Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/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, see <http://www.gnu.org/licenses/>.
 17  */
 18 //#define DEBUG
 19 #include <linux/netdevice.h>
 20 #include <linux/etherdevice.h>
 21 #include <linux/ethtool.h>
 22 #include <linux/module.h>
 23 #include <linux/virtio.h>
 24 #include <linux/virtio_net.h>
 25 #include <linux/scatterlist.h>
 26 #include <linux/if_vlan.h>
 27 #include <linux/slab.h>
 28 #include <linux/cpu.h>
 29 #include <linux/average.h>
 30 #include <net/busy_poll.h>
 31 
 32 static int napi_weight = NAPI_POLL_WEIGHT;
 33 module_param(napi_weight, int, 0444);
 34 
 35 static bool csum = true, gso = true;
 36 module_param(csum, bool, 0444);
 37 module_param(gso, bool, 0444);
 38 
 39 /* FIXME: MTU in config. */
 40 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
 41 #define GOOD_COPY_LEN   128
 42 
 43 /* Weight used for the RX packet size EWMA. The average packet size is used to
 44  * determine the packet buffer size when refilling RX rings. As the entire RX
 45  * ring may be refilled at once, the weight is chosen so that the EWMA will be
 46  * insensitive to short-term, transient changes in packet size.
 47  */
 48 #define RECEIVE_AVG_WEIGHT 64
 49 
 50 /* Minimum alignment for mergeable packet buffers. */
 51 #define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
 52 
 53 #define VIRTNET_DRIVER_VERSION "1.0.0"
 54 
 55 struct virtnet_stats {
 56         struct u64_stats_sync tx_syncp;
 57         struct u64_stats_sync rx_syncp;
 58         u64 tx_bytes;
 59         u64 tx_packets;
 60 
 61         u64 rx_bytes;
 62         u64 rx_packets;
 63 };
 64 
 65 /* Internal representation of a send virtqueue */
 66 struct send_queue {
 67         /* Virtqueue associated with this send _queue */
 68         struct virtqueue *vq;
 69 
 70         /* TX: fragments + linear part + virtio header */
 71         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 72 
 73         /* Name of the send queue: output.$index */
 74         char name[40];
 75 };
 76 
 77 /* Internal representation of a receive virtqueue */
 78 struct receive_queue {
 79         /* Virtqueue associated with this receive_queue */
 80         struct virtqueue *vq;
 81 
 82         struct napi_struct napi;
 83 
 84         /* Chain pages by the private ptr. */
 85         struct page *pages;
 86 
 87         /* Average packet length for mergeable receive buffers. */
 88         struct ewma mrg_avg_pkt_len;
 89 
 90         /* Page frag for packet buffer allocation. */
 91         struct page_frag alloc_frag;
 92 
 93         /* RX: fragments + linear part + virtio header */
 94         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 95 
 96         /* Name of this receive queue: input.$index */
 97         char name[40];
 98 };
 99 
100 struct virtnet_info {
101         struct virtio_device *vdev;
102         struct virtqueue *cvq;
103         struct net_device *dev;
104         struct send_queue *sq;
105         struct receive_queue *rq;
106         unsigned int status;
107 
108         /* Max # of queue pairs supported by the device */
109         u16 max_queue_pairs;
110 
111         /* # of queue pairs currently used by the driver */
112         u16 curr_queue_pairs;
113 
114         /* I like... big packets and I cannot lie! */
115         bool big_packets;
116 
117         /* Host will merge rx buffers for big packets (shake it! shake it!) */
118         bool mergeable_rx_bufs;
119 
120         /* Has control virtqueue */
121         bool has_cvq;
122 
123         /* Host can handle any s/g split between our header and packet data */
124         bool any_header_sg;
125 
126         /* Active statistics */
127         struct virtnet_stats __percpu *stats;
128 
129         /* Work struct for refilling if we run low on memory. */
130         struct delayed_work refill;
131 
132         /* Work struct for config space updates */
133         struct work_struct config_work;
134 
135         /* Does the affinity hint is set for virtqueues? */
136         bool affinity_hint_set;
137 
138         /* CPU hot plug notifier */
139         struct notifier_block nb;
140 };
141 
142 struct skb_vnet_hdr {
143         union {
144                 struct virtio_net_hdr hdr;
145                 struct virtio_net_hdr_mrg_rxbuf mhdr;
146         };
147 };
148 
149 struct padded_vnet_hdr {
150         struct virtio_net_hdr hdr;
151         /*
152          * virtio_net_hdr should be in a separated sg buffer because of a
153          * QEMU bug, and data sg buffer shares same page with this header sg.
154          * This padding makes next sg 16 byte aligned after virtio_net_hdr.
155          */
156         char padding[6];
157 };
158 
159 /* Converting between virtqueue no. and kernel tx/rx queue no.
160  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
161  */
162 static int vq2txq(struct virtqueue *vq)
163 {
164         return (vq->index - 1) / 2;
165 }
166 
167 static int txq2vq(int txq)
168 {
169         return txq * 2 + 1;
170 }
171 
172 static int vq2rxq(struct virtqueue *vq)
173 {
174         return vq->index / 2;
175 }
176 
177 static int rxq2vq(int rxq)
178 {
179         return rxq * 2;
180 }
181 
182 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
183 {
184         return (struct skb_vnet_hdr *)skb->cb;
185 }
186 
187 /*
188  * private is used to chain pages for big packets, put the whole
189  * most recent used list in the beginning for reuse
190  */
191 static void give_pages(struct receive_queue *rq, struct page *page)
192 {
193         struct page *end;
194 
195         /* Find end of list, sew whole thing into vi->rq.pages. */
196         for (end = page; end->private; end = (struct page *)end->private);
197         end->private = (unsigned long)rq->pages;
198         rq->pages = page;
199 }
200 
201 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
202 {
203         struct page *p = rq->pages;
204 
205         if (p) {
206                 rq->pages = (struct page *)p->private;
207                 /* clear private here, it is used to chain pages */
208                 p->private = 0;
209         } else
210                 p = alloc_page(gfp_mask);
211         return p;
212 }
213 
214 static void skb_xmit_done(struct virtqueue *vq)
215 {
216         struct virtnet_info *vi = vq->vdev->priv;
217 
218         /* Suppress further interrupts. */
219         virtqueue_disable_cb(vq);
220 
221         /* We were probably waiting for more output buffers. */
222         netif_wake_subqueue(vi->dev, vq2txq(vq));
223 }
224 
225 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
226 {
227         unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
228         return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
229 }
230 
231 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
232 {
233         return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
234 
235 }
236 
237 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
238 {
239         unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
240         return (unsigned long)buf | (size - 1);
241 }
242 
243 /* Called from bottom half context */
244 static struct sk_buff *page_to_skb(struct receive_queue *rq,
245                                    struct page *page, unsigned int offset,
246                                    unsigned int len, unsigned int truesize)
247 {
248         struct virtnet_info *vi = rq->vq->vdev->priv;
249         struct sk_buff *skb;
250         struct skb_vnet_hdr *hdr;
251         unsigned int copy, hdr_len, hdr_padded_len;
252         char *p;
253 
254         p = page_address(page) + offset;
255 
256         /* copy small packet so we can reuse these pages for small data */
257         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
258         if (unlikely(!skb))
259                 return NULL;
260 
261         hdr = skb_vnet_hdr(skb);
262 
263         if (vi->mergeable_rx_bufs) {
264                 hdr_len = sizeof hdr->mhdr;
265                 hdr_padded_len = sizeof hdr->mhdr;
266         } else {
267                 hdr_len = sizeof hdr->hdr;
268                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
269         }
270 
271         memcpy(hdr, p, hdr_len);
272 
273         len -= hdr_len;
274         offset += hdr_padded_len;
275         p += hdr_padded_len;
276 
277         copy = len;
278         if (copy > skb_tailroom(skb))
279                 copy = skb_tailroom(skb);
280         memcpy(skb_put(skb, copy), p, copy);
281 
282         len -= copy;
283         offset += copy;
284 
285         if (vi->mergeable_rx_bufs) {
286                 if (len)
287                         skb_add_rx_frag(skb, 0, page, offset, len, truesize);
288                 else
289                         put_page(page);
290                 return skb;
291         }
292 
293         /*
294          * Verify that we can indeed put this data into a skb.
295          * This is here to handle cases when the device erroneously
296          * tries to receive more than is possible. This is usually
297          * the case of a broken device.
298          */
299         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
300                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
301                 dev_kfree_skb(skb);
302                 return NULL;
303         }
304         BUG_ON(offset >= PAGE_SIZE);
305         while (len) {
306                 unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
307                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
308                                 frag_size, truesize);
309                 len -= frag_size;
310                 page = (struct page *)page->private;
311                 offset = 0;
312         }
313 
314         if (page)
315                 give_pages(rq, page);
316 
317         return skb;
318 }
319 
320 static struct sk_buff *receive_small(void *buf, unsigned int len)
321 {
322         struct sk_buff * skb = buf;
323 
324         len -= sizeof(struct virtio_net_hdr);
325         skb_trim(skb, len);
326 
327         return skb;
328 }
329 
330 static struct sk_buff *receive_big(struct net_device *dev,
331                                    struct receive_queue *rq,
332                                    void *buf,
333                                    unsigned int len)
334 {
335         struct page *page = buf;
336         struct sk_buff *skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
337 
338         if (unlikely(!skb))
339                 goto err;
340 
341         return skb;
342 
343 err:
344         dev->stats.rx_dropped++;
345         give_pages(rq, page);
346         return NULL;
347 }
348 
349 static struct sk_buff *receive_mergeable(struct net_device *dev,
350                                          struct receive_queue *rq,
351                                          unsigned long ctx,
352                                          unsigned int len)
353 {
354         void *buf = mergeable_ctx_to_buf_address(ctx);
355         struct skb_vnet_hdr *hdr = buf;
356         int num_buf = hdr->mhdr.num_buffers;
357         struct page *page = virt_to_head_page(buf);
358         int offset = buf - page_address(page);
359         unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
360 
361         struct sk_buff *head_skb = page_to_skb(rq, page, offset, len, truesize);
362         struct sk_buff *curr_skb = head_skb;
363 
364         if (unlikely(!curr_skb))
365                 goto err_skb;
366         while (--num_buf) {
367                 int num_skb_frags;
368 
369                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
370                 if (unlikely(!ctx)) {
371                         pr_debug("%s: rx error: %d buffers out of %d missing\n",
372                                  dev->name, num_buf, hdr->mhdr.num_buffers);
373                         dev->stats.rx_length_errors++;
374                         goto err_buf;
375                 }
376 
377                 buf = mergeable_ctx_to_buf_address(ctx);
378                 page = virt_to_head_page(buf);
379 
380                 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
381                 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
382                         struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
383 
384                         if (unlikely(!nskb))
385                                 goto err_skb;
386                         if (curr_skb == head_skb)
387                                 skb_shinfo(curr_skb)->frag_list = nskb;
388                         else
389                                 curr_skb->next = nskb;
390                         curr_skb = nskb;
391                         head_skb->truesize += nskb->truesize;
392                         num_skb_frags = 0;
393                 }
394                 truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
395                 if (curr_skb != head_skb) {
396                         head_skb->data_len += len;
397                         head_skb->len += len;
398                         head_skb->truesize += truesize;
399                 }
400                 offset = buf - page_address(page);
401                 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
402                         put_page(page);
403                         skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
404                                              len, truesize);
405                 } else {
406                         skb_add_rx_frag(curr_skb, num_skb_frags, page,
407                                         offset, len, truesize);
408                 }
409         }
410 
411         ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);
412         return head_skb;
413 
414 err_skb:
415         put_page(page);
416         while (--num_buf) {
417                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
418                 if (unlikely(!ctx)) {
419                         pr_debug("%s: rx error: %d buffers missing\n",
420                                  dev->name, num_buf);
421                         dev->stats.rx_length_errors++;
422                         break;
423                 }
424                 page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
425                 put_page(page);
426         }
427 err_buf:
428         dev->stats.rx_dropped++;
429         dev_kfree_skb(head_skb);
430         return NULL;
431 }
432 
433 static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
434 {
435         struct virtnet_info *vi = rq->vq->vdev->priv;
436         struct net_device *dev = vi->dev;
437         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
438         struct sk_buff *skb;
439         struct skb_vnet_hdr *hdr;
440 
441         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
442                 pr_debug("%s: short packet %i\n", dev->name, len);
443                 dev->stats.rx_length_errors++;
444                 if (vi->mergeable_rx_bufs) {
445                         unsigned long ctx = (unsigned long)buf;
446                         void *base = mergeable_ctx_to_buf_address(ctx);
447                         put_page(virt_to_head_page(base));
448                 } else if (vi->big_packets) {
449                         give_pages(rq, buf);
450                 } else {
451                         dev_kfree_skb(buf);
452                 }
453                 return;
454         }
455 
456         if (vi->mergeable_rx_bufs)
457                 skb = receive_mergeable(dev, rq, (unsigned long)buf, len);
458         else if (vi->big_packets)
459                 skb = receive_big(dev, rq, buf, len);
460         else
461                 skb = receive_small(buf, len);
462 
463         if (unlikely(!skb))
464                 return;
465 
466         hdr = skb_vnet_hdr(skb);
467 
468         u64_stats_update_begin(&stats->rx_syncp);
469         stats->rx_bytes += skb->len;
470         stats->rx_packets++;
471         u64_stats_update_end(&stats->rx_syncp);
472 
473         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
474                 pr_debug("Needs csum!\n");
475                 if (!skb_partial_csum_set(skb,
476                                           hdr->hdr.csum_start,
477                                           hdr->hdr.csum_offset))
478                         goto frame_err;
479         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
480                 skb->ip_summed = CHECKSUM_UNNECESSARY;
481         }
482 
483         skb->protocol = eth_type_trans(skb, dev);
484         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
485                  ntohs(skb->protocol), skb->len, skb->pkt_type);
486 
487         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
488                 pr_debug("GSO!\n");
489                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
490                 case VIRTIO_NET_HDR_GSO_TCPV4:
491                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
492                         break;
493                 case VIRTIO_NET_HDR_GSO_UDP:
494                 {
495                         static bool warned;
496 
497                         if (!warned) {
498                                 warned = true;
499                                 netdev_warn(dev,
500                                             "host using disabled UFO feature; please fix it\n");
501                         }
502                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
503                         break;
504                 }
505                 case VIRTIO_NET_HDR_GSO_TCPV6:
506                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
507                         break;
508                 default:
509                         net_warn_ratelimited("%s: bad gso type %u.\n",
510                                              dev->name, hdr->hdr.gso_type);
511                         goto frame_err;
512                 }
513 
514                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
515                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
516 
517                 skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
518                 if (skb_shinfo(skb)->gso_size == 0) {
519                         net_warn_ratelimited("%s: zero gso size.\n", dev->name);
520                         goto frame_err;
521                 }
522 
523                 /* Header must be checked, and gso_segs computed. */
524                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
525                 skb_shinfo(skb)->gso_segs = 0;
526         }
527 
528         skb_mark_napi_id(skb, &rq->napi);
529 
530         netif_receive_skb(skb);
531         return;
532 
533 frame_err:
534         dev->stats.rx_frame_errors++;
535         dev_kfree_skb(skb);
536 }
537 
538 static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
539 {
540         struct virtnet_info *vi = rq->vq->vdev->priv;
541         struct sk_buff *skb;
542         struct skb_vnet_hdr *hdr;
543         int err;
544 
545         skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
546         if (unlikely(!skb))
547                 return -ENOMEM;
548 
549         skb_put(skb, GOOD_PACKET_LEN);
550 
551         hdr = skb_vnet_hdr(skb);
552         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
553         sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
554         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
555 
556         err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
557         if (err < 0)
558                 dev_kfree_skb(skb);
559 
560         return err;
561 }
562 
563 static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
564 {
565         struct page *first, *list = NULL;
566         char *p;
567         int i, err, offset;
568 
569         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
570 
571         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
572         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
573                 first = get_a_page(rq, gfp);
574                 if (!first) {
575                         if (list)
576                                 give_pages(rq, list);
577                         return -ENOMEM;
578                 }
579                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
580 
581                 /* chain new page in list head to match sg */
582                 first->private = (unsigned long)list;
583                 list = first;
584         }
585 
586         first = get_a_page(rq, gfp);
587         if (!first) {
588                 give_pages(rq, list);
589                 return -ENOMEM;
590         }
591         p = page_address(first);
592 
593         /* rq->sg[0], rq->sg[1] share the same page */
594         /* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
595         sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
596 
597         /* rq->sg[1] for data packet, from offset */
598         offset = sizeof(struct padded_vnet_hdr);
599         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
600 
601         /* chain first in list head */
602         first->private = (unsigned long)list;
603         err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
604                                   first, gfp);
605         if (err < 0)
606                 give_pages(rq, first);
607 
608         return err;
609 }
610 
611 static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
612 {
613         const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
614         unsigned int len;
615 
616         len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
617                         GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
618         return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
619 }
620 
621 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
622 {
623         struct page_frag *alloc_frag = &rq->alloc_frag;
624         char *buf;
625         unsigned long ctx;
626         int err;
627         unsigned int len, hole;
628 
629         len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
630         if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
631                 return -ENOMEM;
632 
633         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
634         ctx = mergeable_buf_to_ctx(buf, len);
635         get_page(alloc_frag->page);
636         alloc_frag->offset += len;
637         hole = alloc_frag->size - alloc_frag->offset;
638         if (hole < len) {
639                 /* To avoid internal fragmentation, if there is very likely not
640                  * enough space for another buffer, add the remaining space to
641                  * the current buffer. This extra space is not included in
642                  * the truesize stored in ctx.
643                  */
644                 len += hole;
645                 alloc_frag->offset += hole;
646         }
647 
648         sg_init_one(rq->sg, buf, len);
649         err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
650         if (err < 0)
651                 put_page(virt_to_head_page(buf));
652 
653         return err;
654 }
655 
656 /*
657  * Returns false if we couldn't fill entirely (OOM).
658  *
659  * Normally run in the receive path, but can also be run from ndo_open
660  * before we're receiving packets, or from refill_work which is
661  * careful to disable receiving (using napi_disable).
662  */
663 static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
664 {
665         struct virtnet_info *vi = rq->vq->vdev->priv;
666         int err;
667         bool oom;
668 
669         gfp |= __GFP_COLD;
670         do {
671                 if (vi->mergeable_rx_bufs)
672                         err = add_recvbuf_mergeable(rq, gfp);
673                 else if (vi->big_packets)
674                         err = add_recvbuf_big(rq, gfp);
675                 else
676                         err = add_recvbuf_small(rq, gfp);
677 
678                 oom = err == -ENOMEM;
679                 if (err)
680                         break;
681         } while (rq->vq->num_free);
682         virtqueue_kick(rq->vq);
683         return !oom;
684 }
685 
686 static void skb_recv_done(struct virtqueue *rvq)
687 {
688         struct virtnet_info *vi = rvq->vdev->priv;
689         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
690 
691         /* Schedule NAPI, Suppress further interrupts if successful. */
692         if (napi_schedule_prep(&rq->napi)) {
693                 virtqueue_disable_cb(rvq);
694                 __napi_schedule(&rq->napi);
695         }
696 }
697 
698 static void virtnet_napi_enable(struct receive_queue *rq)
699 {
700         napi_enable(&rq->napi);
701 
702         /* If all buffers were filled by other side before we napi_enabled, we
703          * won't get another interrupt, so process any outstanding packets
704          * now.  virtnet_poll wants re-enable the queue, so we disable here.
705          * We synchronize against interrupts via NAPI_STATE_SCHED */
706         if (napi_schedule_prep(&rq->napi)) {
707                 virtqueue_disable_cb(rq->vq);
708                 local_bh_disable();
709                 __napi_schedule(&rq->napi);
710                 local_bh_enable();
711         }
712 }
713 
714 static void refill_work(struct work_struct *work)
715 {
716         struct virtnet_info *vi =
717                 container_of(work, struct virtnet_info, refill.work);
718         bool still_empty;
719         int i;
720 
721         for (i = 0; i < vi->curr_queue_pairs; i++) {
722                 struct receive_queue *rq = &vi->rq[i];
723 
724                 napi_disable(&rq->napi);
725                 still_empty = !try_fill_recv(rq, GFP_KERNEL);
726                 virtnet_napi_enable(rq);
727 
728                 /* In theory, this can happen: if we don't get any buffers in
729                  * we will *never* try to fill again.
730                  */
731                 if (still_empty)
732                         schedule_delayed_work(&vi->refill, HZ/2);
733         }
734 }
735 
736 static int virtnet_receive(struct receive_queue *rq, int budget)
737 {
738         struct virtnet_info *vi = rq->vq->vdev->priv;
739         unsigned int len, received = 0;
740         void *buf;
741 
742         while (received < budget &&
743                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
744                 receive_buf(rq, buf, len);
745                 received++;
746         }
747 
748         if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
749                 if (!try_fill_recv(rq, GFP_ATOMIC))
750                         schedule_delayed_work(&vi->refill, 0);
751         }
752 
753         return received;
754 }
755 
756 static int virtnet_poll(struct napi_struct *napi, int budget)
757 {
758         struct receive_queue *rq =
759                 container_of(napi, struct receive_queue, napi);
760         unsigned int r, received = 0;
761 
762 again:
763         received += virtnet_receive(rq, budget - received);
764 
765         /* Out of packets? */
766         if (received < budget) {
767                 r = virtqueue_enable_cb_prepare(rq->vq);
768                 napi_complete(napi);
769                 if (unlikely(virtqueue_poll(rq->vq, r)) &&
770                     napi_schedule_prep(napi)) {
771                         virtqueue_disable_cb(rq->vq);
772                         __napi_schedule(napi);
773                         goto again;
774                 }
775         }
776 
777         return received;
778 }
779 
780 #ifdef CONFIG_NET_RX_BUSY_POLL
781 /* must be called with local_bh_disable()d */
782 static int virtnet_busy_poll(struct napi_struct *napi)
783 {
784         struct receive_queue *rq =
785                 container_of(napi, struct receive_queue, napi);
786         struct virtnet_info *vi = rq->vq->vdev->priv;
787         int r, received = 0, budget = 4;
788 
789         if (!(vi->status & VIRTIO_NET_S_LINK_UP))
790                 return LL_FLUSH_FAILED;
791 
792         if (!napi_schedule_prep(napi))
793                 return LL_FLUSH_BUSY;
794 
795         virtqueue_disable_cb(rq->vq);
796 
797 again:
798         received += virtnet_receive(rq, budget);
799 
800         r = virtqueue_enable_cb_prepare(rq->vq);
801         clear_bit(NAPI_STATE_SCHED, &napi->state);
802         if (unlikely(virtqueue_poll(rq->vq, r)) &&
803             napi_schedule_prep(napi)) {
804                 virtqueue_disable_cb(rq->vq);
805                 if (received < budget) {
806                         budget -= received;
807                         goto again;
808                 } else {
809                         __napi_schedule(napi);
810                 }
811         }
812 
813         return received;
814 }
815 #endif  /* CONFIG_NET_RX_BUSY_POLL */
816 
817 static int virtnet_open(struct net_device *dev)
818 {
819         struct virtnet_info *vi = netdev_priv(dev);
820         int i;
821 
822         for (i = 0; i < vi->max_queue_pairs; i++) {
823                 if (i < vi->curr_queue_pairs)
824                         /* Make sure we have some buffers: if oom use wq. */
825                         if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
826                                 schedule_delayed_work(&vi->refill, 0);
827                 virtnet_napi_enable(&vi->rq[i]);
828         }
829 
830         return 0;
831 }
832 
833 static void free_old_xmit_skbs(struct send_queue *sq)
834 {
835         struct sk_buff *skb;
836         unsigned int len;
837         struct virtnet_info *vi = sq->vq->vdev->priv;
838         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
839 
840         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
841                 pr_debug("Sent skb %p\n", skb);
842 
843                 u64_stats_update_begin(&stats->tx_syncp);
844                 stats->tx_bytes += skb->len;
845                 stats->tx_packets++;
846                 u64_stats_update_end(&stats->tx_syncp);
847 
848                 dev_kfree_skb_any(skb);
849         }
850 }
851 
852 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
853 {
854         struct skb_vnet_hdr *hdr;
855         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
856         struct virtnet_info *vi = sq->vq->vdev->priv;
857         unsigned num_sg;
858         unsigned hdr_len;
859         bool can_push;
860 
861         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
862         if (vi->mergeable_rx_bufs)
863                 hdr_len = sizeof hdr->mhdr;
864         else
865                 hdr_len = sizeof hdr->hdr;
866 
867         can_push = vi->any_header_sg &&
868                 !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
869                 !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
870         /* Even if we can, don't push here yet as this would skew
871          * csum_start offset below. */
872         if (can_push)
873                 hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len);
874         else
875                 hdr = skb_vnet_hdr(skb);
876 
877         if (skb->ip_summed == CHECKSUM_PARTIAL) {
878                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
879                 hdr->hdr.csum_start = skb_checksum_start_offset(skb);
880                 hdr->hdr.csum_offset = skb->csum_offset;
881         } else {
882                 hdr->hdr.flags = 0;
883                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
884         }
885 
886         if (skb_is_gso(skb)) {
887                 hdr->hdr.hdr_len = skb_headlen(skb);
888                 hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
889                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
890                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
891                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
892                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
893                 else
894                         BUG();
895                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
896                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
897         } else {
898                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
899                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
900         }
901 
902         if (vi->mergeable_rx_bufs)
903                 hdr->mhdr.num_buffers = 0;
904 
905         sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
906         if (can_push) {
907                 __skb_push(skb, hdr_len);
908                 num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
909                 /* Pull header back to avoid skew in tx bytes calculations. */
910                 __skb_pull(skb, hdr_len);
911         } else {
912                 sg_set_buf(sq->sg, hdr, hdr_len);
913                 num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
914         }
915         return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
916 }
917 
918 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
919 {
920         struct virtnet_info *vi = netdev_priv(dev);
921         int qnum = skb_get_queue_mapping(skb);
922         struct send_queue *sq = &vi->sq[qnum];
923         int err;
924         struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
925         bool kick = !skb->xmit_more;
926 
927         /* Free up any pending old buffers before queueing new ones. */
928         free_old_xmit_skbs(sq);
929 
930         /* Try to transmit */
931         err = xmit_skb(sq, skb);
932 
933         /* This should not happen! */
934         if (unlikely(err)) {
935                 dev->stats.tx_fifo_errors++;
936                 if (net_ratelimit())
937                         dev_warn(&dev->dev,
938                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
939                 dev->stats.tx_dropped++;
940                 dev_kfree_skb_any(skb);
941                 return NETDEV_TX_OK;
942         }
943 
944         /* Don't wait up for transmitted skbs to be freed. */
945         skb_orphan(skb);
946         nf_reset(skb);
947 
948         /* Apparently nice girls don't return TX_BUSY; stop the queue
949          * before it gets out of hand.  Naturally, this wastes entries. */
950         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
951                 netif_stop_subqueue(dev, qnum);
952                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
953                         /* More just got used, free them then recheck. */
954                         free_old_xmit_skbs(sq);
955                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
956                                 netif_start_subqueue(dev, qnum);
957                                 virtqueue_disable_cb(sq->vq);
958                         }
959                 }
960         }
961 
962         if (kick || netif_xmit_stopped(txq))
963                 virtqueue_kick(sq->vq);
964 
965         return NETDEV_TX_OK;
966 }
967 
968 /*
969  * Send command via the control virtqueue and check status.  Commands
970  * supported by the hypervisor, as indicated by feature bits, should
971  * never fail unless improperly formatted.
972  */
973 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
974                                  struct scatterlist *out)
975 {
976         struct scatterlist *sgs[4], hdr, stat;
977         struct virtio_net_ctrl_hdr ctrl;
978         virtio_net_ctrl_ack status = ~0;
979         unsigned out_num = 0, tmp;
980 
981         /* Caller should know better */
982         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
983 
984         ctrl.class = class;
985         ctrl.cmd = cmd;
986         /* Add header */
987         sg_init_one(&hdr, &ctrl, sizeof(ctrl));
988         sgs[out_num++] = &hdr;
989 
990         if (out)
991                 sgs[out_num++] = out;
992 
993         /* Add return status. */
994         sg_init_one(&stat, &status, sizeof(status));
995         sgs[out_num] = &stat;
996 
997         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
998         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
999 
1000         if (unlikely(!virtqueue_kick(vi->cvq)))
1001                 return status == VIRTIO_NET_OK;
1002 
1003         /* Spin for a response, the kick causes an ioport write, trapping
1004          * into the hypervisor, so the request should be handled immediately.
1005          */
1006         while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1007                !virtqueue_is_broken(vi->cvq))
1008                 cpu_relax();
1009 
1010         return status == VIRTIO_NET_OK;
1011 }
1012 
1013 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1014 {
1015         struct virtnet_info *vi = netdev_priv(dev);
1016         struct virtio_device *vdev = vi->vdev;
1017         int ret;
1018         struct sockaddr *addr = p;
1019         struct scatterlist sg;
1020 
1021         ret = eth_prepare_mac_addr_change(dev, p);
1022         if (ret)
1023                 return ret;
1024 
1025         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1026                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
1027                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1028                                           VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1029                         dev_warn(&vdev->dev,
1030                                  "Failed to set mac address by vq command.\n");
1031                         return -EINVAL;
1032                 }
1033         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
1034                 unsigned int i;
1035 
1036                 /* Naturally, this has an atomicity problem. */
1037                 for (i = 0; i < dev->addr_len; i++)
1038                         virtio_cwrite8(vdev,
1039                                        offsetof(struct virtio_net_config, mac) +
1040                                        i, addr->sa_data[i]);
1041         }
1042 
1043         eth_commit_mac_addr_change(dev, p);
1044 
1045         return 0;
1046 }
1047 
1048 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1049                                                struct rtnl_link_stats64 *tot)
1050 {
1051         struct virtnet_info *vi = netdev_priv(dev);
1052         int cpu;
1053         unsigned int start;
1054 
1055         for_each_possible_cpu(cpu) {
1056                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1057                 u64 tpackets, tbytes, rpackets, rbytes;
1058 
1059                 do {
1060                         start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1061                         tpackets = stats->tx_packets;
1062                         tbytes   = stats->tx_bytes;
1063                 } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1064 
1065                 do {
1066                         start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1067                         rpackets = stats->rx_packets;
1068                         rbytes   = stats->rx_bytes;
1069                 } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1070 
1071                 tot->rx_packets += rpackets;
1072                 tot->tx_packets += tpackets;
1073                 tot->rx_bytes   += rbytes;
1074                 tot->tx_bytes   += tbytes;
1075         }
1076 
1077         tot->tx_dropped = dev->stats.tx_dropped;
1078         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1079         tot->rx_dropped = dev->stats.rx_dropped;
1080         tot->rx_length_errors = dev->stats.rx_length_errors;
1081         tot->rx_frame_errors = dev->stats.rx_frame_errors;
1082 
1083         return tot;
1084 }
1085 
1086 #ifdef CONFIG_NET_POLL_CONTROLLER
1087 static void virtnet_netpoll(struct net_device *dev)
1088 {
1089         struct virtnet_info *vi = netdev_priv(dev);
1090         int i;
1091 
1092         for (i = 0; i < vi->curr_queue_pairs; i++)
1093                 napi_schedule(&vi->rq[i].napi);
1094 }
1095 #endif
1096 
1097 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1098 {
1099         rtnl_lock();
1100         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1101                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1102                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1103         rtnl_unlock();
1104 }
1105 
1106 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1107 {
1108         struct scatterlist sg;
1109         struct virtio_net_ctrl_mq s;
1110         struct net_device *dev = vi->dev;
1111 
1112         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1113                 return 0;
1114 
1115         s.virtqueue_pairs = queue_pairs;
1116         sg_init_one(&sg, &s, sizeof(s));
1117 
1118         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1119                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1120                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1121                          queue_pairs);
1122                 return -EINVAL;
1123         } else {
1124                 vi->curr_queue_pairs = queue_pairs;
1125                 /* virtnet_open() will refill when device is going to up. */
1126                 if (dev->flags & IFF_UP)
1127                         schedule_delayed_work(&vi->refill, 0);
1128         }
1129 
1130         return 0;
1131 }
1132 
1133 static int virtnet_close(struct net_device *dev)
1134 {
1135         struct virtnet_info *vi = netdev_priv(dev);
1136         int i;
1137 
1138         /* Make sure refill_work doesn't re-enable napi! */
1139         cancel_delayed_work_sync(&vi->refill);
1140 
1141         for (i = 0; i < vi->max_queue_pairs; i++)
1142                 napi_disable(&vi->rq[i].napi);
1143 
1144         return 0;
1145 }
1146 
1147 static void virtnet_set_rx_mode(struct net_device *dev)
1148 {
1149         struct virtnet_info *vi = netdev_priv(dev);
1150         struct scatterlist sg[2];
1151         u8 promisc, allmulti;
1152         struct virtio_net_ctrl_mac *mac_data;
1153         struct netdev_hw_addr *ha;
1154         int uc_count;
1155         int mc_count;
1156         void *buf;
1157         int i;
1158 
1159         /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1160         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1161                 return;
1162 
1163         promisc = ((dev->flags & IFF_PROMISC) != 0);
1164         allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1165 
1166         sg_init_one(sg, &promisc, sizeof(promisc));
1167 
1168         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1169                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
1170                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1171                          promisc ? "en" : "dis");
1172 
1173         sg_init_one(sg, &allmulti, sizeof(allmulti));
1174 
1175         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1176                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1177                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1178                          allmulti ? "en" : "dis");
1179 
1180         uc_count = netdev_uc_count(dev);
1181         mc_count = netdev_mc_count(dev);
1182         /* MAC filter - use one buffer for both lists */
1183         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1184                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1185         mac_data = buf;
1186         if (!buf)
1187                 return;
1188 
1189         sg_init_table(sg, 2);
1190 
1191         /* Store the unicast list and count in the front of the buffer */
1192         mac_data->entries = uc_count;
1193         i = 0;
1194         netdev_for_each_uc_addr(ha, dev)
1195                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1196 
1197         sg_set_buf(&sg[0], mac_data,
1198                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1199 
1200         /* multicast list and count fill the end */
1201         mac_data = (void *)&mac_data->macs[uc_count][0];
1202 
1203         mac_data->entries = mc_count;
1204         i = 0;
1205         netdev_for_each_mc_addr(ha, dev)
1206                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1207 
1208         sg_set_buf(&sg[1], mac_data,
1209                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1210 
1211         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1212                                   VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1213                 dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1214 
1215         kfree(buf);
1216 }
1217 
1218 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1219                                    __be16 proto, u16 vid)
1220 {
1221         struct virtnet_info *vi = netdev_priv(dev);
1222         struct scatterlist sg;
1223 
1224         sg_init_one(&sg, &vid, sizeof(vid));
1225 
1226         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1227                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1228                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1229         return 0;
1230 }
1231 
1232 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1233                                     __be16 proto, u16 vid)
1234 {
1235         struct virtnet_info *vi = netdev_priv(dev);
1236         struct scatterlist sg;
1237 
1238         sg_init_one(&sg, &vid, sizeof(vid));
1239 
1240         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1241                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1242                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1243         return 0;
1244 }
1245 
1246 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1247 {
1248         int i;
1249 
1250         if (vi->affinity_hint_set) {
1251                 for (i = 0; i < vi->max_queue_pairs; i++) {
1252                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1253                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1254                 }
1255 
1256                 vi->affinity_hint_set = false;
1257         }
1258 }
1259 
1260 static void virtnet_set_affinity(struct virtnet_info *vi)
1261 {
1262         int i;
1263         int cpu;
1264 
1265         /* In multiqueue mode, when the number of cpu is equal to the number of
1266          * queue pairs, we let the queue pairs to be private to one cpu by
1267          * setting the affinity hint to eliminate the contention.
1268          */
1269         if (vi->curr_queue_pairs == 1 ||
1270             vi->max_queue_pairs != num_online_cpus()) {
1271                 virtnet_clean_affinity(vi, -1);
1272                 return;
1273         }
1274 
1275         i = 0;
1276         for_each_online_cpu(cpu) {
1277                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1278                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1279                 netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1280                 i++;
1281         }
1282 
1283         vi->affinity_hint_set = true;
1284 }
1285 
1286 static int virtnet_cpu_callback(struct notifier_block *nfb,
1287                                 unsigned long action, void *hcpu)
1288 {
1289         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1290 
1291         switch(action & ~CPU_TASKS_FROZEN) {
1292         case CPU_ONLINE:
1293         case CPU_DOWN_FAILED:
1294         case CPU_DEAD:
1295                 virtnet_set_affinity(vi);
1296                 break;
1297         case CPU_DOWN_PREPARE:
1298                 virtnet_clean_affinity(vi, (long)hcpu);
1299                 break;
1300         default:
1301                 break;
1302         }
1303 
1304         return NOTIFY_OK;
1305 }
1306 
1307 static void virtnet_get_ringparam(struct net_device *dev,
1308                                 struct ethtool_ringparam *ring)
1309 {
1310         struct virtnet_info *vi = netdev_priv(dev);
1311 
1312         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1313         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1314         ring->rx_pending = ring->rx_max_pending;
1315         ring->tx_pending = ring->tx_max_pending;
1316 }
1317 
1318 
1319 static void virtnet_get_drvinfo(struct net_device *dev,
1320                                 struct ethtool_drvinfo *info)
1321 {
1322         struct virtnet_info *vi = netdev_priv(dev);
1323         struct virtio_device *vdev = vi->vdev;
1324 
1325         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1326         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1327         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1328 
1329 }
1330 
1331 /* TODO: Eliminate OOO packets during switching */
1332 static int virtnet_set_channels(struct net_device *dev,
1333                                 struct ethtool_channels *channels)
1334 {
1335         struct virtnet_info *vi = netdev_priv(dev);
1336         u16 queue_pairs = channels->combined_count;
1337         int err;
1338 
1339         /* We don't support separate rx/tx channels.
1340          * We don't allow setting 'other' channels.
1341          */
1342         if (channels->rx_count || channels->tx_count || channels->other_count)
1343                 return -EINVAL;
1344 
1345         if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1346                 return -EINVAL;
1347 
1348         get_online_cpus();
1349         err = virtnet_set_queues(vi, queue_pairs);
1350         if (!err) {
1351                 netif_set_real_num_tx_queues(dev, queue_pairs);
1352                 netif_set_real_num_rx_queues(dev, queue_pairs);
1353 
1354                 virtnet_set_affinity(vi);
1355         }
1356         put_online_cpus();
1357 
1358         return err;
1359 }
1360 
1361 static void virtnet_get_channels(struct net_device *dev,
1362                                  struct ethtool_channels *channels)
1363 {
1364         struct virtnet_info *vi = netdev_priv(dev);
1365 
1366         channels->combined_count = vi->curr_queue_pairs;
1367         channels->max_combined = vi->max_queue_pairs;
1368         channels->max_other = 0;
1369         channels->rx_count = 0;
1370         channels->tx_count = 0;
1371         channels->other_count = 0;
1372 }
1373 
1374 static const struct ethtool_ops virtnet_ethtool_ops = {
1375         .get_drvinfo = virtnet_get_drvinfo,
1376         .get_link = ethtool_op_get_link,
1377         .get_ringparam = virtnet_get_ringparam,
1378         .set_channels = virtnet_set_channels,
1379         .get_channels = virtnet_get_channels,
1380 };
1381 
1382 #define MIN_MTU 68
1383 #define MAX_MTU 65535
1384 
1385 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1386 {
1387         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1388                 return -EINVAL;
1389         dev->mtu = new_mtu;
1390         return 0;
1391 }
1392 
1393 static const struct net_device_ops virtnet_netdev = {
1394         .ndo_open            = virtnet_open,
1395         .ndo_stop            = virtnet_close,
1396         .ndo_start_xmit      = start_xmit,
1397         .ndo_validate_addr   = eth_validate_addr,
1398         .ndo_set_mac_address = virtnet_set_mac_address,
1399         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1400         .ndo_change_mtu      = virtnet_change_mtu,
1401         .ndo_get_stats64     = virtnet_stats,
1402         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1403         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1404 #ifdef CONFIG_NET_POLL_CONTROLLER
1405         .ndo_poll_controller = virtnet_netpoll,
1406 #endif
1407 #ifdef CONFIG_NET_RX_BUSY_POLL
1408         .ndo_busy_poll          = virtnet_busy_poll,
1409 #endif
1410 };
1411 
1412 static void virtnet_config_changed_work(struct work_struct *work)
1413 {
1414         struct virtnet_info *vi =
1415                 container_of(work, struct virtnet_info, config_work);
1416         u16 v;
1417 
1418         if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1419                                  struct virtio_net_config, status, &v) < 0)
1420                 return;
1421 
1422         if (v & VIRTIO_NET_S_ANNOUNCE) {
1423                 netdev_notify_peers(vi->dev);
1424                 virtnet_ack_link_announce(vi);
1425         }
1426 
1427         /* Ignore unknown (future) status bits */
1428         v &= VIRTIO_NET_S_LINK_UP;
1429 
1430         if (vi->status == v)
1431                 return;
1432 
1433         vi->status = v;
1434 
1435         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1436                 netif_carrier_on(vi->dev);
1437                 netif_tx_wake_all_queues(vi->dev);
1438         } else {
1439                 netif_carrier_off(vi->dev);
1440                 netif_tx_stop_all_queues(vi->dev);
1441         }
1442 }
1443 
1444 static void virtnet_config_changed(struct virtio_device *vdev)
1445 {
1446         struct virtnet_info *vi = vdev->priv;
1447 
1448         schedule_work(&vi->config_work);
1449 }
1450 
1451 static void virtnet_free_queues(struct virtnet_info *vi)
1452 {
1453         int i;
1454 
1455         for (i = 0; i < vi->max_queue_pairs; i++)
1456                 netif_napi_del(&vi->rq[i].napi);
1457 
1458         kfree(vi->rq);
1459         kfree(vi->sq);
1460 }
1461 
1462 static void free_receive_bufs(struct virtnet_info *vi)
1463 {
1464         int i;
1465 
1466         for (i = 0; i < vi->max_queue_pairs; i++) {
1467                 while (vi->rq[i].pages)
1468                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1469         }
1470 }
1471 
1472 static void free_receive_page_frags(struct virtnet_info *vi)
1473 {
1474         int i;
1475         for (i = 0; i < vi->max_queue_pairs; i++)
1476                 if (vi->rq[i].alloc_frag.page)
1477                         put_page(vi->rq[i].alloc_frag.page);
1478 }
1479 
1480 static void free_unused_bufs(struct virtnet_info *vi)
1481 {
1482         void *buf;
1483         int i;
1484 
1485         for (i = 0; i < vi->max_queue_pairs; i++) {
1486                 struct virtqueue *vq = vi->sq[i].vq;
1487                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1488                         dev_kfree_skb(buf);
1489         }
1490 
1491         for (i = 0; i < vi->max_queue_pairs; i++) {
1492                 struct virtqueue *vq = vi->rq[i].vq;
1493 
1494                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1495                         if (vi->mergeable_rx_bufs) {
1496                                 unsigned long ctx = (unsigned long)buf;
1497                                 void *base = mergeable_ctx_to_buf_address(ctx);
1498                                 put_page(virt_to_head_page(base));
1499                         } else if (vi->big_packets) {
1500                                 give_pages(&vi->rq[i], buf);
1501                         } else {
1502                                 dev_kfree_skb(buf);
1503                         }
1504                 }
1505         }
1506 }
1507 
1508 static void virtnet_del_vqs(struct virtnet_info *vi)
1509 {
1510         struct virtio_device *vdev = vi->vdev;
1511 
1512         virtnet_clean_affinity(vi, -1);
1513 
1514         vdev->config->del_vqs(vdev);
1515 
1516         virtnet_free_queues(vi);
1517 }
1518 
1519 static int virtnet_find_vqs(struct virtnet_info *vi)
1520 {
1521         vq_callback_t **callbacks;
1522         struct virtqueue **vqs;
1523         int ret = -ENOMEM;
1524         int i, total_vqs;
1525         const char **names;
1526 
1527         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1528          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1529          * possible control vq.
1530          */
1531         total_vqs = vi->max_queue_pairs * 2 +
1532                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1533 
1534         /* Allocate space for find_vqs parameters */
1535         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1536         if (!vqs)
1537                 goto err_vq;
1538         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1539         if (!callbacks)
1540                 goto err_callback;
1541         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1542         if (!names)
1543                 goto err_names;
1544 
1545         /* Parameters for control virtqueue, if any */
1546         if (vi->has_cvq) {
1547                 callbacks[total_vqs - 1] = NULL;
1548                 names[total_vqs - 1] = "control";
1549         }
1550 
1551         /* Allocate/initialize parameters for send/receive virtqueues */
1552         for (i = 0; i < vi->max_queue_pairs; i++) {
1553                 callbacks[rxq2vq(i)] = skb_recv_done;
1554                 callbacks[txq2vq(i)] = skb_xmit_done;
1555                 sprintf(vi->rq[i].name, "input.%d", i);
1556                 sprintf(vi->sq[i].name, "output.%d", i);
1557                 names[rxq2vq(i)] = vi->rq[i].name;
1558                 names[txq2vq(i)] = vi->sq[i].name;
1559         }
1560 
1561         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1562                                          names);
1563         if (ret)
1564                 goto err_find;
1565 
1566         if (vi->has_cvq) {
1567                 vi->cvq = vqs[total_vqs - 1];
1568                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1569                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1570         }
1571 
1572         for (i = 0; i < vi->max_queue_pairs; i++) {
1573                 vi->rq[i].vq = vqs[rxq2vq(i)];
1574                 vi->sq[i].vq = vqs[txq2vq(i)];
1575         }
1576 
1577         kfree(names);
1578         kfree(callbacks);
1579         kfree(vqs);
1580 
1581         return 0;
1582 
1583 err_find:
1584         kfree(names);
1585 err_names:
1586         kfree(callbacks);
1587 err_callback:
1588         kfree(vqs);
1589 err_vq:
1590         return ret;
1591 }
1592 
1593 static int virtnet_alloc_queues(struct virtnet_info *vi)
1594 {
1595         int i;
1596 
1597         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1598         if (!vi->sq)
1599                 goto err_sq;
1600         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1601         if (!vi->rq)
1602                 goto err_rq;
1603 
1604         INIT_DELAYED_WORK(&vi->refill, refill_work);
1605         for (i = 0; i < vi->max_queue_pairs; i++) {
1606                 vi->rq[i].pages = NULL;
1607                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1608                                napi_weight);
1609                 napi_hash_add(&vi->rq[i].napi);
1610 
1611                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1612                 ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
1613                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1614         }
1615 
1616         return 0;
1617 
1618 err_rq:
1619         kfree(vi->sq);
1620 err_sq:
1621         return -ENOMEM;
1622 }
1623 
1624 static int init_vqs(struct virtnet_info *vi)
1625 {
1626         int ret;
1627 
1628         /* Allocate send & receive queues */
1629         ret = virtnet_alloc_queues(vi);
1630         if (ret)
1631                 goto err;
1632 
1633         ret = virtnet_find_vqs(vi);
1634         if (ret)
1635                 goto err_free;
1636 
1637         get_online_cpus();
1638         virtnet_set_affinity(vi);
1639         put_online_cpus();
1640 
1641         return 0;
1642 
1643 err_free:
1644         virtnet_free_queues(vi);
1645 err:
1646         return ret;
1647 }
1648 
1649 #ifdef CONFIG_SYSFS
1650 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1651                 struct rx_queue_attribute *attribute, char *buf)
1652 {
1653         struct virtnet_info *vi = netdev_priv(queue->dev);
1654         unsigned int queue_index = get_netdev_rx_queue_index(queue);
1655         struct ewma *avg;
1656 
1657         BUG_ON(queue_index >= vi->max_queue_pairs);
1658         avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1659         return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1660 }
1661 
1662 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1663         __ATTR_RO(mergeable_rx_buffer_size);
1664 
1665 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1666         &mergeable_rx_buffer_size_attribute.attr,
1667         NULL
1668 };
1669 
1670 static const struct attribute_group virtio_net_mrg_rx_group = {
1671         .name = "virtio_net",
1672         .attrs = virtio_net_mrg_rx_attrs
1673 };
1674 #endif
1675 
1676 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1677                                     unsigned int fbit,
1678                                     const char *fname, const char *dname)
1679 {
1680         if (!virtio_has_feature(vdev, fbit))
1681                 return false;
1682 
1683         dev_err(&vdev->dev, "device advertises feature %s but not %s",
1684                 fname, dname);
1685 
1686         return true;
1687 }
1688 
1689 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
1690         virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1691 
1692 static bool virtnet_validate_features(struct virtio_device *vdev)
1693 {
1694         if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1695             (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1696                              "VIRTIO_NET_F_CTRL_VQ") ||
1697              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1698                              "VIRTIO_NET_F_CTRL_VQ") ||
1699              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1700                              "VIRTIO_NET_F_CTRL_VQ") ||
1701              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1702              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1703                              "VIRTIO_NET_F_CTRL_VQ"))) {
1704                 return false;
1705         }
1706 
1707         return true;
1708 }
1709 
1710 static int virtnet_probe(struct virtio_device *vdev)
1711 {
1712         int i, err;
1713         struct net_device *dev;
1714         struct virtnet_info *vi;
1715         u16 max_queue_pairs;
1716 
1717         if (!virtnet_validate_features(vdev))
1718                 return -EINVAL;
1719 
1720         /* Find if host supports multiqueue virtio_net device */
1721         err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1722                                    struct virtio_net_config,
1723                                    max_virtqueue_pairs, &max_queue_pairs);
1724 
1725         /* We need at least 2 queue's */
1726         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1727             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1728             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1729                 max_queue_pairs = 1;
1730 
1731         /* Allocate ourselves a network device with room for our info */
1732         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1733         if (!dev)
1734                 return -ENOMEM;
1735 
1736         /* Set up network device as normal. */
1737         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1738         dev->netdev_ops = &virtnet_netdev;
1739         dev->features = NETIF_F_HIGHDMA;
1740 
1741         dev->ethtool_ops = &virtnet_ethtool_ops;
1742         SET_NETDEV_DEV(dev, &vdev->dev);
1743 
1744         /* Do we support "hardware" checksums? */
1745         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1746                 /* This opens up the world of extra features. */
1747                 dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1748                 if (csum)
1749                         dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1750 
1751                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1752                         dev->hw_features |= NETIF_F_TSO
1753                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1754                 }
1755                 /* Individual feature bits: what can host handle? */
1756                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1757                         dev->hw_features |= NETIF_F_TSO;
1758                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1759                         dev->hw_features |= NETIF_F_TSO6;
1760                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1761                         dev->hw_features |= NETIF_F_TSO_ECN;
1762 
1763                 if (gso)
1764                         dev->features |= dev->hw_features & NETIF_F_ALL_TSO;
1765                 /* (!csum && gso) case will be fixed by register_netdev() */
1766         }
1767         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1768                 dev->features |= NETIF_F_RXCSUM;
1769 
1770         dev->vlan_features = dev->features;
1771 
1772         /* Configuration may specify what MAC to use.  Otherwise random. */
1773         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1774                 virtio_cread_bytes(vdev,
1775                                    offsetof(struct virtio_net_config, mac),
1776                                    dev->dev_addr, dev->addr_len);
1777         else
1778                 eth_hw_addr_random(dev);
1779 
1780         /* Set up our device-specific information */
1781         vi = netdev_priv(dev);
1782         vi->dev = dev;
1783         vi->vdev = vdev;
1784         vdev->priv = vi;
1785         vi->stats = alloc_percpu(struct virtnet_stats);
1786         err = -ENOMEM;
1787         if (vi->stats == NULL)
1788                 goto free;
1789 
1790         for_each_possible_cpu(i) {
1791                 struct virtnet_stats *virtnet_stats;
1792                 virtnet_stats = per_cpu_ptr(vi->stats, i);
1793                 u64_stats_init(&virtnet_stats->tx_syncp);
1794                 u64_stats_init(&virtnet_stats->rx_syncp);
1795         }
1796 
1797         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1798 
1799         /* If we can receive ANY GSO packets, we must allocate large ones. */
1800         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1801             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1802             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1803                 vi->big_packets = true;
1804 
1805         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1806                 vi->mergeable_rx_bufs = true;
1807 
1808         if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1809                 vi->any_header_sg = true;
1810 
1811         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1812                 vi->has_cvq = true;
1813 
1814         if (vi->any_header_sg) {
1815                 if (vi->mergeable_rx_bufs)
1816                         dev->needed_headroom = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1817                 else
1818                         dev->needed_headroom = sizeof(struct virtio_net_hdr);
1819         }
1820 
1821         /* Use single tx/rx queue pair as default */
1822         vi->curr_queue_pairs = 1;
1823         vi->max_queue_pairs = max_queue_pairs;
1824 
1825         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1826         err = init_vqs(vi);
1827         if (err)
1828                 goto free_stats;
1829 
1830 #ifdef CONFIG_SYSFS
1831         if (vi->mergeable_rx_bufs)
1832                 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1833 #endif
1834         netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1835         netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1836 
1837         err = register_netdev(dev);
1838         if (err) {
1839                 pr_debug("virtio_net: registering device failed\n");
1840                 goto free_vqs;
1841         }
1842 
1843         virtio_device_ready(vdev);
1844 
1845         /* Last of all, set up some receive buffers. */
1846         for (i = 0; i < vi->curr_queue_pairs; i++) {
1847                 try_fill_recv(&vi->rq[i], GFP_KERNEL);
1848 
1849                 /* If we didn't even get one input buffer, we're useless. */
1850                 if (vi->rq[i].vq->num_free ==
1851                     virtqueue_get_vring_size(vi->rq[i].vq)) {
1852                         free_unused_bufs(vi);
1853                         err = -ENOMEM;
1854                         goto free_recv_bufs;
1855                 }
1856         }
1857 
1858         vi->nb.notifier_call = &virtnet_cpu_callback;
1859         err = register_hotcpu_notifier(&vi->nb);
1860         if (err) {
1861                 pr_debug("virtio_net: registering cpu notifier failed\n");
1862                 goto free_recv_bufs;
1863         }
1864 
1865         /* Assume link up if device can't report link status,
1866            otherwise get link status from config. */
1867         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1868                 netif_carrier_off(dev);
1869                 schedule_work(&vi->config_work);
1870         } else {
1871                 vi->status = VIRTIO_NET_S_LINK_UP;
1872                 netif_carrier_on(dev);
1873         }
1874 
1875         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1876                  dev->name, max_queue_pairs);
1877 
1878         return 0;
1879 
1880 free_recv_bufs:
1881         vi->vdev->config->reset(vdev);
1882 
1883         free_receive_bufs(vi);
1884         unregister_netdev(dev);
1885 free_vqs:
1886         cancel_delayed_work_sync(&vi->refill);
1887         free_receive_page_frags(vi);
1888         virtnet_del_vqs(vi);
1889 free_stats:
1890         free_percpu(vi->stats);
1891 free:
1892         free_netdev(dev);
1893         return err;
1894 }
1895 
1896 static void remove_vq_common(struct virtnet_info *vi)
1897 {
1898         vi->vdev->config->reset(vi->vdev);
1899 
1900         /* Free unused buffers in both send and recv, if any. */
1901         free_unused_bufs(vi);
1902 
1903         free_receive_bufs(vi);
1904 
1905         free_receive_page_frags(vi);
1906 
1907         virtnet_del_vqs(vi);
1908 }
1909 
1910 static void virtnet_remove(struct virtio_device *vdev)
1911 {
1912         struct virtnet_info *vi = vdev->priv;
1913 
1914         unregister_hotcpu_notifier(&vi->nb);
1915 
1916         /* Make sure no work handler is accessing the device. */
1917         flush_work(&vi->config_work);
1918 
1919         unregister_netdev(vi->dev);
1920 
1921         remove_vq_common(vi);
1922 
1923         free_percpu(vi->stats);
1924         free_netdev(vi->dev);
1925 }
1926 
1927 #ifdef CONFIG_PM_SLEEP
1928 static int virtnet_freeze(struct virtio_device *vdev)
1929 {
1930         struct virtnet_info *vi = vdev->priv;
1931         int i;
1932 
1933         unregister_hotcpu_notifier(&vi->nb);
1934 
1935         /* Make sure no work handler is accessing the device */
1936         flush_work(&vi->config_work);
1937 
1938         netif_device_detach(vi->dev);
1939         cancel_delayed_work_sync(&vi->refill);
1940 
1941         if (netif_running(vi->dev)) {
1942                 for (i = 0; i < vi->max_queue_pairs; i++) {
1943                         napi_disable(&vi->rq[i].napi);
1944                         napi_hash_del(&vi->rq[i].napi);
1945                         netif_napi_del(&vi->rq[i].napi);
1946                 }
1947         }
1948 
1949         remove_vq_common(vi);
1950 
1951         return 0;
1952 }
1953 
1954 static int virtnet_restore(struct virtio_device *vdev)
1955 {
1956         struct virtnet_info *vi = vdev->priv;
1957         int err, i;
1958 
1959         err = init_vqs(vi);
1960         if (err)
1961                 return err;
1962 
1963         virtio_device_ready(vdev);
1964 
1965         if (netif_running(vi->dev)) {
1966                 for (i = 0; i < vi->curr_queue_pairs; i++)
1967                         if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1968                                 schedule_delayed_work(&vi->refill, 0);
1969 
1970                 for (i = 0; i < vi->max_queue_pairs; i++)
1971                         virtnet_napi_enable(&vi->rq[i]);
1972         }
1973 
1974         netif_device_attach(vi->dev);
1975 
1976         rtnl_lock();
1977         virtnet_set_queues(vi, vi->curr_queue_pairs);
1978         rtnl_unlock();
1979 
1980         err = register_hotcpu_notifier(&vi->nb);
1981         if (err)
1982                 return err;
1983 
1984         return 0;
1985 }
1986 #endif
1987 
1988 static struct virtio_device_id id_table[] = {
1989         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1990         { 0 },
1991 };
1992 
1993 static unsigned int features[] = {
1994         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1995         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1996         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_TSO6,
1997         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1998         VIRTIO_NET_F_GUEST_ECN,
1999         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2000         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2001         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2002         VIRTIO_NET_F_CTRL_MAC_ADDR,
2003         VIRTIO_F_ANY_LAYOUT,
2004 };
2005 
2006 static struct virtio_driver virtio_net_driver = {
2007         .feature_table = features,
2008         .feature_table_size = ARRAY_SIZE(features),
2009         .driver.name =  KBUILD_MODNAME,
2010         .driver.owner = THIS_MODULE,
2011         .id_table =     id_table,
2012         .probe =        virtnet_probe,
2013         .remove =       virtnet_remove,
2014         .config_changed = virtnet_config_changed,
2015 #ifdef CONFIG_PM_SLEEP
2016         .freeze =       virtnet_freeze,
2017         .restore =      virtnet_restore,
2018 #endif
2019 };
2020 
2021 module_virtio_driver(virtio_net_driver);
2022 
2023 MODULE_DEVICE_TABLE(virtio, id_table);
2024 MODULE_DESCRIPTION("Virtio network driver");
2025 MODULE_LICENSE("GPL");
2026 

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