drivers/net/virtio_net.c

   1 /* A 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 #include <linux/slab.h>
  29
  30 static int napi_weight = 128;
  31 module_param(napi_weight, int, 0444);
  32
  33 static bool csum = true, gso = true;
  34 module_param(csum, bool, 0444);
  35 module_param(gso, bool, 0444);
  36
  37 /* FIXME: MTU in config. */
  38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
  39 #define GOOD_COPY_LEN   128
  40
  41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
  42 #define VIRTNET_DRIVER_VERSION "1.0.0"
  43
  44 struct virtnet_stats {
  45         struct u64_stats_sync tx_syncp;
  46         struct u64_stats_sync rx_syncp;
  47         u64 tx_bytes;
  48         u64 tx_packets;
  49
  50         u64 rx_bytes;
  51         u64 rx_packets;
  52 };
  53
  54 struct virtnet_info {
  55         struct virtio_device *vdev;
  56         struct virtqueue *rvq, *svq, *cvq;
  57         struct net_device *dev;
  58         struct napi_struct napi;
  59         unsigned int status;
  60
  61         /* Number of input buffers, and max we've ever had. */
  62         unsigned int num, max;
  63
  64         /* I like... big packets and I cannot lie! */
  65         bool big_packets;
  66
  67         /* Host will merge rx buffers for big packets (shake it! shake it!) */
  68         bool mergeable_rx_bufs;
  69
  70         /* enable config space updates */
  71         bool config_enable;
  72
  73         /* Active statistics */
  74         struct virtnet_stats __percpu *stats;
  75
  76         /* Work struct for refilling if we run low on memory. */
  77         struct delayed_work refill;
  78
  79         /* Work struct for config space updates */
  80         struct work_struct config_work;
  81
  82         /* Lock for config space updates */
  83         struct mutex config_lock;
  84
  85         /* Chain pages by the private ptr. */
  86         struct page *pages;
  87
  88         /* fragments + linear part + virtio header */
  89         struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
  90         struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
  91 };
  92
  93 struct skb_vnet_hdr {
  94         union {
  95                 struct virtio_net_hdr hdr;
  96                 struct virtio_net_hdr_mrg_rxbuf mhdr;
  97         };
  98         unsigned int num_sg;
  99 };
 100
 101 struct padded_vnet_hdr {
 102         struct virtio_net_hdr hdr;
 103         /*
 104          * virtio_net_hdr should be in a separated sg buffer because of a
 105          * QEMU bug, and data sg buffer shares same page with this header sg.
 106          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
 107          */
 108         char padding[6];
 109 };
 110
 111 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 112 {
 113         return (struct skb_vnet_hdr *)skb->cb;
 114 }
 115
 116 /*
 117  * private is used to chain pages for big packets, put the whole
 118  * most recent used list in the beginning for reuse
 119  */
 120 static void give_pages(struct virtnet_info *vi, struct page *page)
 121 {
 122         struct page *end;
 123
 124         /* Find end of list, sew whole thing into vi->pages. */
 125         for (end = page; end->private; end = (struct page *)end->private);
 126         end->private = (unsigned long)vi->pages;
 127         vi->pages = page;
 128 }
 129
 130 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 131 {
 132         struct page *p = vi->pages;
 133
 134         if (p) {
 135                 vi->pages = (struct page *)p->private;
 136                 /* clear private here, it is used to chain pages */
 137                 p->private = 0;
 138         } else
 139                 p = alloc_page(gfp_mask);
 140         return p;
 141 }
 142
 143 static void skb_xmit_done(struct virtqueue *svq)
 144 {
 145         struct virtnet_info *vi = svq->vdev->priv;
 146
 147         /* Suppress further interrupts. */
 148         virtqueue_disable_cb(svq);
 149
 150         /* We were probably waiting for more output buffers. */
 151         netif_wake_queue(vi->dev);
 152 }
 153
 154 static void set_skb_frag(struct sk_buff *skb, struct page *page,
 155                          unsigned int offset, unsigned int *len)
 156 {
 157         int size = min((unsigned)PAGE_SIZE - offset, *len);
 158         int i = skb_shinfo(skb)->nr_frags;
 159
 160         __skb_fill_page_desc(skb, i, page, offset, size);
 161
 162         skb->data_len += size;
 163         skb->len += size;
 164         skb->truesize += PAGE_SIZE;
 165         skb_shinfo(skb)->nr_frags++;
 166         *len -= size;
 167 }
 168
 169 /* Called from bottom half context */
 170 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 171                                    struct page *page, unsigned int len)
 172 {
 173         struct sk_buff *skb;
 174         struct skb_vnet_hdr *hdr;
 175         unsigned int copy, hdr_len, offset;
 176         char *p;
 177
 178         p = page_address(page);
 179
 180         /* copy small packet so we can reuse these pages for small data */
 181         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
 182         if (unlikely(!skb))
 183                 return NULL;
 184
 185         hdr = skb_vnet_hdr(skb);
 186
 187         if (vi->mergeable_rx_bufs) {
 188                 hdr_len = sizeof hdr->mhdr;
 189                 offset = hdr_len;
 190         } else {
 191                 hdr_len = sizeof hdr->hdr;
 192                 offset = sizeof(struct padded_vnet_hdr);
 193         }
 194
 195         memcpy(hdr, p, hdr_len);
 196
 197         len -= hdr_len;
 198         p += offset;
 199
 200         copy = len;
 201         if (copy > skb_tailroom(skb))
 202                 copy = skb_tailroom(skb);
 203         memcpy(skb_put(skb, copy), p, copy);
 204
 205         len -= copy;
 206         offset += copy;
 207
 208         /*
 209          * Verify that we can indeed put this data into a skb.
 210          * This is here to handle cases when the device erroneously
 211          * tries to receive more than is possible. This is usually
 212          * the case of a broken device.
 213          */
 214         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
 215                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
 216                 dev_kfree_skb(skb);
 217                 return NULL;
 218         }
 219
 220         while (len) {
 221                 set_skb_frag(skb, page, offset, &len);
 222                 page = (struct page *)page->private;
 223                 offset = 0;
 224         }
 225
 226         if (page)
 227                 give_pages(vi, page);
 228
 229         return skb;
 230 }
 231
 232 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 233 {
 234         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 235         struct page *page;
 236         int num_buf, i, len;
 237
 238         num_buf = hdr->mhdr.num_buffers;
 239         while (--num_buf) {
 240                 i = skb_shinfo(skb)->nr_frags;
 241                 if (i >= MAX_SKB_FRAGS) {
 242                         pr_debug("%s: packet too long\n", skb->dev->name);
 243                         skb->dev->stats.rx_length_errors++;
 244                         return -EINVAL;
 245                 }
 246                 page = virtqueue_get_buf(vi->rvq, &len);
 247                 if (!page) {
 248                         pr_debug("%s: rx error: %d buffers missing\n",
 249                                  skb->dev->name, hdr->mhdr.num_buffers);
 250                         skb->dev->stats.rx_length_errors++;
 251                         return -EINVAL;
 252                 }
 253
 254                 if (len > PAGE_SIZE)
 255                         len = PAGE_SIZE;
 256
 257                 set_skb_frag(skb, page, 0, &len);
 258
 259                 --vi->num;
 260         }
 261         return 0;
 262 }
 263
 264 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 265 {
 266         struct virtnet_info *vi = netdev_priv(dev);
 267         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 268         struct sk_buff *skb;
 269         struct page *page;
 270         struct skb_vnet_hdr *hdr;
 271
 272         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 273                 pr_debug("%s: short packet %i\n", dev->name, len);
 274                 dev->stats.rx_length_errors++;
 275                 if (vi->mergeable_rx_bufs || vi->big_packets)
 276                         give_pages(vi, buf);
 277                 else
 278                         dev_kfree_skb(buf);
 279                 return;
 280         }
 281
 282         if (!vi->mergeable_rx_bufs && !vi->big_packets) {
 283                 skb = buf;
 284                 len -= sizeof(struct virtio_net_hdr);
 285                 skb_trim(skb, len);
 286         } else {
 287                 page = buf;
 288                 skb = page_to_skb(vi, page, len);
 289                 if (unlikely(!skb)) {
 290                         dev->stats.rx_dropped++;
 291                         give_pages(vi, page);
 292                         return;
 293                 }
 294                 if (vi->mergeable_rx_bufs)
 295                         if (receive_mergeable(vi, skb)) {
 296                                 dev_kfree_skb(skb);
 297                                 return;
 298                         }
 299         }
 300
 301         hdr = skb_vnet_hdr(skb);
 302
 303         u64_stats_update_begin(&stats->rx_syncp);
 304         stats->rx_bytes += skb->len;
 305         stats->rx_packets++;
 306         u64_stats_update_end(&stats->rx_syncp);
 307
 308         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 309                 pr_debug("Needs csum!\n");
 310                 if (!skb_partial_csum_set(skb,
 311                                           hdr->hdr.csum_start,
 312                                           hdr->hdr.csum_offset))
 313                         goto frame_err;
 314         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
 315                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 316         }
 317
 318         skb->protocol = eth_type_trans(skb, dev);
 319         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 320                  ntohs(skb->protocol), skb->len, skb->pkt_type);
 321
 322         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 323                 pr_debug("GSO!\n");
 324                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 325                 case VIRTIO_NET_HDR_GSO_TCPV4:
 326                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 327                         break;
 328                 case VIRTIO_NET_HDR_GSO_UDP:
 329                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 330                         break;
 331                 case VIRTIO_NET_HDR_GSO_TCPV6:
 332                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 333                         break;
 334                 default:
 335                         net_warn_ratelimited("%s: bad gso type %u.\n",
 336                                              dev->name, hdr->hdr.gso_type);
 337                         goto frame_err;
 338                 }
 339
 340                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 341                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 342
 343                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 344                 if (skb_shinfo(skb)->gso_size == 0) {
 345                         net_warn_ratelimited("%s: zero gso size.\n", dev->name);
 346                         goto frame_err;
 347                 }
 348
 349                 /* Header must be checked, and gso_segs computed. */
 350                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 351                 skb_shinfo(skb)->gso_segs = 0;
 352         }
 353
 354         netif_receive_skb(skb);
 355         return;
 356
 357 frame_err:
 358         dev->stats.rx_frame_errors++;
 359         dev_kfree_skb(skb);
 360 }
 361
 362 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 363 {
 364         struct sk_buff *skb;
 365         struct skb_vnet_hdr *hdr;
 366         int err;
 367
 368         skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
 369         if (unlikely(!skb))
 370                 return -ENOMEM;
 371
 372         skb_put(skb, MAX_PACKET_LEN);
 373
 374         hdr = skb_vnet_hdr(skb);
 375         sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
 376
 377         skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
 378
 379         err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
 380         if (err < 0)
 381                 dev_kfree_skb(skb);
 382
 383         return err;
 384 }
 385
 386 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
 387 {
 388         struct page *first, *list = NULL;
 389         char *p;
 390         int i, err, offset;
 391
 392         /* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
 393         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
 394                 first = get_a_page(vi, gfp);
 395                 if (!first) {
 396                         if (list)
 397                                 give_pages(vi, list);
 398                         return -ENOMEM;
 399                 }
 400                 sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
 401
 402                 /* chain new page in list head to match sg */
 403                 first->private = (unsigned long)list;
 404                 list = first;
 405         }
 406
 407         first = get_a_page(vi, gfp);
 408         if (!first) {
 409                 give_pages(vi, list);
 410                 return -ENOMEM;
 411         }
 412         p = page_address(first);
 413
 414         /* vi->rx_sg[0], vi->rx_sg[1] share the same page */
 415         /* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
 416         sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
 417
 418         /* vi->rx_sg[1] for data packet, from offset */
 419         offset = sizeof(struct padded_vnet_hdr);
 420         sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
 421
 422         /* chain first in list head */
 423         first->private = (unsigned long)list;
 424         err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
 425                                 first, gfp);
 426         if (err < 0)
 427                 give_pages(vi, first);
 428
 429         return err;
 430 }
 431
 432 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 433 {
 434         struct page *page;
 435         int err;
 436
 437         page = get_a_page(vi, gfp);
 438         if (!page)
 439                 return -ENOMEM;
 440
 441         sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
 442
 443         err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 1, page, gfp);
 444         if (err < 0)
 445                 give_pages(vi, page);
 446
 447         return err;
 448 }
 449
 450 /*
 451  * Returns false if we couldn't fill entirely (OOM).
 452  *
 453  * Normally run in the receive path, but can also be run from ndo_open
 454  * before we're receiving packets, or from refill_work which is
 455  * careful to disable receiving (using napi_disable).
 456  */
 457 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
 458 {
 459         int err;
 460         bool oom;
 461
 462         do {
 463                 if (vi->mergeable_rx_bufs)
 464                         err = add_recvbuf_mergeable(vi, gfp);
 465                 else if (vi->big_packets)
 466                         err = add_recvbuf_big(vi, gfp);
 467                 else
 468                         err = add_recvbuf_small(vi, gfp);
 469
 470                 oom = err == -ENOMEM;
 471                 if (err < 0)
 472                         break;
 473                 ++vi->num;
 474         } while (err > 0);
 475         if (unlikely(vi->num > vi->max))
 476                 vi->max = vi->num;
 477         virtqueue_kick(vi->rvq);
 478         return !oom;
 479 }
 480
 481 static void skb_recv_done(struct virtqueue *rvq)
 482 {
 483         struct virtnet_info *vi = rvq->vdev->priv;
 484         /* Schedule NAPI, Suppress further interrupts if successful. */
 485         if (napi_schedule_prep(&vi->napi)) {
 486                 virtqueue_disable_cb(rvq);
 487                 __napi_schedule(&vi->napi);
 488         }
 489 }
 490
 491 static void virtnet_napi_enable(struct virtnet_info *vi)
 492 {
 493         napi_enable(&vi->napi);
 494
 495         /* If all buffers were filled by other side before we napi_enabled, we
 496          * won't get another interrupt, so process any outstanding packets
 497          * now.  virtnet_poll wants re-enable the queue, so we disable here.
 498          * We synchronize against interrupts via NAPI_STATE_SCHED */
 499         if (napi_schedule_prep(&vi->napi)) {
 500                 virtqueue_disable_cb(vi->rvq);
 501                 local_bh_disable();
 502                 __napi_schedule(&vi->napi);
 503                 local_bh_enable();
 504         }
 505 }
 506
 507 static void refill_work(struct work_struct *work)
 508 {
 509         struct virtnet_info *vi;
 510         bool still_empty;
 511
 512         vi = container_of(work, struct virtnet_info, refill.work);
 513         napi_disable(&vi->napi);
 514         still_empty = !try_fill_recv(vi, GFP_KERNEL);
 515         virtnet_napi_enable(vi);
 516
 517         /* In theory, this can happen: if we don't get any buffers in
 518          * we will *never* try to fill again. */
 519         if (still_empty)
 520                 schedule_delayed_work(&vi->refill, HZ/2);
 521 }
 522
 523 static int virtnet_poll(struct napi_struct *napi, int budget)
 524 {
 525         struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
 526         void *buf;
 527         unsigned int len, received = 0;
 528
 529 again:
 530         while (received < budget &&
 531                (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
 532                 receive_buf(vi->dev, buf, len);
 533                 --vi->num;
 534                 received++;
 535         }
 536
 537         if (vi->num < vi->max / 2) {
 538                 if (!try_fill_recv(vi, GFP_ATOMIC))
 539                         schedule_delayed_work(&vi->refill, 0);
 540         }
 541
 542         /* Out of packets? */
 543         if (received < budget) {
 544                 napi_complete(napi);
 545                 if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
 546                     napi_schedule_prep(napi)) {
 547                         virtqueue_disable_cb(vi->rvq);
 548                         __napi_schedule(napi);
 549                         goto again;
 550                 }
 551         }
 552
 553         return received;
 554 }
 555
 556 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 557 {
 558         struct sk_buff *skb;
 559         unsigned int len, tot_sgs = 0;
 560         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 561
 562         while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
 563                 pr_debug("Sent skb %p\n", skb);
 564
 565                 u64_stats_update_begin(&stats->tx_syncp);
 566                 stats->tx_bytes += skb->len;
 567                 stats->tx_packets++;
 568                 u64_stats_update_end(&stats->tx_syncp);
 569
 570                 tot_sgs += skb_vnet_hdr(skb)->num_sg;
 571                 dev_kfree_skb_any(skb);
 572         }
 573         return tot_sgs;
 574 }
 575
 576 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 577 {
 578         struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 579         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 580
 581         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 582
 583         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 584                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 585                 hdr->hdr.csum_start = skb_checksum_start_offset(skb);
 586                 hdr->hdr.csum_offset = skb->csum_offset;
 587         } else {
 588                 hdr->hdr.flags = 0;
 589                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 590         }
 591
 592         if (skb_is_gso(skb)) {
 593                 hdr->hdr.hdr_len = skb_headlen(skb);
 594                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 595                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 596                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 597                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 598                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 599                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 600                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 601                 else
 602                         BUG();
 603                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
 604                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 605         } else {
 606                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 607                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 608         }
 609
 610         hdr->mhdr.num_buffers = 0;
 611
 612         /* Encode metadata header at front. */
 613         if (vi->mergeable_rx_bufs)
 614                 sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
 615         else
 616                 sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
 617
 618         hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
 619         return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
 620                                  0, skb, GFP_ATOMIC);
 621 }
 622
 623 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 624 {
 625         struct virtnet_info *vi = netdev_priv(dev);
 626         int capacity;
 627
 628         /* Free up any pending old buffers before queueing new ones. */
 629         free_old_xmit_skbs(vi);
 630
 631         /* Try to transmit */
 632         capacity = xmit_skb(vi, skb);
 633
 634         /* This can happen with OOM and indirect buffers. */
 635         if (unlikely(capacity < 0)) {
 636                 if (likely(capacity == -ENOMEM)) {
 637                         if (net_ratelimit())
 638                                 dev_warn(&dev->dev,
 639                                          "TX queue failure: out of memory\n");
 640                 } else {
 641                         dev->stats.tx_fifo_errors++;
 642                         if (net_ratelimit())
 643                                 dev_warn(&dev->dev,
 644                                          "Unexpected TX queue failure: %d\n",
 645                                          capacity);
 646                 }
 647                 dev->stats.tx_dropped++;
 648                 kfree_skb(skb);
 649                 return NETDEV_TX_OK;
 650         }
 651         virtqueue_kick(vi->svq);
 652
 653         /* Don't wait up for transmitted skbs to be freed. */
 654         skb_orphan(skb);
 655         nf_reset(skb);
 656
 657         /* Apparently nice girls don't return TX_BUSY; stop the queue
 658          * before it gets out of hand.  Naturally, this wastes entries. */
 659         if (capacity < 2+MAX_SKB_FRAGS) {
 660                 netif_stop_queue(dev);
 661                 if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) {
 662                         /* More just got used, free them then recheck. */
 663                         capacity += free_old_xmit_skbs(vi);
 664                         if (capacity >= 2+MAX_SKB_FRAGS) {
 665                                 netif_start_queue(dev);
 666                                 virtqueue_disable_cb(vi->svq);
 667                         }
 668                 }
 669         }
 670
 671         return NETDEV_TX_OK;
 672 }
 673
 674 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 675 {
 676         struct virtnet_info *vi = netdev_priv(dev);
 677         struct virtio_device *vdev = vi->vdev;
 678         int ret;
 679
 680         ret = eth_mac_addr(dev, p);
 681         if (ret)
 682                 return ret;
 683
 684         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
 685                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
 686                                   dev->dev_addr, dev->addr_len);
 687
 688         return 0;
 689 }
 690
 691 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 692                                                struct rtnl_link_stats64 *tot)
 693 {
 694         struct virtnet_info *vi = netdev_priv(dev);
 695         int cpu;
 696         unsigned int start;
 697
 698         for_each_possible_cpu(cpu) {
 699                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
 700                 u64 tpackets, tbytes, rpackets, rbytes;
 701
 702                 do {
 703                         start = u64_stats_fetch_begin_bh(&stats->tx_syncp);
 704                         tpackets = stats->tx_packets;
 705                         tbytes   = stats->tx_bytes;
 706                 } while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start));
 707
 708                 do {
 709                         start = u64_stats_fetch_begin_bh(&stats->rx_syncp);
 710                         rpackets = stats->rx_packets;
 711                         rbytes   = stats->rx_bytes;
 712                 } while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start));
 713
 714                 tot->rx_packets += rpackets;
 715                 tot->tx_packets += tpackets;
 716                 tot->rx_bytes   += rbytes;
 717                 tot->tx_bytes   += tbytes;
 718         }
 719
 720         tot->tx_dropped = dev->stats.tx_dropped;
 721         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 722         tot->rx_dropped = dev->stats.rx_dropped;
 723         tot->rx_length_errors = dev->stats.rx_length_errors;
 724         tot->rx_frame_errors = dev->stats.rx_frame_errors;
 725
 726         return tot;
 727 }
 728
 729 #ifdef CONFIG_NET_POLL_CONTROLLER
 730 static void virtnet_netpoll(struct net_device *dev)
 731 {
 732         struct virtnet_info *vi = netdev_priv(dev);
 733
 734         napi_schedule(&vi->napi);
 735 }
 736 #endif
 737
 738 static int virtnet_open(struct net_device *dev)
 739 {
 740         struct virtnet_info *vi = netdev_priv(dev);
 741
 742         /* Make sure we have some buffers: if oom use wq. */
 743         if (!try_fill_recv(vi, GFP_KERNEL))
 744                 schedule_delayed_work(&vi->refill, 0);
 745
 746         virtnet_napi_enable(vi);
 747         return 0;
 748 }
 749
 750 /*
 751  * Send command via the control virtqueue and check status.  Commands
 752  * supported by the hypervisor, as indicated by feature bits, should
 753  * never fail unless improperly formated.
 754  */
 755 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 756                                  struct scatterlist *data, int out, int in)
 757 {
 758         struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
 759         struct virtio_net_ctrl_hdr ctrl;
 760         virtio_net_ctrl_ack status = ~0;
 761         unsigned int tmp;
 762         int i;
 763
 764         /* Caller should know better */
 765         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
 766                 (out + in > VIRTNET_SEND_COMMAND_SG_MAX));
 767
 768         out++; /* Add header */
 769         in++; /* Add return status */
 770
 771         ctrl.class = class;
 772         ctrl.cmd = cmd;
 773
 774         sg_init_table(sg, out + in);
 775
 776         sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
 777         for_each_sg(data, s, out + in - 2, i)
 778                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 779         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 780
 781         BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
 782
 783         virtqueue_kick(vi->cvq);
 784
 785         /*
 786          * Spin for a response, the kick causes an ioport write, trapping
 787          * into the hypervisor, so the request should be handled immediately.
 788          */
 789         while (!virtqueue_get_buf(vi->cvq, &tmp))
 790                 cpu_relax();
 791
 792         return status == VIRTIO_NET_OK;
 793 }
 794
 795 static void virtnet_ack_link_announce(struct virtnet_info *vi)
 796 {
 797         rtnl_lock();
 798         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
 799                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
 800                                   0, 0))
 801                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
 802         rtnl_unlock();
 803 }
 804
 805 static int virtnet_close(struct net_device *dev)
 806 {
 807         struct virtnet_info *vi = netdev_priv(dev);
 808
 809         /* Make sure refill_work doesn't re-enable napi! */
 810         cancel_delayed_work_sync(&vi->refill);
 811         napi_disable(&vi->napi);
 812
 813         return 0;
 814 }
 815
 816 static void virtnet_set_rx_mode(struct net_device *dev)
 817 {
 818         struct virtnet_info *vi = netdev_priv(dev);
 819         struct scatterlist sg[2];
 820         u8 promisc, allmulti;
 821         struct virtio_net_ctrl_mac *mac_data;
 822         struct netdev_hw_addr *ha;
 823         int uc_count;
 824         int mc_count;
 825         void *buf;
 826         int i;
 827
 828         /* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
 829         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 830                 return;
 831
 832         promisc = ((dev->flags & IFF_PROMISC) != 0);
 833         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 834
 835         sg_init_one(sg, &promisc, sizeof(promisc));
 836
 837         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 838                                   VIRTIO_NET_CTRL_RX_PROMISC,
 839                                   sg, 1, 0))
 840                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
 841                          promisc ? "en" : "dis");
 842
 843         sg_init_one(sg, &allmulti, sizeof(allmulti));
 844
 845         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
 846                                   VIRTIO_NET_CTRL_RX_ALLMULTI,
 847                                   sg, 1, 0))
 848                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 849                          allmulti ? "en" : "dis");
 850
 851         uc_count = netdev_uc_count(dev);
 852         mc_count = netdev_mc_count(dev);
 853         /* MAC filter - use one buffer for both lists */
 854         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 855                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 856         mac_data = buf;
 857         if (!buf) {
 858                 dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 859                 return;
 860         }
 861
 862         sg_init_table(sg, 2);
 863
 864         /* Store the unicast list and count in the front of the buffer */
 865         mac_data->entries = uc_count;
 866         i = 0;
 867         netdev_for_each_uc_addr(ha, dev)
 868                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 869
 870         sg_set_buf(&sg[0], mac_data,
 871                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 872
 873         /* multicast list and count fill the end */
 874         mac_data = (void *)&mac_data->macs[uc_count][0];
 875
 876         mac_data->entries = mc_count;
 877         i = 0;
 878         netdev_for_each_mc_addr(ha, dev)
 879                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 880
 881         sg_set_buf(&sg[1], mac_data,
 882                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 883
 884         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 885                                   VIRTIO_NET_CTRL_MAC_TABLE_SET,
 886                                   sg, 2, 0))
 887                 dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
 888
 889         kfree(buf);
 890 }
 891
 892 static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 893 {
 894         struct virtnet_info *vi = netdev_priv(dev);
 895         struct scatterlist sg;
 896
 897         sg_init_one(&sg, &vid, sizeof(vid));
 898
 899         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 900                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 901                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
 902         return 0;
 903 }
 904
 905 static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 906 {
 907         struct virtnet_info *vi = netdev_priv(dev);
 908         struct scatterlist sg;
 909
 910         sg_init_one(&sg, &vid, sizeof(vid));
 911
 912         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 913                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 914                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 915         return 0;
 916 }
 917
 918 static void virtnet_get_ringparam(struct net_device *dev,
 919                                 struct ethtool_ringparam *ring)
 920 {
 921         struct virtnet_info *vi = netdev_priv(dev);
 922
 923         ring->rx_max_pending = virtqueue_get_vring_size(vi->rvq);
 924         ring->tx_max_pending = virtqueue_get_vring_size(vi->svq);
 925         ring->rx_pending = ring->rx_max_pending;
 926         ring->tx_pending = ring->tx_max_pending;
 927
 928 }
 929
 930
 931 static void virtnet_get_drvinfo(struct net_device *dev,
 932                                 struct ethtool_drvinfo *info)
 933 {
 934         struct virtnet_info *vi = netdev_priv(dev);
 935         struct virtio_device *vdev = vi->vdev;
 936
 937         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
 938         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
 939         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
 940
 941 }
 942
 943 static const struct ethtool_ops virtnet_ethtool_ops = {
 944         .get_drvinfo = virtnet_get_drvinfo,
 945         .get_link = ethtool_op_get_link,
 946         .get_ringparam = virtnet_get_ringparam,
 947 };
 948
 949 #define MIN_MTU 68
 950 #define MAX_MTU 65535
 951
 952 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 953 {
 954         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
 955                 return -EINVAL;
 956         dev->mtu = new_mtu;
 957         return 0;
 958 }
 959
 960 static const struct net_device_ops virtnet_netdev = {
 961         .ndo_open            = virtnet_open,
 962         .ndo_stop            = virtnet_close,
 963         .ndo_start_xmit      = start_xmit,
 964         .ndo_validate_addr   = eth_validate_addr,
 965         .ndo_set_mac_address = virtnet_set_mac_address,
 966         .ndo_set_rx_mode     = virtnet_set_rx_mode,
 967         .ndo_change_mtu      = virtnet_change_mtu,
 968         .ndo_get_stats64     = virtnet_stats,
 969         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 970         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
 971 #ifdef CONFIG_NET_POLL_CONTROLLER
 972         .ndo_poll_controller = virtnet_netpoll,
 973 #endif
 974 };
 975
 976 static void virtnet_config_changed_work(struct work_struct *work)
 977 {
 978         struct virtnet_info *vi =
 979                 container_of(work, struct virtnet_info, config_work);
 980         u16 v;
 981
 982         mutex_lock(&vi->config_lock);
 983         if (!vi->config_enable)
 984                 goto done;
 985
 986         if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
 987                               offsetof(struct virtio_net_config, status),
 988                               &v) < 0)
 989                 goto done;
 990
 991         if (v & VIRTIO_NET_S_ANNOUNCE) {
 992                 netdev_notify_peers(vi->dev);
 993                 virtnet_ack_link_announce(vi);
 994         }
 995
 996         /* Ignore unknown (future) status bits */
 997         v &= VIRTIO_NET_S_LINK_UP;
 998
 999         if (vi->status == v)
1000                 goto done;
1001
1002         vi->status = v;
1003
1004         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1005                 netif_carrier_on(vi->dev);
1006                 netif_wake_queue(vi->dev);
1007         } else {
1008                 netif_carrier_off(vi->dev);
1009                 netif_stop_queue(vi->dev);
1010         }
1011 done:
1012         mutex_unlock(&vi->config_lock);
1013 }
1014
1015 static void virtnet_config_changed(struct virtio_device *vdev)
1016 {
1017         struct virtnet_info *vi = vdev->priv;
1018
1019         schedule_work(&vi->config_work);
1020 }
1021
1022 static int init_vqs(struct virtnet_info *vi)
1023 {
1024         struct virtqueue *vqs[3];
1025         vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
1026         const char *names[] = { "input", "output", "control" };
1027         int nvqs, err;
1028
1029         /* We expect two virtqueues, receive then send,
1030          * and optionally control. */
1031         nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
1032
1033         err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
1034         if (err)
1035                 return err;
1036
1037         vi->rvq = vqs[0];
1038         vi->svq = vqs[1];
1039
1040         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
1041                 vi->cvq = vqs[2];
1042
1043                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1044                         vi->dev->features |= NETIF_F_HW_VLAN_FILTER;
1045         }
1046         return 0;
1047 }
1048
1049 static int virtnet_probe(struct virtio_device *vdev)
1050 {
1051         int err;
1052         struct net_device *dev;
1053         struct virtnet_info *vi;
1054
1055         /* Allocate ourselves a network device with room for our info */
1056         dev = alloc_etherdev(sizeof(struct virtnet_info));
1057         if (!dev)
1058                 return -ENOMEM;
1059
1060         /* Set up network device as normal. */
1061         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1062         dev->netdev_ops = &virtnet_netdev;
1063         dev->features = NETIF_F_HIGHDMA;
1064
1065         SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1066         SET_NETDEV_DEV(dev, &vdev->dev);
1067
1068         /* Do we support "hardware" checksums? */
1069         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1070                 /* This opens up the world of extra features. */
1071                 dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1072                 if (csum)
1073                         dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1074
1075                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1076                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1077                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1078                 }
1079                 /* Individual feature bits: what can host handle? */
1080                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1081                         dev->hw_features |= NETIF_F_TSO;
1082                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1083                         dev->hw_features |= NETIF_F_TSO6;
1084                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1085                         dev->hw_features |= NETIF_F_TSO_ECN;
1086                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1087                         dev->hw_features |= NETIF_F_UFO;
1088
1089                 if (gso)
1090                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1091                 /* (!csum && gso) case will be fixed by register_netdev() */
1092         }
1093
1094         /* Configuration may specify what MAC to use.  Otherwise random. */
1095         if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1096                                   offsetof(struct virtio_net_config, mac),
1097                                   dev->dev_addr, dev->addr_len) < 0)
1098                 eth_hw_addr_random(dev);
1099
1100         /* Set up our device-specific information */
1101         vi = netdev_priv(dev);
1102         netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
1103         vi->dev = dev;
1104         vi->vdev = vdev;
1105         vdev->priv = vi;
1106         vi->pages = NULL;
1107         vi->stats = alloc_percpu(struct virtnet_stats);
1108         err = -ENOMEM;
1109         if (vi->stats == NULL)
1110                 goto free;
1111
1112         INIT_DELAYED_WORK(&vi->refill, refill_work);
1113         mutex_init(&vi->config_lock);
1114         vi->config_enable = true;
1115         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1116         sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
1117         sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
1118
1119         /* If we can receive ANY GSO packets, we must allocate large ones. */
1120         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1121             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1122             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1123                 vi->big_packets = true;
1124
1125         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1126                 vi->mergeable_rx_bufs = true;
1127
1128         err = init_vqs(vi);
1129         if (err)
1130                 goto free_stats;
1131
1132         err = register_netdev(dev);
1133         if (err) {
1134                 pr_debug("virtio_net: registering device failed\n");
1135                 goto free_vqs;
1136         }
1137
1138         /* Last of all, set up some receive buffers. */
1139         try_fill_recv(vi, GFP_KERNEL);
1140
1141         /* If we didn't even get one input buffer, we're useless. */
1142         if (vi->num == 0) {
1143                 err = -ENOMEM;
1144                 goto unregister;
1145         }
1146
1147         /* Assume link up if device can't report link status,
1148            otherwise get link status from config. */
1149         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1150                 netif_carrier_off(dev);
1151                 schedule_work(&vi->config_work);
1152         } else {
1153                 vi->status = VIRTIO_NET_S_LINK_UP;
1154                 netif_carrier_on(dev);
1155         }
1156
1157         pr_debug("virtnet: registered device %s\n", dev->name);
1158         return 0;
1159
1160 unregister:
1161         unregister_netdev(dev);
1162 free_vqs:
1163         vdev->config->del_vqs(vdev);
1164 free_stats:
1165         free_percpu(vi->stats);
1166 free:
1167         free_netdev(dev);
1168         return err;
1169 }
1170
1171 static void free_unused_bufs(struct virtnet_info *vi)
1172 {
1173         void *buf;
1174         while (1) {
1175                 buf = virtqueue_detach_unused_buf(vi->svq);
1176                 if (!buf)
1177                         break;
1178                 dev_kfree_skb(buf);
1179         }
1180         while (1) {
1181                 buf = virtqueue_detach_unused_buf(vi->rvq);
1182                 if (!buf)
1183                         break;
1184                 if (vi->mergeable_rx_bufs || vi->big_packets)
1185                         give_pages(vi, buf);
1186                 else
1187                         dev_kfree_skb(buf);
1188                 --vi->num;
1189         }
1190         BUG_ON(vi->num != 0);
1191 }
1192
1193 static void remove_vq_common(struct virtnet_info *vi)
1194 {
1195         vi->vdev->config->reset(vi->vdev);
1196
1197         /* Free unused buffers in both send and recv, if any. */
1198         free_unused_bufs(vi);
1199
1200         vi->vdev->config->del_vqs(vi->vdev);
1201
1202         while (vi->pages)
1203                 __free_pages(get_a_page(vi, GFP_KERNEL), 0);
1204 }
1205
1206 static void virtnet_remove(struct virtio_device *vdev)
1207 {
1208         struct virtnet_info *vi = vdev->priv;
1209
1210         /* Prevent config work handler from accessing the device. */
1211         mutex_lock(&vi->config_lock);
1212         vi->config_enable = false;
1213         mutex_unlock(&vi->config_lock);
1214
1215         unregister_netdev(vi->dev);
1216
1217         remove_vq_common(vi);
1218
1219         flush_work(&vi->config_work);
1220
1221         free_percpu(vi->stats);
1222         free_netdev(vi->dev);
1223 }
1224
1225 #ifdef CONFIG_PM
1226 static int virtnet_freeze(struct virtio_device *vdev)
1227 {
1228         struct virtnet_info *vi = vdev->priv;
1229
1230         /* Prevent config work handler from accessing the device */
1231         mutex_lock(&vi->config_lock);
1232         vi->config_enable = false;
1233         mutex_unlock(&vi->config_lock);
1234
1235         netif_device_detach(vi->dev);
1236         cancel_delayed_work_sync(&vi->refill);
1237
1238         if (netif_running(vi->dev))
1239                 napi_disable(&vi->napi);
1240
1241         remove_vq_common(vi);
1242
1243         flush_work(&vi->config_work);
1244
1245         return 0;
1246 }
1247
1248 static int virtnet_restore(struct virtio_device *vdev)
1249 {
1250         struct virtnet_info *vi = vdev->priv;
1251         int err;
1252
1253         err = init_vqs(vi);
1254         if (err)
1255                 return err;
1256
1257         if (netif_running(vi->dev))
1258                 virtnet_napi_enable(vi);
1259
1260         netif_device_attach(vi->dev);
1261
1262         if (!try_fill_recv(vi, GFP_KERNEL))
1263                 schedule_delayed_work(&vi->refill, 0);
1264
1265         mutex_lock(&vi->config_lock);
1266         vi->config_enable = true;
1267         mutex_unlock(&vi->config_lock);
1268
1269         return 0;
1270 }
1271 #endif
1272
1273 static struct virtio_device_id id_table[] = {
1274         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1275         { 0 },
1276 };
1277
1278 static unsigned int features[] = {
1279         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1280         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1281         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1282         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1283         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1284         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1285         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1286         VIRTIO_NET_F_GUEST_ANNOUNCE,
1287 };
1288
1289 static struct virtio_driver virtio_net_driver = {
1290         .feature_table = features,
1291         .feature_table_size = ARRAY_SIZE(features),
1292         .driver.name =  KBUILD_MODNAME,
1293         .driver.owner = THIS_MODULE,
1294         .id_table =     id_table,
1295         .probe =        virtnet_probe,
1296         .remove =       virtnet_remove,
1297         .config_changed = virtnet_config_changed,
1298 #ifdef CONFIG_PM
1299         .freeze =       virtnet_freeze,
1300         .restore =      virtnet_restore,
1301 #endif
1302 };
1303
1304 static int __init init(void)
1305 {
1306         return register_virtio_driver(&virtio_net_driver);
1307 }
1308
1309 static void __exit fini(void)
1310 {
1311         unregister_virtio_driver(&virtio_net_driver);
1312 }
1313 module_init(init);
1314 module_exit(fini);
1315
1316 MODULE_DEVICE_TABLE(virtio, id_table);
1317 MODULE_DESCRIPTION("Virtio network driver");
1318 MODULE_LICENSE("GPL");