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 #include <linux/if_vlan.h>
  28
  29 static int napi_weight = 128;
  30 module_param(napi_weight, int, 0444);
  31
  32 static int csum = 1, gso = 1;
  33 module_param(csum, bool, 0444);
  34 module_param(gso, bool, 0444);
  35
  36 /* FIXME: MTU in config. */
  37 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  38 #define GOOD_COPY_LEN   128
  39
  40 struct virtnet_info
  41 {
  42         struct virtio_device *vdev;
  43         struct virtqueue *rvq, *svq;
  44         struct net_device *dev;
  45         struct napi_struct napi;
  46
  47         /* The skb we couldn't send because buffers were full. */
  48         struct sk_buff *last_xmit_skb;
  49
  50         /* If we need to free in a timer, this is it. */
  51         struct timer_list xmit_free_timer;
  52
  53         /* Number of input buffers, and max we've ever had. */
  54         unsigned int num, max;
  55
  56         /* For cleaning up after transmission. */
  57         struct tasklet_struct tasklet;
  58         bool free_in_tasklet;
  59
  60         /* I like... big packets and I cannot lie! */
  61         bool big_packets;
  62
  63         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  64         bool mergeable_rx_bufs;
  65
  66         /* Receive & send queues. */
  67         struct sk_buff_head recv;
  68         struct sk_buff_head send;
  69
  70         /* Chain pages by the private ptr. */
  71         struct page *pages;
  72 };
  73
  74 static inline void *skb_vnet_hdr(struct sk_buff *skb)
  75 {
  76         return (struct virtio_net_hdr *)skb->cb;
  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 void trim_pages(struct virtnet_info *vi, struct sk_buff *skb)
  86 {
  87         unsigned int i;
  88
  89         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
  90                 give_a_page(vi, skb_shinfo(skb)->frags[i].page);
  91         skb_shinfo(skb)->nr_frags = 0;
  92         skb->data_len = 0;
  93 }
  94
  95 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
  96 {
  97         struct page *p = vi->pages;
  98
  99         if (p)
 100                 vi->pages = (struct page *)p->private;
 101         else
 102                 p = alloc_page(gfp_mask);
 103         return p;
 104 }
 105
 106 static void skb_xmit_done(struct virtqueue *svq)
 107 {
 108         struct virtnet_info *vi = svq->vdev->priv;
 109
 110         /* Suppress further interrupts. */
 111         svq->vq_ops->disable_cb(svq);
 112
 113         /* We were probably waiting for more output buffers. */
 114         netif_wake_queue(vi->dev);
 115
 116         /* Make sure we re-xmit last_xmit_skb: if there are no more packets
 117          * queued, start_xmit won't be called. */
 118         tasklet_schedule(&vi->tasklet);
 119 }
 120
 121 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 122                         unsigned len)
 123 {
 124         struct virtnet_info *vi = netdev_priv(dev);
 125         struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
 126         int err;
 127         int i;
 128
 129         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 130                 pr_debug("%s: short packet %i\n", dev->name, len);
 131                 dev->stats.rx_length_errors++;
 132                 goto drop;
 133         }
 134
 135         if (vi->mergeable_rx_bufs) {
 136                 struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
 137                 unsigned int copy;
 138                 char *p = page_address(skb_shinfo(skb)->frags[0].page);
 139
 140                 if (len > PAGE_SIZE)
 141                         len = PAGE_SIZE;
 142                 len -= sizeof(struct virtio_net_hdr_mrg_rxbuf);
 143
 144                 memcpy(hdr, p, sizeof(*mhdr));
 145                 p += sizeof(*mhdr);
 146
 147                 copy = len;
 148                 if (copy > skb_tailroom(skb))
 149                         copy = skb_tailroom(skb);
 150
 151                 memcpy(skb_put(skb, copy), p, copy);
 152
 153                 len -= copy;
 154
 155                 if (!len) {
 156                         give_a_page(vi, skb_shinfo(skb)->frags[0].page);
 157                         skb_shinfo(skb)->nr_frags--;
 158                 } else {
 159                         skb_shinfo(skb)->frags[0].page_offset +=
 160                                 sizeof(*mhdr) + copy;
 161                         skb_shinfo(skb)->frags[0].size = len;
 162                         skb->data_len += len;
 163                         skb->len += len;
 164                 }
 165
 166                 while (--mhdr->num_buffers) {
 167                         struct sk_buff *nskb;
 168
 169                         i = skb_shinfo(skb)->nr_frags;
 170                         if (i >= MAX_SKB_FRAGS) {
 171                                 pr_debug("%s: packet too long %d\n", dev->name,
 172                                          len);
 173                                 dev->stats.rx_length_errors++;
 174                                 goto drop;
 175                         }
 176
 177                         nskb = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
 178                         if (!nskb) {
 179                                 pr_debug("%s: rx error: %d buffers missing\n",
 180                                          dev->name, mhdr->num_buffers);
 181                                 dev->stats.rx_length_errors++;
 182                                 goto drop;
 183                         }
 184
 185                         __skb_unlink(nskb, &vi->recv);
 186                         vi->num--;
 187
 188                         skb_shinfo(skb)->frags[i] = skb_shinfo(nskb)->frags[0];
 189                         skb_shinfo(nskb)->nr_frags = 0;
 190                         kfree_skb(nskb);
 191
 192                         if (len > PAGE_SIZE)
 193                                 len = PAGE_SIZE;
 194
 195                         skb_shinfo(skb)->frags[i].size = len;
 196                         skb_shinfo(skb)->nr_frags++;
 197                         skb->data_len += len;
 198                         skb->len += len;
 199                 }
 200         } else {
 201                 len -= sizeof(struct virtio_net_hdr);
 202
 203                 if (len <= MAX_PACKET_LEN)
 204                         trim_pages(vi, skb);
 205
 206                 err = pskb_trim(skb, len);
 207                 if (err) {
 208                         pr_debug("%s: pskb_trim failed %i %d\n", dev->name,
 209                                  len, err);
 210                         dev->stats.rx_dropped++;
 211                         goto drop;
 212                 }
 213         }
 214
 215         skb->truesize += skb->data_len;
 216         dev->stats.rx_bytes += skb->len;
 217         dev->stats.rx_packets++;
 218
 219         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 220                 pr_debug("Needs csum!\n");
 221                 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
 222                         goto frame_err;
 223         }
 224
 225         skb->protocol = eth_type_trans(skb, dev);
 226         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 227                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 228
 229         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 230                 pr_debug("GSO!\n");
 231                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 232                 case VIRTIO_NET_HDR_GSO_TCPV4:
 233                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 234                         break;
 235                 case VIRTIO_NET_HDR_GSO_UDP:
 236                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 237                         break;
 238                 case VIRTIO_NET_HDR_GSO_TCPV6:
 239                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 240                         break;
 241                 default:
 242                         if (net_ratelimit())
 243                                 printk(KERN_WARNING "%s: bad gso type %u.\n",
 244                                        dev->name, hdr->gso_type);
 245                         goto frame_err;
 246                 }
 247
 248                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
 249                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 250
 251                 skb_shinfo(skb)->gso_size = hdr->gso_size;
 252                 if (skb_shinfo(skb)->gso_size == 0) {
 253                         if (net_ratelimit())
 254                                 printk(KERN_WARNING "%s: zero gso size.\n",
 255                                        dev->name);
 256                         goto frame_err;
 257                 }
 258
 259                 /* Header must be checked, and gso_segs computed. */
 260                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 261                 skb_shinfo(skb)->gso_segs = 0;
 262         }
 263
 264         netif_receive_skb(skb);
 265         return;
 266
 267 frame_err:
 268         dev->stats.rx_frame_errors++;
 269 drop:
 270         dev_kfree_skb(skb);
 271 }
 272
 273 static void try_fill_recv_maxbufs(struct virtnet_info *vi)
 274 {
 275         struct sk_buff *skb;
 276         struct scatterlist sg[2+MAX_SKB_FRAGS];
 277         int num, err, i;
 278
 279         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 280         for (;;) {
 281                 struct virtio_net_hdr *hdr;
 282
 283                 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
 284                 if (unlikely(!skb))
 285                         break;
 286
 287                 skb_put(skb, MAX_PACKET_LEN);
 288
 289                 hdr = skb_vnet_hdr(skb);
 290                 sg_set_buf(sg, hdr, sizeof(*hdr));
 291
 292                 if (vi->big_packets) {
 293                         for (i = 0; i < MAX_SKB_FRAGS; i++) {
 294                                 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 295                                 f->page = get_a_page(vi, GFP_ATOMIC);
 296                                 if (!f->page)
 297                                         break;
 298
 299                                 f->page_offset = 0;
 300                                 f->size = PAGE_SIZE;
 301
 302                                 skb->data_len += PAGE_SIZE;
 303                                 skb->len += PAGE_SIZE;
 304
 305                                 skb_shinfo(skb)->nr_frags++;
 306                         }
 307                 }
 308
 309                 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 310                 skb_queue_head(&vi->recv, skb);
 311
 312                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
 313                 if (err) {
 314                         skb_unlink(skb, &vi->recv);
 315                         trim_pages(vi, skb);
 316                         kfree_skb(skb);
 317                         break;
 318                 }
 319                 vi->num++;
 320         }
 321         if (unlikely(vi->num > vi->max))
 322                 vi->max = vi->num;
 323         vi->rvq->vq_ops->kick(vi->rvq);
 324 }
 325
 326 static void try_fill_recv(struct virtnet_info *vi)
 327 {
 328         struct sk_buff *skb;
 329         struct scatterlist sg[1];
 330         int err;
 331
 332         if (!vi->mergeable_rx_bufs) {
 333                 try_fill_recv_maxbufs(vi);
 334                 return;
 335         }
 336
 337         for (;;) {
 338                 skb_frag_t *f;
 339
 340                 skb = netdev_alloc_skb(vi->dev, GOOD_COPY_LEN + NET_IP_ALIGN);
 341                 if (unlikely(!skb))
 342                         break;
 343
 344                 skb_reserve(skb, NET_IP_ALIGN);
 345
 346                 f = &skb_shinfo(skb)->frags[0];
 347                 f->page = get_a_page(vi, GFP_ATOMIC);
 348                 if (!f->page) {
 349                         kfree_skb(skb);
 350                         break;
 351                 }
 352
 353                 f->page_offset = 0;
 354                 f->size = PAGE_SIZE;
 355
 356                 skb_shinfo(skb)->nr_frags++;
 357
 358                 sg_init_one(sg, page_address(f->page), PAGE_SIZE);
 359                 skb_queue_head(&vi->recv, skb);
 360
 361                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 1, skb);
 362                 if (err) {
 363                         skb_unlink(skb, &vi->recv);
 364                         kfree_skb(skb);
 365                         break;
 366                 }
 367                 vi->num++;
 368         }
 369         if (unlikely(vi->num > vi->max))
 370                 vi->max = vi->num;
 371         vi->rvq->vq_ops->kick(vi->rvq);
 372 }
 373
 374 static void skb_recv_done(struct virtqueue *rvq)
 375 {
 376         struct virtnet_info *vi = rvq->vdev->priv;
 377         /* Schedule NAPI, Suppress further interrupts if successful. */
 378         if (netif_rx_schedule_prep(&vi->napi)) {
 379                 rvq->vq_ops->disable_cb(rvq);
 380                 __netif_rx_schedule(&vi->napi);
 381         }
 382 }
 383
 384 static int virtnet_poll(struct napi_struct *napi, int budget)
 385 {
 386         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 387         struct sk_buff *skb = NULL;
 388         unsigned int len, received = 0;
 389
 390 again:
 391         while (received < budget &&
 392                (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
 393                 __skb_unlink(skb, &vi->recv);
 394                 receive_skb(vi->dev, skb, len);
 395                 vi->num--;
 396                 received++;
 397         }
 398
 399         /* FIXME: If we oom and completely run out of inbufs, we need
 400          * to start a timer trying to fill more. */
 401         if (vi->num < vi->max / 2)
 402                 try_fill_recv(vi);
 403
 404         /* Out of packets? */
 405         if (received < budget) {
 406                 netif_rx_complete(napi);
 407                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
 408                     && napi_schedule_prep(napi)) {
 409                         vi->rvq->vq_ops->disable_cb(vi->rvq);
 410                         __netif_rx_schedule(napi);
 411                         goto again;
 412                 }
 413         }
 414
 415         return received;
 416 }
 417
 418 static void free_old_xmit_skbs(struct virtnet_info *vi)
 419 {
 420         struct sk_buff *skb;
 421         unsigned int len;
 422
 423         while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 424                 pr_debug("Sent skb %p\n", skb);
 425                 __skb_unlink(skb, &vi->send);
 426                 vi->dev->stats.tx_bytes += skb->len;
 427                 vi->dev->stats.tx_packets++;
 428                 kfree_skb(skb);
 429         }
 430 }
 431
 432 /* If the virtio transport doesn't always notify us when all in-flight packets
 433  * are consumed, we fall back to using this function on a timer to free them. */
 434 static void xmit_free(unsigned long data)
 435 {
 436         struct virtnet_info *vi = (void *)data;
 437
 438         netif_tx_lock(vi->dev);
 439
 440         free_old_xmit_skbs(vi);
 441
 442         if (!skb_queue_empty(&vi->send))
 443                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 444
 445         netif_tx_unlock(vi->dev);
 446 }
 447
 448 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 449 {
 450         int num, err;
 451         struct scatterlist sg[2+MAX_SKB_FRAGS];
 452         struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
 453         struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
 454         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 455
 456         sg_init_table(sg, 2+MAX_SKB_FRAGS);
 457
 458         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 459
 460         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 461                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 462                 hdr->csum_start = skb->csum_start - skb_headroom(skb);
 463                 hdr->csum_offset = skb->csum_offset;
 464         } else {
 465                 hdr->flags = 0;
 466                 hdr->csum_offset = hdr->csum_start = 0;
 467         }
 468
 469         if (skb_is_gso(skb)) {
 470                 hdr->hdr_len = skb_transport_header(skb) - skb->data;
 471                 hdr->gso_size = skb_shinfo(skb)->gso_size;
 472                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 473                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 474                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 475                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 476                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 477                         hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 478                 else
 479                         BUG();
 480                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 481                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 482         } else {
 483                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 484                 hdr->gso_size = hdr->hdr_len = 0;
 485         }
 486
 487         mhdr->num_buffers = 0;
 488
 489         /* Encode metadata header at front. */
 490         if (vi->mergeable_rx_bufs)
 491                 sg_set_buf(sg, mhdr, sizeof(*mhdr));
 492         else
 493                 sg_set_buf(sg, hdr, sizeof(*hdr));
 494
 495         num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 496
 497         err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
 498         if (!err && !vi->free_in_tasklet)
 499                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 500
 501         return err;
 502 }
 503
 504 static void xmit_tasklet(unsigned long data)
 505 {
 506         struct virtnet_info *vi = (void *)data;
 507
 508         netif_tx_lock_bh(vi->dev);
 509         if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
 510                 vi->svq->vq_ops->kick(vi->svq);
 511                 vi->last_xmit_skb = NULL;
 512         }
 513         if (vi->free_in_tasklet)
 514                 free_old_xmit_skbs(vi);
 515         netif_tx_unlock_bh(vi->dev);
 516 }
 517
 518 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 519 {
 520         struct virtnet_info *vi = netdev_priv(dev);
 521
 522 again:
 523         /* Free up any pending old buffers before queueing new ones. */
 524         free_old_xmit_skbs(vi);
 525
 526         /* If we has a buffer left over from last time, send it now. */
 527         if (unlikely(vi->last_xmit_skb) &&
 528             xmit_skb(vi, vi->last_xmit_skb) != 0)
 529                 goto stop_queue;
 530
 531         vi->last_xmit_skb = NULL;
 532
 533         /* Put new one in send queue and do transmit */
 534         if (likely(skb)) {
 535                 __skb_queue_head(&vi->send, skb);
 536                 if (xmit_skb(vi, skb) != 0) {
 537                         vi->last_xmit_skb = skb;
 538                         skb = NULL;
 539                         goto stop_queue;
 540                 }
 541         }
 542 done:
 543         vi->svq->vq_ops->kick(vi->svq);
 544         return NETDEV_TX_OK;
 545
 546 stop_queue:
 547         pr_debug("%s: virtio not prepared to send\n", dev->name);
 548         netif_stop_queue(dev);
 549
 550         /* Activate callback for using skbs: if this returns false it
 551          * means some were used in the meantime. */
 552         if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
 553                 vi->svq->vq_ops->disable_cb(vi->svq);
 554                 netif_start_queue(dev);
 555                 goto again;
 556         }
 557         if (skb) {
 558                 /* Drop this skb: we only queue one. */
 559                 vi->dev->stats.tx_dropped++;
 560                 kfree_skb(skb);
 561         }
 562         goto done;
 563 }
 564
 565 #ifdef CONFIG_NET_POLL_CONTROLLER
 566 static void virtnet_netpoll(struct net_device *dev)
 567 {
 568         struct virtnet_info *vi = netdev_priv(dev);
 569
 570         napi_schedule(&vi->napi);
 571 }
 572 #endif
 573
 574 static int virtnet_open(struct net_device *dev)
 575 {
 576         struct virtnet_info *vi = netdev_priv(dev);
 577
 578         napi_enable(&vi->napi);
 579
 580         /* If all buffers were filled by other side before we napi_enabled, we
 581          * won't get another interrupt, so process any outstanding packets
 582          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 583          * We synchronize against interrupts via NAPI_STATE_SCHED */
 584         if (netif_rx_schedule_prep(&vi->napi)) {
 585                 vi->rvq->vq_ops->disable_cb(vi->rvq);
 586                 __netif_rx_schedule(&vi->napi);
 587         }
 588         return 0;
 589 }
 590
 591 static int virtnet_close(struct net_device *dev)
 592 {
 593         struct virtnet_info *vi = netdev_priv(dev);
 594
 595         napi_disable(&vi->napi);
 596
 597         return 0;
 598 }
 599
 600 static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 601 {
 602         struct virtnet_info *vi = netdev_priv(dev);
 603         struct virtio_device *vdev = vi->vdev;
 604
 605         if (data && !virtio_has_feature(vdev, VIRTIO_NET_F_CSUM))
 606                 return -ENOSYS;
 607
 608         return ethtool_op_set_tx_hw_csum(dev, data);
 609 }
 610
 611 static struct ethtool_ops virtnet_ethtool_ops = {
 612         .set_tx_csum = virtnet_set_tx_csum,
 613         .set_sg = ethtool_op_set_sg,
 614         .set_tso = ethtool_op_set_tso,
 615         .get_link = ethtool_op_get_link,
 616 };
 617
 618 #define MIN_MTU 68
 619 #define MAX_MTU 65535
 620
 621 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 622 {
 623         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 624                 return -EINVAL;
 625         dev->mtu = new_mtu;
 626         return 0;
 627 }
 628
 629 static const struct net_device_ops virtnet_netdev = {
 630         .ndo_open            = virtnet_open,
 631         .ndo_stop            = virtnet_close,
 632         .ndo_start_xmit      = start_xmit,
 633         .ndo_validate_addr   = eth_validate_addr,
 634         .ndo_set_mac_address = eth_mac_addr,
 635         .ndo_change_mtu      = virtnet_change_mtu,
 636 #ifdef CONFIG_NET_POLL_CONTROLLER
 637         .ndo_poll_controller = virtnet_netpoll,
 638 #endif
 639 };
 640
 641 static int virtnet_probe(struct virtio_device *vdev)
 642 {
 643         int err;
 644         struct net_device *dev;
 645         struct virtnet_info *vi;
 646
 647         /* Allocate ourselves a network device with room for our info */
 648         dev = alloc_etherdev(sizeof(struct virtnet_info));
 649         if (!dev)
 650                 return -ENOMEM;
 651
 652         /* Set up network device as normal. */
 653         dev->netdev_ops = &virtnet_netdev;
 654         dev->features = NETIF_F_HIGHDMA;
 655         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
 656         SET_NETDEV_DEV(dev, &vdev->dev);
 657
 658         /* Do we support "hardware" checksums? */
 659         if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 660                 /* This opens up the world of extra features. */
 661                 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
 662                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 663                         dev->features |= NETIF_F_TSO | NETIF_F_UFO
 664                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
 665                 }
 666                 /* Individual feature bits: what can host handle? */
 667                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
 668                         dev->features |= NETIF_F_TSO;
 669                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
 670                         dev->features |= NETIF_F_TSO6;
 671                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
 672                         dev->features |= NETIF_F_TSO_ECN;
 673                 if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
 674                         dev->features |= NETIF_F_UFO;
 675         }
 676
 677         /* Configuration may specify what MAC to use.  Otherwise random. */
 678         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 679                 vdev->config->get(vdev,
 680                                   offsetof(struct virtio_net_config, mac),
 681                                   dev->dev_addr, dev->addr_len);
 682         } else
 683                 random_ether_addr(dev->dev_addr);
 684
 685         /* Set up our device-specific information */
 686         vi = netdev_priv(dev);
 687         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
 688         vi->dev = dev;
 689         vi->vdev = vdev;
 690         vdev->priv = vi;
 691         vi->pages = NULL;
 692
 693         /* If they give us a callback when all buffers are done, we don't need
 694          * the timer. */
 695         vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
 696
 697         /* If we can receive ANY GSO packets, we must allocate large ones. */
 698         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
 699             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
 700             || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 701                 vi->big_packets = true;
 702
 703         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 704                 vi->mergeable_rx_bufs = true;
 705
 706         /* We expect two virtqueues, receive then send. */
 707         vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
 708         if (IS_ERR(vi->rvq)) {
 709                 err = PTR_ERR(vi->rvq);
 710                 goto free;
 711         }
 712
 713         vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
 714         if (IS_ERR(vi->svq)) {
 715                 err = PTR_ERR(vi->svq);
 716                 goto free_recv;
 717         }
 718
 719         /* Initialize our empty receive and send queues. */
 720         skb_queue_head_init(&vi->recv);
 721         skb_queue_head_init(&vi->send);
 722
 723         tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
 724
 725         if (!vi->free_in_tasklet)
 726                 setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
 727
 728         err = register_netdev(dev);
 729         if (err) {
 730                 pr_debug("virtio_net: registering device failed\n");
 731                 goto free_send;
 732         }
 733
 734         /* Last of all, set up some receive buffers. */
 735         try_fill_recv(vi);
 736
 737         /* If we didn't even get one input buffer, we're useless. */
 738         if (vi->num == 0) {
 739                 err = -ENOMEM;
 740                 goto unregister;
 741         }
 742
 743         netif_carrier_on(dev);
 744
 745         pr_debug("virtnet: registered device %s\n", dev->name);
 746         return 0;
 747
 748 unregister:
 749         unregister_netdev(dev);
 750 free_send:
 751         vdev->config->del_vq(vi->svq);
 752 free_recv:
 753         vdev->config->del_vq(vi->rvq);
 754 free:
 755         free_netdev(dev);
 756         return err;
 757 }
 758
 759 static void virtnet_remove(struct virtio_device *vdev)
 760 {
 761         struct virtnet_info *vi = vdev->priv;
 762         struct sk_buff *skb;
 763
 764         /* Stop all the virtqueues. */
 765         vdev->config->reset(vdev);
 766
 767         if (!vi->free_in_tasklet)
 768                 del_timer_sync(&vi->xmit_free_timer);
 769
 770         /* Free our skbs in send and recv queues, if any. */
 771         while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
 772                 kfree_skb(skb);
 773                 vi->num--;
 774         }
 775         __skb_queue_purge(&vi->send);
 776
 777         BUG_ON(vi->num != 0);
 778
 779         vdev->config->del_vq(vi->svq);
 780         vdev->config->del_vq(vi->rvq);
 781         unregister_netdev(vi->dev);
 782
 783         while (vi->pages)
 784                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
 785
 786         free_netdev(vi->dev);
 787 }
 788
 789 static struct virtio_device_id id_table[] = {
 790         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
 791         { 0 },
 792 };
 793
 794 static unsigned int features[] = {
 795         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
 796         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
 797         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
 798         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
 799         VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
 800         VIRTIO_NET_F_MRG_RXBUF,
 801         VIRTIO_F_NOTIFY_ON_EMPTY,
 802 };
 803
 804 static struct virtio_driver virtio_net = {
 805         .feature_table = features,
 806         .feature_table_size = ARRAY_SIZE(features),
 807         .driver.name =  KBUILD_MODNAME,
 808         .driver.owner = THIS_MODULE,
 809         .id_table =     id_table,
 810         .probe =        virtnet_probe,
 811         .remove =       __devexit_p(virtnet_remove),
 812 };
 813
 814 static int __init init(void)
 815 {
 816         return register_virtio_driver(&virtio_net);
 817 }
 818
 819 static void __exit fini(void)
 820 {
 821         unregister_virtio_driver(&virtio_net);
 822 }
 823 module_init(init);
 824 module_exit(fini);
 825
 826 MODULE_DEVICE_TABLE(virtio, id_table);
 827 MODULE_DESCRIPTION("Virtio network driver");
 828 MODULE_LICENSE("GPL");