Version:  2.0.40 2.2.26 2.4.37 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 4.6

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         /* Ethtool settings */
151         u8 duplex;
152         u32 speed;
153 };
154 
155 struct padded_vnet_hdr {
156         struct virtio_net_hdr_mrg_rxbuf hdr;
157         /*
158          * hdr is in a separate sg buffer, and data sg buffer shares same page
159          * with this header sg. This padding makes next sg 16 byte aligned
160          * after the header.
161          */
162         char padding[4];
163 };
164 
165 /* Converting between virtqueue no. and kernel tx/rx queue no.
166  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
167  */
168 static int vq2txq(struct virtqueue *vq)
169 {
170         return (vq->index - 1) / 2;
171 }
172 
173 static int txq2vq(int txq)
174 {
175         return txq * 2 + 1;
176 }
177 
178 static int vq2rxq(struct virtqueue *vq)
179 {
180         return vq->index / 2;
181 }
182 
183 static int rxq2vq(int rxq)
184 {
185         return rxq * 2;
186 }
187 
188 static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
189 {
190         return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
191 }
192 
193 /*
194  * private is used to chain pages for big packets, put the whole
195  * most recent used list in the beginning for reuse
196  */
197 static void give_pages(struct receive_queue *rq, struct page *page)
198 {
199         struct page *end;
200 
201         /* Find end of list, sew whole thing into vi->rq.pages. */
202         for (end = page; end->private; end = (struct page *)end->private);
203         end->private = (unsigned long)rq->pages;
204         rq->pages = page;
205 }
206 
207 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
208 {
209         struct page *p = rq->pages;
210 
211         if (p) {
212                 rq->pages = (struct page *)p->private;
213                 /* clear private here, it is used to chain pages */
214                 p->private = 0;
215         } else
216                 p = alloc_page(gfp_mask);
217         return p;
218 }
219 
220 static void skb_xmit_done(struct virtqueue *vq)
221 {
222         struct virtnet_info *vi = vq->vdev->priv;
223 
224         /* Suppress further interrupts. */
225         virtqueue_disable_cb(vq);
226 
227         /* We were probably waiting for more output buffers. */
228         netif_wake_subqueue(vi->dev, vq2txq(vq));
229 }
230 
231 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
232 {
233         unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
234         return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
235 }
236 
237 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
238 {
239         return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
240 
241 }
242 
243 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
244 {
245         unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
246         return (unsigned long)buf | (size - 1);
247 }
248 
249 /* Called from bottom half context */
250 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
251                                    struct receive_queue *rq,
252                                    struct page *page, unsigned int offset,
253                                    unsigned int len, unsigned int truesize)
254 {
255         struct sk_buff *skb;
256         struct virtio_net_hdr_mrg_rxbuf *hdr;
257         unsigned int copy, hdr_len, hdr_padded_len;
258         char *p;
259 
260         p = page_address(page) + offset;
261 
262         /* copy small packet so we can reuse these pages for small data */
263         skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN);
264         if (unlikely(!skb))
265                 return NULL;
266 
267         hdr = skb_vnet_hdr(skb);
268 
269         hdr_len = vi->hdr_len;
270         if (vi->mergeable_rx_bufs)
271                 hdr_padded_len = sizeof *hdr;
272         else
273                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
274 
275         memcpy(hdr, p, hdr_len);
276 
277         len -= hdr_len;
278         offset += hdr_padded_len;
279         p += hdr_padded_len;
280 
281         copy = len;
282         if (copy > skb_tailroom(skb))
283                 copy = skb_tailroom(skb);
284         memcpy(skb_put(skb, copy), p, copy);
285 
286         len -= copy;
287         offset += copy;
288 
289         if (vi->mergeable_rx_bufs) {
290                 if (len)
291                         skb_add_rx_frag(skb, 0, page, offset, len, truesize);
292                 else
293                         put_page(page);
294                 return skb;
295         }
296 
297         /*
298          * Verify that we can indeed put this data into a skb.
299          * This is here to handle cases when the device erroneously
300          * tries to receive more than is possible. This is usually
301          * the case of a broken device.
302          */
303         if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
304                 net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
305                 dev_kfree_skb(skb);
306                 return NULL;
307         }
308         BUG_ON(offset >= PAGE_SIZE);
309         while (len) {
310                 unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
311                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
312                                 frag_size, truesize);
313                 len -= frag_size;
314                 page = (struct page *)page->private;
315                 offset = 0;
316         }
317 
318         if (page)
319                 give_pages(rq, page);
320 
321         return skb;
322 }
323 
324 static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
325 {
326         struct sk_buff * skb = buf;
327 
328         len -= vi->hdr_len;
329         skb_trim(skb, len);
330 
331         return skb;
332 }
333 
334 static struct sk_buff *receive_big(struct net_device *dev,
335                                    struct virtnet_info *vi,
336                                    struct receive_queue *rq,
337                                    void *buf,
338                                    unsigned int len)
339 {
340         struct page *page = buf;
341         struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
342 
343         if (unlikely(!skb))
344                 goto err;
345 
346         return skb;
347 
348 err:
349         dev->stats.rx_dropped++;
350         give_pages(rq, page);
351         return NULL;
352 }
353 
354 static struct sk_buff *receive_mergeable(struct net_device *dev,
355                                          struct virtnet_info *vi,
356                                          struct receive_queue *rq,
357                                          unsigned long ctx,
358                                          unsigned int len)
359 {
360         void *buf = mergeable_ctx_to_buf_address(ctx);
361         struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
362         u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
363         struct page *page = virt_to_head_page(buf);
364         int offset = buf - page_address(page);
365         unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
366 
367         struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
368                                                truesize);
369         struct sk_buff *curr_skb = head_skb;
370 
371         if (unlikely(!curr_skb))
372                 goto err_skb;
373         while (--num_buf) {
374                 int num_skb_frags;
375 
376                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
377                 if (unlikely(!ctx)) {
378                         pr_debug("%s: rx error: %d buffers out of %d missing\n",
379                                  dev->name, num_buf,
380                                  virtio16_to_cpu(vi->vdev,
381                                                  hdr->num_buffers));
382                         dev->stats.rx_length_errors++;
383                         goto err_buf;
384                 }
385 
386                 buf = mergeable_ctx_to_buf_address(ctx);
387                 page = virt_to_head_page(buf);
388 
389                 num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
390                 if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
391                         struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
392 
393                         if (unlikely(!nskb))
394                                 goto err_skb;
395                         if (curr_skb == head_skb)
396                                 skb_shinfo(curr_skb)->frag_list = nskb;
397                         else
398                                 curr_skb->next = nskb;
399                         curr_skb = nskb;
400                         head_skb->truesize += nskb->truesize;
401                         num_skb_frags = 0;
402                 }
403                 truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
404                 if (curr_skb != head_skb) {
405                         head_skb->data_len += len;
406                         head_skb->len += len;
407                         head_skb->truesize += truesize;
408                 }
409                 offset = buf - page_address(page);
410                 if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
411                         put_page(page);
412                         skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
413                                              len, truesize);
414                 } else {
415                         skb_add_rx_frag(curr_skb, num_skb_frags, page,
416                                         offset, len, truesize);
417                 }
418         }
419 
420         ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
421         return head_skb;
422 
423 err_skb:
424         put_page(page);
425         while (--num_buf) {
426                 ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
427                 if (unlikely(!ctx)) {
428                         pr_debug("%s: rx error: %d buffers missing\n",
429                                  dev->name, num_buf);
430                         dev->stats.rx_length_errors++;
431                         break;
432                 }
433                 page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
434                 put_page(page);
435         }
436 err_buf:
437         dev->stats.rx_dropped++;
438         dev_kfree_skb(head_skb);
439         return NULL;
440 }
441 
442 static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
443                         void *buf, unsigned int len)
444 {
445         struct net_device *dev = vi->dev;
446         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
447         struct sk_buff *skb;
448         struct virtio_net_hdr_mrg_rxbuf *hdr;
449 
450         if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
451                 pr_debug("%s: short packet %i\n", dev->name, len);
452                 dev->stats.rx_length_errors++;
453                 if (vi->mergeable_rx_bufs) {
454                         unsigned long ctx = (unsigned long)buf;
455                         void *base = mergeable_ctx_to_buf_address(ctx);
456                         put_page(virt_to_head_page(base));
457                 } else if (vi->big_packets) {
458                         give_pages(rq, buf);
459                 } else {
460                         dev_kfree_skb(buf);
461                 }
462                 return;
463         }
464 
465         if (vi->mergeable_rx_bufs)
466                 skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
467         else if (vi->big_packets)
468                 skb = receive_big(dev, vi, rq, buf, len);
469         else
470                 skb = receive_small(vi, buf, len);
471 
472         if (unlikely(!skb))
473                 return;
474 
475         hdr = skb_vnet_hdr(skb);
476 
477         u64_stats_update_begin(&stats->rx_syncp);
478         stats->rx_bytes += skb->len;
479         stats->rx_packets++;
480         u64_stats_update_end(&stats->rx_syncp);
481 
482         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
483                 pr_debug("Needs csum!\n");
484                 if (!skb_partial_csum_set(skb,
485                           virtio16_to_cpu(vi->vdev, hdr->hdr.csum_start),
486                           virtio16_to_cpu(vi->vdev, hdr->hdr.csum_offset)))
487                         goto frame_err;
488         } else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
489                 skb->ip_summed = CHECKSUM_UNNECESSARY;
490         }
491 
492         skb->protocol = eth_type_trans(skb, dev);
493         pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
494                  ntohs(skb->protocol), skb->len, skb->pkt_type);
495 
496         if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
497                 pr_debug("GSO!\n");
498                 switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
499                 case VIRTIO_NET_HDR_GSO_TCPV4:
500                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
501                         break;
502                 case VIRTIO_NET_HDR_GSO_UDP:
503                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
504                         break;
505                 case VIRTIO_NET_HDR_GSO_TCPV6:
506                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
507                         break;
508                 default:
509                         net_warn_ratelimited("%s: bad gso type %u.\n",
510                                              dev->name, hdr->hdr.gso_type);
511                         goto frame_err;
512                 }
513 
514                 if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
515                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
516 
517                 skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
518                                                             hdr->hdr.gso_size);
519                 if (skb_shinfo(skb)->gso_size == 0) {
520                         net_warn_ratelimited("%s: zero gso size.\n", dev->name);
521                         goto frame_err;
522                 }
523 
524                 /* Header must be checked, and gso_segs computed. */
525                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
526                 skb_shinfo(skb)->gso_segs = 0;
527         }
528 
529         napi_gro_receive(&rq->napi, skb);
530         return;
531 
532 frame_err:
533         dev->stats.rx_frame_errors++;
534         dev_kfree_skb(skb);
535 }
536 
537 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
538                              gfp_t gfp)
539 {
540         struct sk_buff *skb;
541         struct virtio_net_hdr_mrg_rxbuf *hdr;
542         int err;
543 
544         skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
545         if (unlikely(!skb))
546                 return -ENOMEM;
547 
548         skb_put(skb, GOOD_PACKET_LEN);
549 
550         hdr = skb_vnet_hdr(skb);
551         sg_init_table(rq->sg, 2);
552         sg_set_buf(rq->sg, hdr, vi->hdr_len);
553         skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
554 
555         err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
556         if (err < 0)
557                 dev_kfree_skb(skb);
558 
559         return err;
560 }
561 
562 static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
563                            gfp_t gfp)
564 {
565         struct page *first, *list = NULL;
566         char *p;
567         int i, err, offset;
568 
569         sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
570 
571         /* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
572         for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
573                 first = get_a_page(rq, gfp);
574                 if (!first) {
575                         if (list)
576                                 give_pages(rq, list);
577                         return -ENOMEM;
578                 }
579                 sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
580 
581                 /* chain new page in list head to match sg */
582                 first->private = (unsigned long)list;
583                 list = first;
584         }
585 
586         first = get_a_page(rq, gfp);
587         if (!first) {
588                 give_pages(rq, list);
589                 return -ENOMEM;
590         }
591         p = page_address(first);
592 
593         /* rq->sg[0], rq->sg[1] share the same page */
594         /* a separated rq->sg[0] for header - required in case !any_header_sg */
595         sg_set_buf(&rq->sg[0], p, vi->hdr_len);
596 
597         /* rq->sg[1] for data packet, from offset */
598         offset = sizeof(struct padded_vnet_hdr);
599         sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
600 
601         /* chain first in list head */
602         first->private = (unsigned long)list;
603         err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
604                                   first, gfp);
605         if (err < 0)
606                 give_pages(rq, first);
607 
608         return err;
609 }
610 
611 static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
612 {
613         const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
614         unsigned int len;
615 
616         len = hdr_len + clamp_t(unsigned int, ewma_pkt_len_read(avg_pkt_len),
617                         GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
618         return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
619 }
620 
621 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
622 {
623         struct page_frag *alloc_frag = &rq->alloc_frag;
624         char *buf;
625         unsigned long ctx;
626         int err;
627         unsigned int len, hole;
628 
629         len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
630         if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
631                 return -ENOMEM;
632 
633         buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
634         ctx = mergeable_buf_to_ctx(buf, len);
635         get_page(alloc_frag->page);
636         alloc_frag->offset += len;
637         hole = alloc_frag->size - alloc_frag->offset;
638         if (hole < len) {
639                 /* To avoid internal fragmentation, if there is very likely not
640                  * enough space for another buffer, add the remaining space to
641                  * the current buffer. This extra space is not included in
642                  * the truesize stored in ctx.
643                  */
644                 len += hole;
645                 alloc_frag->offset += hole;
646         }
647 
648         sg_init_one(rq->sg, buf, len);
649         err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
650         if (err < 0)
651                 put_page(virt_to_head_page(buf));
652 
653         return err;
654 }
655 
656 /*
657  * Returns false if we couldn't fill entirely (OOM).
658  *
659  * Normally run in the receive path, but can also be run from ndo_open
660  * before we're receiving packets, or from refill_work which is
661  * careful to disable receiving (using napi_disable).
662  */
663 static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
664                           gfp_t gfp)
665 {
666         int err;
667         bool oom;
668 
669         gfp |= __GFP_COLD;
670         do {
671                 if (vi->mergeable_rx_bufs)
672                         err = add_recvbuf_mergeable(rq, gfp);
673                 else if (vi->big_packets)
674                         err = add_recvbuf_big(vi, rq, gfp);
675                 else
676                         err = add_recvbuf_small(vi, rq, gfp);
677 
678                 oom = err == -ENOMEM;
679                 if (err)
680                         break;
681         } while (rq->vq->num_free);
682         virtqueue_kick(rq->vq);
683         return !oom;
684 }
685 
686 static void skb_recv_done(struct virtqueue *rvq)
687 {
688         struct virtnet_info *vi = rvq->vdev->priv;
689         struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
690 
691         /* Schedule NAPI, Suppress further interrupts if successful. */
692         if (napi_schedule_prep(&rq->napi)) {
693                 virtqueue_disable_cb(rvq);
694                 __napi_schedule(&rq->napi);
695         }
696 }
697 
698 static void virtnet_napi_enable(struct receive_queue *rq)
699 {
700         napi_enable(&rq->napi);
701 
702         /* If all buffers were filled by other side before we napi_enabled, we
703          * won't get another interrupt, so process any outstanding packets
704          * now.  virtnet_poll wants re-enable the queue, so we disable here.
705          * We synchronize against interrupts via NAPI_STATE_SCHED */
706         if (napi_schedule_prep(&rq->napi)) {
707                 virtqueue_disable_cb(rq->vq);
708                 local_bh_disable();
709                 __napi_schedule(&rq->napi);
710                 local_bh_enable();
711         }
712 }
713 
714 static void refill_work(struct work_struct *work)
715 {
716         struct virtnet_info *vi =
717                 container_of(work, struct virtnet_info, refill.work);
718         bool still_empty;
719         int i;
720 
721         for (i = 0; i < vi->curr_queue_pairs; i++) {
722                 struct receive_queue *rq = &vi->rq[i];
723 
724                 napi_disable(&rq->napi);
725                 still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
726                 virtnet_napi_enable(rq);
727 
728                 /* In theory, this can happen: if we don't get any buffers in
729                  * we will *never* try to fill again.
730                  */
731                 if (still_empty)
732                         schedule_delayed_work(&vi->refill, HZ/2);
733         }
734 }
735 
736 static int virtnet_receive(struct receive_queue *rq, int budget)
737 {
738         struct virtnet_info *vi = rq->vq->vdev->priv;
739         unsigned int len, received = 0;
740         void *buf;
741 
742         while (received < budget &&
743                (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
744                 receive_buf(vi, rq, buf, len);
745                 received++;
746         }
747 
748         if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
749                 if (!try_fill_recv(vi, rq, GFP_ATOMIC))
750                         schedule_delayed_work(&vi->refill, 0);
751         }
752 
753         return received;
754 }
755 
756 static int virtnet_poll(struct napi_struct *napi, int budget)
757 {
758         struct receive_queue *rq =
759                 container_of(napi, struct receive_queue, napi);
760         unsigned int r, received;
761 
762         received = virtnet_receive(rq, budget);
763 
764         /* Out of packets? */
765         if (received < budget) {
766                 r = virtqueue_enable_cb_prepare(rq->vq);
767                 napi_complete_done(napi, received);
768                 if (unlikely(virtqueue_poll(rq->vq, r)) &&
769                     napi_schedule_prep(napi)) {
770                         virtqueue_disable_cb(rq->vq);
771                         __napi_schedule(napi);
772                 }
773         }
774 
775         return received;
776 }
777 
778 #ifdef CONFIG_NET_RX_BUSY_POLL
779 /* must be called with local_bh_disable()d */
780 static int virtnet_busy_poll(struct napi_struct *napi)
781 {
782         struct receive_queue *rq =
783                 container_of(napi, struct receive_queue, napi);
784         struct virtnet_info *vi = rq->vq->vdev->priv;
785         int r, received = 0, budget = 4;
786 
787         if (!(vi->status & VIRTIO_NET_S_LINK_UP))
788                 return LL_FLUSH_FAILED;
789 
790         if (!napi_schedule_prep(napi))
791                 return LL_FLUSH_BUSY;
792 
793         virtqueue_disable_cb(rq->vq);
794 
795 again:
796         received += virtnet_receive(rq, budget);
797 
798         r = virtqueue_enable_cb_prepare(rq->vq);
799         clear_bit(NAPI_STATE_SCHED, &napi->state);
800         if (unlikely(virtqueue_poll(rq->vq, r)) &&
801             napi_schedule_prep(napi)) {
802                 virtqueue_disable_cb(rq->vq);
803                 if (received < budget) {
804                         budget -= received;
805                         goto again;
806                 } else {
807                         __napi_schedule(napi);
808                 }
809         }
810 
811         return received;
812 }
813 #endif  /* CONFIG_NET_RX_BUSY_POLL */
814 
815 static int virtnet_open(struct net_device *dev)
816 {
817         struct virtnet_info *vi = netdev_priv(dev);
818         int i;
819 
820         for (i = 0; i < vi->max_queue_pairs; i++) {
821                 if (i < vi->curr_queue_pairs)
822                         /* Make sure we have some buffers: if oom use wq. */
823                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
824                                 schedule_delayed_work(&vi->refill, 0);
825                 virtnet_napi_enable(&vi->rq[i]);
826         }
827 
828         return 0;
829 }
830 
831 static void free_old_xmit_skbs(struct send_queue *sq)
832 {
833         struct sk_buff *skb;
834         unsigned int len;
835         struct virtnet_info *vi = sq->vq->vdev->priv;
836         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
837 
838         while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
839                 pr_debug("Sent skb %p\n", skb);
840 
841                 u64_stats_update_begin(&stats->tx_syncp);
842                 stats->tx_bytes += skb->len;
843                 stats->tx_packets++;
844                 u64_stats_update_end(&stats->tx_syncp);
845 
846                 dev_kfree_skb_any(skb);
847         }
848 }
849 
850 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
851 {
852         struct virtio_net_hdr_mrg_rxbuf *hdr;
853         const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
854         struct virtnet_info *vi = sq->vq->vdev->priv;
855         unsigned num_sg;
856         unsigned hdr_len = vi->hdr_len;
857         bool can_push;
858 
859         pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
860 
861         can_push = vi->any_header_sg &&
862                 !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
863                 !skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
864         /* Even if we can, don't push here yet as this would skew
865          * csum_start offset below. */
866         if (can_push)
867                 hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
868         else
869                 hdr = skb_vnet_hdr(skb);
870 
871         if (skb->ip_summed == CHECKSUM_PARTIAL) {
872                 hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
873                 hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
874                                                 skb_checksum_start_offset(skb));
875                 hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
876                                                          skb->csum_offset);
877         } else {
878                 hdr->hdr.flags = 0;
879                 hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
880         }
881 
882         if (skb_is_gso(skb)) {
883                 hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
884                 hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
885                                                     skb_shinfo(skb)->gso_size);
886                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
887                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
888                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
889                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
890                 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
891                         hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
892                 else
893                         BUG();
894                 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
895                         hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
896         } else {
897                 hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
898                 hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
899         }
900 
901         if (vi->mergeable_rx_bufs)
902                 hdr->num_buffers = 0;
903 
904         sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2));
905         if (can_push) {
906                 __skb_push(skb, hdr_len);
907                 num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
908                 /* Pull header back to avoid skew in tx bytes calculations. */
909                 __skb_pull(skb, hdr_len);
910         } else {
911                 sg_set_buf(sq->sg, hdr, hdr_len);
912                 num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
913         }
914         return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
915 }
916 
917 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
918 {
919         struct virtnet_info *vi = netdev_priv(dev);
920         int qnum = skb_get_queue_mapping(skb);
921         struct send_queue *sq = &vi->sq[qnum];
922         int err;
923         struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
924         bool kick = !skb->xmit_more;
925 
926         /* Free up any pending old buffers before queueing new ones. */
927         free_old_xmit_skbs(sq);
928 
929         /* timestamp packet in software */
930         skb_tx_timestamp(skb);
931 
932         /* Try to transmit */
933         err = xmit_skb(sq, skb);
934 
935         /* This should not happen! */
936         if (unlikely(err)) {
937                 dev->stats.tx_fifo_errors++;
938                 if (net_ratelimit())
939                         dev_warn(&dev->dev,
940                                  "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
941                 dev->stats.tx_dropped++;
942                 dev_kfree_skb_any(skb);
943                 return NETDEV_TX_OK;
944         }
945 
946         /* Don't wait up for transmitted skbs to be freed. */
947         skb_orphan(skb);
948         nf_reset(skb);
949 
950         /* If running out of space, stop queue to avoid getting packets that we
951          * are then unable to transmit.
952          * An alternative would be to force queuing layer to requeue the skb by
953          * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
954          * returned in a normal path of operation: it means that driver is not
955          * maintaining the TX queue stop/start state properly, and causes
956          * the stack to do a non-trivial amount of useless work.
957          * Since most packets only take 1 or 2 ring slots, stopping the queue
958          * early means 16 slots are typically wasted.
959          */
960         if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
961                 netif_stop_subqueue(dev, qnum);
962                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
963                         /* More just got used, free them then recheck. */
964                         free_old_xmit_skbs(sq);
965                         if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
966                                 netif_start_subqueue(dev, qnum);
967                                 virtqueue_disable_cb(sq->vq);
968                         }
969                 }
970         }
971 
972         if (kick || netif_xmit_stopped(txq))
973                 virtqueue_kick(sq->vq);
974 
975         return NETDEV_TX_OK;
976 }
977 
978 /*
979  * Send command via the control virtqueue and check status.  Commands
980  * supported by the hypervisor, as indicated by feature bits, should
981  * never fail unless improperly formatted.
982  */
983 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
984                                  struct scatterlist *out)
985 {
986         struct scatterlist *sgs[4], hdr, stat;
987         unsigned out_num = 0, tmp;
988 
989         /* Caller should know better */
990         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
991 
992         vi->ctrl_status = ~0;
993         vi->ctrl_hdr.class = class;
994         vi->ctrl_hdr.cmd = cmd;
995         /* Add header */
996         sg_init_one(&hdr, &vi->ctrl_hdr, sizeof(vi->ctrl_hdr));
997         sgs[out_num++] = &hdr;
998 
999         if (out)
1000                 sgs[out_num++] = out;
1001 
1002         /* Add return status. */
1003         sg_init_one(&stat, &vi->ctrl_status, sizeof(vi->ctrl_status));
1004         sgs[out_num] = &stat;
1005 
1006         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
1007         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
1008 
1009         if (unlikely(!virtqueue_kick(vi->cvq)))
1010                 return vi->ctrl_status == VIRTIO_NET_OK;
1011 
1012         /* Spin for a response, the kick causes an ioport write, trapping
1013          * into the hypervisor, so the request should be handled immediately.
1014          */
1015         while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1016                !virtqueue_is_broken(vi->cvq))
1017                 cpu_relax();
1018 
1019         return vi->ctrl_status == VIRTIO_NET_OK;
1020 }
1021 
1022 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1023 {
1024         struct virtnet_info *vi = netdev_priv(dev);
1025         struct virtio_device *vdev = vi->vdev;
1026         int ret;
1027         struct sockaddr *addr = p;
1028         struct scatterlist sg;
1029 
1030         ret = eth_prepare_mac_addr_change(dev, p);
1031         if (ret)
1032                 return ret;
1033 
1034         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1035                 sg_init_one(&sg, addr->sa_data, dev->addr_len);
1036                 if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1037                                           VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1038                         dev_warn(&vdev->dev,
1039                                  "Failed to set mac address by vq command.\n");
1040                         return -EINVAL;
1041                 }
1042         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
1043                    !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1044                 unsigned int i;
1045 
1046                 /* Naturally, this has an atomicity problem. */
1047                 for (i = 0; i < dev->addr_len; i++)
1048                         virtio_cwrite8(vdev,
1049                                        offsetof(struct virtio_net_config, mac) +
1050                                        i, addr->sa_data[i]);
1051         }
1052 
1053         eth_commit_mac_addr_change(dev, p);
1054 
1055         return 0;
1056 }
1057 
1058 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1059                                                struct rtnl_link_stats64 *tot)
1060 {
1061         struct virtnet_info *vi = netdev_priv(dev);
1062         int cpu;
1063         unsigned int start;
1064 
1065         for_each_possible_cpu(cpu) {
1066                 struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1067                 u64 tpackets, tbytes, rpackets, rbytes;
1068 
1069                 do {
1070                         start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1071                         tpackets = stats->tx_packets;
1072                         tbytes   = stats->tx_bytes;
1073                 } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1074 
1075                 do {
1076                         start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1077                         rpackets = stats->rx_packets;
1078                         rbytes   = stats->rx_bytes;
1079                 } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1080 
1081                 tot->rx_packets += rpackets;
1082                 tot->tx_packets += tpackets;
1083                 tot->rx_bytes   += rbytes;
1084                 tot->tx_bytes   += tbytes;
1085         }
1086 
1087         tot->tx_dropped = dev->stats.tx_dropped;
1088         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1089         tot->rx_dropped = dev->stats.rx_dropped;
1090         tot->rx_length_errors = dev->stats.rx_length_errors;
1091         tot->rx_frame_errors = dev->stats.rx_frame_errors;
1092 
1093         return tot;
1094 }
1095 
1096 #ifdef CONFIG_NET_POLL_CONTROLLER
1097 static void virtnet_netpoll(struct net_device *dev)
1098 {
1099         struct virtnet_info *vi = netdev_priv(dev);
1100         int i;
1101 
1102         for (i = 0; i < vi->curr_queue_pairs; i++)
1103                 napi_schedule(&vi->rq[i].napi);
1104 }
1105 #endif
1106 
1107 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1108 {
1109         rtnl_lock();
1110         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1111                                   VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1112                 dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1113         rtnl_unlock();
1114 }
1115 
1116 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1117 {
1118         struct scatterlist sg;
1119         struct virtio_net_ctrl_mq s;
1120         struct net_device *dev = vi->dev;
1121 
1122         if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1123                 return 0;
1124 
1125         s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
1126         sg_init_one(&sg, &s, sizeof(s));
1127 
1128         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1129                                   VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1130                 dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1131                          queue_pairs);
1132                 return -EINVAL;
1133         } else {
1134                 vi->curr_queue_pairs = queue_pairs;
1135                 /* virtnet_open() will refill when device is going to up. */
1136                 if (dev->flags & IFF_UP)
1137                         schedule_delayed_work(&vi->refill, 0);
1138         }
1139 
1140         return 0;
1141 }
1142 
1143 static int virtnet_close(struct net_device *dev)
1144 {
1145         struct virtnet_info *vi = netdev_priv(dev);
1146         int i;
1147 
1148         /* Make sure refill_work doesn't re-enable napi! */
1149         cancel_delayed_work_sync(&vi->refill);
1150 
1151         for (i = 0; i < vi->max_queue_pairs; i++)
1152                 napi_disable(&vi->rq[i].napi);
1153 
1154         return 0;
1155 }
1156 
1157 static void virtnet_set_rx_mode(struct net_device *dev)
1158 {
1159         struct virtnet_info *vi = netdev_priv(dev);
1160         struct scatterlist sg[2];
1161         struct virtio_net_ctrl_mac *mac_data;
1162         struct netdev_hw_addr *ha;
1163         int uc_count;
1164         int mc_count;
1165         void *buf;
1166         int i;
1167 
1168         /* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1169         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1170                 return;
1171 
1172         vi->ctrl_promisc = ((dev->flags & IFF_PROMISC) != 0);
1173         vi->ctrl_allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1174 
1175         sg_init_one(sg, &vi->ctrl_promisc, sizeof(vi->ctrl_promisc));
1176 
1177         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1178                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
1179                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1180                          vi->ctrl_promisc ? "en" : "dis");
1181 
1182         sg_init_one(sg, &vi->ctrl_allmulti, sizeof(vi->ctrl_allmulti));
1183 
1184         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1185                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1186                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1187                          vi->ctrl_allmulti ? "en" : "dis");
1188 
1189         uc_count = netdev_uc_count(dev);
1190         mc_count = netdev_mc_count(dev);
1191         /* MAC filter - use one buffer for both lists */
1192         buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1193                       (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1194         mac_data = buf;
1195         if (!buf)
1196                 return;
1197 
1198         sg_init_table(sg, 2);
1199 
1200         /* Store the unicast list and count in the front of the buffer */
1201         mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
1202         i = 0;
1203         netdev_for_each_uc_addr(ha, dev)
1204                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1205 
1206         sg_set_buf(&sg[0], mac_data,
1207                    sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1208 
1209         /* multicast list and count fill the end */
1210         mac_data = (void *)&mac_data->macs[uc_count][0];
1211 
1212         mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
1213         i = 0;
1214         netdev_for_each_mc_addr(ha, dev)
1215                 memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1216 
1217         sg_set_buf(&sg[1], mac_data,
1218                    sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1219 
1220         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1221                                   VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1222                 dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1223 
1224         kfree(buf);
1225 }
1226 
1227 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1228                                    __be16 proto, u16 vid)
1229 {
1230         struct virtnet_info *vi = netdev_priv(dev);
1231         struct scatterlist sg;
1232 
1233         sg_init_one(&sg, &vid, sizeof(vid));
1234 
1235         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1236                                   VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1237                 dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1238         return 0;
1239 }
1240 
1241 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1242                                     __be16 proto, u16 vid)
1243 {
1244         struct virtnet_info *vi = netdev_priv(dev);
1245         struct scatterlist sg;
1246 
1247         sg_init_one(&sg, &vid, sizeof(vid));
1248 
1249         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1250                                   VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1251                 dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1252         return 0;
1253 }
1254 
1255 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1256 {
1257         int i;
1258 
1259         if (vi->affinity_hint_set) {
1260                 for (i = 0; i < vi->max_queue_pairs; i++) {
1261                         virtqueue_set_affinity(vi->rq[i].vq, -1);
1262                         virtqueue_set_affinity(vi->sq[i].vq, -1);
1263                 }
1264 
1265                 vi->affinity_hint_set = false;
1266         }
1267 }
1268 
1269 static void virtnet_set_affinity(struct virtnet_info *vi)
1270 {
1271         int i;
1272         int cpu;
1273 
1274         /* In multiqueue mode, when the number of cpu is equal to the number of
1275          * queue pairs, we let the queue pairs to be private to one cpu by
1276          * setting the affinity hint to eliminate the contention.
1277          */
1278         if (vi->curr_queue_pairs == 1 ||
1279             vi->max_queue_pairs != num_online_cpus()) {
1280                 virtnet_clean_affinity(vi, -1);
1281                 return;
1282         }
1283 
1284         i = 0;
1285         for_each_online_cpu(cpu) {
1286                 virtqueue_set_affinity(vi->rq[i].vq, cpu);
1287                 virtqueue_set_affinity(vi->sq[i].vq, cpu);
1288                 netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1289                 i++;
1290         }
1291 
1292         vi->affinity_hint_set = true;
1293 }
1294 
1295 static int virtnet_cpu_callback(struct notifier_block *nfb,
1296                                 unsigned long action, void *hcpu)
1297 {
1298         struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1299 
1300         switch(action & ~CPU_TASKS_FROZEN) {
1301         case CPU_ONLINE:
1302         case CPU_DOWN_FAILED:
1303         case CPU_DEAD:
1304                 virtnet_set_affinity(vi);
1305                 break;
1306         case CPU_DOWN_PREPARE:
1307                 virtnet_clean_affinity(vi, (long)hcpu);
1308                 break;
1309         default:
1310                 break;
1311         }
1312 
1313         return NOTIFY_OK;
1314 }
1315 
1316 static void virtnet_get_ringparam(struct net_device *dev,
1317                                 struct ethtool_ringparam *ring)
1318 {
1319         struct virtnet_info *vi = netdev_priv(dev);
1320 
1321         ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1322         ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1323         ring->rx_pending = ring->rx_max_pending;
1324         ring->tx_pending = ring->tx_max_pending;
1325 }
1326 
1327 
1328 static void virtnet_get_drvinfo(struct net_device *dev,
1329                                 struct ethtool_drvinfo *info)
1330 {
1331         struct virtnet_info *vi = netdev_priv(dev);
1332         struct virtio_device *vdev = vi->vdev;
1333 
1334         strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1335         strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1336         strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1337 
1338 }
1339 
1340 /* TODO: Eliminate OOO packets during switching */
1341 static int virtnet_set_channels(struct net_device *dev,
1342                                 struct ethtool_channels *channels)
1343 {
1344         struct virtnet_info *vi = netdev_priv(dev);
1345         u16 queue_pairs = channels->combined_count;
1346         int err;
1347 
1348         /* We don't support separate rx/tx channels.
1349          * We don't allow setting 'other' channels.
1350          */
1351         if (channels->rx_count || channels->tx_count || channels->other_count)
1352                 return -EINVAL;
1353 
1354         if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1355                 return -EINVAL;
1356 
1357         get_online_cpus();
1358         err = virtnet_set_queues(vi, queue_pairs);
1359         if (!err) {
1360                 netif_set_real_num_tx_queues(dev, queue_pairs);
1361                 netif_set_real_num_rx_queues(dev, queue_pairs);
1362 
1363                 virtnet_set_affinity(vi);
1364         }
1365         put_online_cpus();
1366 
1367         return err;
1368 }
1369 
1370 static void virtnet_get_channels(struct net_device *dev,
1371                                  struct ethtool_channels *channels)
1372 {
1373         struct virtnet_info *vi = netdev_priv(dev);
1374 
1375         channels->combined_count = vi->curr_queue_pairs;
1376         channels->max_combined = vi->max_queue_pairs;
1377         channels->max_other = 0;
1378         channels->rx_count = 0;
1379         channels->tx_count = 0;
1380         channels->other_count = 0;
1381 }
1382 
1383 /* Check if the user is trying to change anything besides speed/duplex */
1384 static bool virtnet_validate_ethtool_cmd(const struct ethtool_cmd *cmd)
1385 {
1386         struct ethtool_cmd diff1 = *cmd;
1387         struct ethtool_cmd diff2 = {};
1388 
1389         /* cmd is always set so we need to clear it, validate the port type
1390          * and also without autonegotiation we can ignore advertising
1391          */
1392         ethtool_cmd_speed_set(&diff1, 0);
1393         diff2.port = PORT_OTHER;
1394         diff1.advertising = 0;
1395         diff1.duplex = 0;
1396         diff1.cmd = 0;
1397 
1398         return !memcmp(&diff1, &diff2, sizeof(diff1));
1399 }
1400 
1401 static int virtnet_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1402 {
1403         struct virtnet_info *vi = netdev_priv(dev);
1404         u32 speed;
1405 
1406         speed = ethtool_cmd_speed(cmd);
1407         /* don't allow custom speed and duplex */
1408         if (!ethtool_validate_speed(speed) ||
1409             !ethtool_validate_duplex(cmd->duplex) ||
1410             !virtnet_validate_ethtool_cmd(cmd))
1411                 return -EINVAL;
1412         vi->speed = speed;
1413         vi->duplex = cmd->duplex;
1414 
1415         return 0;
1416 }
1417 
1418 static int virtnet_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1419 {
1420         struct virtnet_info *vi = netdev_priv(dev);
1421 
1422         ethtool_cmd_speed_set(cmd, vi->speed);
1423         cmd->duplex = vi->duplex;
1424         cmd->port = PORT_OTHER;
1425 
1426         return 0;
1427 }
1428 
1429 static void virtnet_init_settings(struct net_device *dev)
1430 {
1431         struct virtnet_info *vi = netdev_priv(dev);
1432 
1433         vi->speed = SPEED_UNKNOWN;
1434         vi->duplex = DUPLEX_UNKNOWN;
1435 }
1436 
1437 static const struct ethtool_ops virtnet_ethtool_ops = {
1438         .get_drvinfo = virtnet_get_drvinfo,
1439         .get_link = ethtool_op_get_link,
1440         .get_ringparam = virtnet_get_ringparam,
1441         .set_channels = virtnet_set_channels,
1442         .get_channels = virtnet_get_channels,
1443         .get_ts_info = ethtool_op_get_ts_info,
1444         .get_settings = virtnet_get_settings,
1445         .set_settings = virtnet_set_settings,
1446 };
1447 
1448 #define MIN_MTU 68
1449 #define MAX_MTU 65535
1450 
1451 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1452 {
1453         if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1454                 return -EINVAL;
1455         dev->mtu = new_mtu;
1456         return 0;
1457 }
1458 
1459 static const struct net_device_ops virtnet_netdev = {
1460         .ndo_open            = virtnet_open,
1461         .ndo_stop            = virtnet_close,
1462         .ndo_start_xmit      = start_xmit,
1463         .ndo_validate_addr   = eth_validate_addr,
1464         .ndo_set_mac_address = virtnet_set_mac_address,
1465         .ndo_set_rx_mode     = virtnet_set_rx_mode,
1466         .ndo_change_mtu      = virtnet_change_mtu,
1467         .ndo_get_stats64     = virtnet_stats,
1468         .ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1469         .ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1470 #ifdef CONFIG_NET_POLL_CONTROLLER
1471         .ndo_poll_controller = virtnet_netpoll,
1472 #endif
1473 #ifdef CONFIG_NET_RX_BUSY_POLL
1474         .ndo_busy_poll          = virtnet_busy_poll,
1475 #endif
1476 };
1477 
1478 static void virtnet_config_changed_work(struct work_struct *work)
1479 {
1480         struct virtnet_info *vi =
1481                 container_of(work, struct virtnet_info, config_work);
1482         u16 v;
1483 
1484         if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1485                                  struct virtio_net_config, status, &v) < 0)
1486                 return;
1487 
1488         if (v & VIRTIO_NET_S_ANNOUNCE) {
1489                 netdev_notify_peers(vi->dev);
1490                 virtnet_ack_link_announce(vi);
1491         }
1492 
1493         /* Ignore unknown (future) status bits */
1494         v &= VIRTIO_NET_S_LINK_UP;
1495 
1496         if (vi->status == v)
1497                 return;
1498 
1499         vi->status = v;
1500 
1501         if (vi->status & VIRTIO_NET_S_LINK_UP) {
1502                 netif_carrier_on(vi->dev);
1503                 netif_tx_wake_all_queues(vi->dev);
1504         } else {
1505                 netif_carrier_off(vi->dev);
1506                 netif_tx_stop_all_queues(vi->dev);
1507         }
1508 }
1509 
1510 static void virtnet_config_changed(struct virtio_device *vdev)
1511 {
1512         struct virtnet_info *vi = vdev->priv;
1513 
1514         schedule_work(&vi->config_work);
1515 }
1516 
1517 static void virtnet_free_queues(struct virtnet_info *vi)
1518 {
1519         int i;
1520 
1521         for (i = 0; i < vi->max_queue_pairs; i++) {
1522                 napi_hash_del(&vi->rq[i].napi);
1523                 netif_napi_del(&vi->rq[i].napi);
1524         }
1525 
1526         kfree(vi->rq);
1527         kfree(vi->sq);
1528 }
1529 
1530 static void free_receive_bufs(struct virtnet_info *vi)
1531 {
1532         int i;
1533 
1534         for (i = 0; i < vi->max_queue_pairs; i++) {
1535                 while (vi->rq[i].pages)
1536                         __free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1537         }
1538 }
1539 
1540 static void free_receive_page_frags(struct virtnet_info *vi)
1541 {
1542         int i;
1543         for (i = 0; i < vi->max_queue_pairs; i++)
1544                 if (vi->rq[i].alloc_frag.page)
1545                         put_page(vi->rq[i].alloc_frag.page);
1546 }
1547 
1548 static void free_unused_bufs(struct virtnet_info *vi)
1549 {
1550         void *buf;
1551         int i;
1552 
1553         for (i = 0; i < vi->max_queue_pairs; i++) {
1554                 struct virtqueue *vq = vi->sq[i].vq;
1555                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1556                         dev_kfree_skb(buf);
1557         }
1558 
1559         for (i = 0; i < vi->max_queue_pairs; i++) {
1560                 struct virtqueue *vq = vi->rq[i].vq;
1561 
1562                 while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1563                         if (vi->mergeable_rx_bufs) {
1564                                 unsigned long ctx = (unsigned long)buf;
1565                                 void *base = mergeable_ctx_to_buf_address(ctx);
1566                                 put_page(virt_to_head_page(base));
1567                         } else if (vi->big_packets) {
1568                                 give_pages(&vi->rq[i], buf);
1569                         } else {
1570                                 dev_kfree_skb(buf);
1571                         }
1572                 }
1573         }
1574 }
1575 
1576 static void virtnet_del_vqs(struct virtnet_info *vi)
1577 {
1578         struct virtio_device *vdev = vi->vdev;
1579 
1580         virtnet_clean_affinity(vi, -1);
1581 
1582         vdev->config->del_vqs(vdev);
1583 
1584         virtnet_free_queues(vi);
1585 }
1586 
1587 static int virtnet_find_vqs(struct virtnet_info *vi)
1588 {
1589         vq_callback_t **callbacks;
1590         struct virtqueue **vqs;
1591         int ret = -ENOMEM;
1592         int i, total_vqs;
1593         const char **names;
1594 
1595         /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1596          * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1597          * possible control vq.
1598          */
1599         total_vqs = vi->max_queue_pairs * 2 +
1600                     virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1601 
1602         /* Allocate space for find_vqs parameters */
1603         vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1604         if (!vqs)
1605                 goto err_vq;
1606         callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1607         if (!callbacks)
1608                 goto err_callback;
1609         names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1610         if (!names)
1611                 goto err_names;
1612 
1613         /* Parameters for control virtqueue, if any */
1614         if (vi->has_cvq) {
1615                 callbacks[total_vqs - 1] = NULL;
1616                 names[total_vqs - 1] = "control";
1617         }
1618 
1619         /* Allocate/initialize parameters for send/receive virtqueues */
1620         for (i = 0; i < vi->max_queue_pairs; i++) {
1621                 callbacks[rxq2vq(i)] = skb_recv_done;
1622                 callbacks[txq2vq(i)] = skb_xmit_done;
1623                 sprintf(vi->rq[i].name, "input.%d", i);
1624                 sprintf(vi->sq[i].name, "output.%d", i);
1625                 names[rxq2vq(i)] = vi->rq[i].name;
1626                 names[txq2vq(i)] = vi->sq[i].name;
1627         }
1628 
1629         ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1630                                          names);
1631         if (ret)
1632                 goto err_find;
1633 
1634         if (vi->has_cvq) {
1635                 vi->cvq = vqs[total_vqs - 1];
1636                 if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1637                         vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1638         }
1639 
1640         for (i = 0; i < vi->max_queue_pairs; i++) {
1641                 vi->rq[i].vq = vqs[rxq2vq(i)];
1642                 vi->sq[i].vq = vqs[txq2vq(i)];
1643         }
1644 
1645         kfree(names);
1646         kfree(callbacks);
1647         kfree(vqs);
1648 
1649         return 0;
1650 
1651 err_find:
1652         kfree(names);
1653 err_names:
1654         kfree(callbacks);
1655 err_callback:
1656         kfree(vqs);
1657 err_vq:
1658         return ret;
1659 }
1660 
1661 static int virtnet_alloc_queues(struct virtnet_info *vi)
1662 {
1663         int i;
1664 
1665         vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1666         if (!vi->sq)
1667                 goto err_sq;
1668         vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1669         if (!vi->rq)
1670                 goto err_rq;
1671 
1672         INIT_DELAYED_WORK(&vi->refill, refill_work);
1673         for (i = 0; i < vi->max_queue_pairs; i++) {
1674                 vi->rq[i].pages = NULL;
1675                 netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1676                                napi_weight);
1677 
1678                 sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1679                 ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
1680                 sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1681         }
1682 
1683         return 0;
1684 
1685 err_rq:
1686         kfree(vi->sq);
1687 err_sq:
1688         return -ENOMEM;
1689 }
1690 
1691 static int init_vqs(struct virtnet_info *vi)
1692 {
1693         int ret;
1694 
1695         /* Allocate send & receive queues */
1696         ret = virtnet_alloc_queues(vi);
1697         if (ret)
1698                 goto err;
1699 
1700         ret = virtnet_find_vqs(vi);
1701         if (ret)
1702                 goto err_free;
1703 
1704         get_online_cpus();
1705         virtnet_set_affinity(vi);
1706         put_online_cpus();
1707 
1708         return 0;
1709 
1710 err_free:
1711         virtnet_free_queues(vi);
1712 err:
1713         return ret;
1714 }
1715 
1716 #ifdef CONFIG_SYSFS
1717 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1718                 struct rx_queue_attribute *attribute, char *buf)
1719 {
1720         struct virtnet_info *vi = netdev_priv(queue->dev);
1721         unsigned int queue_index = get_netdev_rx_queue_index(queue);
1722         struct ewma_pkt_len *avg;
1723 
1724         BUG_ON(queue_index >= vi->max_queue_pairs);
1725         avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1726         return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1727 }
1728 
1729 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1730         __ATTR_RO(mergeable_rx_buffer_size);
1731 
1732 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1733         &mergeable_rx_buffer_size_attribute.attr,
1734         NULL
1735 };
1736 
1737 static const struct attribute_group virtio_net_mrg_rx_group = {
1738         .name = "virtio_net",
1739         .attrs = virtio_net_mrg_rx_attrs
1740 };
1741 #endif
1742 
1743 static bool virtnet_fail_on_feature(struct virtio_device *vdev,
1744                                     unsigned int fbit,
1745                                     const char *fname, const char *dname)
1746 {
1747         if (!virtio_has_feature(vdev, fbit))
1748                 return false;
1749 
1750         dev_err(&vdev->dev, "device advertises feature %s but not %s",
1751                 fname, dname);
1752 
1753         return true;
1754 }
1755 
1756 #define VIRTNET_FAIL_ON(vdev, fbit, dbit)                       \
1757         virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
1758 
1759 static bool virtnet_validate_features(struct virtio_device *vdev)
1760 {
1761         if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
1762             (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
1763                              "VIRTIO_NET_F_CTRL_VQ") ||
1764              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
1765                              "VIRTIO_NET_F_CTRL_VQ") ||
1766              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
1767                              "VIRTIO_NET_F_CTRL_VQ") ||
1768              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
1769              VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
1770                              "VIRTIO_NET_F_CTRL_VQ"))) {
1771                 return false;
1772         }
1773 
1774         return true;
1775 }
1776 
1777 static int virtnet_probe(struct virtio_device *vdev)
1778 {
1779         int i, err;
1780         struct net_device *dev;
1781         struct virtnet_info *vi;
1782         u16 max_queue_pairs;
1783 
1784         if (!vdev->config->get) {
1785                 dev_err(&vdev->dev, "%s failure: config access disabled\n",
1786                         __func__);
1787                 return -EINVAL;
1788         }
1789 
1790         if (!virtnet_validate_features(vdev))
1791                 return -EINVAL;
1792 
1793         /* Find if host supports multiqueue virtio_net device */
1794         err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1795                                    struct virtio_net_config,
1796                                    max_virtqueue_pairs, &max_queue_pairs);
1797 
1798         /* We need at least 2 queue's */
1799         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1800             max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1801             !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1802                 max_queue_pairs = 1;
1803 
1804         /* Allocate ourselves a network device with room for our info */
1805         dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1806         if (!dev)
1807                 return -ENOMEM;
1808 
1809         /* Set up network device as normal. */
1810         dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1811         dev->netdev_ops = &virtnet_netdev;
1812         dev->features = NETIF_F_HIGHDMA;
1813 
1814         dev->ethtool_ops = &virtnet_ethtool_ops;
1815         SET_NETDEV_DEV(dev, &vdev->dev);
1816 
1817         /* Do we support "hardware" checksums? */
1818         if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1819                 /* This opens up the world of extra features. */
1820                 dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1821                 if (csum)
1822                         dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
1823 
1824                 if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1825                         dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1826                                 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
1827                 }
1828                 /* Individual feature bits: what can host handle? */
1829                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1830                         dev->hw_features |= NETIF_F_TSO;
1831                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1832                         dev->hw_features |= NETIF_F_TSO6;
1833                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1834                         dev->hw_features |= NETIF_F_TSO_ECN;
1835                 if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1836                         dev->hw_features |= NETIF_F_UFO;
1837 
1838                 dev->features |= NETIF_F_GSO_ROBUST;
1839 
1840                 if (gso)
1841                         dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1842                 /* (!csum && gso) case will be fixed by register_netdev() */
1843         }
1844         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1845                 dev->features |= NETIF_F_RXCSUM;
1846 
1847         dev->vlan_features = dev->features;
1848 
1849         /* Configuration may specify what MAC to use.  Otherwise random. */
1850         if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1851                 virtio_cread_bytes(vdev,
1852                                    offsetof(struct virtio_net_config, mac),
1853                                    dev->dev_addr, dev->addr_len);
1854         else
1855                 eth_hw_addr_random(dev);
1856 
1857         /* Set up our device-specific information */
1858         vi = netdev_priv(dev);
1859         vi->dev = dev;
1860         vi->vdev = vdev;
1861         vdev->priv = vi;
1862         vi->stats = alloc_percpu(struct virtnet_stats);
1863         err = -ENOMEM;
1864         if (vi->stats == NULL)
1865                 goto free;
1866 
1867         for_each_possible_cpu(i) {
1868                 struct virtnet_stats *virtnet_stats;
1869                 virtnet_stats = per_cpu_ptr(vi->stats, i);
1870                 u64_stats_init(&virtnet_stats->tx_syncp);
1871                 u64_stats_init(&virtnet_stats->rx_syncp);
1872         }
1873 
1874         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1875 
1876         /* If we can receive ANY GSO packets, we must allocate large ones. */
1877         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1878             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1879             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1880             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1881                 vi->big_packets = true;
1882 
1883         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1884                 vi->mergeable_rx_bufs = true;
1885 
1886         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
1887             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1888                 vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1889         else
1890                 vi->hdr_len = sizeof(struct virtio_net_hdr);
1891 
1892         if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
1893             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
1894                 vi->any_header_sg = true;
1895 
1896         if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1897                 vi->has_cvq = true;
1898 
1899         if (vi->any_header_sg)
1900                 dev->needed_headroom = vi->hdr_len;
1901 
1902         /* Use single tx/rx queue pair as default */
1903         vi->curr_queue_pairs = 1;
1904         vi->max_queue_pairs = max_queue_pairs;
1905 
1906         /* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1907         err = init_vqs(vi);
1908         if (err)
1909                 goto free_stats;
1910 
1911 #ifdef CONFIG_SYSFS
1912         if (vi->mergeable_rx_bufs)
1913                 dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1914 #endif
1915         netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1916         netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1917 
1918         virtnet_init_settings(dev);
1919 
1920         err = register_netdev(dev);
1921         if (err) {
1922                 pr_debug("virtio_net: registering device failed\n");
1923                 goto free_vqs;
1924         }
1925 
1926         virtio_device_ready(vdev);
1927 
1928         /* Last of all, set up some receive buffers. */
1929         for (i = 0; i < vi->curr_queue_pairs; i++) {
1930                 try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
1931 
1932                 /* If we didn't even get one input buffer, we're useless. */
1933                 if (vi->rq[i].vq->num_free ==
1934                     virtqueue_get_vring_size(vi->rq[i].vq)) {
1935                         free_unused_bufs(vi);
1936                         err = -ENOMEM;
1937                         goto free_recv_bufs;
1938                 }
1939         }
1940 
1941         vi->nb.notifier_call = &virtnet_cpu_callback;
1942         err = register_hotcpu_notifier(&vi->nb);
1943         if (err) {
1944                 pr_debug("virtio_net: registering cpu notifier failed\n");
1945                 goto free_recv_bufs;
1946         }
1947 
1948         /* Assume link up if device can't report link status,
1949            otherwise get link status from config. */
1950         if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1951                 netif_carrier_off(dev);
1952                 schedule_work(&vi->config_work);
1953         } else {
1954                 vi->status = VIRTIO_NET_S_LINK_UP;
1955                 netif_carrier_on(dev);
1956         }
1957 
1958         pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1959                  dev->name, max_queue_pairs);
1960 
1961         return 0;
1962 
1963 free_recv_bufs:
1964         vi->vdev->config->reset(vdev);
1965 
1966         free_receive_bufs(vi);
1967         unregister_netdev(dev);
1968 free_vqs:
1969         cancel_delayed_work_sync(&vi->refill);
1970         free_receive_page_frags(vi);
1971         virtnet_del_vqs(vi);
1972 free_stats:
1973         free_percpu(vi->stats);
1974 free:
1975         free_netdev(dev);
1976         return err;
1977 }
1978 
1979 static void remove_vq_common(struct virtnet_info *vi)
1980 {
1981         vi->vdev->config->reset(vi->vdev);
1982 
1983         /* Free unused buffers in both send and recv, if any. */
1984         free_unused_bufs(vi);
1985 
1986         free_receive_bufs(vi);
1987 
1988         free_receive_page_frags(vi);
1989 
1990         virtnet_del_vqs(vi);
1991 }
1992 
1993 static void virtnet_remove(struct virtio_device *vdev)
1994 {
1995         struct virtnet_info *vi = vdev->priv;
1996 
1997         unregister_hotcpu_notifier(&vi->nb);
1998 
1999         /* Make sure no work handler is accessing the device. */
2000         flush_work(&vi->config_work);
2001 
2002         unregister_netdev(vi->dev);
2003 
2004         remove_vq_common(vi);
2005 
2006         free_percpu(vi->stats);
2007         free_netdev(vi->dev);
2008 }
2009 
2010 #ifdef CONFIG_PM_SLEEP
2011 static int virtnet_freeze(struct virtio_device *vdev)
2012 {
2013         struct virtnet_info *vi = vdev->priv;
2014         int i;
2015 
2016         unregister_hotcpu_notifier(&vi->nb);
2017 
2018         /* Make sure no work handler is accessing the device */
2019         flush_work(&vi->config_work);
2020 
2021         netif_device_detach(vi->dev);
2022         cancel_delayed_work_sync(&vi->refill);
2023 
2024         if (netif_running(vi->dev)) {
2025                 for (i = 0; i < vi->max_queue_pairs; i++)
2026                         napi_disable(&vi->rq[i].napi);
2027         }
2028 
2029         remove_vq_common(vi);
2030 
2031         return 0;
2032 }
2033 
2034 static int virtnet_restore(struct virtio_device *vdev)
2035 {
2036         struct virtnet_info *vi = vdev->priv;
2037         int err, i;
2038 
2039         err = init_vqs(vi);
2040         if (err)
2041                 return err;
2042 
2043         virtio_device_ready(vdev);
2044 
2045         if (netif_running(vi->dev)) {
2046                 for (i = 0; i < vi->curr_queue_pairs; i++)
2047                         if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
2048                                 schedule_delayed_work(&vi->refill, 0);
2049 
2050                 for (i = 0; i < vi->max_queue_pairs; i++)
2051                         virtnet_napi_enable(&vi->rq[i]);
2052         }
2053 
2054         netif_device_attach(vi->dev);
2055 
2056         rtnl_lock();
2057         virtnet_set_queues(vi, vi->curr_queue_pairs);
2058         rtnl_unlock();
2059 
2060         err = register_hotcpu_notifier(&vi->nb);
2061         if (err)
2062                 return err;
2063 
2064         return 0;
2065 }
2066 #endif
2067 
2068 static struct virtio_device_id id_table[] = {
2069         { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
2070         { 0 },
2071 };
2072 
2073 static unsigned int features[] = {
2074         VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
2075         VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
2076         VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
2077         VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
2078         VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
2079         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
2080         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
2081         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
2082         VIRTIO_NET_F_CTRL_MAC_ADDR,
2083         VIRTIO_F_ANY_LAYOUT,
2084 };
2085 
2086 static struct virtio_driver virtio_net_driver = {
2087         .feature_table = features,
2088         .feature_table_size = ARRAY_SIZE(features),
2089         .driver.name =  KBUILD_MODNAME,
2090         .driver.owner = THIS_MODULE,
2091         .id_table =     id_table,
2092         .probe =        virtnet_probe,
2093         .remove =       virtnet_remove,
2094         .config_changed = virtnet_config_changed,
2095 #ifdef CONFIG_PM_SLEEP
2096         .freeze =       virtnet_freeze,
2097         .restore =      virtnet_restore,
2098 #endif
2099 };
2100 
2101 module_virtio_driver(virtio_net_driver);
2102 
2103 MODULE_DEVICE_TABLE(virtio, id_table);
2104 MODULE_DESCRIPTION("Virtio network driver");
2105 MODULE_LICENSE("GPL");
2106 

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