Version:  2.0.40 2.2.26 2.4.37 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 4.6 4.7 4.8

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         struct virtio_net_ctrl_mq ctrl_mq;
148         u8 ctrl_promisc;
149         u8 ctrl_allmulti;
150         u16 ctrl_vid;
151 
152         /* Ethtool settings */
153         u8 duplex;
154         u32 speed;
155 };
156 
157 struct padded_vnet_hdr {
158         struct virtio_net_hdr_mrg_rxbuf hdr;
159         /*
160          * hdr is in a separate sg buffer, and data sg buffer shares same page
161          * with this header sg. This padding makes next sg 16 byte aligned
162          * after the header.
163          */
164         char padding[4];
165 };
166 
167 /* Converting between virtqueue no. and kernel tx/rx queue no.
168  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
169  */
170 static int vq2txq(struct virtqueue *vq)
171 {
172         return (vq->index - 1) / 2;
173 }
174 
175 static int txq2vq(int txq)
176 {
177         return txq * 2 + 1;
178 }
179 
180 static int vq2rxq(struct virtqueue *vq)
181 {
182         return vq->index / 2;
183 }
184 
185 static int rxq2vq(int rxq)
186 {
187         return rxq * 2;
188 }
189 
190 static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
191 {
192         return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
193 }
194 
195 /*
196  * private is used to chain pages for big packets, put the whole
197  * most recent used list in the beginning for reuse
198  */
199 static void give_pages(struct receive_queue *rq, struct page *page)
200 {
201         struct page *end;
202 
203         /* Find end of list, sew whole thing into vi->rq.pages. */
204         for (end = page; end->private; end = (struct page *)end->private);
205         end->private = (unsigned long)rq->pages;
206         rq->pages = page;
207 }
208 
209 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
210 {
211         struct page *p = rq->pages;
212 
213         if (p) {
214                 rq->pages = (struct page *)p->private;
215                 /* clear private here, it is used to chain pages */
216                 p->private = 0;
217         } else
218                 p = alloc_page(gfp_mask);
219         return p;
220 }
221 
222 static void skb_xmit_done(struct virtqueue *vq)
223 {
224         struct virtnet_info *vi = vq->vdev->priv;
225 
226         /* Suppress further interrupts. */
227         virtqueue_disable_cb(vq);
228 
229         /* We were probably waiting for more output buffers. */
230         netif_wake_subqueue(vi->dev, vq2txq(vq));
231 }
232 
233 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
234 {
235         unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
236         return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
237 }
238 
239 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
240 {
241         return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
242 
243 }
244 
245 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
246 {
247         unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
248         return (unsigned long)buf | (size - 1);
249 }
250 
251 /* Called from bottom half context */
252 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
253                                    struct receive_queue *rq,
254                                    struct page *page, unsigned int offset,
255                                    unsigned int len, unsigned int truesize)
256 {
257         struct sk_buff *skb;
258         struct virtio_net_hdr_mrg_rxbuf *hdr;
259         unsigned int copy, hdr_len, hdr_padded_len;
260         char *p;
261 
262         p = page_address(page) + offset;
263 
264         /* copy small packet so we can reuse these pages for small data */
265         skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN);
266         if (unlikely(!skb))
267                 return NULL;
268 
269         hdr = skb_vnet_hdr(skb);
270 
271         hdr_len = vi->hdr_len;
272         if (vi->mergeable_rx_bufs)
273                 hdr_padded_len = sizeof *hdr;
274         else
275                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
276 
277         memcpy(hdr, p, hdr_len);
278 
279         len -= hdr_len;
280         offset += hdr_padded_len;
281         p += hdr_padded_len;
282 
283         copy = len;
284         if (copy > skb_tailroom(skb))
285                 copy = skb_tailroom(skb);
286         memcpy(skb_put(skb, copy), p, copy);
287 
288         len -= copy;
289         offset += copy;
290 
291         if (vi->mergeable_rx_bufs) {
292                 if (len)
293                         skb_add_rx_frag(skb, 0, page, offset, len, truesize);
294                 else
295                         put_page(page);
296                 return skb;
297         }
298 
299         /*
300          * Verify that we can indeed put this data into a skb.
301          * This is here to handle cases when the device erroneously
302          * tries to receive more than is possible. This is usually
303          * the case of a broken device.
304          */
305         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
306                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
307                 dev_kfree_skb(skb);
308                 return NULL;
309         }
310         BUG_ON(offset >= PAGE_SIZE);
311         while (len) {
312                 unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
313                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
314                                 frag_size, truesize);
315                 len -= frag_size;
316                 page = (struct page *)page->private;
317                 offset = 0;
318         }
319 
320         if (page)
321                 give_pages(rq, page);
322 
323         return skb;
324 }
325 
326 static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
327 {
328         struct sk_buff * skb = buf;
329 
330         len -= vi->hdr_len;
331         skb_trim(skb, len);
332 
333         return skb;
334 }
335 
336 static struct sk_buff *receive_big(struct net_device *dev,
337                                    struct virtnet_info *vi,
338                                    struct receive_queue *rq,
339                                    void *buf,
340                                    unsigned int len)
341 {
342         struct page *page = buf;
343         struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
344 
345         if (unlikely(!skb))
346                 goto err;
347 
348         return skb;
349 
350 err:
351         dev->stats.rx_dropped++;
352         give_pages(rq, page);
353         return NULL;
354 }
355 
356 static struct sk_buff *receive_mergeable(struct net_device *dev,
357                                          struct virtnet_info *vi,
358                                          struct receive_queue *rq,
359                                          unsigned long ctx,
360                                          unsigned int len)
361 {
362         void *buf = mergeable_ctx_to_buf_address(ctx);
363         struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
364         u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
365         struct page *page = virt_to_head_page(buf);
366         int offset = buf - page_address(page);
367         unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
368 
369         struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
370                                                truesize);
371         struct sk_buff *curr_skb = head_skb;
372 
373         if (unlikely(!curr_skb))
374                 goto err_skb;
375         while (--num_buf) {
376                 int num_skb_frags;
377 
378                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
379                 if (unlikely(!ctx)) {
380                         pr_debug("%s: rx error: %d buffers out of %d missing\n",
381                                  dev->name, num_buf,
382                                  virtio16_to_cpu(vi->vdev,
383                                                  hdr->num_buffers));
384                         dev->stats.rx_length_errors++;
385                         goto err_buf;
386                 }
387 
388                 buf = mergeable_ctx_to_buf_address(ctx);
389                 page = virt_to_head_page(buf);
390 
391                 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
392                 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
393                         struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
394 
395                         if (unlikely(!nskb))
396                                 goto err_skb;
397                         if (curr_skb == head_skb)
398                                 skb_shinfo(curr_skb)->frag_list = nskb;
399                         else
400                                 curr_skb->next = nskb;
401                         curr_skb = nskb;
402                         head_skb->truesize += nskb->truesize;
403                         num_skb_frags = 0;
404                 }
405                 truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
406                 if (curr_skb != head_skb) {
407                         head_skb->data_len += len;
408                         head_skb->len += len;
409                         head_skb->truesize += truesize;
410                 }
411                 offset = buf - page_address(page);
412                 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
413                         put_page(page);
414                         skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
415                                              len, truesize);
416                 } else {
417                         skb_add_rx_frag(curr_skb, num_skb_frags, page,
418                                         offset, len, truesize);
419                 }
420         }
421 
422         ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
423         return head_skb;
424 
425 err_skb:
426         put_page(page);
427         while (--num_buf) {
428                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
429                 if (unlikely(!ctx)) {
430                         pr_debug("%s: rx error: %d buffers missing\n",
431                                  dev->name, num_buf);
432                         dev->stats.rx_length_errors++;
433                         break;
434                 }
435                 page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
436                 put_page(page);
437         }
438 err_buf:
439         dev->stats.rx_dropped++;
440         dev_kfree_skb(head_skb);
441         return NULL;
442 }
443 
444 static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
445                         void *buf, unsigned int len)
446 {
447         struct net_device *dev = vi->dev;
448         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
449         struct sk_buff *skb;
450         struct virtio_net_hdr_mrg_rxbuf *hdr;
451 
452         if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
453                 pr_debug("%s: short packet %i\n", dev->name, len);
454                 dev->stats.rx_length_errors++;
455                 if (vi->mergeable_rx_bufs) {
456                         unsigned long ctx = (unsigned long)buf;
457                         void *base = mergeable_ctx_to_buf_address(ctx);
458                         put_page(virt_to_head_page(base));
459                 } else if (vi->big_packets) {
460                         give_pages(rq, buf);
461                 } else {
462                         dev_kfree_skb(buf);
463                 }
464                 return;
465         }
466 
467         if (vi->mergeable_rx_bufs)
468                 skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
469         else if (vi->big_packets)
470                 skb = receive_big(dev, vi, rq, buf, len);
471         else
472                 skb = receive_small(vi, buf, len);
473 
474         if (unlikely(!skb))
475                 return;
476 
477         hdr = skb_vnet_hdr(skb);
478 
479         u64_stats_update_begin(&stats->rx_syncp);
480         stats->rx_bytes += skb->len;
481         stats->rx_packets++;
482         u64_stats_update_end(&stats->rx_syncp);
483 
484         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
485                 skb->ip_summed = CHECKSUM_UNNECESSARY;
486 
487         if (virtio_net_hdr_to_skb(skb, &hdr->hdr,
488                                   virtio_is_little_endian(vi->vdev))) {
489                 net_warn_ratelimited("%s: bad gso: type: %u, size: %u\n",
490                                      dev->name, hdr->hdr.gso_type,
491                                      hdr->hdr.gso_size);
492                 goto frame_err;
493         }
494 
495         skb->protocol = eth_type_trans(skb, dev);
496         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
497                  ntohs(skb->protocol), skb->len, skb->pkt_type);
498 
499         napi_gro_receive(&rq->napi, skb);
500         return;
501 
502 frame_err:
503         dev->stats.rx_frame_errors++;
504         dev_kfree_skb(skb);
505 }
506 
507 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
508                              gfp_t gfp)
509 {
510         struct sk_buff *skb;
511         struct virtio_net_hdr_mrg_rxbuf *hdr;
512         int err;
513 
514         skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
515         if (unlikely(!skb))
516                 return -ENOMEM;
517 
518         skb_put(skb, GOOD_PACKET_LEN);
519 
520         hdr = skb_vnet_hdr(skb);
521         sg_init_table(rq->sg, 2);
522         sg_set_buf(rq->sg, hdr, vi->hdr_len);
523         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
524 
525         err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
526         if (err < 0)
527                 dev_kfree_skb(skb);
528 
529         return err;
530 }
531 
532 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
533                            gfp_t gfp)
534 {
535         struct page *first, *list = NULL;
536         char *p;
537         int i, err, offset;
538 
539         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
540 
541         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
542         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
543                 first = get_a_page(rq, gfp);
544                 if (!first) {
545                         if (list)
546                                 give_pages(rq, list);
547                         return -ENOMEM;
548                 }
549                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
550 
551                 /* chain new page in list head to match sg */
552                 first->private = (unsigned long)list;
553                 list = first;
554         }
555 
556         first = get_a_page(rq, gfp);
557         if (!first) {
558                 give_pages(rq, list);
559                 return -ENOMEM;
560         }
561         p = page_address(first);
562 
563         /* rq->sg[0], rq->sg[1] share the same page */
564         /* a separated rq->sg[0] for header - required in case !any_header_sg */
565         sg_set_buf(&rq->sg[0], p, vi->hdr_len);
566 
567         /* rq->sg[1] for data packet, from offset */
568         offset = sizeof(struct padded_vnet_hdr);
569         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
570 
571         /* chain first in list head */
572         first->private = (unsigned long)list;
573         err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
574                                   first, gfp);
575         if (err < 0)
576                 give_pages(rq, first);
577 
578         return err;
579 }
580 
581 static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
582 {
583         const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
584         unsigned int len;
585 
586         len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
587                         GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
588         return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
589 }
590 
591 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
592 {
593         struct page_frag *alloc_frag = &rq->alloc_frag;
594         char *buf;
595         unsigned long ctx;
596         int err;
597         unsigned int len, hole;
598 
599         len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
600         if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
601                 return -ENOMEM;
602 
603         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
604         ctx = mergeable_buf_to_ctx(buf, len);
605         get_page(alloc_frag->page);
606         alloc_frag->offset += len;
607         hole = alloc_frag->size - alloc_frag->offset;
608         if (hole < len) {
609                 /* To avoid internal fragmentation, if there is very likely not
610                  * enough space for another buffer, add the remaining space to
611                  * the current buffer. This extra space is not included in
612                  * the truesize stored in ctx.
613                  */
614                 len += hole;
615                 alloc_frag->offset += hole;
616         }
617 
618         sg_init_one(rq->sg, buf, len);
619         err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
620         if (err < 0)
621                 put_page(virt_to_head_page(buf));
622 
623         return err;
624 }
625 
626 /*
627  * Returns false if we couldn't fill entirely (OOM).
628  *
629  * Normally run in the receive path, but can also be run from ndo_open
630  * before we're receiving packets, or from refill_work which is
631  * careful to disable receiving (using napi_disable).
632  */
633 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
634                           gfp_t gfp)
635 {
636         int err;
637         bool oom;
638 
639         gfp |= __GFP_COLD;
640         do {
641                 if (vi->mergeable_rx_bufs)
642                         err = add_recvbuf_mergeable(rq, gfp);
643                 else if (vi->big_packets)
644                         err = add_recvbuf_big(vi, rq, gfp);
645                 else
646                         err = add_recvbuf_small(vi, rq, gfp);
647 
648                 oom = err == -ENOMEM;
649                 if (err)
650                         break;
651         } while (rq->vq->num_free);
652         virtqueue_kick(rq->vq);
653         return !oom;
654 }
655 
656 static void skb_recv_done(struct virtqueue *rvq)
657 {
658         struct virtnet_info *vi = rvq->vdev->priv;
659         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
660 
661         /* Schedule NAPI, Suppress further interrupts if successful. */
662         if (napi_schedule_prep(&rq->napi)) {
663                 virtqueue_disable_cb(rvq);
664                 __napi_schedule(&rq->napi);
665         }
666 }
667 
668 static void virtnet_napi_enable(struct receive_queue *rq)
669 {
670         napi_enable(&rq->napi);
671 
672         /* If all buffers were filled by other side before we napi_enabled, we
673          * won't get another interrupt, so process any outstanding packets
674          * now.  virtnet_poll wants re-enable the queue, so we disable here.
675          * We synchronize against interrupts via NAPI_STATE_SCHED */
676         if (napi_schedule_prep(&rq->napi)) {
677                 virtqueue_disable_cb(rq->vq);
678                 local_bh_disable();
679                 __napi_schedule(&rq->napi);
680                 local_bh_enable();
681         }
682 }
683 
684 static void refill_work(struct work_struct *work)
685 {
686         struct virtnet_info *vi =
687                 container_of(work, struct virtnet_info, refill.work);
688         bool still_empty;
689         int i;
690 
691         for (i = 0; i < vi->curr_queue_pairs; i++) {
692                 struct receive_queue *rq = &vi->rq[i];
693 
694                 napi_disable(&rq->napi);
695                 still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
696                 virtnet_napi_enable(rq);
697 
698                 /* In theory, this can happen: if we don't get any buffers in
699                  * we will *never* try to fill again.
700                  */
701                 if (still_empty)
702                         schedule_delayed_work(&vi->refill, HZ/2);
703         }
704 }
705 
706 static int virtnet_receive(struct receive_queue *rq, int budget)
707 {
708         struct virtnet_info *vi = rq->vq->vdev->priv;
709         unsigned int len, received = 0;
710         void *buf;
711 
712         while (received < budget &&
713                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
714                 receive_buf(vi, rq, buf, len);
715                 received++;
716         }
717 
718         if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
719                 if (!try_fill_recv(vi, rq, GFP_ATOMIC))
720                         schedule_delayed_work(&vi->refill, 0);
721         }
722 
723         return received;
724 }
725 
726 static int virtnet_poll(struct napi_struct *napi, int budget)
727 {
728         struct receive_queue *rq =
729                 container_of(napi, struct receive_queue, napi);
730         unsigned int r, received;
731 
732         received = virtnet_receive(rq, budget);
733 
734         /* Out of packets? */
735         if (received < budget) {
736                 r = virtqueue_enable_cb_prepare(rq->vq);
737                 napi_complete_done(napi, received);
738                 if (unlikely(virtqueue_poll(rq->vq, r)) &&
739                     napi_schedule_prep(napi)) {
740                         virtqueue_disable_cb(rq->vq);
741                         __napi_schedule(napi);
742                 }
743         }
744 
745         return received;
746 }
747 
748 #ifdef CONFIG_NET_RX_BUSY_POLL
749 /* must be called with local_bh_disable()d */
750 static int virtnet_busy_poll(struct napi_struct *napi)
751 {
752         struct receive_queue *rq =
753                 container_of(napi, struct receive_queue, napi);
754         struct virtnet_info *vi = rq->vq->vdev->priv;
755         int r, received = 0, budget = 4;
756 
757         if (!(vi->status & VIRTIO_NET_S_LINK_UP))
758                 return LL_FLUSH_FAILED;
759 
760         if (!napi_schedule_prep(napi))
761                 return LL_FLUSH_BUSY;
762 
763         virtqueue_disable_cb(rq->vq);
764 
765 again:
766         received += virtnet_receive(rq, budget);
767 
768         r = virtqueue_enable_cb_prepare(rq->vq);
769         clear_bit(NAPI_STATE_SCHED, &napi->state);
770         if (unlikely(virtqueue_poll(rq->vq, r)) &&
771             napi_schedule_prep(napi)) {
772                 virtqueue_disable_cb(rq->vq);
773                 if (received < budget) {
774                         budget -= received;
775                         goto again;
776                 } else {
777                         __napi_schedule(napi);
778                 }
779         }
780 
781         return received;
782 }
783 #endif  /* CONFIG_NET_RX_BUSY_POLL */
784 
785 static int virtnet_open(struct net_device *dev)
786 {
787         struct virtnet_info *vi = netdev_priv(dev);
788         int i;
789 
790         for (i = 0; i < vi->max_queue_pairs; i++) {
791                 if (i < vi->curr_queue_pairs)
792                         /* Make sure we have some buffers: if oom use wq. */
793                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
794                                 schedule_delayed_work(&vi->refill, 0);
795                 virtnet_napi_enable(&vi->rq[i]);
796         }
797 
798         return 0;
799 }
800 
801 static void free_old_xmit_skbs(struct send_queue *sq)
802 {
803         struct sk_buff *skb;
804         unsigned int len;
805         struct virtnet_info *vi = sq->vq->vdev->priv;
806         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
807 
808         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
809                 pr_debug("Sent skb %p\n", skb);
810 
811                 u64_stats_update_begin(&stats->tx_syncp);
812                 stats->tx_bytes += skb->len;
813                 stats->tx_packets++;
814                 u64_stats_update_end(&stats->tx_syncp);
815 
816                 dev_kfree_skb_any(skb);
817         }
818 }
819 
820 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
821 {
822         struct virtio_net_hdr_mrg_rxbuf *hdr;
823         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
824         struct virtnet_info *vi = sq->vq->vdev->priv;
825         unsigned num_sg;
826         unsigned hdr_len = vi->hdr_len;
827         bool can_push;
828 
829         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
830 
831         can_push = vi->any_header_sg &&
832                 !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
833                 !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
834         /* Even if we can, don't push here yet as this would skew
835          * csum_start offset below. */
836         if (can_push)
837                 hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
838         else
839                 hdr = skb_vnet_hdr(skb);
840 
841         if (virtio_net_hdr_from_skb(skb, &hdr->hdr,
842                                     virtio_is_little_endian(vi->vdev)))
843                 BUG();
844 
845         if (vi->mergeable_rx_bufs)
846                 hdr->num_buffers = 0;
847 
848         sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
849         if (can_push) {
850                 __skb_push(skb, hdr_len);
851                 num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
852                 /* Pull header back to avoid skew in tx bytes calculations. */
853                 __skb_pull(skb, hdr_len);
854         } else {
855                 sg_set_buf(sq->sg, hdr, hdr_len);
856                 num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
857         }
858         return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
859 }
860 
861 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
862 {
863         struct virtnet_info *vi = netdev_priv(dev);
864         int qnum = skb_get_queue_mapping(skb);
865         struct send_queue *sq = &vi->sq[qnum];
866         int err;
867         struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
868         bool kick = !skb->xmit_more;
869 
870         /* Free up any pending old buffers before queueing new ones. */
871         free_old_xmit_skbs(sq);
872 
873         /* timestamp packet in software */
874         skb_tx_timestamp(skb);
875 
876         /* Try to transmit */
877         err = xmit_skb(sq, skb);
878 
879         /* This should not happen! */
880         if (unlikely(err)) {
881                 dev->stats.tx_fifo_errors++;
882                 if (net_ratelimit())
883                         dev_warn(&dev->dev,
884                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
885                 dev->stats.tx_dropped++;
886                 dev_kfree_skb_any(skb);
887                 return NETDEV_TX_OK;
888         }
889 
890         /* Don't wait up for transmitted skbs to be freed. */
891         skb_orphan(skb);
892         nf_reset(skb);
893 
894         /* If running out of space, stop queue to avoid getting packets that we
895          * are then unable to transmit.
896          * An alternative would be to force queuing layer to requeue the skb by
897          * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
898          * returned in a normal path of operation: it means that driver is not
899          * maintaining the TX queue stop/start state properly, and causes
900          * the stack to do a non-trivial amount of useless work.
901          * Since most packets only take 1 or 2 ring slots, stopping the queue
902          * early means 16 slots are typically wasted.
903          */
904         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
905                 netif_stop_subqueue(dev, qnum);
906                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
907                         /* More just got used, free them then recheck. */
908                         free_old_xmit_skbs(sq);
909                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
910                                 netif_start_subqueue(dev, qnum);
911                                 virtqueue_disable_cb(sq->vq);
912                         }
913                 }
914         }
915 
916         if (kick || netif_xmit_stopped(txq))
917                 virtqueue_kick(sq->vq);
918 
919         return NETDEV_TX_OK;
920 }
921 
922 /*
923  * Send command via the control virtqueue and check status.  Commands
924  * supported by the hypervisor, as indicated by feature bits, should
925  * never fail unless improperly formatted.
926  */
927 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
928                                  struct scatterlist *out)
929 {
930         struct scatterlist *sgs[4], hdr, stat;
931         unsigned out_num = 0, tmp;
932 
933         /* Caller should know better */
934         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
935 
936         vi->ctrl_status = ~0;
937         vi->ctrl_hdr.class = class;
938         vi->ctrl_hdr.cmd = cmd;
939         /* Add header */
940         sg_init_one(&hdr, &vi->ctrl_hdr, sizeof(vi->ctrl_hdr));
941         sgs[out_num++] = &hdr;
942 
943         if (out)
944                 sgs[out_num++] = out;
945 
946         /* Add return status. */
947         sg_init_one(&stat, &vi->ctrl_status, sizeof(vi->ctrl_status));
948         sgs[out_num] = &stat;
949 
950         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
951         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
952 
953         if (unlikely(!virtqueue_kick(vi->cvq)))
954                 return vi->ctrl_status == VIRTIO_NET_OK;
955 
956         /* Spin for a response, the kick causes an ioport write, trapping
957          * into the hypervisor, so the request should be handled immediately.
958          */
959         while (!virtqueue_get_buf(vi->cvq, &tmp) &&
960                !virtqueue_is_broken(vi->cvq))
961                 cpu_relax();
962 
963         return vi->ctrl_status == VIRTIO_NET_OK;
964 }
965 
966 static int virtnet_set_mac_address(struct net_device *dev, void *p)
967 {
968         struct virtnet_info *vi = netdev_priv(dev);
969         struct virtio_device *vdev = vi->vdev;
970         int ret;
971         struct sockaddr *addr = p;
972         struct scatterlist sg;
973 
974         ret = eth_prepare_mac_addr_change(dev, p);
975         if (ret)
976                 return ret;
977 
978         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
979                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
980                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
981                                           VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
982                         dev_warn(&vdev->dev,
983                                  "Failed to set mac address by vq command.\n");
984                         return -EINVAL;
985                 }
986         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
987                    !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
988                 unsigned int i;
989 
990                 /* Naturally, this has an atomicity problem. */
991                 for (i = 0; i < dev->addr_len; i++)
992                         virtio_cwrite8(vdev,
993                                        offsetof(struct virtio_net_config, mac) +
994                                        i, addr->sa_data[i]);
995         }
996 
997         eth_commit_mac_addr_change(dev, p);
998 
999         return 0;
1000 }
1001 
1002 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1003                                                struct rtnl_link_stats64 *tot)
1004 {
1005         struct virtnet_info *vi = netdev_priv(dev);
1006         int cpu;
1007         unsigned int start;
1008 
1009         for_each_possible_cpu(cpu) {
1010                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1011                 u64 tpackets, tbytes, rpackets, rbytes;
1012 
1013                 do {
1014                         start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1015                         tpackets = stats->tx_packets;
1016                         tbytes   = stats->tx_bytes;
1017                 } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1018 
1019                 do {
1020                         start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1021                         rpackets = stats->rx_packets;
1022                         rbytes   = stats->rx_bytes;
1023                 } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1024 
1025                 tot->rx_packets += rpackets;
1026                 tot->tx_packets += tpackets;
1027                 tot->rx_bytes   += rbytes;
1028                 tot->tx_bytes   += tbytes;
1029         }
1030 
1031         tot->tx_dropped = dev->stats.tx_dropped;
1032         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1033         tot->rx_dropped = dev->stats.rx_dropped;
1034         tot->rx_length_errors = dev->stats.rx_length_errors;
1035         tot->rx_frame_errors = dev->stats.rx_frame_errors;
1036 
1037         return tot;
1038 }
1039 
1040 #ifdef CONFIG_NET_POLL_CONTROLLER
1041 static void virtnet_netpoll(struct net_device *dev)
1042 {
1043         struct virtnet_info *vi = netdev_priv(dev);
1044         int i;
1045 
1046         for (i = 0; i < vi->curr_queue_pairs; i++)
1047                 napi_schedule(&vi->rq[i].napi);
1048 }
1049 #endif
1050 
1051 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1052 {
1053         rtnl_lock();
1054         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1055                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1056                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1057         rtnl_unlock();
1058 }
1059 
1060 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1061 {
1062         struct scatterlist sg;
1063         struct net_device *dev = vi->dev;
1064 
1065         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1066                 return 0;
1067 
1068         vi->ctrl_mq.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1069         sg_init_one(&sg, &vi->ctrl_mq, sizeof(vi->ctrl_mq));
1070 
1071         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1072                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1073                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1074                          queue_pairs);
1075                 return -EINVAL;
1076         } else {
1077                 vi->curr_queue_pairs = queue_pairs;
1078                 /* virtnet_open() will refill when device is going to up. */
1079                 if (dev->flags & IFF_UP)
1080                         schedule_delayed_work(&vi->refill, 0);
1081         }
1082 
1083         return 0;
1084 }
1085 
1086 static int virtnet_close(struct net_device *dev)
1087 {
1088         struct virtnet_info *vi = netdev_priv(dev);
1089         int i;
1090 
1091         /* Make sure refill_work doesn't re-enable napi! */
1092         cancel_delayed_work_sync(&vi->refill);
1093 
1094         for (i = 0; i < vi->max_queue_pairs; i++)
1095                 napi_disable(&vi->rq[i].napi);
1096 
1097         return 0;
1098 }
1099 
1100 static void virtnet_set_rx_mode(struct net_device *dev)
1101 {
1102         struct virtnet_info *vi = netdev_priv(dev);
1103         struct scatterlist sg[2];
1104         struct virtio_net_ctrl_mac *mac_data;
1105         struct netdev_hw_addr *ha;
1106         int uc_count;
1107         int mc_count;
1108         void *buf;
1109         int i;
1110 
1111         /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1112         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1113                 return;
1114 
1115         vi->ctrl_promisc = ((dev->flags & IFF_PROMISC) != 0);
1116         vi->ctrl_allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1117 
1118         sg_init_one(sg, &vi->ctrl_promisc, sizeof(vi->ctrl_promisc));
1119 
1120         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1121                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
1122                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1123                          vi->ctrl_promisc ? "en" : "dis");
1124 
1125         sg_init_one(sg, &vi->ctrl_allmulti, sizeof(vi->ctrl_allmulti));
1126 
1127         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1128                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1129                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1130                          vi->ctrl_allmulti ? "en" : "dis");
1131 
1132         uc_count = netdev_uc_count(dev);
1133         mc_count = netdev_mc_count(dev);
1134         /* MAC filter - use one buffer for both lists */
1135         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1136                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1137         mac_data = buf;
1138         if (!buf)
1139                 return;
1140 
1141         sg_init_table(sg, 2);
1142 
1143         /* Store the unicast list and count in the front of the buffer */
1144         mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1145         i = 0;
1146         netdev_for_each_uc_addr(ha, dev)
1147                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1148 
1149         sg_set_buf(&sg[0], mac_data,
1150                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1151 
1152         /* multicast list and count fill the end */
1153         mac_data = (void *)&mac_data->macs[uc_count][0];
1154 
1155         mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1156         i = 0;
1157         netdev_for_each_mc_addr(ha, dev)
1158                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1159 
1160         sg_set_buf(&sg[1], mac_data,
1161                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1162 
1163         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1164                                   VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1165                 dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1166 
1167         kfree(buf);
1168 }
1169 
1170 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1171                                    __be16 proto, u16 vid)
1172 {
1173         struct virtnet_info *vi = netdev_priv(dev);
1174         struct scatterlist sg;
1175 
1176         vi->ctrl_vid = vid;
1177         sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
1178 
1179         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1180                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1181                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1182         return 0;
1183 }
1184 
1185 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1186                                     __be16 proto, u16 vid)
1187 {
1188         struct virtnet_info *vi = netdev_priv(dev);
1189         struct scatterlist sg;
1190 
1191         vi->ctrl_vid = vid;
1192         sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
1193 
1194         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1195                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1196                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1197         return 0;
1198 }
1199 
1200 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1201 {
1202         int i;
1203 
1204         if (vi->affinity_hint_set) {
1205                 for (i = 0; i < vi->max_queue_pairs; i++) {
1206                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1207                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1208                 }
1209 
1210                 vi->affinity_hint_set = false;
1211         }
1212 }
1213 
1214 static void virtnet_set_affinity(struct virtnet_info *vi)
1215 {
1216         int i;
1217         int cpu;
1218 
1219         /* In multiqueue mode, when the number of cpu is equal to the number of
1220          * queue pairs, we let the queue pairs to be private to one cpu by
1221          * setting the affinity hint to eliminate the contention.
1222          */
1223         if (vi->curr_queue_pairs == 1 ||
1224             vi->max_queue_pairs != num_online_cpus()) {
1225                 virtnet_clean_affinity(vi, -1);
1226                 return;
1227         }
1228 
1229         i = 0;
1230         for_each_online_cpu(cpu) {
1231                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1232                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1233                 netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1234                 i++;
1235         }
1236 
1237         vi->affinity_hint_set = true;
1238 }
1239 
1240 static int virtnet_cpu_callback(struct notifier_block *nfb,
1241                                 unsigned long action, void *hcpu)
1242 {
1243         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1244 
1245         switch(action & ~CPU_TASKS_FROZEN) {
1246         case CPU_ONLINE:
1247         case CPU_DOWN_FAILED:
1248         case CPU_DEAD:
1249                 virtnet_set_affinity(vi);
1250                 break;
1251         case CPU_DOWN_PREPARE:
1252                 virtnet_clean_affinity(vi, (long)hcpu);
1253                 break;
1254         default:
1255                 break;
1256         }
1257 
1258         return NOTIFY_OK;
1259 }
1260 
1261 static void virtnet_get_ringparam(struct net_device *dev,
1262                                 struct ethtool_ringparam *ring)
1263 {
1264         struct virtnet_info *vi = netdev_priv(dev);
1265 
1266         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1267         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1268         ring->rx_pending = ring->rx_max_pending;
1269         ring->tx_pending = ring->tx_max_pending;
1270 }
1271 
1272 
1273 static void virtnet_get_drvinfo(struct net_device *dev,
1274                                 struct ethtool_drvinfo *info)
1275 {
1276         struct virtnet_info *vi = netdev_priv(dev);
1277         struct virtio_device *vdev = vi->vdev;
1278 
1279         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1280         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1281         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1282 
1283 }
1284 
1285 /* TODO: Eliminate OOO packets during switching */
1286 static int virtnet_set_channels(struct net_device *dev,
1287                                 struct ethtool_channels *channels)
1288 {
1289         struct virtnet_info *vi = netdev_priv(dev);
1290         u16 queue_pairs = channels->combined_count;
1291         int err;
1292 
1293         /* We don't support separate rx/tx channels.
1294          * We don't allow setting 'other' channels.
1295          */
1296         if (channels->rx_count || channels->tx_count || channels->other_count)
1297                 return -EINVAL;
1298 
1299         if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1300                 return -EINVAL;
1301 
1302         get_online_cpus();
1303         err = virtnet_set_queues(vi, queue_pairs);
1304         if (!err) {
1305                 netif_set_real_num_tx_queues(dev, queue_pairs);
1306                 netif_set_real_num_rx_queues(dev, queue_pairs);
1307 
1308                 virtnet_set_affinity(vi);
1309         }
1310         put_online_cpus();
1311 
1312         return err;
1313 }
1314 
1315 static void virtnet_get_channels(struct net_device *dev,
1316                                  struct ethtool_channels *channels)
1317 {
1318         struct virtnet_info *vi = netdev_priv(dev);
1319 
1320         channels->combined_count = vi->curr_queue_pairs;
1321         channels->max_combined = vi->max_queue_pairs;
1322         channels->max_other = 0;
1323         channels->rx_count = 0;
1324         channels->tx_count = 0;
1325         channels->other_count = 0;
1326 }
1327 
1328 /* Check if the user is trying to change anything besides speed/duplex */
1329 static bool virtnet_validate_ethtool_cmd(const struct ethtool_cmd *cmd)
1330 {
1331         struct ethtool_cmd diff1 = *cmd;
1332         struct ethtool_cmd diff2 = {};
1333 
1334         /* cmd is always set so we need to clear it, validate the port type
1335          * and also without autonegotiation we can ignore advertising
1336          */
1337         ethtool_cmd_speed_set(&diff1, 0);
1338         diff2.port = PORT_OTHER;
1339         diff1.advertising = 0;
1340         diff1.duplex = 0;
1341         diff1.cmd = 0;
1342 
1343         return !memcmp(&diff1, &diff2, sizeof(diff1));
1344 }
1345 
1346 static int virtnet_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1347 {
1348         struct virtnet_info *vi = netdev_priv(dev);
1349         u32 speed;
1350 
1351         speed = ethtool_cmd_speed(cmd);
1352         /* don't allow custom speed and duplex */
1353         if (!ethtool_validate_speed(speed) ||
1354             !ethtool_validate_duplex(cmd->duplex) ||
1355             !virtnet_validate_ethtool_cmd(cmd))
1356                 return -EINVAL;
1357         vi->speed = speed;
1358         vi->duplex = cmd->duplex;
1359 
1360         return 0;
1361 }
1362 
1363 static int virtnet_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1364 {
1365         struct virtnet_info *vi = netdev_priv(dev);
1366 
1367         ethtool_cmd_speed_set(cmd, vi->speed);
1368         cmd->duplex = vi->duplex;
1369         cmd->port = PORT_OTHER;
1370 
1371         return 0;
1372 }
1373 
1374 static void virtnet_init_settings(struct net_device *dev)
1375 {
1376         struct virtnet_info *vi = netdev_priv(dev);
1377 
1378         vi->speed = SPEED_UNKNOWN;
1379         vi->duplex = DUPLEX_UNKNOWN;
1380 }
1381 
1382 static const struct ethtool_ops virtnet_ethtool_ops = {
1383         .get_drvinfo = virtnet_get_drvinfo,
1384         .get_link = ethtool_op_get_link,
1385         .get_ringparam = virtnet_get_ringparam,
1386         .set_channels = virtnet_set_channels,
1387         .get_channels = virtnet_get_channels,
1388         .get_ts_info = ethtool_op_get_ts_info,
1389         .get_settings = virtnet_get_settings,
1390         .set_settings = virtnet_set_settings,
1391 };
1392 
1393 #define MIN_MTU 68
1394 #define MAX_MTU 65535
1395 
1396 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1397 {
1398         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1399                 return -EINVAL;
1400         dev->mtu = new_mtu;
1401         return 0;
1402 }
1403 
1404 static const struct net_device_ops virtnet_netdev = {
1405         .ndo_open            = virtnet_open,
1406         .ndo_stop            = virtnet_close,
1407         .ndo_start_xmit      = start_xmit,
1408         .ndo_validate_addr   = eth_validate_addr,
1409         .ndo_set_mac_address = virtnet_set_mac_address,
1410         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1411         .ndo_change_mtu      = virtnet_change_mtu,
1412         .ndo_get_stats64     = virtnet_stats,
1413         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1414         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1415 #ifdef CONFIG_NET_POLL_CONTROLLER
1416         .ndo_poll_controller = virtnet_netpoll,
1417 #endif
1418 #ifdef CONFIG_NET_RX_BUSY_POLL
1419         .ndo_busy_poll          = virtnet_busy_poll,
1420 #endif
1421 };
1422 
1423 static void virtnet_config_changed_work(struct work_struct *work)
1424 {
1425         struct virtnet_info *vi =
1426                 container_of(work, struct virtnet_info, config_work);
1427         u16 v;
1428 
1429         if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1430                                  struct virtio_net_config, status, &v) < 0)
1431                 return;
1432 
1433         if (v & VIRTIO_NET_S_ANNOUNCE) {
1434                 netdev_notify_peers(vi->dev);
1435                 virtnet_ack_link_announce(vi);
1436         }
1437 
1438         /* Ignore unknown (future) status bits */
1439         v &= VIRTIO_NET_S_LINK_UP;
1440 
1441         if (vi->status == v)
1442                 return;
1443 
1444         vi->status = v;
1445 
1446         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1447                 netif_carrier_on(vi->dev);
1448                 netif_tx_wake_all_queues(vi->dev);
1449         } else {
1450                 netif_carrier_off(vi->dev);
1451                 netif_tx_stop_all_queues(vi->dev);
1452         }
1453 }
1454 
1455 static void virtnet_config_changed(struct virtio_device *vdev)
1456 {
1457         struct virtnet_info *vi = vdev->priv;
1458 
1459         schedule_work(&vi->config_work);
1460 }
1461 
1462 static void virtnet_free_queues(struct virtnet_info *vi)
1463 {
1464         int i;
1465 
1466         for (i = 0; i < vi->max_queue_pairs; i++) {
1467                 napi_hash_del(&vi->rq[i].napi);
1468                 netif_napi_del(&vi->rq[i].napi);
1469         }
1470 
1471         kfree(vi->rq);
1472         kfree(vi->sq);
1473 }
1474 
1475 static void free_receive_bufs(struct virtnet_info *vi)
1476 {
1477         int i;
1478 
1479         for (i = 0; i < vi->max_queue_pairs; i++) {
1480                 while (vi->rq[i].pages)
1481                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1482         }
1483 }
1484 
1485 static void free_receive_page_frags(struct virtnet_info *vi)
1486 {
1487         int i;
1488         for (i = 0; i < vi->max_queue_pairs; i++)
1489                 if (vi->rq[i].alloc_frag.page)
1490                         put_page(vi->rq[i].alloc_frag.page);
1491 }
1492 
1493 static void free_unused_bufs(struct virtnet_info *vi)
1494 {
1495         void *buf;
1496         int i;
1497 
1498         for (i = 0; i < vi->max_queue_pairs; i++) {
1499                 struct virtqueue *vq = vi->sq[i].vq;
1500                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1501                         dev_kfree_skb(buf);
1502         }
1503 
1504         for (i = 0; i < vi->max_queue_pairs; i++) {
1505                 struct virtqueue *vq = vi->rq[i].vq;
1506 
1507                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1508                         if (vi->mergeable_rx_bufs) {
1509                                 unsigned long ctx = (unsigned long)buf;
1510                                 void *base = mergeable_ctx_to_buf_address(ctx);
1511                                 put_page(virt_to_head_page(base));
1512                         } else if (vi->big_packets) {
1513                                 give_pages(&vi->rq[i], buf);
1514                         } else {
1515                                 dev_kfree_skb(buf);
1516                         }
1517                 }
1518         }
1519 }
1520 
1521 static void virtnet_del_vqs(struct virtnet_info *vi)
1522 {
1523         struct virtio_device *vdev = vi->vdev;
1524 
1525         virtnet_clean_affinity(vi, -1);
1526 
1527         vdev->config->del_vqs(vdev);
1528 
1529         virtnet_free_queues(vi);
1530 }
1531 
1532 static int virtnet_find_vqs(struct virtnet_info *vi)
1533 {
1534         vq_callback_t **callbacks;
1535         struct virtqueue **vqs;
1536         int ret = -ENOMEM;
1537         int i, total_vqs;
1538         const char **names;
1539 
1540         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1541          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1542          * possible control vq.
1543          */
1544         total_vqs = vi->max_queue_pairs * 2 +
1545                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1546 
1547         /* Allocate space for find_vqs parameters */
1548         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1549         if (!vqs)
1550                 goto err_vq;
1551         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1552         if (!callbacks)
1553                 goto err_callback;
1554         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1555         if (!names)
1556                 goto err_names;
1557 
1558         /* Parameters for control virtqueue, if any */
1559         if (vi->has_cvq) {
1560                 callbacks[total_vqs - 1] = NULL;
1561                 names[total_vqs - 1] = "control";
1562         }
1563 
1564         /* Allocate/initialize parameters for send/receive virtqueues */
1565         for (i = 0; i < vi->max_queue_pairs; i++) {
1566                 callbacks[rxq2vq(i)] = skb_recv_done;
1567                 callbacks[txq2vq(i)] = skb_xmit_done;
1568                 sprintf(vi->rq[i].name, "input.%d", i);
1569                 sprintf(vi->sq[i].name, "output.%d", i);
1570                 names[rxq2vq(i)] = vi->rq[i].name;
1571                 names[txq2vq(i)] = vi->sq[i].name;
1572         }
1573 
1574         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1575                                          names);
1576         if (ret)
1577                 goto err_find;
1578 
1579         if (vi->has_cvq) {
1580                 vi->cvq = vqs[total_vqs - 1];
1581                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1582                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1583         }
1584 
1585         for (i = 0; i < vi->max_queue_pairs; i++) {
1586                 vi->rq[i].vq = vqs[rxq2vq(i)];
1587                 vi->sq[i].vq = vqs[txq2vq(i)];
1588         }
1589 
1590         kfree(names);
1591         kfree(callbacks);
1592         kfree(vqs);
1593 
1594         return 0;
1595 
1596 err_find:
1597         kfree(names);
1598 err_names:
1599         kfree(callbacks);
1600 err_callback:
1601         kfree(vqs);
1602 err_vq:
1603         return ret;
1604 }
1605 
1606 static int virtnet_alloc_queues(struct virtnet_info *vi)
1607 {
1608         int i;
1609 
1610         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1611         if (!vi->sq)
1612                 goto err_sq;
1613         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1614         if (!vi->rq)
1615                 goto err_rq;
1616 
1617         INIT_DELAYED_WORK(&vi->refill, refill_work);
1618         for (i = 0; i < vi->max_queue_pairs; i++) {
1619                 vi->rq[i].pages = NULL;
1620                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1621                                napi_weight);
1622 
1623                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1624                 ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
1625                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1626         }
1627 
1628         return 0;
1629 
1630 err_rq:
1631         kfree(vi->sq);
1632 err_sq:
1633         return -ENOMEM;
1634 }
1635 
1636 static int init_vqs(struct virtnet_info *vi)
1637 {
1638         int ret;
1639 
1640         /* Allocate send & receive queues */
1641         ret = virtnet_alloc_queues(vi);
1642         if (ret)
1643                 goto err;
1644 
1645         ret = virtnet_find_vqs(vi);
1646         if (ret)
1647                 goto err_free;
1648 
1649         get_online_cpus();
1650         virtnet_set_affinity(vi);
1651         put_online_cpus();
1652 
1653         return 0;
1654 
1655 err_free:
1656         virtnet_free_queues(vi);
1657 err:
1658         return ret;
1659 }
1660 
1661 #ifdef CONFIG_SYSFS
1662 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1663                 struct rx_queue_attribute *attribute, char *buf)
1664 {
1665         struct virtnet_info *vi = netdev_priv(queue->dev);
1666         unsigned int queue_index = get_netdev_rx_queue_index(queue);
1667         struct ewma_pkt_len *avg;
1668 
1669         BUG_ON(queue_index >= vi->max_queue_pairs);
1670         avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1671         return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1672 }
1673 
1674 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1675         __ATTR_RO(mergeable_rx_buffer_size);
1676 
1677 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1678         &mergeable_rx_buffer_size_attribute.attr,
1679         NULL
1680 };
1681 
1682 static const struct attribute_group virtio_net_mrg_rx_group = {
1683         .name = "virtio_net",
1684         .attrs = virtio_net_mrg_rx_attrs
1685 };
1686 #endif
1687 
1688 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1689                                     unsigned int fbit,
1690                                     const char *fname, const char *dname)
1691 {
1692         if (!virtio_has_feature(vdev, fbit))
1693                 return false;
1694 
1695         dev_err(&vdev->dev, "device advertises feature %s but not %s",
1696                 fname, dname);
1697 
1698         return true;
1699 }
1700 
1701 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
1702         virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1703 
1704 static bool virtnet_validate_features(struct virtio_device *vdev)
1705 {
1706         if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1707             (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1708                              "VIRTIO_NET_F_CTRL_VQ") ||
1709              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1710                              "VIRTIO_NET_F_CTRL_VQ") ||
1711              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1712                              "VIRTIO_NET_F_CTRL_VQ") ||
1713              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1714              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1715                              "VIRTIO_NET_F_CTRL_VQ"))) {
1716                 return false;
1717         }
1718 
1719         return true;
1720 }
1721 
1722 static int virtnet_probe(struct virtio_device *vdev)
1723 {
1724         int i, err;
1725         struct net_device *dev;
1726         struct virtnet_info *vi;
1727         u16 max_queue_pairs;
1728         int mtu;
1729 
1730         if (!vdev->config->get) {
1731                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
1732                         __func__);
1733                 return -EINVAL;
1734         }
1735 
1736         if (!virtnet_validate_features(vdev))
1737                 return -EINVAL;
1738 
1739         /* Find if host supports multiqueue virtio_net device */
1740         err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1741                                    struct virtio_net_config,
1742                                    max_virtqueue_pairs, &max_queue_pairs);
1743 
1744         /* We need at least 2 queue's */
1745         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1746             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1747             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1748                 max_queue_pairs = 1;
1749 
1750         /* Allocate ourselves a network device with room for our info */
1751         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1752         if (!dev)
1753                 return -ENOMEM;
1754 
1755         /* Set up network device as normal. */
1756         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1757         dev->netdev_ops = &virtnet_netdev;
1758         dev->features = NETIF_F_HIGHDMA;
1759 
1760         dev->ethtool_ops = &virtnet_ethtool_ops;
1761         SET_NETDEV_DEV(dev, &vdev->dev);
1762 
1763         /* Do we support "hardware" checksums? */
1764         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1765                 /* This opens up the world of extra features. */
1766                 dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1767                 if (csum)
1768                         dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1769 
1770                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1771                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1772                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1773                 }
1774                 /* Individual feature bits: what can host handle? */
1775                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1776                         dev->hw_features |= NETIF_F_TSO;
1777                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1778                         dev->hw_features |= NETIF_F_TSO6;
1779                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1780                         dev->hw_features |= NETIF_F_TSO_ECN;
1781                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1782                         dev->hw_features |= NETIF_F_UFO;
1783 
1784                 dev->features |= NETIF_F_GSO_ROBUST;
1785 
1786                 if (gso)
1787                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1788                 /* (!csum && gso) case will be fixed by register_netdev() */
1789         }
1790         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1791                 dev->features |= NETIF_F_RXCSUM;
1792 
1793         dev->vlan_features = dev->features;
1794 
1795         /* Configuration may specify what MAC to use.  Otherwise random. */
1796         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1797                 virtio_cread_bytes(vdev,
1798                                    offsetof(struct virtio_net_config, mac),
1799                                    dev->dev_addr, dev->addr_len);
1800         else
1801                 eth_hw_addr_random(dev);
1802 
1803         /* Set up our device-specific information */
1804         vi = netdev_priv(dev);
1805         vi->dev = dev;
1806         vi->vdev = vdev;
1807         vdev->priv = vi;
1808         vi->stats = alloc_percpu(struct virtnet_stats);
1809         err = -ENOMEM;
1810         if (vi->stats == NULL)
1811                 goto free;
1812 
1813         for_each_possible_cpu(i) {
1814                 struct virtnet_stats *virtnet_stats;
1815                 virtnet_stats = per_cpu_ptr(vi->stats, i);
1816                 u64_stats_init(&virtnet_stats->tx_syncp);
1817                 u64_stats_init(&virtnet_stats->rx_syncp);
1818         }
1819 
1820         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1821 
1822         /* If we can receive ANY GSO packets, we must allocate large ones. */
1823         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1824             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1825             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1826             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1827                 vi->big_packets = true;
1828 
1829         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1830                 vi->mergeable_rx_bufs = true;
1831 
1832         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
1833             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1834                 vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1835         else
1836                 vi->hdr_len = sizeof(struct virtio_net_hdr);
1837 
1838         if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
1839             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1840                 vi->any_header_sg = true;
1841 
1842         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1843                 vi->has_cvq = true;
1844 
1845         if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
1846                 mtu = virtio_cread16(vdev,
1847                                      offsetof(struct virtio_net_config,
1848                                               mtu));
1849                 if (virtnet_change_mtu(dev, mtu))
1850                         __virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
1851         }
1852 
1853         if (vi->any_header_sg)
1854                 dev->needed_headroom = vi->hdr_len;
1855 
1856         /* Use single tx/rx queue pair as default */
1857         vi->curr_queue_pairs = 1;
1858         vi->max_queue_pairs = max_queue_pairs;
1859 
1860         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1861         err = init_vqs(vi);
1862         if (err)
1863                 goto free_stats;
1864 
1865 #ifdef CONFIG_SYSFS
1866         if (vi->mergeable_rx_bufs)
1867                 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1868 #endif
1869         netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1870         netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1871 
1872         virtnet_init_settings(dev);
1873 
1874         err = register_netdev(dev);
1875         if (err) {
1876                 pr_debug("virtio_net: registering device failed\n");
1877                 goto free_vqs;
1878         }
1879 
1880         virtio_device_ready(vdev);
1881 
1882         vi->nb.notifier_call = &virtnet_cpu_callback;
1883         err = register_hotcpu_notifier(&vi->nb);
1884         if (err) {
1885                 pr_debug("virtio_net: registering cpu notifier failed\n");
1886                 goto free_unregister_netdev;
1887         }
1888 
1889         /* Assume link up if device can't report link status,
1890            otherwise get link status from config. */
1891         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1892                 netif_carrier_off(dev);
1893                 schedule_work(&vi->config_work);
1894         } else {
1895                 vi->status = VIRTIO_NET_S_LINK_UP;
1896                 netif_carrier_on(dev);
1897         }
1898 
1899         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1900                  dev->name, max_queue_pairs);
1901 
1902         return 0;
1903 
1904 free_unregister_netdev:
1905         vi->vdev->config->reset(vdev);
1906 
1907         unregister_netdev(dev);
1908 free_vqs:
1909         cancel_delayed_work_sync(&vi->refill);
1910         free_receive_page_frags(vi);
1911         virtnet_del_vqs(vi);
1912 free_stats:
1913         free_percpu(vi->stats);
1914 free:
1915         free_netdev(dev);
1916         return err;
1917 }
1918 
1919 static void remove_vq_common(struct virtnet_info *vi)
1920 {
1921         vi->vdev->config->reset(vi->vdev);
1922 
1923         /* Free unused buffers in both send and recv, if any. */
1924         free_unused_bufs(vi);
1925 
1926         free_receive_bufs(vi);
1927 
1928         free_receive_page_frags(vi);
1929 
1930         virtnet_del_vqs(vi);
1931 }
1932 
1933 static void virtnet_remove(struct virtio_device *vdev)
1934 {
1935         struct virtnet_info *vi = vdev->priv;
1936 
1937         unregister_hotcpu_notifier(&vi->nb);
1938 
1939         /* Make sure no work handler is accessing the device. */
1940         flush_work(&vi->config_work);
1941 
1942         unregister_netdev(vi->dev);
1943 
1944         remove_vq_common(vi);
1945 
1946         free_percpu(vi->stats);
1947         free_netdev(vi->dev);
1948 }
1949 
1950 #ifdef CONFIG_PM_SLEEP
1951 static int virtnet_freeze(struct virtio_device *vdev)
1952 {
1953         struct virtnet_info *vi = vdev->priv;
1954         int i;
1955 
1956         unregister_hotcpu_notifier(&vi->nb);
1957 
1958         /* Make sure no work handler is accessing the device */
1959         flush_work(&vi->config_work);
1960 
1961         netif_device_detach(vi->dev);
1962         cancel_delayed_work_sync(&vi->refill);
1963 
1964         if (netif_running(vi->dev)) {
1965                 for (i = 0; i < vi->max_queue_pairs; i++)
1966                         napi_disable(&vi->rq[i].napi);
1967         }
1968 
1969         remove_vq_common(vi);
1970 
1971         return 0;
1972 }
1973 
1974 static int virtnet_restore(struct virtio_device *vdev)
1975 {
1976         struct virtnet_info *vi = vdev->priv;
1977         int err, i;
1978 
1979         err = init_vqs(vi);
1980         if (err)
1981                 return err;
1982 
1983         virtio_device_ready(vdev);
1984 
1985         if (netif_running(vi->dev)) {
1986                 for (i = 0; i < vi->curr_queue_pairs; i++)
1987                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
1988                                 schedule_delayed_work(&vi->refill, 0);
1989 
1990                 for (i = 0; i < vi->max_queue_pairs; i++)
1991                         virtnet_napi_enable(&vi->rq[i]);
1992         }
1993 
1994         netif_device_attach(vi->dev);
1995 
1996         rtnl_lock();
1997         virtnet_set_queues(vi, vi->curr_queue_pairs);
1998         rtnl_unlock();
1999 
2000         err = register_hotcpu_notifier(&vi->nb);
2001         if (err)
2002                 return err;
2003 
2004         return 0;
2005 }
2006 #endif
2007 
2008 static struct virtio_device_id id_table[] = {
2009         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2010         { 0 },
2011 };
2012 
2013 static unsigned int features[] = {
2014         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
2015         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
2016         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
2017         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
2018         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
2019         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2020         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2021         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2022         VIRTIO_NET_F_CTRL_MAC_ADDR,
2023         VIRTIO_F_ANY_LAYOUT,
2024         VIRTIO_NET_F_MTU,
2025 };
2026 
2027 static struct virtio_driver virtio_net_driver = {
2028         .feature_table = features,
2029         .feature_table_size = ARRAY_SIZE(features),
2030         .driver.name =  KBUILD_MODNAME,
2031         .driver.owner = THIS_MODULE,
2032         .id_table =     id_table,
2033         .probe =        virtnet_probe,
2034         .remove =       virtnet_remove,
2035         .config_changed = virtnet_config_changed,
2036 #ifdef CONFIG_PM_SLEEP
2037         .freeze =       virtnet_freeze,
2038         .restore =      virtnet_restore,
2039 #endif
2040 };
2041 
2042 module_virtio_driver(virtio_net_driver);
2043 
2044 MODULE_DEVICE_TABLE(virtio, id_table);
2045 MODULE_DESCRIPTION("Virtio network driver");
2046 MODULE_LICENSE("GPL");
2047 

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