net/vmw_vsock/virtio_transport.c

   1 /*
   2  * virtio transport for vsock
   3  *
   4  * Copyright (C) 2013-2015 Red Hat, Inc.
   5  * Author: Asias He <asias@redhat.com>
   6  *         Stefan Hajnoczi <stefanha@redhat.com>
   7  *
   8  * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s
   9  * early virtio-vsock proof-of-concept bits.
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.
  12  */
  13 #include <linux/spinlock.h>
  14 #include <linux/module.h>
  15 #include <linux/list.h>
  16 #include <linux/atomic.h>
  17 #include <linux/virtio.h>
  18 #include <linux/virtio_ids.h>
  19 #include <linux/virtio_config.h>
  20 #include <linux/virtio_vsock.h>
  21 #include <net/sock.h>
  22 #include <linux/mutex.h>
  23 #include <net/af_vsock.h>
  24
  25 static struct workqueue_struct *virtio_vsock_workqueue;
  26 static struct virtio_vsock *the_virtio_vsock;
  27 static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */
  28
  29 struct virtio_vsock {
  30         struct virtio_device *vdev;
  31         struct virtqueue *vqs[VSOCK_VQ_MAX];
  32
  33         /* Virtqueue processing is deferred to a workqueue */
  34         struct work_struct tx_work;
  35         struct work_struct rx_work;
  36         struct work_struct event_work;
  37
  38         /* The following fields are protected by tx_lock.  vqs[VSOCK_VQ_TX]
  39          * must be accessed with tx_lock held.
  40          */
  41         struct mutex tx_lock;
  42
  43         struct work_struct send_pkt_work;
  44         spinlock_t send_pkt_list_lock;
  45         struct list_head send_pkt_list;
  46
  47         struct work_struct loopback_work;
  48         spinlock_t loopback_list_lock; /* protects loopback_list */
  49         struct list_head loopback_list;
  50
  51         atomic_t queued_replies;
  52
  53         /* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
  54          * must be accessed with rx_lock held.
  55          */
  56         struct mutex rx_lock;
  57         int rx_buf_nr;
  58         int rx_buf_max_nr;
  59
  60         /* The following fields are protected by event_lock.
  61          * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
  62          */
  63         struct mutex event_lock;
  64         struct virtio_vsock_event event_list[8];
  65
  66         u32 guest_cid;
  67 };
  68
  69 static struct virtio_vsock *virtio_vsock_get(void)
  70 {
  71         return the_virtio_vsock;
  72 }
  73
  74 static u32 virtio_transport_get_local_cid(void)
  75 {
  76         struct virtio_vsock *vsock = virtio_vsock_get();
  77
  78         return vsock->guest_cid;
  79 }
  80
  81 static void virtio_transport_loopback_work(struct work_struct *work)
  82 {
  83         struct virtio_vsock *vsock =
  84                 container_of(work, struct virtio_vsock, loopback_work);
  85         LIST_HEAD(pkts);
  86
  87         spin_lock_bh(&vsock->loopback_list_lock);
  88         list_splice_init(&vsock->loopback_list, &pkts);
  89         spin_unlock_bh(&vsock->loopback_list_lock);
  90
  91         mutex_lock(&vsock->rx_lock);
  92         while (!list_empty(&pkts)) {
  93                 struct virtio_vsock_pkt *pkt;
  94
  95                 pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
  96                 list_del_init(&pkt->list);
  97
  98                 virtio_transport_recv_pkt(pkt);
  99         }
 100         mutex_unlock(&vsock->rx_lock);
 101 }
 102
 103 static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
 104                                               struct virtio_vsock_pkt *pkt)
 105 {
 106         int len = pkt->len;
 107
 108         spin_lock_bh(&vsock->loopback_list_lock);
 109         list_add_tail(&pkt->list, &vsock->loopback_list);
 110         spin_unlock_bh(&vsock->loopback_list_lock);
 111
 112         queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
 113
 114         return len;
 115 }
 116
 117 static void
 118 virtio_transport_send_pkt_work(struct work_struct *work)
 119 {
 120         struct virtio_vsock *vsock =
 121                 container_of(work, struct virtio_vsock, send_pkt_work);
 122         struct virtqueue *vq;
 123         bool added = false;
 124         bool restart_rx = false;
 125
 126         mutex_lock(&vsock->tx_lock);
 127
 128         vq = vsock->vqs[VSOCK_VQ_TX];
 129
 130         for (;;) {
 131                 struct virtio_vsock_pkt *pkt;
 132                 struct scatterlist hdr, buf, *sgs[2];
 133                 int ret, in_sg = 0, out_sg = 0;
 134                 bool reply;
 135
 136                 spin_lock_bh(&vsock->send_pkt_list_lock);
 137                 if (list_empty(&vsock->send_pkt_list)) {
 138                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 139                         break;
 140                 }
 141
 142                 pkt = list_first_entry(&vsock->send_pkt_list,
 143                                        struct virtio_vsock_pkt, list);
 144                 list_del_init(&pkt->list);
 145                 spin_unlock_bh(&vsock->send_pkt_list_lock);
 146
 147                 reply = pkt->reply;
 148
 149                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 150                 sgs[out_sg++] = &hdr;
 151                 if (pkt->buf) {
 152                         sg_init_one(&buf, pkt->buf, pkt->len);
 153                         sgs[out_sg++] = &buf;
 154                 }
 155
 156                 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL);
 157                 /* Usually this means that there is no more space available in
 158                  * the vq
 159                  */
 160                 if (ret < 0) {
 161                         spin_lock_bh(&vsock->send_pkt_list_lock);
 162                         list_add(&pkt->list, &vsock->send_pkt_list);
 163                         spin_unlock_bh(&vsock->send_pkt_list_lock);
 164                         break;
 165                 }
 166
 167                 if (reply) {
 168                         struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 169                         int val;
 170
 171                         val = atomic_dec_return(&vsock->queued_replies);
 172
 173                         /* Do we now have resources to resume rx processing? */
 174                         if (val + 1 == virtqueue_get_vring_size(rx_vq))
 175                                 restart_rx = true;
 176                 }
 177
 178                 added = true;
 179         }
 180
 181         if (added)
 182                 virtqueue_kick(vq);
 183
 184         mutex_unlock(&vsock->tx_lock);
 185
 186         if (restart_rx)
 187                 queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 188 }
 189
 190 static int
 191 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 192 {
 193         struct virtio_vsock *vsock;
 194         int len = pkt->len;
 195
 196         vsock = virtio_vsock_get();
 197         if (!vsock) {
 198                 virtio_transport_free_pkt(pkt);
 199                 return -ENODEV;
 200         }
 201
 202         if (le32_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid)
 203                 return virtio_transport_send_pkt_loopback(vsock, pkt);
 204
 205         if (pkt->reply)
 206                 atomic_inc(&vsock->queued_replies);
 207
 208         spin_lock_bh(&vsock->send_pkt_list_lock);
 209         list_add_tail(&pkt->list, &vsock->send_pkt_list);
 210         spin_unlock_bh(&vsock->send_pkt_list_lock);
 211
 212         queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 213         return len;
 214 }
 215
 216 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 217 {
 218         int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
 219         struct virtio_vsock_pkt *pkt;
 220         struct scatterlist hdr, buf, *sgs[2];
 221         struct virtqueue *vq;
 222         int ret;
 223
 224         vq = vsock->vqs[VSOCK_VQ_RX];
 225
 226         do {
 227                 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 228                 if (!pkt)
 229                         break;
 230
 231                 pkt->buf = kmalloc(buf_len, GFP_KERNEL);
 232                 if (!pkt->buf) {
 233                         virtio_transport_free_pkt(pkt);
 234                         break;
 235                 }
 236
 237                 pkt->len = buf_len;
 238
 239                 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr));
 240                 sgs[0] = &hdr;
 241
 242                 sg_init_one(&buf, pkt->buf, buf_len);
 243                 sgs[1] = &buf;
 244                 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL);
 245                 if (ret) {
 246                         virtio_transport_free_pkt(pkt);
 247                         break;
 248                 }
 249                 vsock->rx_buf_nr++;
 250         } while (vq->num_free);
 251         if (vsock->rx_buf_nr > vsock->rx_buf_max_nr)
 252                 vsock->rx_buf_max_nr = vsock->rx_buf_nr;
 253         virtqueue_kick(vq);
 254 }
 255
 256 static void virtio_transport_tx_work(struct work_struct *work)
 257 {
 258         struct virtio_vsock *vsock =
 259                 container_of(work, struct virtio_vsock, tx_work);
 260         struct virtqueue *vq;
 261         bool added = false;
 262
 263         vq = vsock->vqs[VSOCK_VQ_TX];
 264         mutex_lock(&vsock->tx_lock);
 265         do {
 266                 struct virtio_vsock_pkt *pkt;
 267                 unsigned int len;
 268
 269                 virtqueue_disable_cb(vq);
 270                 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) {
 271                         virtio_transport_free_pkt(pkt);
 272                         added = true;
 273                 }
 274         } while (!virtqueue_enable_cb(vq));
 275         mutex_unlock(&vsock->tx_lock);
 276
 277         if (added)
 278                 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
 279 }
 280
 281 /* Is there space left for replies to rx packets? */
 282 static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
 283 {
 284         struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX];
 285         int val;
 286
 287         smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
 288         val = atomic_read(&vsock->queued_replies);
 289
 290         return val < virtqueue_get_vring_size(vq);
 291 }
 292
 293 static void virtio_transport_rx_work(struct work_struct *work)
 294 {
 295         struct virtio_vsock *vsock =
 296                 container_of(work, struct virtio_vsock, rx_work);
 297         struct virtqueue *vq;
 298
 299         vq = vsock->vqs[VSOCK_VQ_RX];
 300
 301         mutex_lock(&vsock->rx_lock);
 302
 303         do {
 304                 virtqueue_disable_cb(vq);
 305                 for (;;) {
 306                         struct virtio_vsock_pkt *pkt;
 307                         unsigned int len;
 308
 309                         if (!virtio_transport_more_replies(vsock)) {
 310                                 /* Stop rx until the device processes already
 311                                  * pending replies.  Leave rx virtqueue
 312                                  * callbacks disabled.
 313                                  */
 314                                 goto out;
 315                         }
 316
 317                         pkt = virtqueue_get_buf(vq, &len);
 318                         if (!pkt) {
 319                                 break;
 320                         }
 321
 322                         vsock->rx_buf_nr--;
 323
 324                         /* Drop short/long packets */
 325                         if (unlikely(len < sizeof(pkt->hdr) ||
 326                                      len > sizeof(pkt->hdr) + pkt->len)) {
 327                                 virtio_transport_free_pkt(pkt);
 328                                 continue;
 329                         }
 330
 331                         pkt->len = len - sizeof(pkt->hdr);
 332                         virtio_transport_recv_pkt(pkt);
 333                 }
 334         } while (!virtqueue_enable_cb(vq));
 335
 336 out:
 337         if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 338                 virtio_vsock_rx_fill(vsock);
 339         mutex_unlock(&vsock->rx_lock);
 340 }
 341
 342 /* event_lock must be held */
 343 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock,
 344                                        struct virtio_vsock_event *event)
 345 {
 346         struct scatterlist sg;
 347         struct virtqueue *vq;
 348
 349         vq = vsock->vqs[VSOCK_VQ_EVENT];
 350
 351         sg_init_one(&sg, event, sizeof(*event));
 352
 353         return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL);
 354 }
 355
 356 /* event_lock must be held */
 357 static void virtio_vsock_event_fill(struct virtio_vsock *vsock)
 358 {
 359         size_t i;
 360
 361         for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) {
 362                 struct virtio_vsock_event *event = &vsock->event_list[i];
 363
 364                 virtio_vsock_event_fill_one(vsock, event);
 365         }
 366
 367         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 368 }
 369
 370 static void virtio_vsock_reset_sock(struct sock *sk)
 371 {
 372         lock_sock(sk);
 373         sk->sk_state = SS_UNCONNECTED;
 374         sk->sk_err = ECONNRESET;
 375         sk->sk_error_report(sk);
 376         release_sock(sk);
 377 }
 378
 379 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock)
 380 {
 381         struct virtio_device *vdev = vsock->vdev;
 382         __le64 guest_cid;
 383
 384         vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid),
 385                           &guest_cid, sizeof(guest_cid));
 386         vsock->guest_cid = le64_to_cpu(guest_cid);
 387 }
 388
 389 /* event_lock must be held */
 390 static void virtio_vsock_event_handle(struct virtio_vsock *vsock,
 391                                       struct virtio_vsock_event *event)
 392 {
 393         switch (le32_to_cpu(event->id)) {
 394         case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET:
 395                 virtio_vsock_update_guest_cid(vsock);
 396                 vsock_for_each_connected_socket(virtio_vsock_reset_sock);
 397                 break;
 398         }
 399 }
 400
 401 static void virtio_transport_event_work(struct work_struct *work)
 402 {
 403         struct virtio_vsock *vsock =
 404                 container_of(work, struct virtio_vsock, event_work);
 405         struct virtqueue *vq;
 406
 407         vq = vsock->vqs[VSOCK_VQ_EVENT];
 408
 409         mutex_lock(&vsock->event_lock);
 410
 411         do {
 412                 struct virtio_vsock_event *event;
 413                 unsigned int len;
 414
 415                 virtqueue_disable_cb(vq);
 416                 while ((event = virtqueue_get_buf(vq, &len)) != NULL) {
 417                         if (len == sizeof(*event))
 418                                 virtio_vsock_event_handle(vsock, event);
 419
 420                         virtio_vsock_event_fill_one(vsock, event);
 421                 }
 422         } while (!virtqueue_enable_cb(vq));
 423
 424         virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
 425
 426         mutex_unlock(&vsock->event_lock);
 427 }
 428
 429 static void virtio_vsock_event_done(struct virtqueue *vq)
 430 {
 431         struct virtio_vsock *vsock = vq->vdev->priv;
 432
 433         if (!vsock)
 434                 return;
 435         queue_work(virtio_vsock_workqueue, &vsock->event_work);
 436 }
 437
 438 static void virtio_vsock_tx_done(struct virtqueue *vq)
 439 {
 440         struct virtio_vsock *vsock = vq->vdev->priv;
 441
 442         if (!vsock)
 443                 return;
 444         queue_work(virtio_vsock_workqueue, &vsock->tx_work);
 445 }
 446
 447 static void virtio_vsock_rx_done(struct virtqueue *vq)
 448 {
 449         struct virtio_vsock *vsock = vq->vdev->priv;
 450
 451         if (!vsock)
 452                 return;
 453         queue_work(virtio_vsock_workqueue, &vsock->rx_work);
 454 }
 455
 456 static struct virtio_transport virtio_transport = {
 457         .transport = {
 458                 .get_local_cid            = virtio_transport_get_local_cid,
 459
 460                 .init                     = virtio_transport_do_socket_init,
 461                 .destruct                 = virtio_transport_destruct,
 462                 .release                  = virtio_transport_release,
 463                 .connect                  = virtio_transport_connect,
 464                 .shutdown                 = virtio_transport_shutdown,
 465
 466                 .dgram_bind               = virtio_transport_dgram_bind,
 467                 .dgram_dequeue            = virtio_transport_dgram_dequeue,
 468                 .dgram_enqueue            = virtio_transport_dgram_enqueue,
 469                 .dgram_allow              = virtio_transport_dgram_allow,
 470
 471                 .stream_dequeue           = virtio_transport_stream_dequeue,
 472                 .stream_enqueue           = virtio_transport_stream_enqueue,
 473                 .stream_has_data          = virtio_transport_stream_has_data,
 474                 .stream_has_space         = virtio_transport_stream_has_space,
 475                 .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
 476                 .stream_is_active         = virtio_transport_stream_is_active,
 477                 .stream_allow             = virtio_transport_stream_allow,
 478
 479                 .notify_poll_in           = virtio_transport_notify_poll_in,
 480                 .notify_poll_out          = virtio_transport_notify_poll_out,
 481                 .notify_recv_init         = virtio_transport_notify_recv_init,
 482                 .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
 483                 .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
 484                 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
 485                 .notify_send_init         = virtio_transport_notify_send_init,
 486                 .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
 487                 .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
 488                 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
 489
 490                 .set_buffer_size          = virtio_transport_set_buffer_size,
 491                 .set_min_buffer_size      = virtio_transport_set_min_buffer_size,
 492                 .set_max_buffer_size      = virtio_transport_set_max_buffer_size,
 493                 .get_buffer_size          = virtio_transport_get_buffer_size,
 494                 .get_min_buffer_size      = virtio_transport_get_min_buffer_size,
 495                 .get_max_buffer_size      = virtio_transport_get_max_buffer_size,
 496         },
 497
 498         .send_pkt = virtio_transport_send_pkt,
 499 };
 500
 501 static int virtio_vsock_probe(struct virtio_device *vdev)
 502 {
 503         vq_callback_t *callbacks[] = {
 504                 virtio_vsock_rx_done,
 505                 virtio_vsock_tx_done,
 506                 virtio_vsock_event_done,
 507         };
 508         static const char * const names[] = {
 509                 "rx",
 510                 "tx",
 511                 "event",
 512         };
 513         struct virtio_vsock *vsock = NULL;
 514         int ret;
 515
 516         ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
 517         if (ret)
 518                 return ret;
 519
 520         /* Only one virtio-vsock device per guest is supported */
 521         if (the_virtio_vsock) {
 522                 ret = -EBUSY;
 523                 goto out;
 524         }
 525
 526         vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
 527         if (!vsock) {
 528                 ret = -ENOMEM;
 529                 goto out;
 530         }
 531
 532         vsock->vdev = vdev;
 533
 534         ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX,
 535                                             vsock->vqs, callbacks, names,
 536                                             NULL);
 537         if (ret < 0)
 538                 goto out;
 539
 540         virtio_vsock_update_guest_cid(vsock);
 541
 542         ret = vsock_core_init(&virtio_transport.transport);
 543         if (ret < 0)
 544                 goto out_vqs;
 545
 546         vsock->rx_buf_nr = 0;
 547         vsock->rx_buf_max_nr = 0;
 548         atomic_set(&vsock->queued_replies, 0);
 549
 550         vdev->priv = vsock;
 551         the_virtio_vsock = vsock;
 552         mutex_init(&vsock->tx_lock);
 553         mutex_init(&vsock->rx_lock);
 554         mutex_init(&vsock->event_lock);
 555         spin_lock_init(&vsock->send_pkt_list_lock);
 556         INIT_LIST_HEAD(&vsock->send_pkt_list);
 557         spin_lock_init(&vsock->loopback_list_lock);
 558         INIT_LIST_HEAD(&vsock->loopback_list);
 559         INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 560         INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 561         INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 562         INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
 563         INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
 564
 565         mutex_lock(&vsock->rx_lock);
 566         virtio_vsock_rx_fill(vsock);
 567         mutex_unlock(&vsock->rx_lock);
 568
 569         mutex_lock(&vsock->event_lock);
 570         virtio_vsock_event_fill(vsock);
 571         mutex_unlock(&vsock->event_lock);
 572
 573         mutex_unlock(&the_virtio_vsock_mutex);
 574         return 0;
 575
 576 out_vqs:
 577         vsock->vdev->config->del_vqs(vsock->vdev);
 578 out:
 579         kfree(vsock);
 580         mutex_unlock(&the_virtio_vsock_mutex);
 581         return ret;
 582 }
 583
 584 static void virtio_vsock_remove(struct virtio_device *vdev)
 585 {
 586         struct virtio_vsock *vsock = vdev->priv;
 587         struct virtio_vsock_pkt *pkt;
 588
 589         flush_work(&vsock->loopback_work);
 590         flush_work(&vsock->rx_work);
 591         flush_work(&vsock->tx_work);
 592         flush_work(&vsock->event_work);
 593         flush_work(&vsock->send_pkt_work);
 594
 595         vdev->config->reset(vdev);
 596
 597         mutex_lock(&vsock->rx_lock);
 598         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX])))
 599                 virtio_transport_free_pkt(pkt);
 600         mutex_unlock(&vsock->rx_lock);
 601
 602         mutex_lock(&vsock->tx_lock);
 603         while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX])))
 604                 virtio_transport_free_pkt(pkt);
 605         mutex_unlock(&vsock->tx_lock);
 606
 607         spin_lock_bh(&vsock->send_pkt_list_lock);
 608         while (!list_empty(&vsock->send_pkt_list)) {
 609                 pkt = list_first_entry(&vsock->send_pkt_list,
 610                                        struct virtio_vsock_pkt, list);
 611                 list_del(&pkt->list);
 612                 virtio_transport_free_pkt(pkt);
 613         }
 614         spin_unlock_bh(&vsock->send_pkt_list_lock);
 615
 616         spin_lock_bh(&vsock->loopback_list_lock);
 617         while (!list_empty(&vsock->loopback_list)) {
 618                 pkt = list_first_entry(&vsock->loopback_list,
 619                                        struct virtio_vsock_pkt, list);
 620                 list_del(&pkt->list);
 621                 virtio_transport_free_pkt(pkt);
 622         }
 623         spin_unlock_bh(&vsock->loopback_list_lock);
 624
 625         mutex_lock(&the_virtio_vsock_mutex);
 626         the_virtio_vsock = NULL;
 627         vsock_core_exit();
 628         mutex_unlock(&the_virtio_vsock_mutex);
 629
 630         vdev->config->del_vqs(vdev);
 631
 632         kfree(vsock);
 633 }
 634
 635 static struct virtio_device_id id_table[] = {
 636         { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID },
 637         { 0 },
 638 };
 639
 640 static unsigned int features[] = {
 641 };
 642
 643 static struct virtio_driver virtio_vsock_driver = {
 644         .feature_table = features,
 645         .feature_table_size = ARRAY_SIZE(features),
 646         .driver.name = KBUILD_MODNAME,
 647         .driver.owner = THIS_MODULE,
 648         .id_table = id_table,
 649         .probe = virtio_vsock_probe,
 650         .remove = virtio_vsock_remove,
 651 };
 652
 653 static int __init virtio_vsock_init(void)
 654 {
 655         int ret;
 656
 657         virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
 658         if (!virtio_vsock_workqueue)
 659                 return -ENOMEM;
 660         ret = register_virtio_driver(&virtio_vsock_driver);
 661         if (ret)
 662                 destroy_workqueue(virtio_vsock_workqueue);
 663         return ret;
 664 }
 665
 666 static void __exit virtio_vsock_exit(void)
 667 {
 668         unregister_virtio_driver(&virtio_vsock_driver);
 669         destroy_workqueue(virtio_vsock_workqueue);
 670 }
 671
 672 module_init(virtio_vsock_init);
 673 module_exit(virtio_vsock_exit);
 674 MODULE_LICENSE("GPL v2");
 675 MODULE_AUTHOR("Asias He");
 676 MODULE_DESCRIPTION("virtio transport for vsock");
 677 MODULE_DEVICE_TABLE(virtio, id_table);