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(dev->priv, skb_shinfo(skb)->frags[i].page);
 129                 skb->data_len = 0;
 130                 skb_shinfo(skb)->nr_frags = 0;
 131         }
 132
 133         err = pskb_trim(skb, len);
 134         if (err) {
 135                 pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err);
 136                 dev->stats.rx_dropped++;
 137                 goto drop;
 138         }
 139         skb->truesize += skb->data_len;
 140         dev->stats.rx_bytes += skb->len;
 141         dev->stats.rx_packets++;
 142
 143         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 144                 pr_debug("Needs csum!\n");
 145                 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
 146                         goto frame_err;
 147         }
 148
 149         skb->protocol = eth_type_trans(skb, dev);
 150         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 151                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 152
 153         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 154                 pr_debug("GSO!\n");
 155                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 156                 case VIRTIO_NET_HDR_GSO_TCPV4:
 157                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 158                         break;
 159                 case VIRTIO_NET_HDR_GSO_UDP:
 160                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 161                         break;
 162                 case VIRTIO_NET_HDR_GSO_TCPV6:
 163                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 164                         break;
 165                 default:
 166                         if (net_ratelimit())
 167                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 168                                        dev->name, hdr->gso_type);
 169                         goto frame_err;
 170                 }
 171
 172                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
 173                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 174
 175                 skb_shinfo(skb)->gso_size = hdr->gso_size;
 176                 if (skb_shinfo(skb)->gso_size == 0) {
 177                         if (net_ratelimit())
 178                                 printk(KERN_WARNING "%s: zero gso size.\n",
 179                                        dev->name);
 180                         goto frame_err;
 181                 }
 182
 183                 /* Header must be checked, and gso_segs computed. */
 184                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 185                 skb_shinfo(skb)->gso_segs = 0;
 186         }
 187
 188         netif_receive_skb(skb);
 189         return;
 190
 191 frame_err:
 192         dev->stats.rx_frame_errors++;
 193 drop:
 194         dev_kfree_skb(skb);
 195 }
 196
 197 static void try_fill_recv(struct virtnet_info *vi)
 198 {
 199         struct sk_buff *skb;
 200         struct scatterlist sg[2+MAX_SKB_FRAGS];
 201         int num, err, i;
 202
 203         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 204         for (;;) {
 205                 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
 206                 if (unlikely(!skb))
 207                         break;
 208
 209                 skb_put(skb, MAX_PACKET_LEN);
 210                 vnet_hdr_to_sg(sg, skb);
 211
 212                 if (vi->big_packets) {
 213                         for (i = 0; i < MAX_SKB_FRAGS; i++) {
 214                                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 215                                 f->page = get_a_page(vi, GFP_ATOMIC);
 216                                 if (!f->page)
 217                                         break;
 218
 219                                 f->page_offset = 0;
 220                                 f->size = PAGE_SIZE;
 221
 222                                 skb->data_len += PAGE_SIZE;
 223                                 skb->len += PAGE_SIZE;
 224
 225                                 skb_shinfo(skb)->nr_frags++;
 226                         }
 227                 }
 228
 229                 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 230                 skb_queue_head(&vi->recv, skb);
 231
 232                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
 233                 if (err) {
 234                         skb_unlink(skb, &vi->recv);
 235                         kfree_skb(skb);
 236                         break;
 237                 }
 238                 vi->num++;
 239         }
 240         if (unlikely(vi->num > vi->max))
 241                 vi->max = vi->num;
 242         vi->rvq->vq_ops->kick(vi->rvq);
 243 }
 244
 245 static void skb_recv_done(struct virtqueue *rvq)
 246 {
 247         struct virtnet_info *vi = rvq->vdev->priv;
 248         /* Schedule NAPI, Suppress further interrupts if successful. */
 249         if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
 250                 rvq->vq_ops->disable_cb(rvq);
 251                 __netif_rx_schedule(vi->dev, &vi->napi);
 252         }
 253 }
 254
 255 static int virtnet_poll(struct napi_struct *napi, int budget)
 256 {
 257         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 258         struct sk_buff *skb = NULL;
 259         unsigned int len, received = 0;
 260
 261 again:
 262         while (received < budget &&
 263                (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 264                 __skb_unlink(skb, &vi->recv);
 265                 receive_skb(vi->dev, skb, len);
 266                 vi->num--;
 267                 received++;
 268         }
 269
 270         /* FIXME: If we oom and completely run out of inbufs, we need
 271          * to start a timer trying to fill more. */
 272         if (vi->num < vi->max / 2)
 273                 try_fill_recv(vi);
 274
 275         /* Out of packets? */
 276         if (received < budget) {
 277                 netif_rx_complete(vi->dev, napi);
 278                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
 279                     && napi_schedule_prep(napi)) {
 280                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 281                         __netif_rx_schedule(vi->dev, napi);
 282                         goto again;
 283                 }
 284         }
 285
 286         return received;
 287 }
 288
 289 static void free_old_xmit_skbs(struct virtnet_info *vi)
 290 {
 291         struct sk_buff *skb;
 292         unsigned int len;
 293
 294         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 295                 pr_debug("Sent skb %p\n", skb);
 296                 __skb_unlink(skb, &vi->send);
 297                 vi->dev->stats.tx_bytes += skb->len;
 298                 vi->dev->stats.tx_packets++;
 299                 kfree_skb(skb);
 300         }
 301 }
 302
 303 /* If the virtio transport doesn't always notify us when all in-flight packets
 304  * are consumed, we fall back to using this function on a timer to free them. */
 305 static void xmit_free(unsigned long data)
 306 {
 307         struct virtnet_info *vi = (void *)data;
 308
 309         netif_tx_lock(vi->dev);
 310
 311         free_old_xmit_skbs(vi);
 312
 313         if (!skb_queue_empty(&vi->send))
 314                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 315
 316         netif_tx_unlock(vi->dev);
 317 }
 318
 319 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 320 {
 321         int num, err;
 322         struct scatterlist sg[2+MAX_SKB_FRAGS];
 323         struct virtio_net_hdr *hdr;
 324         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 325
 326         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 327
 328         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 329
 330         /* Encode metadata header at front. */
 331         hdr = skb_vnet_hdr(skb);
 332         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 333                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 334                 hdr->csum_start = skb->csum_start - skb_headroom(skb);
 335                 hdr->csum_offset = skb->csum_offset;
 336         } else {
 337                 hdr->flags = 0;
 338                 hdr->csum_offset = hdr->csum_start = 0;
 339         }
 340
 341         if (skb_is_gso(skb)) {
 342                 hdr->hdr_len = skb_transport_header(skb) - skb->data;
 343                 hdr->gso_size = skb_shinfo(skb)->gso_size;
 344                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 345                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 346                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 347                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 348                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 349                         hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 350                 else
 351                         BUG();
 352                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 353                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 354         } else {
 355                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 356                 hdr->gso_size = hdr->hdr_len = 0;
 357         }
 358
 359         vnet_hdr_to_sg(sg, skb);
 360         num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 361
 362         err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
 363         if (!err && !vi->free_in_tasklet)
 364                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 365
 366         return err;
 367 }
 368
 369 static void xmit_tasklet(unsigned long data)
 370 {
 371         struct virtnet_info *vi = (void *)data;
 372
 373         netif_tx_lock_bh(vi->dev);
 374         if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
 375                 vi->svq->vq_ops->kick(vi->svq);
 376                 vi->last_xmit_skb = NULL;
 377         }
 378         if (vi->free_in_tasklet)
 379                 free_old_xmit_skbs(vi);
 380         netif_tx_unlock_bh(vi->dev);
 381 }
 382
 383 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 384 {
 385         struct virtnet_info *vi = netdev_priv(dev);
 386
 387 again:
 388         /* Free up any pending old buffers before queueing new ones. */
 389         free_old_xmit_skbs(vi);
 390
 391         /* If we has a buffer left over from last time, send it now. */
 392         if (unlikely(vi->last_xmit_skb) &&
 393             xmit_skb(vi, vi->last_xmit_skb) != 0)
 394                 goto stop_queue;
 395
 396         vi->last_xmit_skb = NULL;
 397
 398         /* Put new one in send queue and do transmit */
 399         if (likely(skb)) {
 400                 __skb_queue_head(&vi->send, skb);
 401                 if (xmit_skb(vi, skb) != 0) {
 402                         vi->last_xmit_skb = skb;
 403                         skb = NULL;
 404                         goto stop_queue;
 405                 }
 406         }
 407 done:
 408         vi->svq->vq_ops->kick(vi->svq);
 409         return NETDEV_TX_OK;
 410
 411 stop_queue:
 412         pr_debug("%s: virtio not prepared to send\n", dev->name);
 413         netif_stop_queue(dev);
 414
 415         /* Activate callback for using skbs: if this returns false it
 416          * means some were used in the meantime. */
 417         if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 418                 vi->svq->vq_ops->disable_cb(vi->svq);
 419                 netif_start_queue(dev);
 420                 goto again;
 421         }
 422         if (skb) {
 423                 /* Drop this skb: we only queue one. */
 424                 vi->dev->stats.tx_dropped++;
 425                 kfree_skb(skb);
 426         }
 427         goto done;
 428 }
 429
 430 #ifdef CONFIG_NET_POLL_CONTROLLER
 431 static void virtnet_netpoll(struct net_device *dev)
 432 {
 433         struct virtnet_info *vi = netdev_priv(dev);
 434
 435         napi_schedule(&vi->napi);
 436 }
 437 #endif
 438
 439 static int virtnet_open(struct net_device *dev)
 440 {
 441         struct virtnet_info *vi = netdev_priv(dev);
 442
 443         napi_enable(&vi->napi);
 444
 445         /* If all buffers were filled by other side before we napi_enabled, we
 446          * won't get another interrupt, so process any outstanding packets
 447          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 448          * We synchronize against interrupts via NAPI_STATE_SCHED */
 449         if (netif_rx_schedule_prep(dev, &vi->napi)) {
 450                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 451                 __netif_rx_schedule(dev, &vi->napi);
 452         }
 453         return 0;
 454 }
 455
 456 static int virtnet_close(struct net_device *dev)
 457 {
 458         struct virtnet_info *vi = netdev_priv(dev);
 459
 460         napi_disable(&vi->napi);
 461
 462         return 0;
 463 }
 464
 465 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 466 {
 467         struct virtnet_info *vi = netdev_priv(dev);
 468         struct virtio_device *vdev = vi->vdev;
 469
 470         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 471                 return -ENOSYS;
 472
 473         return ethtool_op_set_tx_hw_csum(dev, data);
 474 }
 475
 476 static struct ethtool_ops virtnet_ethtool_ops = {
 477         .set_tx_csum = virtnet_set_tx_csum,
 478         .set_sg = ethtool_op_set_sg,
 479 };
 480
 481 static int virtnet_probe(struct virtio_device *vdev)
 482 {
 483         int err;
 484         struct net_device *dev;
 485         struct virtnet_info *vi;
 486
 487         /* Allocate ourselves a network device with room for our info */
 488         dev = alloc_etherdev(sizeof(struct virtnet_info));
 489         if (!dev)
 490                 return -ENOMEM;
 491
 492         /* Set up network device as normal. */
 493         dev->open = virtnet_open;
 494         dev->stop = virtnet_close;
 495         dev->hard_start_xmit = start_xmit;
 496         dev->features = NETIF_F_HIGHDMA;
 497 #ifdef CONFIG_NET_POLL_CONTROLLER
 498         dev->poll_controller = virtnet_netpoll;
 499 #endif
 500         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 501         SET_NETDEV_DEV(dev, &vdev->dev);
 502
 503         /* Do we support "hardware" checksums? */
 504         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 505                 /* This opens up the world of extra features. */
 506                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 507                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 508                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 509                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 510                 }
 511                 /* Individual feature bits: what can host handle? */
 512                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 513                         dev->features |= NETIF_F_TSO;
 514                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 515                         dev->features |= NETIF_F_TSO6;
 516                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 517                         dev->features |= NETIF_F_TSO_ECN;
 518                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 519                         dev->features |= NETIF_F_UFO;
 520         }
 521
 522         /* Configuration may specify what MAC to use.  Otherwise random. */
 523         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 524                 vdev->config->get(vdev,
 525                                   offsetof(struct virtio_net_config, mac),
 526                                   dev->dev_addr, dev->addr_len);
 527         } else
 528                 random_ether_addr(dev->dev_addr);
 529
 530         /* Set up our device-specific information */
 531         vi = netdev_priv(dev);
 532         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 533         vi->dev = dev;
 534         vi->vdev = vdev;
 535         vdev->priv = vi;
 536         vi->pages = NULL;
 537
 538         /* If they give us a callback when all buffers are done, we don't need
 539          * the timer. */
 540         vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
 541
 542         /* If we can receive ANY GSO packets, we must allocate large ones. */
 543         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
 544             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
 545             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 546                 vi->big_packets = true;
 547
 548         /* We expect two virtqueues, receive then send. */
 549         vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
 550         if (IS_ERR(vi->rvq)) {
 551                 err = PTR_ERR(vi->rvq);
 552                 goto free;
 553         }
 554
 555         vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
 556         if (IS_ERR(vi->svq)) {
 557                 err = PTR_ERR(vi->svq);
 558                 goto free_recv;
 559         }
 560
 561         /* Initialize our empty receive and send queues. */
 562         skb_queue_head_init(&vi->recv);
 563         skb_queue_head_init(&vi->send);
 564
 565         tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
 566
 567         if (!vi->free_in_tasklet)
 568                 setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
 569
 570         err = register_netdev(dev);
 571         if (err) {
 572                 pr_debug("virtio_net: registering device failed\n");
 573                 goto free_send;
 574         }
 575
 576         /* Last of all, set up some receive buffers. */
 577         try_fill_recv(vi);
 578
 579         /* If we didn't even get one input buffer, we're useless. */
 580         if (vi->num == 0) {
 581                 err = -ENOMEM;
 582                 goto unregister;
 583         }
 584
 585         pr_debug("virtnet: registered device %s\n", dev->name);
 586         return 0;
 587
 588 unregister:
 589         unregister_netdev(dev);
 590 free_send:
 591         vdev->config->del_vq(vi->svq);
 592 free_recv:
 593         vdev->config->del_vq(vi->rvq);
 594 free:
 595         free_netdev(dev);
 596         return err;
 597 }
 598
 599 static void virtnet_remove(struct virtio_device *vdev)
 600 {
 601         struct virtnet_info *vi = vdev->priv;
 602         struct sk_buff *skb;
 603
 604         /* Stop all the virtqueues. */
 605         vdev->config->reset(vdev);
 606
 607         if (!vi->free_in_tasklet)
 608                 del_timer_sync(&vi->xmit_free_timer);
 609
 610         /* Free our skbs in send and recv queues, if any. */
 611         while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
 612                 kfree_skb(skb);
 613                 vi->num--;
 614         }
 615         __skb_queue_purge(&vi->send);
 616
 617         BUG_ON(vi->num != 0);
 618
 619         vdev->config->del_vq(vi->svq);
 620         vdev->config->del_vq(vi->rvq);
 621         unregister_netdev(vi->dev);
 622
 623         while (vi->pages)
 624                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
 625
 626         free_netdev(vi->dev);
 627 }
 628
 629 static struct virtio_device_id id_table[] = {
 630         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
 631         { 0 },
 632 };
 633
 634 static unsigned int features[] = {
 635         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
 636         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
 637         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
 638         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
 639         VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
 640         VIRTIO_F_NOTIFY_ON_EMPTY,
 641 };
 642
 643 static struct virtio_driver virtio_net = {
 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 =        virtnet_probe,
 650         .remove =       __devexit_p(virtnet_remove),
 651 };
 652
 653 static int __init init(void)
 654 {
 655         return register_virtio_driver(&virtio_net);
 656 }
 657
 658 static void __exit fini(void)
 659 {
 660         unregister_virtio_driver(&virtio_net);
 661 }
 662 module_init(init);
 663 module_exit(fini);
 664
 665 MODULE_DEVICE_TABLE(virtio, id_table);
 666 MODULE_DESCRIPTION("Virtio network driver");
 667 MODULE_LICENSE("GPL");