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
 168
 169         if (usb_lock_device_for_reset(sdev->udev, NULL) < 0) {
 170                 dev_err(&urb->dev->dev, "could not obtain lock to reset device\n");
 171                 return 0;
 172         }
 173         usb_reset_device(sdev->udev);
 174         usb_unlock_device(sdev->udev);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * clear_halt, set_interface, and set_configuration require special tricks.
 181  */
 182 static void tweak_special_requests(struct urb *urb)
 183 {
 184         if (!urb || !urb->setup_packet)
 185                 return;
 186
 187         if (usb_pipetype(urb->pipe) != PIPE_CONTROL)
 188                 return;
 189
 190         if (is_clear_halt_cmd(urb))
 191                 /* tweak clear_halt */
 192                  tweak_clear_halt_cmd(urb);
 193
 194         else if (is_set_interface_cmd(urb))
 195                 /* tweak set_interface */
 196                 tweak_set_interface_cmd(urb);
 197
 198         else if (is_set_configuration_cmd(urb))
 199                 /* tweak set_configuration */
 200                 tweak_set_configuration_cmd(urb);
 201
 202         else if (is_reset_device_cmd(urb))
 203                 tweak_reset_device_cmd(urb);
 204         else
 205                 usbip_dbg_stub_rx("no need to tweak\n");
 206 }
 207
 208 /*
 209  * stub_recv_unlink() unlinks the URB by a call to usb_unlink_urb().
 210  * By unlinking the urb asynchronously, stub_rx can continuously
 211  * process coming urbs.  Even if the urb is unlinked, its completion
 212  * handler will be called and stub_tx will send a return pdu.
 213  *
 214  * See also comments about unlinking strategy in vhci_hcd.c.
 215  */
 216 static int stub_recv_cmd_unlink(struct stub_device *sdev,
 217                                 struct usbip_header *pdu)
 218 {
 219         int ret, i;
 220         unsigned long flags;
 221         struct stub_priv *priv;
 222
 223         spin_lock_irqsave(&sdev->priv_lock, flags);
 224
 225         list_for_each_entry(priv, &sdev->priv_init, list) {
 226                 if (priv->seqnum != pdu->u.cmd_unlink.seqnum)
 227                         continue;
 228
 229                 /*
 230                  * This matched urb is not completed yet (i.e., be in
 231                  * flight in usb hcd hardware/driver). Now we are
 232                  * cancelling it. The unlinking flag means that we are
 233                  * now not going to return the normal result pdu of a
 234                  * submission request, but going to return a result pdu
 235                  * of the unlink request.
 236                  */
 237                 priv->unlinking = 1;
 238
 239                 /*
 240                  * In the case that unlinking flag is on, prev->seqnum
 241                  * is changed from the seqnum of the cancelling urb to
 242                  * the seqnum of the unlink request. This will be used
 243                  * to make the result pdu of the unlink request.
 244                  */
 245                 priv->seqnum = pdu->base.seqnum;
 246
 247                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 248
 249                 /*
 250                  * usb_unlink_urb() is now out of spinlocking to avoid
 251                  * spinlock recursion since stub_complete() is
 252                  * sometimes called in this context but not in the
 253                  * interrupt context.  If stub_complete() is executed
 254                  * before we call usb_unlink_urb(), usb_unlink_urb()
 255                  * will return an error value. In this case, stub_tx
 256                  * will return the result pdu of this unlink request
 257                  * though submission is completed and actual unlinking
 258                  * is not executed. OK?
 259                  */
 260                 /* In the above case, urb->status is not -ECONNRESET,
 261                  * so a driver in a client host will know the failure
 262                  * of the unlink request ?
 263                  */
 264                 for (i = priv->completed_urbs; i < priv->num_urbs; i++) {
 265                         ret = usb_unlink_urb(priv->urbs[i]);
 266                         if (ret != -EINPROGRESS)
 267                                 dev_err(&priv->urbs[i]->dev->dev,
 268                                         "failed to unlink %d/%d urb of seqnum %lu, ret %d\n",
 269                                         i + 1, priv->num_urbs,
 270                                         priv->seqnum, ret);
 271                 }
 272                 return 0;
 273         }
 274
 275         usbip_dbg_stub_rx("seqnum %d is not pending\n",
 276                           pdu->u.cmd_unlink.seqnum);
 277
 278         /*
 279          * The urb of the unlink target is not found in priv_init queue. It was
 280          * already completed and its results is/was going to be sent by a
 281          * CMD_RET pdu. In this case, usb_unlink_urb() is not needed. We only
 282          * return the completeness of this unlink request to vhci_hcd.
 283          */
 284         stub_enqueue_ret_unlink(sdev, pdu->base.seqnum, 0);
 285
 286         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 287
 288         return 0;
 289 }
 290
 291 static int valid_request(struct stub_device *sdev, struct usbip_header *pdu)
 292 {
 293         struct usbip_device *ud = &sdev->ud;
 294         int valid = 0;
 295
 296         if (pdu->base.devid == sdev->devid) {
 297                 spin_lock_irq(&ud->lock);
 298                 if (ud->status == SDEV_ST_USED) {
 299                         /* A request is valid. */
 300                         valid = 1;
 301                 }
 302                 spin_unlock_irq(&ud->lock);
 303         }
 304
 305         return valid;
 306 }
 307
 308 static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
 309                                          struct usbip_header *pdu)
 310 {
 311         struct stub_priv *priv;
 312         struct usbip_device *ud = &sdev->ud;
 313         unsigned long flags;
 314
 315         spin_lock_irqsave(&sdev->priv_lock, flags);
 316
 317         priv = kmem_cache_zalloc(stub_priv_cache, GFP_ATOMIC);
 318         if (!priv) {
 319                 dev_err(&sdev->udev->dev, "alloc stub_priv\n");
 320                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 321                 usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 322                 return NULL;
 323         }
 324
 325         priv->seqnum = pdu->base.seqnum;
 326         priv->sdev = sdev;
 327
 328         /*
 329          * After a stub_priv is linked to a list_head,
 330          * our error handler can free allocated data.
 331          */
 332         list_add_tail(&priv->list, &sdev->priv_init);
 333
 334         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 335
 336         return priv;
 337 }
 338
 339 static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu)
 340 {
 341         struct usb_device *udev = sdev->udev;
 342         struct usb_host_endpoint *ep;
 343         struct usb_endpoint_descriptor *epd = NULL;
 344         int epnum = pdu->base.ep;
 345         int dir = pdu->base.direction;
 346
 347         if (epnum < 0 || epnum > 15)
 348                 goto err_ret;
 349
 350         if (dir == USBIP_DIR_IN)
 351                 ep = udev->ep_in[epnum & 0x7f];
 352         else
 353                 ep = udev->ep_out[epnum & 0x7f];
 354         if (!ep)
 355                 goto err_ret;
 356
 357         epd = &ep->desc;
 358
 359         if (usb_endpoint_xfer_control(epd)) {
 360                 if (dir == USBIP_DIR_OUT)
 361                         return usb_sndctrlpipe(udev, epnum);
 362                 else
 363                         return usb_rcvctrlpipe(udev, epnum);
 364         }
 365
 366         if (usb_endpoint_xfer_bulk(epd)) {
 367                 if (dir == USBIP_DIR_OUT)
 368                         return usb_sndbulkpipe(udev, epnum);
 369                 else
 370                         return usb_rcvbulkpipe(udev, epnum);
 371         }
 372
 373         if (usb_endpoint_xfer_int(epd)) {
 374                 if (dir == USBIP_DIR_OUT)
 375                         return usb_sndintpipe(udev, epnum);
 376                 else
 377                         return usb_rcvintpipe(udev, epnum);
 378         }
 379
 380         if (usb_endpoint_xfer_isoc(epd)) {
 381                 /* validate number of packets */
 382                 if (pdu->u.cmd_submit.number_of_packets < 0 ||
 383                     pdu->u.cmd_submit.number_of_packets >
 384                     USBIP_MAX_ISO_PACKETS) {
 385                         dev_err(&sdev->udev->dev,
 386                                 "CMD_SUBMIT: isoc invalid num packets %d\n",
 387                                 pdu->u.cmd_submit.number_of_packets);
 388                         return -1;
 389                 }
 390                 if (dir == USBIP_DIR_OUT)
 391                         return usb_sndisocpipe(udev, epnum);
 392                 else
 393                         return usb_rcvisocpipe(udev, epnum);
 394         }
 395
 396 err_ret:
 397         /* NOT REACHED */
 398         dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum);
 399         return -1;
 400 }
 401
 402 static void masking_bogus_flags(struct urb *urb)
 403 {
 404         int                             xfertype;
 405         struct usb_device               *dev;
 406         struct usb_host_endpoint        *ep;
 407         int                             is_out;
 408         unsigned int    allowed;
 409
 410         if (!urb || urb->hcpriv || !urb->complete)
 411                 return;
 412         dev = urb->dev;
 413         if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
 414                 return;
 415
 416         ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out)
 417                 [usb_pipeendpoint(urb->pipe)];
 418         if (!ep)
 419                 return;
 420
 421         xfertype = usb_endpoint_type(&ep->desc);
 422         if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
 423                 struct usb_ctrlrequest *setup =
 424                         (struct usb_ctrlrequest *) urb->setup_packet;
 425
 426                 if (!setup)
 427                         return;
 428                 is_out = !(setup->bRequestType & USB_DIR_IN) ||
 429                         !setup->wLength;
 430         } else {
 431                 is_out = usb_endpoint_dir_out(&ep->desc);
 432         }
 433
 434         /* enforce simple/standard policy */
 435         allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT |
 436                    URB_DIR_MASK | URB_FREE_BUFFER);
 437         switch (xfertype) {
 438         case USB_ENDPOINT_XFER_BULK:
 439                 if (is_out)
 440                         allowed |= URB_ZERO_PACKET;
 441                 /* FALLTHROUGH */
 442         case USB_ENDPOINT_XFER_CONTROL:
 443                 allowed |= URB_NO_FSBR; /* only affects UHCI */
 444                 /* FALLTHROUGH */
 445         default:                        /* all non-iso endpoints */
 446                 if (!is_out)
 447                         allowed |= URB_SHORT_NOT_OK;
 448                 break;
 449         case USB_ENDPOINT_XFER_ISOC:
 450                 allowed |= URB_ISO_ASAP;
 451                 break;
 452         }
 453         urb->transfer_flags &= allowed;
 454 }
 455
 456 static int stub_recv_xbuff(struct usbip_device *ud, struct stub_priv *priv)
 457 {
 458         int ret;
 459         int i;
 460
 461         for (i = 0; i < priv->num_urbs; i++) {
 462                 ret = usbip_recv_xbuff(ud, priv->urbs[i]);
 463                 if (ret < 0)
 464                         break;
 465         }
 466
 467         return ret;
 468 }
 469
 470 static void stub_recv_cmd_submit(struct stub_device *sdev,
 471                                  struct usbip_header *pdu)
 472 {
 473         struct stub_priv *priv;
 474         struct usbip_device *ud = &sdev->ud;
 475         struct usb_device *udev = sdev->udev;
 476         struct scatterlist *sgl = NULL, *sg;
 477         void *buffer = NULL;
 478         unsigned long long buf_len;
 479         int nents;
 480         int num_urbs = 1;
 481         int pipe = get_pipe(sdev, pdu);
 482         int use_sg = pdu->u.cmd_submit.transfer_flags & URB_DMA_MAP_SG;
 483         int support_sg = 1;
 484         int np = 0;
 485         int ret, i;
 486
 487         if (pipe == -1)
 488                 return;
 489
 490         /*
 491          * Smatch reported the error case where use_sg is true and buf_len is 0.
 492          * In this case, It adds SDEV_EVENT_ERROR_MALLOC and stub_priv will be
 493          * released by stub event handler and connection will be shut down.
 494          */
 495         priv = stub_priv_alloc(sdev, pdu);
 496         if (!priv)
 497                 return;
 498
 499         buf_len = (unsigned long long)pdu->u.cmd_submit.transfer_buffer_length;
 500
 501         if (use_sg && !buf_len) {
 502                 dev_err(&udev->dev, "sg buffer with zero length\n");
 503                 goto err_malloc;
 504         }
 505
 506         /* allocate urb transfer buffer, if needed */
 507         if (buf_len) {
 508                 if (use_sg) {
 509                         sgl = sgl_alloc(buf_len, GFP_KERNEL, &nents);
 510                         if (!sgl)
 511                                 goto err_malloc;
 512
 513                         /* Check if the server's HCD supports SG */
 514                         if (!udev->bus->sg_tablesize) {
 515                                 /*
 516                                  * If the server's HCD doesn't support SG, break
 517                                  * a single SG request into several URBs and map
 518                                  * each SG list entry to corresponding URB
 519                                  * buffer. The previously allocated SG list is
 520                                  * stored in priv->sgl (If the server's HCD
 521                                  * support SG, SG list is stored only in
 522                                  * urb->sg) and it is used as an indicator that
 523                                  * the server split single SG request into
 524                                  * several URBs. Later, priv->sgl is used by
 525                                  * stub_complete() and stub_send_ret_submit() to
 526                                  * reassemble the divied URBs.
 527                                  */
 528                                 support_sg = 0;
 529                                 num_urbs = nents;
 530                                 priv->completed_urbs = 0;
 531                                 pdu->u.cmd_submit.transfer_flags &=
 532                                                                 ~URB_DMA_MAP_SG;
 533                         }
 534                 } else {
 535                         buffer = kzalloc(buf_len, GFP_KERNEL);
 536                         if (!buffer)
 537                                 goto err_malloc;
 538                 }
 539         }
 540
 541         /* allocate urb array */
 542         priv->num_urbs = num_urbs;
 543         priv->urbs = kmalloc_array(num_urbs, sizeof(*priv->urbs), GFP_KERNEL);
 544         if (!priv->urbs)
 545                 goto err_urbs;
 546
 547         /* setup a urb */
 548         if (support_sg) {
 549                 if (usb_pipeisoc(pipe))
 550                         np = pdu->u.cmd_submit.number_of_packets;
 551
 552                 priv->urbs[0] = usb_alloc_urb(np, GFP_KERNEL);
 553                 if (!priv->urbs[0])
 554                         goto err_urb;
 555
 556                 if (buf_len) {
 557                         if (use_sg) {
 558                                 priv->urbs[0]->sg = sgl;
 559                                 priv->urbs[0]->num_sgs = nents;
 560                                 priv->urbs[0]->transfer_buffer = NULL;
 561                         } else {
 562                                 priv->urbs[0]->transfer_buffer = buffer;
 563                         }
 564                 }
 565
 566                 /* copy urb setup packet */
 567                 priv->urbs[0]->setup_packet = kmemdup(&pdu->u.cmd_submit.setup,
 568                                         8, GFP_KERNEL);
 569                 if (!priv->urbs[0]->setup_packet) {
 570                         usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 571                         return;
 572                 }
 573
 574                 usbip_pack_pdu(pdu, priv->urbs[0], USBIP_CMD_SUBMIT, 0);
 575         } else {
 576                 for_each_sg(sgl, sg, nents, i) {
 577                         priv->urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
 578                         /* The URBs which is previously allocated will be freed
 579                          * in stub_device_cleanup_urbs() if error occurs.
 580                          */
 581                         if (!priv->urbs[i])
 582                                 goto err_urb;
 583
 584                         usbip_pack_pdu(pdu, priv->urbs[i], USBIP_CMD_SUBMIT, 0);
 585                         priv->urbs[i]->transfer_buffer = sg_virt(sg);
 586                         priv->urbs[i]->transfer_buffer_length = sg->length;
 587                 }
 588                 priv->sgl = sgl;
 589         }
 590
 591         for (i = 0; i < num_urbs; i++) {
 592                 /* set other members from the base header of pdu */
 593                 priv->urbs[i]->context = (void *) priv;
 594                 priv->urbs[i]->dev = udev;
 595                 priv->urbs[i]->pipe = pipe;
 596                 priv->urbs[i]->complete = stub_complete;
 597
 598                 /* no need to submit an intercepted request, but harmless? */
 599                 tweak_special_requests(priv->urbs[i]);
 600
 601                 masking_bogus_flags(priv->urbs[i]);
 602         }
 603
 604         if (stub_recv_xbuff(ud, priv) < 0)
 605                 return;
 606
 607         if (usbip_recv_iso(ud, priv->urbs[0]) < 0)
 608                 return;
 609
 610         /* urb is now ready to submit */
 611         for (i = 0; i < priv->num_urbs; i++) {
 612                 ret = usb_submit_urb(priv->urbs[i], GFP_KERNEL);
 613
 614                 if (ret == 0)
 615                         usbip_dbg_stub_rx("submit urb ok, seqnum %u\n",
 616                                         pdu->base.seqnum);
 617                 else {
 618                         dev_err(&udev->dev, "submit_urb error, %d\n", ret);
 619                         usbip_dump_header(pdu);
 620                         usbip_dump_urb(priv->urbs[i]);
 621
 622                         /*
 623                          * Pessimistic.
 624                          * This connection will be discarded.
 625                          */
 626                         usbip_event_add(ud, SDEV_EVENT_ERROR_SUBMIT);
 627                         break;
 628                 }
 629         }
 630
 631         usbip_dbg_stub_rx("Leave\n");
 632         return;
 633
 634 err_urb:
 635         kfree(priv->urbs);
 636 err_urbs:
 637         kfree(buffer);
 638         sgl_free(sgl);
 639 err_malloc:
 640         usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 641 }
 642
 643 /* recv a pdu */
 644 static void stub_rx_pdu(struct usbip_device *ud)
 645 {
 646         int ret;
 647         struct usbip_header pdu;
 648         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 649         struct device *dev = &sdev->udev->dev;
 650
 651         usbip_dbg_stub_rx("Enter\n");
 652
 653         memset(&pdu, 0, sizeof(pdu));
 654
 655         /* receive a pdu header */
 656         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 657         if (ret != sizeof(pdu)) {
 658                 dev_err(dev, "recv a header, %d\n", ret);
 659                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 660                 return;
 661         }
 662
 663         usbip_header_correct_endian(&pdu, 0);
 664
 665         if (usbip_dbg_flag_stub_rx)
 666                 usbip_dump_header(&pdu);
 667
 668         if (!valid_request(sdev, &pdu)) {
 669                 dev_err(dev, "recv invalid request\n");
 670                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 671                 return;
 672         }
 673
 674         switch (pdu.base.command) {
 675         case USBIP_CMD_UNLINK:
 676                 stub_recv_cmd_unlink(sdev, &pdu);
 677                 break;
 678
 679         case USBIP_CMD_SUBMIT:
 680                 stub_recv_cmd_submit(sdev, &pdu);
 681                 break;
 682
 683         default:
 684                 /* NOTREACHED */
 685                 dev_err(dev, "unknown pdu\n");
 686                 usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
 687                 break;
 688         }
 689 }
 690
 691 int stub_rx_loop(void *data)
 692 {
 693         struct usbip_device *ud = data;
 694
 695         while (!kthread_should_stop()) {
 696                 if (usbip_event_happened(ud))
 697                         break;
 698
 699                 stub_rx_pdu(ud);
 700         }
 701
 702         return 0;
 703 }