Version:  2.0.40 2.2.26 2.4.37 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5

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 /* RX packet size EWMA. The average packet size is used to determine the packet
 44  * buffer size when refilling RX rings. As the entire RX ring may be refilled
 45  * at once, the weight is chosen so that the EWMA will be insensitive to short-
 46  * term, transient changes in packet size.
 47  */
 48 DECLARE_EWMA(pkt_len, 1, 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.$index */
 74         char name[40];
 75 };
 76 
 77 /* Internal representation of a receive virtqueue */
 78 struct receive_queue {
 79         /* Virtqueue associated with this receive_queue */
 80         struct virtqueue *vq;
 81 
 82         struct napi_struct napi;
 83 
 84         /* Chain pages by the private ptr. */
 85         struct page *pages;
 86 
 87         /* Average packet length for mergeable receive buffers. */
 88         struct ewma_pkt_len mrg_avg_pkt_len;
 89 
 90         /* Page frag for packet buffer allocation. */
 91         struct page_frag alloc_frag;
 92 
 93         /* RX: fragments + linear part + virtio header */
 94         struct scatterlist sg[MAX_SKB_FRAGS + 2];
 95 
 96         /* Name of this receive queue: input.$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         /* Packet virtio header size */
127         u8 hdr_len;
128 
129         /* Active statistics */
130         struct virtnet_stats __percpu *stats;
131 
132         /* Work struct for refilling if we run low on memory. */
133         struct delayed_work refill;
134 
135         /* Work struct for config space updates */
136         struct work_struct config_work;
137 
138         /* Does the affinity hint is set for virtqueues? */
139         bool affinity_hint_set;
140 
141         /* CPU hot plug notifier */
142         struct notifier_block nb;
143 
144         /* Control VQ buffers: protected by the rtnl lock */
145         struct virtio_net_ctrl_hdr ctrl_hdr;
146         virtio_net_ctrl_ack ctrl_status;
147         u8 ctrl_promisc;
148         u8 ctrl_allmulti;
149 };
150 
151 struct padded_vnet_hdr {
152         struct virtio_net_hdr_mrg_rxbuf hdr;
153         /*
154          * hdr is in a separate sg buffer, and data sg buffer shares same page
155          * with this header sg. This padding makes next sg 16 byte aligned
156          * after the header.
157          */
158         char padding[4];
159 };
160 
161 /* Converting between virtqueue no. and kernel tx/rx queue no.
162  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
163  */
164 static int vq2txq(struct virtqueue *vq)
165 {
166         return (vq->index - 1) / 2;
167 }
168 
169 static int txq2vq(int txq)
170 {
171         return txq * 2 + 1;
172 }
173 
174 static int vq2rxq(struct virtqueue *vq)
175 {
176         return vq->index / 2;
177 }
178 
179 static int rxq2vq(int rxq)
180 {
181         return rxq * 2;
182 }
183 
184 static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
185 {
186         return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
187 }
188 
189 /*
190  * private is used to chain pages for big packets, put the whole
191  * most recent used list in the beginning for reuse
192  */
193 static void give_pages(struct receive_queue *rq, struct page *page)
194 {
195         struct page *end;
196 
197         /* Find end of list, sew whole thing into vi->rq.pages. */
198         for (end = page; end->private; end = (struct page *)end->private);
199         end->private = (unsigned long)rq->pages;
200         rq->pages = page;
201 }
202 
203 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
204 {
205         struct page *p = rq->pages;
206 
207         if (p) {
208                 rq->pages = (struct page *)p->private;
209                 /* clear private here, it is used to chain pages */
210                 p->private = 0;
211         } else
212                 p = alloc_page(gfp_mask);
213         return p;
214 }
215 
216 static void skb_xmit_done(struct virtqueue *vq)
217 {
218         struct virtnet_info *vi = vq->vdev->priv;
219 
220         /* Suppress further interrupts. */
221         virtqueue_disable_cb(vq);
222 
223         /* We were probably waiting for more output buffers. */
224         netif_wake_subqueue(vi->dev, vq2txq(vq));
225 }
226 
227 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
228 {
229         unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
230         return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
231 }
232 
233 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
234 {
235         return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
236 
237 }
238 
239 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
240 {
241         unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
242         return (unsigned long)buf | (size - 1);
243 }
244 
245 /* Called from bottom half context */
246 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
247                                    struct receive_queue *rq,
248                                    struct page *page, unsigned int offset,
249                                    unsigned int len, unsigned int truesize)
250 {
251         struct sk_buff *skb;
252         struct virtio_net_hdr_mrg_rxbuf *hdr;
253         unsigned int copy, hdr_len, hdr_padded_len;
254         char *p;
255 
256         p = page_address(page) + offset;
257 
258         /* copy small packet so we can reuse these pages for small data */
259         skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
260         if (unlikely(!skb))
261                 return NULL;
262 
263         hdr = skb_vnet_hdr(skb);
264 
265         hdr_len = vi->hdr_len;
266         if (vi->mergeable_rx_bufs)
267                 hdr_padded_len = sizeof *hdr;
268         else
269                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
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(struct virtnet_info *vi, void *buf, unsigned int len)
321 {
322         struct sk_buff * skb = buf;
323 
324         len -= vi->hdr_len;
325         skb_trim(skb, len);
326 
327         return skb;
328 }
329 
330 static struct sk_buff *receive_big(struct net_device *dev,
331                                    struct virtnet_info *vi,
332                                    struct receive_queue *rq,
333                                    void *buf,
334                                    unsigned int len)
335 {
336         struct page *page = buf;
337         struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
338 
339         if (unlikely(!skb))
340                 goto err;
341 
342         return skb;
343 
344 err:
345         dev->stats.rx_dropped++;
346         give_pages(rq, page);
347         return NULL;
348 }
349 
350 static struct sk_buff *receive_mergeable(struct net_device *dev,
351                                          struct virtnet_info *vi,
352                                          struct receive_queue *rq,
353                                          unsigned long ctx,
354                                          unsigned int len)
355 {
356         void *buf = mergeable_ctx_to_buf_address(ctx);
357         struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
358         u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
359         struct page *page = virt_to_head_page(buf);
360         int offset = buf - page_address(page);
361         unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
362 
363         struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
364                                                truesize);
365         struct sk_buff *curr_skb = head_skb;
366 
367         if (unlikely(!curr_skb))
368                 goto err_skb;
369         while (--num_buf) {
370                 int num_skb_frags;
371 
372                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
373                 if (unlikely(!ctx)) {
374                         pr_debug("%s: rx error: %d buffers out of %d missing\n",
375                                  dev->name, num_buf,
376                                  virtio16_to_cpu(vi->vdev,
377                                                  hdr->num_buffers));
378                         dev->stats.rx_length_errors++;
379                         goto err_buf;
380                 }
381 
382                 buf = mergeable_ctx_to_buf_address(ctx);
383                 page = virt_to_head_page(buf);
384 
385                 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
386                 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
387                         struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
388 
389                         if (unlikely(!nskb))
390                                 goto err_skb;
391                         if (curr_skb == head_skb)
392                                 skb_shinfo(curr_skb)->frag_list = nskb;
393                         else
394                                 curr_skb->next = nskb;
395                         curr_skb = nskb;
396                         head_skb->truesize += nskb->truesize;
397                         num_skb_frags = 0;
398                 }
399                 truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
400                 if (curr_skb != head_skb) {
401                         head_skb->data_len += len;
402                         head_skb->len += len;
403                         head_skb->truesize += truesize;
404                 }
405                 offset = buf - page_address(page);
406                 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
407                         put_page(page);
408                         skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
409                                              len, truesize);
410                 } else {
411                         skb_add_rx_frag(curr_skb, num_skb_frags, page,
412                                         offset, len, truesize);
413                 }
414         }
415 
416         ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
417         return head_skb;
418 
419 err_skb:
420         put_page(page);
421         while (--num_buf) {
422                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
423                 if (unlikely(!ctx)) {
424                         pr_debug("%s: rx error: %d buffers missing\n",
425                                  dev->name, num_buf);
426                         dev->stats.rx_length_errors++;
427                         break;
428                 }
429                 page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
430                 put_page(page);
431         }
432 err_buf:
433         dev->stats.rx_dropped++;
434         dev_kfree_skb(head_skb);
435         return NULL;
436 }
437 
438 static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
439                         void *buf, unsigned int len)
440 {
441         struct net_device *dev = vi->dev;
442         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
443         struct sk_buff *skb;
444         struct virtio_net_hdr_mrg_rxbuf *hdr;
445 
446         if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
447                 pr_debug("%s: short packet %i\n", dev->name, len);
448                 dev->stats.rx_length_errors++;
449                 if (vi->mergeable_rx_bufs) {
450                         unsigned long ctx = (unsigned long)buf;
451                         void *base = mergeable_ctx_to_buf_address(ctx);
452                         put_page(virt_to_head_page(base));
453                 } else if (vi->big_packets) {
454                         give_pages(rq, buf);
455                 } else {
456                         dev_kfree_skb(buf);
457                 }
458                 return;
459         }
460 
461         if (vi->mergeable_rx_bufs)
462                 skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
463         else if (vi->big_packets)
464                 skb = receive_big(dev, vi, rq, buf, len);
465         else
466                 skb = receive_small(vi, buf, len);
467 
468         if (unlikely(!skb))
469                 return;
470 
471         hdr = skb_vnet_hdr(skb);
472 
473         u64_stats_update_begin(&stats->rx_syncp);
474         stats->rx_bytes += skb->len;
475         stats->rx_packets++;
476         u64_stats_update_end(&stats->rx_syncp);
477 
478         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
479                 pr_debug("Needs csum!\n");
480                 if (!skb_partial_csum_set(skb,
481                           virtio16_to_cpu(vi->vdev, hdr->hdr.csum_start),
482                           virtio16_to_cpu(vi->vdev, hdr->hdr.csum_offset)))
483                         goto frame_err;
484         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
485                 skb->ip_summed = CHECKSUM_UNNECESSARY;
486         }
487 
488         skb->protocol = eth_type_trans(skb, dev);
489         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
490                  ntohs(skb->protocol), skb->len, skb->pkt_type);
491 
492         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
493                 pr_debug("GSO!\n");
494                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
495                 case VIRTIO_NET_HDR_GSO_TCPV4:
496                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
497                         break;
498                 case VIRTIO_NET_HDR_GSO_UDP:
499                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
500                         break;
501                 case VIRTIO_NET_HDR_GSO_TCPV6:
502                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
503                         break;
504                 default:
505                         net_warn_ratelimited("%s: bad gso type %u.\n",
506                                              dev->name, hdr->hdr.gso_type);
507                         goto frame_err;
508                 }
509 
510                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
511                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
512 
513                 skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
514                                                             hdr->hdr.gso_size);
515                 if (skb_shinfo(skb)->gso_size == 0) {
516                         net_warn_ratelimited("%s: zero gso size.\n", dev->name);
517                         goto frame_err;
518                 }
519 
520                 /* Header must be checked, and gso_segs computed. */
521                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
522                 skb_shinfo(skb)->gso_segs = 0;
523         }
524 
525         napi_gro_receive(&rq->napi, skb);
526         return;
527 
528 frame_err:
529         dev->stats.rx_frame_errors++;
530         dev_kfree_skb(skb);
531 }
532 
533 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
534                              gfp_t gfp)
535 {
536         struct sk_buff *skb;
537         struct virtio_net_hdr_mrg_rxbuf *hdr;
538         int err;
539 
540         skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
541         if (unlikely(!skb))
542                 return -ENOMEM;
543 
544         skb_put(skb, GOOD_PACKET_LEN);
545 
546         hdr = skb_vnet_hdr(skb);
547         sg_init_table(rq->sg, 2);
548         sg_set_buf(rq->sg, hdr, vi->hdr_len);
549         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
550 
551         err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
552         if (err < 0)
553                 dev_kfree_skb(skb);
554 
555         return err;
556 }
557 
558 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
559                            gfp_t gfp)
560 {
561         struct page *first, *list = NULL;
562         char *p;
563         int i, err, offset;
564 
565         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
566 
567         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
568         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
569                 first = get_a_page(rq, gfp);
570                 if (!first) {
571                         if (list)
572                                 give_pages(rq, list);
573                         return -ENOMEM;
574                 }
575                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
576 
577                 /* chain new page in list head to match sg */
578                 first->private = (unsigned long)list;
579                 list = first;
580         }
581 
582         first = get_a_page(rq, gfp);
583         if (!first) {
584                 give_pages(rq, list);
585                 return -ENOMEM;
586         }
587         p = page_address(first);
588 
589         /* rq->sg[0], rq->sg[1] share the same page */
590         /* a separated rq->sg[0] for header - required in case !any_header_sg */
591         sg_set_buf(&rq->sg[0], p, vi->hdr_len);
592 
593         /* rq->sg[1] for data packet, from offset */
594         offset = sizeof(struct padded_vnet_hdr);
595         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
596 
597         /* chain first in list head */
598         first->private = (unsigned long)list;
599         err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
600                                   first, gfp);
601         if (err < 0)
602                 give_pages(rq, first);
603 
604         return err;
605 }
606 
607 static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
608 {
609         const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
610         unsigned int len;
611 
612         len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
613                         GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
614         return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
615 }
616 
617 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
618 {
619         struct page_frag *alloc_frag = &rq->alloc_frag;
620         char *buf;
621         unsigned long ctx;
622         int err;
623         unsigned int len, hole;
624 
625         len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
626         if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
627                 return -ENOMEM;
628 
629         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
630         ctx = mergeable_buf_to_ctx(buf, len);
631         get_page(alloc_frag->page);
632         alloc_frag->offset += len;
633         hole = alloc_frag->size - alloc_frag->offset;
634         if (hole < len) {
635                 /* To avoid internal fragmentation, if there is very likely not
636                  * enough space for another buffer, add the remaining space to
637                  * the current buffer. This extra space is not included in
638                  * the truesize stored in ctx.
639                  */
640                 len += hole;
641                 alloc_frag->offset += hole;
642         }
643 
644         sg_init_one(rq->sg, buf, len);
645         err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
646         if (err < 0)
647                 put_page(virt_to_head_page(buf));
648 
649         return err;
650 }
651 
652 /*
653  * Returns false if we couldn't fill entirely (OOM).
654  *
655  * Normally run in the receive path, but can also be run from ndo_open
656  * before we're receiving packets, or from refill_work which is
657  * careful to disable receiving (using napi_disable).
658  */
659 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
660                           gfp_t gfp)
661 {
662         int err;
663         bool oom;
664 
665         gfp |= __GFP_COLD;
666         do {
667                 if (vi->mergeable_rx_bufs)
668                         err = add_recvbuf_mergeable(rq, gfp);
669                 else if (vi->big_packets)
670                         err = add_recvbuf_big(vi, rq, gfp);
671                 else
672                         err = add_recvbuf_small(vi, rq, gfp);
673 
674                 oom = err == -ENOMEM;
675                 if (err)
676                         break;
677         } while (rq->vq->num_free);
678         virtqueue_kick(rq->vq);
679         return !oom;
680 }
681 
682 static void skb_recv_done(struct virtqueue *rvq)
683 {
684         struct virtnet_info *vi = rvq->vdev->priv;
685         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
686 
687         /* Schedule NAPI, Suppress further interrupts if successful. */
688         if (napi_schedule_prep(&rq->napi)) {
689                 virtqueue_disable_cb(rvq);
690                 __napi_schedule(&rq->napi);
691         }
692 }
693 
694 static void virtnet_napi_enable(struct receive_queue *rq)
695 {
696         napi_enable(&rq->napi);
697 
698         /* If all buffers were filled by other side before we napi_enabled, we
699          * won't get another interrupt, so process any outstanding packets
700          * now.  virtnet_poll wants re-enable the queue, so we disable here.
701          * We synchronize against interrupts via NAPI_STATE_SCHED */
702         if (napi_schedule_prep(&rq->napi)) {
703                 virtqueue_disable_cb(rq->vq);
704                 local_bh_disable();
705                 __napi_schedule(&rq->napi);
706                 local_bh_enable();
707         }
708 }
709 
710 static void refill_work(struct work_struct *work)
711 {
712         struct virtnet_info *vi =
713                 container_of(work, struct virtnet_info, refill.work);
714         bool still_empty;
715         int i;
716 
717         for (i = 0; i < vi->curr_queue_pairs; i++) {
718                 struct receive_queue *rq = &vi->rq[i];
719 
720                 napi_disable(&rq->napi);
721                 still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
722                 virtnet_napi_enable(rq);
723 
724                 /* In theory, this can happen: if we don't get any buffers in
725                  * we will *never* try to fill again.
726                  */
727                 if (still_empty)
728                         schedule_delayed_work(&vi->refill, HZ/2);
729         }
730 }
731 
732 static int virtnet_receive(struct receive_queue *rq, int budget)
733 {
734         struct virtnet_info *vi = rq->vq->vdev->priv;
735         unsigned int len, received = 0;
736         void *buf;
737 
738         while (received < budget &&
739                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
740                 receive_buf(vi, rq, buf, len);
741                 received++;
742         }
743 
744         if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
745                 if (!try_fill_recv(vi, rq, GFP_ATOMIC))
746                         schedule_delayed_work(&vi->refill, 0);
747         }
748 
749         return received;
750 }
751 
752 static int virtnet_poll(struct napi_struct *napi, int budget)
753 {
754         struct receive_queue *rq =
755                 container_of(napi, struct receive_queue, napi);
756         unsigned int r, received;
757 
758         received = virtnet_receive(rq, budget);
759 
760         /* Out of packets? */
761         if (received < budget) {
762                 r = virtqueue_enable_cb_prepare(rq->vq);
763                 napi_complete_done(napi, received);
764                 if (unlikely(virtqueue_poll(rq->vq, r)) &&
765                     napi_schedule_prep(napi)) {
766                         virtqueue_disable_cb(rq->vq);
767                         __napi_schedule(napi);
768                 }
769         }
770 
771         return received;
772 }
773 
774 #ifdef CONFIG_NET_RX_BUSY_POLL
775 /* must be called with local_bh_disable()d */
776 static int virtnet_busy_poll(struct napi_struct *napi)
777 {
778         struct receive_queue *rq =
779                 container_of(napi, struct receive_queue, napi);
780         struct virtnet_info *vi = rq->vq->vdev->priv;
781         int r, received = 0, budget = 4;
782 
783         if (!(vi->status & VIRTIO_NET_S_LINK_UP))
784                 return LL_FLUSH_FAILED;
785 
786         if (!napi_schedule_prep(napi))
787                 return LL_FLUSH_BUSY;
788 
789         virtqueue_disable_cb(rq->vq);
790 
791 again:
792         received += virtnet_receive(rq, budget);
793 
794         r = virtqueue_enable_cb_prepare(rq->vq);
795         clear_bit(NAPI_STATE_SCHED, &napi->state);
796         if (unlikely(virtqueue_poll(rq->vq, r)) &&
797             napi_schedule_prep(napi)) {
798                 virtqueue_disable_cb(rq->vq);
799                 if (received < budget) {
800                         budget -= received;
801                         goto again;
802                 } else {
803                         __napi_schedule(napi);
804                 }
805         }
806 
807         return received;
808 }
809 #endif  /* CONFIG_NET_RX_BUSY_POLL */
810 
811 static int virtnet_open(struct net_device *dev)
812 {
813         struct virtnet_info *vi = netdev_priv(dev);
814         int i;
815 
816         for (i = 0; i < vi->max_queue_pairs; i++) {
817                 if (i < vi->curr_queue_pairs)
818                         /* Make sure we have some buffers: if oom use wq. */
819                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
820                                 schedule_delayed_work(&vi->refill, 0);
821                 virtnet_napi_enable(&vi->rq[i]);
822         }
823 
824         return 0;
825 }
826 
827 static void free_old_xmit_skbs(struct send_queue *sq)
828 {
829         struct sk_buff *skb;
830         unsigned int len;
831         struct virtnet_info *vi = sq->vq->vdev->priv;
832         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
833 
834         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
835                 pr_debug("Sent skb %p\n", skb);
836 
837                 u64_stats_update_begin(&stats->tx_syncp);
838                 stats->tx_bytes += skb->len;
839                 stats->tx_packets++;
840                 u64_stats_update_end(&stats->tx_syncp);
841 
842                 dev_kfree_skb_any(skb);
843         }
844 }
845 
846 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
847 {
848         struct virtio_net_hdr_mrg_rxbuf *hdr;
849         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
850         struct virtnet_info *vi = sq->vq->vdev->priv;
851         unsigned num_sg;
852         unsigned hdr_len = vi->hdr_len;
853         bool can_push;
854 
855         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
856 
857         can_push = vi->any_header_sg &&
858                 !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
859                 !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
860         /* Even if we can, don't push here yet as this would skew
861          * csum_start offset below. */
862         if (can_push)
863                 hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
864         else
865                 hdr = skb_vnet_hdr(skb);
866 
867         if (skb->ip_summed == CHECKSUM_PARTIAL) {
868                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
869                 hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
870                                                 skb_checksum_start_offset(skb));
871                 hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
872                                                          skb->csum_offset);
873         } else {
874                 hdr->hdr.flags = 0;
875                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
876         }
877 
878         if (skb_is_gso(skb)) {
879                 hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
880                 hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
881                                                     skb_shinfo(skb)->gso_size);
882                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
883                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
884                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
885                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
886                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
887                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
888                 else
889                         BUG();
890                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
891                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
892         } else {
893                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
894                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
895         }
896 
897         if (vi->mergeable_rx_bufs)
898                 hdr->num_buffers = 0;
899 
900         sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
901         if (can_push) {
902                 __skb_push(skb, hdr_len);
903                 num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
904                 /* Pull header back to avoid skew in tx bytes calculations. */
905                 __skb_pull(skb, hdr_len);
906         } else {
907                 sg_set_buf(sq->sg, hdr, hdr_len);
908                 num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
909         }
910         return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
911 }
912 
913 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
914 {
915         struct virtnet_info *vi = netdev_priv(dev);
916         int qnum = skb_get_queue_mapping(skb);
917         struct send_queue *sq = &vi->sq[qnum];
918         int err;
919         struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
920         bool kick = !skb->xmit_more;
921 
922         /* Free up any pending old buffers before queueing new ones. */
923         free_old_xmit_skbs(sq);
924 
925         /* timestamp packet in software */
926         skb_tx_timestamp(skb);
927 
928         /* Try to transmit */
929         err = xmit_skb(sq, skb);
930 
931         /* This should not happen! */
932         if (unlikely(err)) {
933                 dev->stats.tx_fifo_errors++;
934                 if (net_ratelimit())
935                         dev_warn(&dev->dev,
936                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
937                 dev->stats.tx_dropped++;
938                 dev_kfree_skb_any(skb);
939                 return NETDEV_TX_OK;
940         }
941 
942         /* Don't wait up for transmitted skbs to be freed. */
943         skb_orphan(skb);
944         nf_reset(skb);
945 
946         /* If running out of space, stop queue to avoid getting packets that we
947          * are then unable to transmit.
948          * An alternative would be to force queuing layer to requeue the skb by
949          * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
950          * returned in a normal path of operation: it means that driver is not
951          * maintaining the TX queue stop/start state properly, and causes
952          * the stack to do a non-trivial amount of useless work.
953          * Since most packets only take 1 or 2 ring slots, stopping the queue
954          * early means 16 slots are typically wasted.
955          */
956         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
957                 netif_stop_subqueue(dev, qnum);
958                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
959                         /* More just got used, free them then recheck. */
960                         free_old_xmit_skbs(sq);
961                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
962                                 netif_start_subqueue(dev, qnum);
963                                 virtqueue_disable_cb(sq->vq);
964                         }
965                 }
966         }
967 
968         if (kick || netif_xmit_stopped(txq))
969                 virtqueue_kick(sq->vq);
970 
971         return NETDEV_TX_OK;
972 }
973 
974 /*
975  * Send command via the control virtqueue and check status.  Commands
976  * supported by the hypervisor, as indicated by feature bits, should
977  * never fail unless improperly formatted.
978  */
979 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
980                                  struct scatterlist *out)
981 {
982         struct scatterlist *sgs[4], hdr, stat;
983         unsigned out_num = 0, tmp;
984 
985         /* Caller should know better */
986         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
987 
988         vi->ctrl_status = ~0;
989         vi->ctrl_hdr.class = class;
990         vi->ctrl_hdr.cmd = cmd;
991         /* Add header */
992         sg_init_one(&hdr, &vi->ctrl_hdr, sizeof(vi->ctrl_hdr));
993         sgs[out_num++] = &hdr;
994 
995         if (out)
996                 sgs[out_num++] = out;
997 
998         /* Add return status. */
999         sg_init_one(&stat, &vi->ctrl_status, sizeof(vi->ctrl_status));
1000         sgs[out_num] = &stat;
1001 
1002         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
1003         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
1004 
1005         if (unlikely(!virtqueue_kick(vi->cvq)))
1006                 return vi->ctrl_status == VIRTIO_NET_OK;
1007 
1008         /* Spin for a response, the kick causes an ioport write, trapping
1009          * into the hypervisor, so the request should be handled immediately.
1010          */
1011         while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1012                !virtqueue_is_broken(vi->cvq))
1013                 cpu_relax();
1014 
1015         return vi->ctrl_status == VIRTIO_NET_OK;
1016 }
1017 
1018 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1019 {
1020         struct virtnet_info *vi = netdev_priv(dev);
1021         struct virtio_device *vdev = vi->vdev;
1022         int ret;
1023         struct sockaddr *addr = p;
1024         struct scatterlist sg;
1025 
1026         ret = eth_prepare_mac_addr_change(dev, p);
1027         if (ret)
1028                 return ret;
1029 
1030         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1031                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
1032                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1033                                           VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1034                         dev_warn(&vdev->dev,
1035                                  "Failed to set mac address by vq command.\n");
1036                         return -EINVAL;
1037                 }
1038         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
1039                    !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1040                 unsigned int i;
1041 
1042                 /* Naturally, this has an atomicity problem. */
1043                 for (i = 0; i < dev->addr_len; i++)
1044                         virtio_cwrite8(vdev,
1045                                        offsetof(struct virtio_net_config, mac) +
1046                                        i, addr->sa_data[i]);
1047         }
1048 
1049         eth_commit_mac_addr_change(dev, p);
1050 
1051         return 0;
1052 }
1053 
1054 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1055                                                struct rtnl_link_stats64 *tot)
1056 {
1057         struct virtnet_info *vi = netdev_priv(dev);
1058         int cpu;
1059         unsigned int start;
1060 
1061         for_each_possible_cpu(cpu) {
1062                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1063                 u64 tpackets, tbytes, rpackets, rbytes;
1064 
1065                 do {
1066                         start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1067                         tpackets = stats->tx_packets;
1068                         tbytes   = stats->tx_bytes;
1069                 } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1070 
1071                 do {
1072                         start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1073                         rpackets = stats->rx_packets;
1074                         rbytes   = stats->rx_bytes;
1075                 } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1076 
1077                 tot->rx_packets += rpackets;
1078                 tot->tx_packets += tpackets;
1079                 tot->rx_bytes   += rbytes;
1080                 tot->tx_bytes   += tbytes;
1081         }
1082 
1083         tot->tx_dropped = dev->stats.tx_dropped;
1084         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1085         tot->rx_dropped = dev->stats.rx_dropped;
1086         tot->rx_length_errors = dev->stats.rx_length_errors;
1087         tot->rx_frame_errors = dev->stats.rx_frame_errors;
1088 
1089         return tot;
1090 }
1091 
1092 #ifdef CONFIG_NET_POLL_CONTROLLER
1093 static void virtnet_netpoll(struct net_device *dev)
1094 {
1095         struct virtnet_info *vi = netdev_priv(dev);
1096         int i;
1097 
1098         for (i = 0; i < vi->curr_queue_pairs; i++)
1099                 napi_schedule(&vi->rq[i].napi);
1100 }
1101 #endif
1102 
1103 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1104 {
1105         rtnl_lock();
1106         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1107                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1108                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1109         rtnl_unlock();
1110 }
1111 
1112 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1113 {
1114         struct scatterlist sg;
1115         struct virtio_net_ctrl_mq s;
1116         struct net_device *dev = vi->dev;
1117 
1118         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1119                 return 0;
1120 
1121         s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1122         sg_init_one(&sg, &s, sizeof(s));
1123 
1124         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1125                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1126                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1127                          queue_pairs);
1128                 return -EINVAL;
1129         } else {
1130                 vi->curr_queue_pairs = queue_pairs;
1131                 /* virtnet_open() will refill when device is going to up. */
1132                 if (dev->flags & IFF_UP)
1133                         schedule_delayed_work(&vi->refill, 0);
1134         }
1135 
1136         return 0;
1137 }
1138 
1139 static int virtnet_close(struct net_device *dev)
1140 {
1141         struct virtnet_info *vi = netdev_priv(dev);
1142         int i;
1143 
1144         /* Make sure refill_work doesn't re-enable napi! */
1145         cancel_delayed_work_sync(&vi->refill);
1146 
1147         for (i = 0; i < vi->max_queue_pairs; i++)
1148                 napi_disable(&vi->rq[i].napi);
1149 
1150         return 0;
1151 }
1152 
1153 static void virtnet_set_rx_mode(struct net_device *dev)
1154 {
1155         struct virtnet_info *vi = netdev_priv(dev);
1156         struct scatterlist sg[2];
1157         struct virtio_net_ctrl_mac *mac_data;
1158         struct netdev_hw_addr *ha;
1159         int uc_count;
1160         int mc_count;
1161         void *buf;
1162         int i;
1163 
1164         /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1165         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1166                 return;
1167 
1168         vi->ctrl_promisc = ((dev->flags & IFF_PROMISC) != 0);
1169         vi->ctrl_allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1170 
1171         sg_init_one(sg, &vi->ctrl_promisc, sizeof(vi->ctrl_promisc));
1172 
1173         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1174                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
1175                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1176                          vi->ctrl_promisc ? "en" : "dis");
1177 
1178         sg_init_one(sg, &vi->ctrl_allmulti, sizeof(vi->ctrl_allmulti));
1179 
1180         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1181                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1182                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1183                          vi->ctrl_allmulti ? "en" : "dis");
1184 
1185         uc_count = netdev_uc_count(dev);
1186         mc_count = netdev_mc_count(dev);
1187         /* MAC filter - use one buffer for both lists */
1188         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1189                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1190         mac_data = buf;
1191         if (!buf)
1192                 return;
1193 
1194         sg_init_table(sg, 2);
1195 
1196         /* Store the unicast list and count in the front of the buffer */
1197         mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1198         i = 0;
1199         netdev_for_each_uc_addr(ha, dev)
1200                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1201 
1202         sg_set_buf(&sg[0], mac_data,
1203                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1204 
1205         /* multicast list and count fill the end */
1206         mac_data = (void *)&mac_data->macs[uc_count][0];
1207 
1208         mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1209         i = 0;
1210         netdev_for_each_mc_addr(ha, dev)
1211                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1212 
1213         sg_set_buf(&sg[1], mac_data,
1214                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1215 
1216         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1217                                   VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1218                 dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1219 
1220         kfree(buf);
1221 }
1222 
1223 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1224                                    __be16 proto, u16 vid)
1225 {
1226         struct virtnet_info *vi = netdev_priv(dev);
1227         struct scatterlist sg;
1228 
1229         sg_init_one(&sg, &vid, sizeof(vid));
1230 
1231         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1232                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1233                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1234         return 0;
1235 }
1236 
1237 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1238                                     __be16 proto, u16 vid)
1239 {
1240         struct virtnet_info *vi = netdev_priv(dev);
1241         struct scatterlist sg;
1242 
1243         sg_init_one(&sg, &vid, sizeof(vid));
1244 
1245         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1246                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1247                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1248         return 0;
1249 }
1250 
1251 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1252 {
1253         int i;
1254 
1255         if (vi->affinity_hint_set) {
1256                 for (i = 0; i < vi->max_queue_pairs; i++) {
1257                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1258                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1259                 }
1260 
1261                 vi->affinity_hint_set = false;
1262         }
1263 }
1264 
1265 static void virtnet_set_affinity(struct virtnet_info *vi)
1266 {
1267         int i;
1268         int cpu;
1269 
1270         /* In multiqueue mode, when the number of cpu is equal to the number of
1271          * queue pairs, we let the queue pairs to be private to one cpu by
1272          * setting the affinity hint to eliminate the contention.
1273          */
1274         if (vi->curr_queue_pairs == 1 ||
1275             vi->max_queue_pairs != num_online_cpus()) {
1276                 virtnet_clean_affinity(vi, -1);
1277                 return;
1278         }
1279 
1280         i = 0;
1281         for_each_online_cpu(cpu) {
1282                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1283                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1284                 netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1285                 i++;
1286         }
1287 
1288         vi->affinity_hint_set = true;
1289 }
1290 
1291 static int virtnet_cpu_callback(struct notifier_block *nfb,
1292                                 unsigned long action, void *hcpu)
1293 {
1294         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1295 
1296         switch(action & ~CPU_TASKS_FROZEN) {
1297         case CPU_ONLINE:
1298         case CPU_DOWN_FAILED:
1299         case CPU_DEAD:
1300                 virtnet_set_affinity(vi);
1301                 break;
1302         case CPU_DOWN_PREPARE:
1303                 virtnet_clean_affinity(vi, (long)hcpu);
1304                 break;
1305         default:
1306                 break;
1307         }
1308 
1309         return NOTIFY_OK;
1310 }
1311 
1312 static void virtnet_get_ringparam(struct net_device *dev,
1313                                 struct ethtool_ringparam *ring)
1314 {
1315         struct virtnet_info *vi = netdev_priv(dev);
1316 
1317         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1318         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1319         ring->rx_pending = ring->rx_max_pending;
1320         ring->tx_pending = ring->tx_max_pending;
1321 }
1322 
1323 
1324 static void virtnet_get_drvinfo(struct net_device *dev,
1325                                 struct ethtool_drvinfo *info)
1326 {
1327         struct virtnet_info *vi = netdev_priv(dev);
1328         struct virtio_device *vdev = vi->vdev;
1329 
1330         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1331         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1332         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1333 
1334 }
1335 
1336 /* TODO: Eliminate OOO packets during switching */
1337 static int virtnet_set_channels(struct net_device *dev,
1338                                 struct ethtool_channels *channels)
1339 {
1340         struct virtnet_info *vi = netdev_priv(dev);
1341         u16 queue_pairs = channels->combined_count;
1342         int err;
1343 
1344         /* We don't support separate rx/tx channels.
1345          * We don't allow setting 'other' channels.
1346          */
1347         if (channels->rx_count || channels->tx_count || channels->other_count)
1348                 return -EINVAL;
1349 
1350         if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1351                 return -EINVAL;
1352 
1353         get_online_cpus();
1354         err = virtnet_set_queues(vi, queue_pairs);
1355         if (!err) {
1356                 netif_set_real_num_tx_queues(dev, queue_pairs);
1357                 netif_set_real_num_rx_queues(dev, queue_pairs);
1358 
1359                 virtnet_set_affinity(vi);
1360         }
1361         put_online_cpus();
1362 
1363         return err;
1364 }
1365 
1366 static void virtnet_get_channels(struct net_device *dev,
1367                                  struct ethtool_channels *channels)
1368 {
1369         struct virtnet_info *vi = netdev_priv(dev);
1370 
1371         channels->combined_count = vi->curr_queue_pairs;
1372         channels->max_combined = vi->max_queue_pairs;
1373         channels->max_other = 0;
1374         channels->rx_count = 0;
1375         channels->tx_count = 0;
1376         channels->other_count = 0;
1377 }
1378 
1379 static const struct ethtool_ops virtnet_ethtool_ops = {
1380         .get_drvinfo = virtnet_get_drvinfo,
1381         .get_link = ethtool_op_get_link,
1382         .get_ringparam = virtnet_get_ringparam,
1383         .set_channels = virtnet_set_channels,
1384         .get_channels = virtnet_get_channels,
1385         .get_ts_info = ethtool_op_get_ts_info,
1386 };
1387 
1388 #define MIN_MTU 68
1389 #define MAX_MTU 65535
1390 
1391 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1392 {
1393         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1394                 return -EINVAL;
1395         dev->mtu = new_mtu;
1396         return 0;
1397 }
1398 
1399 static const struct net_device_ops virtnet_netdev = {
1400         .ndo_open            = virtnet_open,
1401         .ndo_stop            = virtnet_close,
1402         .ndo_start_xmit      = start_xmit,
1403         .ndo_validate_addr   = eth_validate_addr,
1404         .ndo_set_mac_address = virtnet_set_mac_address,
1405         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1406         .ndo_change_mtu      = virtnet_change_mtu,
1407         .ndo_get_stats64     = virtnet_stats,
1408         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1409         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1410 #ifdef CONFIG_NET_POLL_CONTROLLER
1411         .ndo_poll_controller = virtnet_netpoll,
1412 #endif
1413 #ifdef CONFIG_NET_RX_BUSY_POLL
1414         .ndo_busy_poll          = virtnet_busy_poll,
1415 #endif
1416 };
1417 
1418 static void virtnet_config_changed_work(struct work_struct *work)
1419 {
1420         struct virtnet_info *vi =
1421                 container_of(work, struct virtnet_info, config_work);
1422         u16 v;
1423 
1424         if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1425                                  struct virtio_net_config, status, &v) < 0)
1426                 return;
1427 
1428         if (v & VIRTIO_NET_S_ANNOUNCE) {
1429                 netdev_notify_peers(vi->dev);
1430                 virtnet_ack_link_announce(vi);
1431         }
1432 
1433         /* Ignore unknown (future) status bits */
1434         v &= VIRTIO_NET_S_LINK_UP;
1435 
1436         if (vi->status == v)
1437                 return;
1438 
1439         vi->status = v;
1440 
1441         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1442                 netif_carrier_on(vi->dev);
1443                 netif_tx_wake_all_queues(vi->dev);
1444         } else {
1445                 netif_carrier_off(vi->dev);
1446                 netif_tx_stop_all_queues(vi->dev);
1447         }
1448 }
1449 
1450 static void virtnet_config_changed(struct virtio_device *vdev)
1451 {
1452         struct virtnet_info *vi = vdev->priv;
1453 
1454         schedule_work(&vi->config_work);
1455 }
1456 
1457 static void virtnet_free_queues(struct virtnet_info *vi)
1458 {
1459         int i;
1460 
1461         for (i = 0; i < vi->max_queue_pairs; i++) {
1462                 napi_hash_del(&vi->rq[i].napi);
1463                 netif_napi_del(&vi->rq[i].napi);
1464         }
1465 
1466         kfree(vi->rq);
1467         kfree(vi->sq);
1468 }
1469 
1470 static void free_receive_bufs(struct virtnet_info *vi)
1471 {
1472         int i;
1473 
1474         for (i = 0; i < vi->max_queue_pairs; i++) {
1475                 while (vi->rq[i].pages)
1476                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1477         }
1478 }
1479 
1480 static void free_receive_page_frags(struct virtnet_info *vi)
1481 {
1482         int i;
1483         for (i = 0; i < vi->max_queue_pairs; i++)
1484                 if (vi->rq[i].alloc_frag.page)
1485                         put_page(vi->rq[i].alloc_frag.page);
1486 }
1487 
1488 static void free_unused_bufs(struct virtnet_info *vi)
1489 {
1490         void *buf;
1491         int i;
1492 
1493         for (i = 0; i < vi->max_queue_pairs; i++) {
1494                 struct virtqueue *vq = vi->sq[i].vq;
1495                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1496                         dev_kfree_skb(buf);
1497         }
1498 
1499         for (i = 0; i < vi->max_queue_pairs; i++) {
1500                 struct virtqueue *vq = vi->rq[i].vq;
1501 
1502                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1503                         if (vi->mergeable_rx_bufs) {
1504                                 unsigned long ctx = (unsigned long)buf;
1505                                 void *base = mergeable_ctx_to_buf_address(ctx);
1506                                 put_page(virt_to_head_page(base));
1507                         } else if (vi->big_packets) {
1508                                 give_pages(&vi->rq[i], buf);
1509                         } else {
1510                                 dev_kfree_skb(buf);
1511                         }
1512                 }
1513         }
1514 }
1515 
1516 static void virtnet_del_vqs(struct virtnet_info *vi)
1517 {
1518         struct virtio_device *vdev = vi->vdev;
1519 
1520         virtnet_clean_affinity(vi, -1);
1521 
1522         vdev->config->del_vqs(vdev);
1523 
1524         virtnet_free_queues(vi);
1525 }
1526 
1527 static int virtnet_find_vqs(struct virtnet_info *vi)
1528 {
1529         vq_callback_t **callbacks;
1530         struct virtqueue **vqs;
1531         int ret = -ENOMEM;
1532         int i, total_vqs;
1533         const char **names;
1534 
1535         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1536          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1537          * possible control vq.
1538          */
1539         total_vqs = vi->max_queue_pairs * 2 +
1540                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1541 
1542         /* Allocate space for find_vqs parameters */
1543         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1544         if (!vqs)
1545                 goto err_vq;
1546         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1547         if (!callbacks)
1548                 goto err_callback;
1549         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1550         if (!names)
1551                 goto err_names;
1552 
1553         /* Parameters for control virtqueue, if any */
1554         if (vi->has_cvq) {
1555                 callbacks[total_vqs - 1] = NULL;
1556                 names[total_vqs - 1] = "control";
1557         }
1558 
1559         /* Allocate/initialize parameters for send/receive virtqueues */
1560         for (i = 0; i < vi->max_queue_pairs; i++) {
1561                 callbacks[rxq2vq(i)] = skb_recv_done;
1562                 callbacks[txq2vq(i)] = skb_xmit_done;
1563                 sprintf(vi->rq[i].name, "input.%d", i);
1564                 sprintf(vi->sq[i].name, "output.%d", i);
1565                 names[rxq2vq(i)] = vi->rq[i].name;
1566                 names[txq2vq(i)] = vi->sq[i].name;
1567         }
1568 
1569         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1570                                          names);
1571         if (ret)
1572                 goto err_find;
1573 
1574         if (vi->has_cvq) {
1575                 vi->cvq = vqs[total_vqs - 1];
1576                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1577                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1578         }
1579 
1580         for (i = 0; i < vi->max_queue_pairs; i++) {
1581                 vi->rq[i].vq = vqs[rxq2vq(i)];
1582                 vi->sq[i].vq = vqs[txq2vq(i)];
1583         }
1584 
1585         kfree(names);
1586         kfree(callbacks);
1587         kfree(vqs);
1588 
1589         return 0;
1590 
1591 err_find:
1592         kfree(names);
1593 err_names:
1594         kfree(callbacks);
1595 err_callback:
1596         kfree(vqs);
1597 err_vq:
1598         return ret;
1599 }
1600 
1601 static int virtnet_alloc_queues(struct virtnet_info *vi)
1602 {
1603         int i;
1604 
1605         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1606         if (!vi->sq)
1607                 goto err_sq;
1608         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1609         if (!vi->rq)
1610                 goto err_rq;
1611 
1612         INIT_DELAYED_WORK(&vi->refill, refill_work);
1613         for (i = 0; i < vi->max_queue_pairs; i++) {
1614                 vi->rq[i].pages = NULL;
1615                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1616                                napi_weight);
1617 
1618                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1619                 ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
1620                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1621         }
1622 
1623         return 0;
1624 
1625 err_rq:
1626         kfree(vi->sq);
1627 err_sq:
1628         return -ENOMEM;
1629 }
1630 
1631 static int init_vqs(struct virtnet_info *vi)
1632 {
1633         int ret;
1634 
1635         /* Allocate send & receive queues */
1636         ret = virtnet_alloc_queues(vi);
1637         if (ret)
1638                 goto err;
1639 
1640         ret = virtnet_find_vqs(vi);
1641         if (ret)
1642                 goto err_free;
1643 
1644         get_online_cpus();
1645         virtnet_set_affinity(vi);
1646         put_online_cpus();
1647 
1648         return 0;
1649 
1650 err_free:
1651         virtnet_free_queues(vi);
1652 err:
1653         return ret;
1654 }
1655 
1656 #ifdef CONFIG_SYSFS
1657 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1658                 struct rx_queue_attribute *attribute, char *buf)
1659 {
1660         struct virtnet_info *vi = netdev_priv(queue->dev);
1661         unsigned int queue_index = get_netdev_rx_queue_index(queue);
1662         struct ewma_pkt_len *avg;
1663 
1664         BUG_ON(queue_index >= vi->max_queue_pairs);
1665         avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1666         return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1667 }
1668 
1669 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1670         __ATTR_RO(mergeable_rx_buffer_size);
1671 
1672 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1673         &mergeable_rx_buffer_size_attribute.attr,
1674         NULL
1675 };
1676 
1677 static const struct attribute_group virtio_net_mrg_rx_group = {
1678         .name = "virtio_net",
1679         .attrs = virtio_net_mrg_rx_attrs
1680 };
1681 #endif
1682 
1683 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1684                                     unsigned int fbit,
1685                                     const char *fname, const char *dname)
1686 {
1687         if (!virtio_has_feature(vdev, fbit))
1688                 return false;
1689 
1690         dev_err(&vdev->dev, "device advertises feature %s but not %s",
1691                 fname, dname);
1692 
1693         return true;
1694 }
1695 
1696 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
1697         virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1698 
1699 static bool virtnet_validate_features(struct virtio_device *vdev)
1700 {
1701         if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1702             (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1703                              "VIRTIO_NET_F_CTRL_VQ") ||
1704              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1705                              "VIRTIO_NET_F_CTRL_VQ") ||
1706              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1707                              "VIRTIO_NET_F_CTRL_VQ") ||
1708              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1709              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1710                              "VIRTIO_NET_F_CTRL_VQ"))) {
1711                 return false;
1712         }
1713 
1714         return true;
1715 }
1716 
1717 static int virtnet_probe(struct virtio_device *vdev)
1718 {
1719         int i, err;
1720         struct net_device *dev;
1721         struct virtnet_info *vi;
1722         u16 max_queue_pairs;
1723 
1724         if (!vdev->config->get) {
1725                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
1726                         __func__);
1727                 return -EINVAL;
1728         }
1729 
1730         if (!virtnet_validate_features(vdev))
1731                 return -EINVAL;
1732 
1733         /* Find if host supports multiqueue virtio_net device */
1734         err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1735                                    struct virtio_net_config,
1736                                    max_virtqueue_pairs, &max_queue_pairs);
1737 
1738         /* We need at least 2 queue's */
1739         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1740             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1741             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1742                 max_queue_pairs = 1;
1743 
1744         /* Allocate ourselves a network device with room for our info */
1745         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1746         if (!dev)
1747                 return -ENOMEM;
1748 
1749         /* Set up network device as normal. */
1750         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1751         dev->netdev_ops = &virtnet_netdev;
1752         dev->features = NETIF_F_HIGHDMA;
1753 
1754         dev->ethtool_ops = &virtnet_ethtool_ops;
1755         SET_NETDEV_DEV(dev, &vdev->dev);
1756 
1757         /* Do we support "hardware" checksums? */
1758         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1759                 /* This opens up the world of extra features. */
1760                 dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1761                 if (csum)
1762                         dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1763 
1764                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1765                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1766                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1767                 }
1768                 /* Individual feature bits: what can host handle? */
1769                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1770                         dev->hw_features |= NETIF_F_TSO;
1771                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1772                         dev->hw_features |= NETIF_F_TSO6;
1773                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1774                         dev->hw_features |= NETIF_F_TSO_ECN;
1775                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1776                         dev->hw_features |= NETIF_F_UFO;
1777 
1778                 dev->features |= NETIF_F_GSO_ROBUST;
1779 
1780                 if (gso)
1781                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1782                 /* (!csum && gso) case will be fixed by register_netdev() */
1783         }
1784         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1785                 dev->features |= NETIF_F_RXCSUM;
1786 
1787         dev->vlan_features = dev->features;
1788 
1789         /* Configuration may specify what MAC to use.  Otherwise random. */
1790         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1791                 virtio_cread_bytes(vdev,
1792                                    offsetof(struct virtio_net_config, mac),
1793                                    dev->dev_addr, dev->addr_len);
1794         else
1795                 eth_hw_addr_random(dev);
1796 
1797         /* Set up our device-specific information */
1798         vi = netdev_priv(dev);
1799         vi->dev = dev;
1800         vi->vdev = vdev;
1801         vdev->priv = vi;
1802         vi->stats = alloc_percpu(struct virtnet_stats);
1803         err = -ENOMEM;
1804         if (vi->stats == NULL)
1805                 goto free;
1806 
1807         for_each_possible_cpu(i) {
1808                 struct virtnet_stats *virtnet_stats;
1809                 virtnet_stats = per_cpu_ptr(vi->stats, i);
1810                 u64_stats_init(&virtnet_stats->tx_syncp);
1811                 u64_stats_init(&virtnet_stats->rx_syncp);
1812         }
1813 
1814         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1815 
1816         /* If we can receive ANY GSO packets, we must allocate large ones. */
1817         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1818             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1819             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1820             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1821                 vi->big_packets = true;
1822 
1823         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1824                 vi->mergeable_rx_bufs = true;
1825 
1826         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
1827             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1828                 vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1829         else
1830                 vi->hdr_len = sizeof(struct virtio_net_hdr);
1831 
1832         if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
1833             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1834                 vi->any_header_sg = true;
1835 
1836         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1837                 vi->has_cvq = true;
1838 
1839         if (vi->any_header_sg)
1840                 dev->needed_headroom = vi->hdr_len;
1841 
1842         /* Use single tx/rx queue pair as default */
1843         vi->curr_queue_pairs = 1;
1844         vi->max_queue_pairs = max_queue_pairs;
1845 
1846         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1847         err = init_vqs(vi);
1848         if (err)
1849                 goto free_stats;
1850 
1851 #ifdef CONFIG_SYSFS
1852         if (vi->mergeable_rx_bufs)
1853                 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1854 #endif
1855         netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1856         netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1857 
1858         err = register_netdev(dev);
1859         if (err) {
1860                 pr_debug("virtio_net: registering device failed\n");
1861                 goto free_vqs;
1862         }
1863 
1864         virtio_device_ready(vdev);
1865 
1866         /* Last of all, set up some receive buffers. */
1867         for (i = 0; i < vi->curr_queue_pairs; i++) {
1868                 try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
1869 
1870                 /* If we didn't even get one input buffer, we're useless. */
1871                 if (vi->rq[i].vq->num_free ==
1872                     virtqueue_get_vring_size(vi->rq[i].vq)) {
1873                         free_unused_bufs(vi);
1874                         err = -ENOMEM;
1875                         goto free_recv_bufs;
1876                 }
1877         }
1878 
1879         vi->nb.notifier_call = &virtnet_cpu_callback;
1880         err = register_hotcpu_notifier(&vi->nb);
1881         if (err) {
1882                 pr_debug("virtio_net: registering cpu notifier failed\n");
1883                 goto free_recv_bufs;
1884         }
1885 
1886         /* Assume link up if device can't report link status,
1887            otherwise get link status from config. */
1888         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1889                 netif_carrier_off(dev);
1890                 schedule_work(&vi->config_work);
1891         } else {
1892                 vi->status = VIRTIO_NET_S_LINK_UP;
1893                 netif_carrier_on(dev);
1894         }
1895 
1896         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1897                  dev->name, max_queue_pairs);
1898 
1899         return 0;
1900 
1901 free_recv_bufs:
1902         vi->vdev->config->reset(vdev);
1903 
1904         free_receive_bufs(vi);
1905         unregister_netdev(dev);
1906 free_vqs:
1907         cancel_delayed_work_sync(&vi->refill);
1908         free_receive_page_frags(vi);
1909         virtnet_del_vqs(vi);
1910 free_stats:
1911         free_percpu(vi->stats);
1912 free:
1913         free_netdev(dev);
1914         return err;
1915 }
1916 
1917 static void remove_vq_common(struct virtnet_info *vi)
1918 {
1919         vi->vdev->config->reset(vi->vdev);
1920 
1921         /* Free unused buffers in both send and recv, if any. */
1922         free_unused_bufs(vi);
1923 
1924         free_receive_bufs(vi);
1925 
1926         free_receive_page_frags(vi);
1927 
1928         virtnet_del_vqs(vi);
1929 }
1930 
1931 static void virtnet_remove(struct virtio_device *vdev)
1932 {
1933         struct virtnet_info *vi = vdev->priv;
1934 
1935         unregister_hotcpu_notifier(&vi->nb);
1936 
1937         /* Make sure no work handler is accessing the device. */
1938         flush_work(&vi->config_work);
1939 
1940         unregister_netdev(vi->dev);
1941 
1942         remove_vq_common(vi);
1943 
1944         free_percpu(vi->stats);
1945         free_netdev(vi->dev);
1946 }
1947 
1948 #ifdef CONFIG_PM_SLEEP
1949 static int virtnet_freeze(struct virtio_device *vdev)
1950 {
1951         struct virtnet_info *vi = vdev->priv;
1952         int i;
1953 
1954         unregister_hotcpu_notifier(&vi->nb);
1955 
1956         /* Make sure no work handler is accessing the device */
1957         flush_work(&vi->config_work);
1958 
1959         netif_device_detach(vi->dev);
1960         cancel_delayed_work_sync(&vi->refill);
1961 
1962         if (netif_running(vi->dev)) {
1963                 for (i = 0; i < vi->max_queue_pairs; i++)
1964                         napi_disable(&vi->rq[i].napi);
1965         }
1966 
1967         remove_vq_common(vi);
1968 
1969         return 0;
1970 }
1971 
1972 static int virtnet_restore(struct virtio_device *vdev)
1973 {
1974         struct virtnet_info *vi = vdev->priv;
1975         int err, i;
1976 
1977         err = init_vqs(vi);
1978         if (err)
1979                 return err;
1980 
1981         virtio_device_ready(vdev);
1982 
1983         if (netif_running(vi->dev)) {
1984                 for (i = 0; i < vi->curr_queue_pairs; i++)
1985                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
1986                                 schedule_delayed_work(&vi->refill, 0);
1987 
1988                 for (i = 0; i < vi->max_queue_pairs; i++)
1989                         virtnet_napi_enable(&vi->rq[i]);
1990         }
1991 
1992         netif_device_attach(vi->dev);
1993 
1994         rtnl_lock();
1995         virtnet_set_queues(vi, vi->curr_queue_pairs);
1996         rtnl_unlock();
1997 
1998         err = register_hotcpu_notifier(&vi->nb);
1999         if (err)
2000                 return err;
2001 
2002         return 0;
2003 }
2004 #endif
2005 
2006 static struct virtio_device_id id_table[] = {
2007         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2008         { 0 },
2009 };
2010 
2011 static unsigned int features[] = {
2012         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
2013         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
2014         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
2015         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
2016         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
2017         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2018         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2019         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2020         VIRTIO_NET_F_CTRL_MAC_ADDR,
2021         VIRTIO_F_ANY_LAYOUT,
2022 };
2023 
2024 static struct virtio_driver virtio_net_driver = {
2025         .feature_table = features,
2026         .feature_table_size = ARRAY_SIZE(features),
2027         .driver.name =  KBUILD_MODNAME,
2028         .driver.owner = THIS_MODULE,
2029         .id_table =     id_table,
2030         .probe =        virtnet_probe,
2031         .remove =       virtnet_remove,
2032         .config_changed = virtnet_config_changed,
2033 #ifdef CONFIG_PM_SLEEP
2034         .freeze =       virtnet_freeze,
2035         .restore =      virtnet_restore,
2036 #endif
2037 };
2038 
2039 module_virtio_driver(virtio_net_driver);
2040 
2041 MODULE_DEVICE_TABLE(virtio, id_table);
2042 MODULE_DESCRIPTION("Virtio network driver");
2043 MODULE_LICENSE("GPL");
2044 

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