root/drivers/usb/usbip/stub_tx.c

DEFINITIONS

1. stub_enqueue_ret_unlink
2. stub_complete
3. setup_base_pdu
4. setup_ret_submit_pdu
5. setup_ret_unlink_pdu
6. dequeue_from_priv_tx
7. stub_send_ret_submit
8. dequeue_from_unlink_tx
9. stub_send_ret_unlink
10. stub_tx_loop

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   4  */
   5 
   6 #include <linux/kthread.h>
   7 #include <linux/socket.h>
   8 #include <linux/scatterlist.h>
   9 
  10 #include "usbip_common.h"
  11 #include "stub.h"
  12 
  13 /* be in spin_lock_irqsave(&sdev->priv_lock, flags) */
  14 void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
  15                              __u32 status)
  16 {
  17         struct stub_unlink *unlink;
  18 
  19         unlink = kzalloc(sizeof(struct stub_unlink), GFP_ATOMIC);
  20         if (!unlink) {
  21                 usbip_event_add(&sdev->ud, VDEV_EVENT_ERROR_MALLOC);
  22                 return;
  23         }
  24 
  25         unlink->seqnum = seqnum;
  26         unlink->status = status;
  27 
  28         list_add_tail(&unlink->list, &sdev->unlink_tx);
  29 }
  30 
  31 /**
  32  * stub_complete - completion handler of a usbip urb
  33  * @urb: pointer to the urb completed
  34  *
  35  * When a urb has completed, the USB core driver calls this function mostly in
  36  * the interrupt context. To return the result of a urb, the completed urb is
  37  * linked to the pending list of returning.
  38  *
  39  */
  40 void stub_complete(struct urb *urb)
  41 {
  42         struct stub_priv *priv = (struct stub_priv *) urb->context;
  43         struct stub_device *sdev = priv->sdev;
  44         unsigned long flags;
  45 
  46         usbip_dbg_stub_tx("complete! status %d\n", urb->status);
  47 
  48         switch (urb->status) {
  49         case 0:
  50                 /* OK */
  51                 break;
  52         case -ENOENT:
  53                 dev_info(&urb->dev->dev,
  54                          "stopped by a call to usb_kill_urb() because of cleaning up a virtual connection\n");
  55                 return;
  56         case -ECONNRESET:
  57                 dev_info(&urb->dev->dev,
  58                          "unlinked by a call to usb_unlink_urb()\n");
  59                 break;
  60         case -EPIPE:
  61                 dev_info(&urb->dev->dev, "endpoint %d is stalled\n",
  62                          usb_pipeendpoint(urb->pipe));
  63                 break;
  64         case -ESHUTDOWN:
  65                 dev_info(&urb->dev->dev, "device removed?\n");
  66                 break;
  67         default:
  68                 dev_info(&urb->dev->dev,
  69                          "urb completion with non-zero status %d\n",
  70                          urb->status);
  71                 break;
  72         }
  73 
  74         /*
  75          * If the server breaks single SG request into the several URBs, the
  76          * URBs must be reassembled before sending completed URB to the vhci.
  77          * Don't wake up the tx thread until all the URBs are completed.
  78          */
  79         if (priv->sgl) {
  80                 priv->completed_urbs++;
  81 
  82                 /* Only save the first error status */
  83                 if (urb->status && !priv->urb_status)
  84                         priv->urb_status = urb->status;
  85 
  86                 if (priv->completed_urbs < priv->num_urbs)
  87                         return;
  88         }
  89 
  90         /* link a urb to the queue of tx. */
  91         spin_lock_irqsave(&sdev->priv_lock, flags);
  92         if (sdev->ud.tcp_socket == NULL) {
  93                 usbip_dbg_stub_tx("ignore urb for closed connection\n");
  94                 /* It will be freed in stub_device_cleanup_urbs(). */
  95         } else if (priv->unlinking) {
  96                 stub_enqueue_ret_unlink(sdev, priv->seqnum, urb->status);
  97                 stub_free_priv_and_urb(priv);
  98         } else {
  99                 list_move_tail(&priv->list, &sdev->priv_tx);
 100         }
 101         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 102 
 103         /* wake up tx_thread */
 104         wake_up(&sdev->tx_waitq);
 105 }
 106 
 107 static inline void setup_base_pdu(struct usbip_header_basic *base,
 108                                   __u32 command, __u32 seqnum)
 109 {
 110         base->command   = command;
 111         base->seqnum    = seqnum;
 112         base->devid     = 0;
 113         base->ep        = 0;
 114         base->direction = 0;
 115 }
 116 
 117 static void setup_ret_submit_pdu(struct usbip_header *rpdu, struct urb *urb)
 118 {
 119         struct stub_priv *priv = (struct stub_priv *) urb->context;
 120 
 121         setup_base_pdu(&rpdu->base, USBIP_RET_SUBMIT, priv->seqnum);
 122         usbip_pack_pdu(rpdu, urb, USBIP_RET_SUBMIT, 1);
 123 }
 124 
 125 static void setup_ret_unlink_pdu(struct usbip_header *rpdu,
 126                                  struct stub_unlink *unlink)
 127 {
 128         setup_base_pdu(&rpdu->base, USBIP_RET_UNLINK, unlink->seqnum);
 129         rpdu->u.ret_unlink.status = unlink->status;
 130 }
 131 
 132 static struct stub_priv *dequeue_from_priv_tx(struct stub_device *sdev)
 133 {
 134         unsigned long flags;
 135         struct stub_priv *priv, *tmp;
 136 
 137         spin_lock_irqsave(&sdev->priv_lock, flags);
 138 
 139         list_for_each_entry_safe(priv, tmp, &sdev->priv_tx, list) {
 140                 list_move_tail(&priv->list, &sdev->priv_free);
 141                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 142                 return priv;
 143         }
 144 
 145         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 146 
 147         return NULL;
 148 }
 149 
 150 static int stub_send_ret_submit(struct stub_device *sdev)
 151 {
 152         unsigned long flags;
 153         struct stub_priv *priv, *tmp;
 154 
 155         struct msghdr msg;
 156         size_t txsize;
 157 
 158         size_t total_size = 0;
 159 
 160         while ((priv = dequeue_from_priv_tx(sdev)) != NULL) {
 161                 struct urb *urb = priv->urbs[0];
 162                 struct usbip_header pdu_header;
 163                 struct usbip_iso_packet_descriptor *iso_buffer = NULL;
 164                 struct kvec *iov = NULL;
 165                 struct scatterlist *sg;
 166                 u32 actual_length = 0;
 167                 int iovnum = 0;
 168                 int ret;
 169                 int i;
 170 
 171                 txsize = 0;
 172                 memset(&pdu_header, 0, sizeof(pdu_header));
 173                 memset(&msg, 0, sizeof(msg));
 174 
 175                 if (urb->actual_length > 0 && !urb->transfer_buffer &&
 176                    !urb->num_sgs) {
 177                         dev_err(&sdev->udev->dev,
 178                                 "urb: actual_length %d transfer_buffer null\n",
 179                                 urb->actual_length);
 180                         return -1;
 181                 }
 182 
 183                 if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
 184                         iovnum = 2 + urb->number_of_packets;
 185                 else if (usb_pipein(urb->pipe) && urb->actual_length > 0 &&
 186                         urb->num_sgs)
 187                         iovnum = 1 + urb->num_sgs;
 188                 else if (usb_pipein(urb->pipe) && priv->sgl)
 189                         iovnum = 1 + priv->num_urbs;
 190                 else
 191                         iovnum = 2;
 192 
 193                 iov = kcalloc(iovnum, sizeof(struct kvec), GFP_KERNEL);
 194 
 195                 if (!iov) {
 196                         usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_MALLOC);
 197                         return -1;
 198                 }
 199 
 200                 iovnum = 0;
 201 
 202                 /* 1. setup usbip_header */
 203                 setup_ret_submit_pdu(&pdu_header, urb);
 204                 usbip_dbg_stub_tx("setup txdata seqnum: %d\n",
 205                                   pdu_header.base.seqnum);
 206 
 207                 if (priv->sgl) {
 208                         for (i = 0; i < priv->num_urbs; i++)
 209                                 actual_length += priv->urbs[i]->actual_length;
 210 
 211                         pdu_header.u.ret_submit.status = priv->urb_status;
 212                         pdu_header.u.ret_submit.actual_length = actual_length;
 213                 }
 214 
 215                 usbip_header_correct_endian(&pdu_header, 1);
 216 
 217                 iov[iovnum].iov_base = &pdu_header;
 218                 iov[iovnum].iov_len  = sizeof(pdu_header);
 219                 iovnum++;
 220                 txsize += sizeof(pdu_header);
 221 
 222                 /* 2. setup transfer buffer */
 223                 if (usb_pipein(urb->pipe) && priv->sgl) {
 224                         /* If the server split a single SG request into several
 225                          * URBs because the server's HCD doesn't support SG,
 226                          * reassemble the split URB buffers into a single
 227                          * return command.
 228                          */
 229                         for (i = 0; i < priv->num_urbs; i++) {
 230                                 iov[iovnum].iov_base =
 231                                         priv->urbs[i]->transfer_buffer;
 232                                 iov[iovnum].iov_len =
 233                                         priv->urbs[i]->actual_length;
 234                                 iovnum++;
 235                         }
 236                         txsize += actual_length;
 237                 } else if (usb_pipein(urb->pipe) &&
 238                     usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS &&
 239                     urb->actual_length > 0) {
 240                         if (urb->num_sgs) {
 241                                 unsigned int copy = urb->actual_length;
 242                                 int size;
 243 
 244                                 for_each_sg(urb->sg, sg, urb->num_sgs, i) {
 245                                         if (copy == 0)
 246                                                 break;
 247 
 248                                         if (copy < sg->length)
 249                                                 size = copy;
 250                                         else
 251                                                 size = sg->length;
 252 
 253                                         iov[iovnum].iov_base = sg_virt(sg);
 254                                         iov[iovnum].iov_len = size;
 255 
 256                                         iovnum++;
 257                                         copy -= size;
 258                                 }
 259                         } else {
 260                                 iov[iovnum].iov_base = urb->transfer_buffer;
 261                                 iov[iovnum].iov_len  = urb->actual_length;
 262                                 iovnum++;
 263                         }
 264                         txsize += urb->actual_length;
 265                 } else if (usb_pipein(urb->pipe) &&
 266                            usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
 267                         /*
 268                          * For isochronous packets: actual length is the sum of
 269                          * the actual length of the individual, packets, but as
 270                          * the packet offsets are not changed there will be
 271                          * padding between the packets. To optimally use the
 272                          * bandwidth the padding is not transmitted.
 273                          */
 274 
 275                         int i;
 276 
 277                         for (i = 0; i < urb->number_of_packets; i++) {
 278                                 iov[iovnum].iov_base = urb->transfer_buffer +
 279                                         urb->iso_frame_desc[i].offset;
 280                                 iov[iovnum].iov_len =
 281                                         urb->iso_frame_desc[i].actual_length;
 282                                 iovnum++;
 283                                 txsize += urb->iso_frame_desc[i].actual_length;
 284                         }
 285 
 286                         if (txsize != sizeof(pdu_header) + urb->actual_length) {
 287                                 dev_err(&sdev->udev->dev,
 288                                         "actual length of urb %d does not match iso packet sizes %zu\n",
 289                                         urb->actual_length,
 290                                         txsize-sizeof(pdu_header));
 291                                 kfree(iov);
 292                                 usbip_event_add(&sdev->ud,
 293                                                 SDEV_EVENT_ERROR_TCP);
 294                            return -1;
 295                         }
 296                 }
 297 
 298                 /* 3. setup iso_packet_descriptor */
 299                 if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
 300                         ssize_t len = 0;
 301 
 302                         iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
 303                         if (!iso_buffer) {
 304                                 usbip_event_add(&sdev->ud,
 305                                                 SDEV_EVENT_ERROR_MALLOC);
 306                                 kfree(iov);
 307                                 return -1;
 308                         }
 309 
 310                         iov[iovnum].iov_base = iso_buffer;
 311                         iov[iovnum].iov_len  = len;
 312                         txsize += len;
 313                         iovnum++;
 314                 }
 315 
 316                 ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg,
 317                                                 iov,  iovnum, txsize);
 318                 if (ret != txsize) {
 319                         dev_err(&sdev->udev->dev,
 320                                 "sendmsg failed!, retval %d for %zd\n",
 321                                 ret, txsize);
 322                         kfree(iov);
 323                         kfree(iso_buffer);
 324                         usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
 325                         return -1;
 326                 }
 327 
 328                 kfree(iov);
 329                 kfree(iso_buffer);
 330 
 331                 total_size += txsize;
 332         }
 333 
 334         spin_lock_irqsave(&sdev->priv_lock, flags);
 335         list_for_each_entry_safe(priv, tmp, &sdev->priv_free, list) {
 336                 stub_free_priv_and_urb(priv);
 337         }
 338         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 339 
 340         return total_size;
 341 }
 342 
 343 static struct stub_unlink *dequeue_from_unlink_tx(struct stub_device *sdev)
 344 {
 345         unsigned long flags;
 346         struct stub_unlink *unlink, *tmp;
 347 
 348         spin_lock_irqsave(&sdev->priv_lock, flags);
 349 
 350         list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
 351                 list_move_tail(&unlink->list, &sdev->unlink_free);
 352                 spin_unlock_irqrestore(&sdev->priv_lock, flags);
 353                 return unlink;
 354         }
 355 
 356         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 357 
 358         return NULL;
 359 }
 360 
 361 static int stub_send_ret_unlink(struct stub_device *sdev)
 362 {
 363         unsigned long flags;
 364         struct stub_unlink *unlink, *tmp;
 365 
 366         struct msghdr msg;
 367         struct kvec iov[1];
 368         size_t txsize;
 369 
 370         size_t total_size = 0;
 371 
 372         while ((unlink = dequeue_from_unlink_tx(sdev)) != NULL) {
 373                 int ret;
 374                 struct usbip_header pdu_header;
 375 
 376                 txsize = 0;
 377                 memset(&pdu_header, 0, sizeof(pdu_header));
 378                 memset(&msg, 0, sizeof(msg));
 379                 memset(&iov, 0, sizeof(iov));
 380 
 381                 usbip_dbg_stub_tx("setup ret unlink %lu\n", unlink->seqnum);
 382 
 383                 /* 1. setup usbip_header */
 384                 setup_ret_unlink_pdu(&pdu_header, unlink);
 385                 usbip_header_correct_endian(&pdu_header, 1);
 386 
 387                 iov[0].iov_base = &pdu_header;
 388                 iov[0].iov_len  = sizeof(pdu_header);
 389                 txsize += sizeof(pdu_header);
 390 
 391                 ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov,
 392                                      1, txsize);
 393                 if (ret != txsize) {
 394                         dev_err(&sdev->udev->dev,
 395                                 "sendmsg failed!, retval %d for %zd\n",
 396                                 ret, txsize);
 397                         usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
 398                         return -1;
 399                 }
 400 
 401                 usbip_dbg_stub_tx("send txdata\n");
 402                 total_size += txsize;
 403         }
 404 
 405         spin_lock_irqsave(&sdev->priv_lock, flags);
 406 
 407         list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free, list) {
 408                 list_del(&unlink->list);
 409                 kfree(unlink);
 410         }
 411 
 412         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 413 
 414         return total_size;
 415 }
 416 
 417 int stub_tx_loop(void *data)
 418 {
 419         struct usbip_device *ud = data;
 420         struct stub_device *sdev = container_of(ud, struct stub_device, ud);
 421 
 422         while (!kthread_should_stop()) {
 423                 if (usbip_event_happened(ud))
 424                         break;
 425 
 426                 /*
 427                  * send_ret_submit comes earlier than send_ret_unlink.  stub_rx
 428                  * looks at only priv_init queue. If the completion of a URB is
 429                  * earlier than the receive of CMD_UNLINK, priv is moved to
 430                  * priv_tx queue and stub_rx does not find the target priv. In
 431                  * this case, vhci_rx receives the result of the submit request
 432                  * and then receives the result of the unlink request. The
 433                  * result of the submit is given back to the usbcore as the
 434                  * completion of the unlink request. The request of the
 435                  * unlink is ignored. This is ok because a driver who calls
 436                  * usb_unlink_urb() understands the unlink was too late by
 437                  * getting the status of the given-backed URB which has the
 438                  * status of usb_submit_urb().
 439                  */
 440                 if (stub_send_ret_submit(sdev) < 0)
 441                         break;
 442 
 443                 if (stub_send_ret_unlink(sdev) < 0)
 444                         break;
 445 
 446                 wait_event_interruptible(sdev->tx_waitq,
 447                                          (!list_empty(&sdev->priv_tx) ||
 448                                           !list_empty(&sdev->unlink_tx) ||
 449                                           kthread_should_stop()));
 450         }
 451 
 452         return 0;
 453 }