git.oblomov.eu Git - linux-2.6/blob - drivers/net/virtio_net.c

   1 /* A simple network driver using virtio.
   2  *
   3  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 //#define DEBUG
  20 #include <linux/netdevice.h>
  21 #include <linux/etherdevice.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/module.h>
  24 #include <linux/virtio.h>
  25 #include <linux/virtio_net.h>
  26 #include <linux/scatterlist.h>
  27
  28 static int napi_weight = 128;
  29 module_param(napi_weight, int, 0444);
  30
  31 static int csum = 1, gso = 1;
  32 module_param(csum, bool, 0444);
  33 module_param(gso, bool, 0444);
  34
  35 /* FIXME: MTU in config. */
  36 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
  37
  38 struct virtnet_info
  39 {
  40         struct virtio_device *vdev;
  41         struct virtqueue *rvq, *svq;
  42         struct net_device *dev;
  43         struct napi_struct napi;
  44
  45         /* The skb we couldn't send because buffers were full. */
  46         struct sk_buff *last_xmit_skb;
  47
  48         /* If we need to free in a timer, this is it. */
  49         struct timer_list xmit_free_timer;
  50
  51         /* Number of input buffers, and max we've ever had. */
  52         unsigned int num, max;
  53
  54         /* For cleaning up after transmission. */
  55         struct tasklet_struct tasklet;
  56         bool free_in_tasklet;
  57
  58         /* I like... big packets and I cannot lie! */
  59         bool big_packets;
  60
  61         /* Receive & send queues. */
  62         struct sk_buff_head recv;
  63         struct sk_buff_head send;
  64
  65         /* Chain pages by the private ptr. */
  66         struct page *pages;
  67 };
  68
  69 static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
  70 {
  71         return (struct virtio_net_hdr *)skb->cb;
  72 }
  73
  74 static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
  75 {
  76         sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
  77 }
  78
  79 static void give_a_page(struct virtnet_info *vi, struct page *page)
  80 {
  81         page->private = (unsigned long)vi->pages;
  82         vi->pages = page;
  83 }
  84
  85 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
  86 {
  87         struct page *p = vi->pages;
  88
  89         if (p)
  90                 vi->pages = (struct page *)p->private;
  91         else
  92                 p = alloc_page(gfp_mask);
  93         return p;
  94 }
  95
  96 static void skb_xmit_done(struct virtqueue *svq)
  97 {
  98         struct virtnet_info *vi = svq->vdev->priv;
  99
 100         /* Suppress further interrupts. */
 101         svq->vq_ops->disable_cb(svq);
 102
 103         /* We were probably waiting for more output buffers. */
 104         netif_wake_queue(vi->dev);
 105
 106         /* Make sure we re-xmit last_xmit_skb: if there are no more packets
 107          * queued, start_xmit won't be called. */
 108         tasklet_schedule(&vi->tasklet);
 109 }
 110
 111 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 112                         unsigned len)
 113 {
 114         struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
 115         int err;
 116
 117         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 118                 pr_debug("%s: short packet %i\n", dev->name, len);
 119                 dev->stats.rx_length_errors++;
 120                 goto drop;
 121         }
 122         len -= sizeof(struct virtio_net_hdr);
 123
 124         if (len <= MAX_PACKET_LEN) {
 125                 unsigned int i;
 126
 127                 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 128                         give_a_page(netdev_priv(dev),
 129                                     skb_shinfo(skb)->frags[i].page);
 130                 skb->data_len = 0;
 131                 skb_shinfo(skb)->nr_frags = 0;
 132         }
 133
 134         err = pskb_trim(skb, len);
 135         if (err) {
 136                 pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err);
 137                 dev->stats.rx_dropped++;
 138                 goto drop;
 139         }
 140         skb->truesize += skb->data_len;
 141         dev->stats.rx_bytes += skb->len;
 142         dev->stats.rx_packets++;
 143
 144         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 145                 pr_debug("Needs csum!\n");
 146                 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
 147                         goto frame_err;
 148         }
 149
 150         skb->protocol = eth_type_trans(skb, dev);
 151         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 152                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 153
 154         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 155                 pr_debug("GSO!\n");
 156                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 157                 case VIRTIO_NET_HDR_GSO_TCPV4:
 158                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 159                         break;
 160                 case VIRTIO_NET_HDR_GSO_UDP:
 161                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 162                         break;
 163                 case VIRTIO_NET_HDR_GSO_TCPV6:
 164                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 165                         break;
 166                 default:
 167                         if (net_ratelimit())
 168                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 169                                        dev->name, hdr->gso_type);
 170                         goto frame_err;
 171                 }
 172
 173                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
 174                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 175
 176                 skb_shinfo(skb)->gso_size = hdr->gso_size;
 177                 if (skb_shinfo(skb)->gso_size == 0) {
 178                         if (net_ratelimit())
 179                                 printk(KERN_WARNING "%s: zero gso size.\n",
 180                                        dev->name);
 181                         goto frame_err;
 182                 }
 183
 184                 /* Header must be checked, and gso_segs computed. */
 185                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 186                 skb_shinfo(skb)->gso_segs = 0;
 187         }
 188
 189         netif_receive_skb(skb);
 190         return;
 191
 192 frame_err:
 193         dev->stats.rx_frame_errors++;
 194 drop:
 195         dev_kfree_skb(skb);
 196 }
 197
 198 static void try_fill_recv(struct virtnet_info *vi)
 199 {
 200         struct sk_buff *skb;
 201         struct scatterlist sg[2+MAX_SKB_FRAGS];
 202         int num, err, i;
 203
 204         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 205         for (;;) {
 206                 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
 207                 if (unlikely(!skb))
 208                         break;
 209
 210                 skb_put(skb, MAX_PACKET_LEN);
 211                 vnet_hdr_to_sg(sg, skb);
 212
 213                 if (vi->big_packets) {
 214                         for (i = 0; i < MAX_SKB_FRAGS; i++) {
 215                                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 216                                 f->page = get_a_page(vi, GFP_ATOMIC);
 217                                 if (!f->page)
 218                                         break;
 219
 220                                 f->page_offset = 0;
 221                                 f->size = PAGE_SIZE;
 222
 223                                 skb->data_len += PAGE_SIZE;
 224                                 skb->len += PAGE_SIZE;
 225
 226                                 skb_shinfo(skb)->nr_frags++;
 227                         }
 228                 }
 229
 230                 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 231                 skb_queue_head(&vi->recv, skb);
 232
 233                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
 234                 if (err) {
 235                         skb_unlink(skb, &vi->recv);
 236                         kfree_skb(skb);
 237                         break;
 238                 }
 239                 vi->num++;
 240         }
 241         if (unlikely(vi->num > vi->max))
 242                 vi->max = vi->num;
 243         vi->rvq->vq_ops->kick(vi->rvq);
 244 }
 245
 246 static void skb_recv_done(struct virtqueue *rvq)
 247 {
 248         struct virtnet_info *vi = rvq->vdev->priv;
 249         /* Schedule NAPI, Suppress further interrupts if successful. */
 250         if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
 251                 rvq->vq_ops->disable_cb(rvq);
 252                 __netif_rx_schedule(vi->dev, &vi->napi);
 253         }
 254 }
 255
 256 static int virtnet_poll(struct napi_struct *napi, int budget)
 257 {
 258         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 259         struct sk_buff *skb = NULL;
 260         unsigned int len, received = 0;
 261
 262 again:
 263         while (received < budget &&
 264                (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 265                 __skb_unlink(skb, &vi->recv);
 266                 receive_skb(vi->dev, skb, len);
 267                 vi->num--;
 268                 received++;
 269         }
 270
 271         /* FIXME: If we oom and completely run out of inbufs, we need
 272          * to start a timer trying to fill more. */
 273         if (vi->num < vi->max / 2)
 274                 try_fill_recv(vi);
 275
 276         /* Out of packets? */
 277         if (received < budget) {
 278                 netif_rx_complete(vi->dev, napi);
 279                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
 280                     && napi_schedule_prep(napi)) {
 281                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 282                         __netif_rx_schedule(vi->dev, napi);
 283                         goto again;
 284                 }
 285         }
 286
 287         return received;
 288 }
 289
 290 static void free_old_xmit_skbs(struct virtnet_info *vi)
 291 {
 292         struct sk_buff *skb;
 293         unsigned int len;
 294
 295         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 296                 pr_debug("Sent skb %p\n", skb);
 297                 __skb_unlink(skb, &vi->send);
 298                 vi->dev->stats.tx_bytes += skb->len;
 299                 vi->dev->stats.tx_packets++;
 300                 kfree_skb(skb);
 301         }
 302 }
 303
 304 /* If the virtio transport doesn't always notify us when all in-flight packets
 305  * are consumed, we fall back to using this function on a timer to free them. */
 306 static void xmit_free(unsigned long data)
 307 {
 308         struct virtnet_info *vi = (void *)data;
 309
 310         netif_tx_lock(vi->dev);
 311
 312         free_old_xmit_skbs(vi);
 313
 314         if (!skb_queue_empty(&vi->send))
 315                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 316
 317         netif_tx_unlock(vi->dev);
 318 }
 319
 320 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 321 {
 322         int num, err;
 323         struct scatterlist sg[2+MAX_SKB_FRAGS];
 324         struct virtio_net_hdr *hdr;
 325         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 326
 327         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 328
 329         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 330
 331         /* Encode metadata header at front. */
 332         hdr = skb_vnet_hdr(skb);
 333         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 334                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 335                 hdr->csum_start = skb->csum_start - skb_headroom(skb);
 336                 hdr->csum_offset = skb->csum_offset;
 337         } else {
 338                 hdr->flags = 0;
 339                 hdr->csum_offset = hdr->csum_start = 0;
 340         }
 341
 342         if (skb_is_gso(skb)) {
 343                 hdr->hdr_len = skb_transport_header(skb) - skb->data;
 344                 hdr->gso_size = skb_shinfo(skb)->gso_size;
 345                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 346                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 347                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 348                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 349                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 350                         hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 351                 else
 352                         BUG();
 353                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 354                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 355         } else {
 356                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 357                 hdr->gso_size = hdr->hdr_len = 0;
 358         }
 359
 360         vnet_hdr_to_sg(sg, skb);
 361         num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 362
 363         err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
 364         if (!err && !vi->free_in_tasklet)
 365                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 366
 367         return err;
 368 }
 369
 370 static void xmit_tasklet(unsigned long data)
 371 {
 372         struct virtnet_info *vi = (void *)data;
 373
 374         netif_tx_lock_bh(vi->dev);
 375         if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
 376                 vi->svq->vq_ops->kick(vi->svq);
 377                 vi->last_xmit_skb = NULL;
 378         }
 379         if (vi->free_in_tasklet)
 380                 free_old_xmit_skbs(vi);
 381         netif_tx_unlock_bh(vi->dev);
 382 }
 383
 384 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 385 {
 386         struct virtnet_info *vi = netdev_priv(dev);
 387
 388 again:
 389         /* Free up any pending old buffers before queueing new ones. */
 390         free_old_xmit_skbs(vi);
 391
 392         /* If we has a buffer left over from last time, send it now. */
 393         if (unlikely(vi->last_xmit_skb) &&
 394             xmit_skb(vi, vi->last_xmit_skb) != 0)
 395                 goto stop_queue;
 396
 397         vi->last_xmit_skb = NULL;
 398
 399         /* Put new one in send queue and do transmit */
 400         if (likely(skb)) {
 401                 __skb_queue_head(&vi->send, skb);
 402                 if (xmit_skb(vi, skb) != 0) {
 403                         vi->last_xmit_skb = skb;
 404                         skb = NULL;
 405                         goto stop_queue;
 406                 }
 407         }
 408 done:
 409         vi->svq->vq_ops->kick(vi->svq);
 410         return NETDEV_TX_OK;
 411
 412 stop_queue:
 413         pr_debug("%s: virtio not prepared to send\n", dev->name);
 414         netif_stop_queue(dev);
 415
 416         /* Activate callback for using skbs: if this returns false it
 417          * means some were used in the meantime. */
 418         if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 419                 vi->svq->vq_ops->disable_cb(vi->svq);
 420                 netif_start_queue(dev);
 421                 goto again;
 422         }
 423         if (skb) {
 424                 /* Drop this skb: we only queue one. */
 425                 vi->dev->stats.tx_dropped++;
 426                 kfree_skb(skb);
 427         }
 428         goto done;
 429 }
 430
 431 #ifdef CONFIG_NET_POLL_CONTROLLER
 432 static void virtnet_netpoll(struct net_device *dev)
 433 {
 434         struct virtnet_info *vi = netdev_priv(dev);
 435
 436         napi_schedule(&vi->napi);
 437 }
 438 #endif
 439
 440 static int virtnet_open(struct net_device *dev)
 441 {
 442         struct virtnet_info *vi = netdev_priv(dev);
 443
 444         napi_enable(&vi->napi);
 445
 446         /* If all buffers were filled by other side before we napi_enabled, we
 447          * won't get another interrupt, so process any outstanding packets
 448          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 449          * We synchronize against interrupts via NAPI_STATE_SCHED */
 450         if (netif_rx_schedule_prep(dev, &vi->napi)) {
 451                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 452                 __netif_rx_schedule(dev, &vi->napi);
 453         }
 454         return 0;
 455 }
 456
 457 static int virtnet_close(struct net_device *dev)
 458 {
 459         struct virtnet_info *vi = netdev_priv(dev);
 460
 461         napi_disable(&vi->napi);
 462
 463         return 0;
 464 }
 465
 466 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 467 {
 468         struct virtnet_info *vi = netdev_priv(dev);
 469         struct virtio_device *vdev = vi->vdev;
 470
 471         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 472                 return -ENOSYS;
 473
 474         return ethtool_op_set_tx_hw_csum(dev, data);
 475 }
 476
 477 static struct ethtool_ops virtnet_ethtool_ops = {
 478         .set_tx_csum = virtnet_set_tx_csum,
 479         .set_sg = ethtool_op_set_sg,
 480 };
 481
 482 static int virtnet_probe(struct virtio_device *vdev)
 483 {
 484         int err;
 485         struct net_device *dev;
 486         struct virtnet_info *vi;
 487
 488         /* Allocate ourselves a network device with room for our info */
 489         dev = alloc_etherdev(sizeof(struct virtnet_info));
 490         if (!dev)
 491                 return -ENOMEM;
 492
 493         /* Set up network device as normal. */
 494         dev->open = virtnet_open;
 495         dev->stop = virtnet_close;
 496         dev->hard_start_xmit = start_xmit;
 497         dev->features = NETIF_F_HIGHDMA;
 498 #ifdef CONFIG_NET_POLL_CONTROLLER
 499         dev->poll_controller = virtnet_netpoll;
 500 #endif
 501         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 502         SET_NETDEV_DEV(dev, &vdev->dev);
 503
 504         /* Do we support "hardware" checksums? */
 505         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 506                 /* This opens up the world of extra features. */
 507                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 508                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 509                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 510                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 511                 }
 512                 /* Individual feature bits: what can host handle? */
 513                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 514                         dev->features |= NETIF_F_TSO;
 515                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 516                         dev->features |= NETIF_F_TSO6;
 517                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 518                         dev->features |= NETIF_F_TSO_ECN;
 519                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 520                         dev->features |= NETIF_F_UFO;
 521         }
 522
 523         /* Configuration may specify what MAC to use.  Otherwise random. */
 524         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 525                 vdev->config->get(vdev,
 526                                   offsetof(struct virtio_net_config, mac),
 527                                   dev->dev_addr, dev->addr_len);
 528         } else
 529                 random_ether_addr(dev->dev_addr);
 530
 531         /* Set up our device-specific information */
 532         vi = netdev_priv(dev);
 533         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 534         vi->dev = dev;
 535         vi->vdev = vdev;
 536         vdev->priv = vi;
 537         vi->pages = NULL;
 538
 539         /* If they give us a callback when all buffers are done, we don't need
 540          * the timer. */
 541         vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
 542
 543         /* If we can receive ANY GSO packets, we must allocate large ones. */
 544         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
 545             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
 546             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 547                 vi->big_packets = true;
 548
 549         /* We expect two virtqueues, receive then send. */
 550         vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
 551         if (IS_ERR(vi->rvq)) {
 552                 err = PTR_ERR(vi->rvq);
 553                 goto free;
 554         }
 555
 556         vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
 557         if (IS_ERR(vi->svq)) {
 558                 err = PTR_ERR(vi->svq);
 559                 goto free_recv;
 560         }
 561
 562         /* Initialize our empty receive and send queues. */
 563         skb_queue_head_init(&vi->recv);
 564         skb_queue_head_init(&vi->send);
 565
 566         tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
 567
 568         if (!vi->free_in_tasklet)
 569                 setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
 570
 571         err = register_netdev(dev);
 572         if (err) {
 573                 pr_debug("virtio_net: registering device failed\n");
 574                 goto free_send;
 575         }
 576
 577         /* Last of all, set up some receive buffers. */
 578         try_fill_recv(vi);
 579
 580         /* If we didn't even get one input buffer, we're useless. */
 581         if (vi->num == 0) {
 582                 err = -ENOMEM;
 583                 goto unregister;
 584         }
 585
 586         pr_debug("virtnet: registered device %s\n", dev->name);
 587         return 0;
 588
 589 unregister:
 590         unregister_netdev(dev);
 591 free_send:
 592         vdev->config->del_vq(vi->svq);
 593 free_recv:
 594         vdev->config->del_vq(vi->rvq);
 595 free:
 596         free_netdev(dev);
 597         return err;
 598 }
 599
 600 static void virtnet_remove(struct virtio_device *vdev)
 601 {
 602         struct virtnet_info *vi = vdev->priv;
 603         struct sk_buff *skb;
 604
 605         /* Stop all the virtqueues. */
 606         vdev->config->reset(vdev);
 607
 608         if (!vi->free_in_tasklet)
 609                 del_timer_sync(&vi->xmit_free_timer);
 610
 611         /* Free our skbs in send and recv queues, if any. */
 612         while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
 613                 kfree_skb(skb);
 614                 vi->num--;
 615         }
 616         __skb_queue_purge(&vi->send);
 617
 618         BUG_ON(vi->num != 0);
 619
 620         vdev->config->del_vq(vi->svq);
 621         vdev->config->del_vq(vi->rvq);
 622         unregister_netdev(vi->dev);
 623
 624         while (vi->pages)
 625                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
 626
 627         free_netdev(vi->dev);
 628 }
 629
 630 static struct virtio_device_id id_table[] = {
 631         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
 632         { 0 },
 633 };
 634
 635 static unsigned int features[] = {
 636         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
 637         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
 638         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
 639         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
 640         VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
 641         VIRTIO_F_NOTIFY_ON_EMPTY,
 642 };
 643
 644 static struct virtio_driver virtio_net = {
 645         .feature_table = features,
 646         .feature_table_size = ARRAY_SIZE(features),
 647         .driver.name =  KBUILD_MODNAME,
 648         .driver.owner = THIS_MODULE,
 649         .id_table =     id_table,
 650         .probe =        virtnet_probe,
 651         .remove =       __devexit_p(virtnet_remove),
 652 };
 653
 654 static int __init init(void)
 655 {
 656         return register_virtio_driver(&virtio_net);
 657 }
 658
 659 static void __exit fini(void)
 660 {
 661         unregister_virtio_driver(&virtio_net);
 662 }
 663 module_init(init);
 664 module_exit(fini);
 665
 666 MODULE_DEVICE_TABLE(virtio, id_table);
 667 MODULE_DESCRIPTION("Virtio network driver");
 668 MODULE_LICENSE("GPL");