xref: /openbmc/linux/drivers/net/virtio_net.c (revision 609e478b)
1 /* A network driver using virtio.
2  *
3  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 //#define DEBUG
19 #include <linux/netdevice.h>
20 #include <linux/etherdevice.h>
21 #include <linux/ethtool.h>
22 #include <linux/module.h>
23 #include <linux/virtio.h>
24 #include <linux/virtio_net.h>
25 #include <linux/scatterlist.h>
26 #include <linux/if_vlan.h>
27 #include <linux/slab.h>
28 #include <linux/cpu.h>
29 #include <linux/average.h>
30 #include <net/busy_poll.h>
31 
32 static int napi_weight = NAPI_POLL_WEIGHT;
33 module_param(napi_weight, int, 0444);
34 
35 static bool csum = true, gso = true;
36 module_param(csum, bool, 0444);
37 module_param(gso, bool, 0444);
38 
39 /* FIXME: MTU in config. */
40 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
41 #define GOOD_COPY_LEN	128
42 
43 /* Weight used for the RX packet size EWMA. The average packet size is used to
44  * determine the packet buffer size when refilling RX rings. As the entire RX
45  * ring may be refilled at once, the weight is chosen so that the EWMA will be
46  * insensitive to short-term, transient changes in packet size.
47  */
48 #define RECEIVE_AVG_WEIGHT 64
49 
50 /* Minimum alignment for mergeable packet buffers. */
51 #define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
52 
53 #define VIRTNET_DRIVER_VERSION "1.0.0"
54 
55 struct virtnet_stats {
56 	struct u64_stats_sync tx_syncp;
57 	struct u64_stats_sync rx_syncp;
58 	u64 tx_bytes;
59 	u64 tx_packets;
60 
61 	u64 rx_bytes;
62 	u64 rx_packets;
63 };
64 
65 /* Internal representation of a send virtqueue */
66 struct send_queue {
67 	/* Virtqueue associated with this send _queue */
68 	struct virtqueue *vq;
69 
70 	/* TX: fragments + linear part + virtio header */
71 	struct scatterlist sg[MAX_SKB_FRAGS + 2];
72 
73 	/* Name of the send queue: output.$index */
74 	char name[40];
75 };
76 
77 /* Internal representation of a receive virtqueue */
78 struct receive_queue {
79 	/* Virtqueue associated with this receive_queue */
80 	struct virtqueue *vq;
81 
82 	struct napi_struct napi;
83 
84 	/* Chain pages by the private ptr. */
85 	struct page *pages;
86 
87 	/* Average packet length for mergeable receive buffers. */
88 	struct ewma mrg_avg_pkt_len;
89 
90 	/* Page frag for packet buffer allocation. */
91 	struct page_frag alloc_frag;
92 
93 	/* RX: fragments + linear part + virtio header */
94 	struct scatterlist sg[MAX_SKB_FRAGS + 2];
95 
96 	/* Name of this receive queue: input.$index */
97 	char name[40];
98 };
99 
100 struct virtnet_info {
101 	struct virtio_device *vdev;
102 	struct virtqueue *cvq;
103 	struct net_device *dev;
104 	struct send_queue *sq;
105 	struct receive_queue *rq;
106 	unsigned int status;
107 
108 	/* Max # of queue pairs supported by the device */
109 	u16 max_queue_pairs;
110 
111 	/* # of queue pairs currently used by the driver */
112 	u16 curr_queue_pairs;
113 
114 	/* I like... big packets and I cannot lie! */
115 	bool big_packets;
116 
117 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
118 	bool mergeable_rx_bufs;
119 
120 	/* Has control virtqueue */
121 	bool has_cvq;
122 
123 	/* Host can handle any s/g split between our header and packet data */
124 	bool any_header_sg;
125 
126 	/* Active statistics */
127 	struct virtnet_stats __percpu *stats;
128 
129 	/* Work struct for refilling if we run low on memory. */
130 	struct delayed_work refill;
131 
132 	/* Work struct for config space updates */
133 	struct work_struct config_work;
134 
135 	/* Does the affinity hint is set for virtqueues? */
136 	bool affinity_hint_set;
137 
138 	/* CPU hot plug notifier */
139 	struct notifier_block nb;
140 };
141 
142 struct skb_vnet_hdr {
143 	union {
144 		struct virtio_net_hdr hdr;
145 		struct virtio_net_hdr_mrg_rxbuf mhdr;
146 	};
147 };
148 
149 struct padded_vnet_hdr {
150 	struct virtio_net_hdr hdr;
151 	/*
152 	 * virtio_net_hdr should be in a separated sg buffer because of a
153 	 * QEMU bug, and data sg buffer shares same page with this header sg.
154 	 * This padding makes next sg 16 byte aligned after virtio_net_hdr.
155 	 */
156 	char padding[6];
157 };
158 
159 /* Converting between virtqueue no. and kernel tx/rx queue no.
160  * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
161  */
162 static int vq2txq(struct virtqueue *vq)
163 {
164 	return (vq->index - 1) / 2;
165 }
166 
167 static int txq2vq(int txq)
168 {
169 	return txq * 2 + 1;
170 }
171 
172 static int vq2rxq(struct virtqueue *vq)
173 {
174 	return vq->index / 2;
175 }
176 
177 static int rxq2vq(int rxq)
178 {
179 	return rxq * 2;
180 }
181 
182 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
183 {
184 	return (struct skb_vnet_hdr *)skb->cb;
185 }
186 
187 /*
188  * private is used to chain pages for big packets, put the whole
189  * most recent used list in the beginning for reuse
190  */
191 static void give_pages(struct receive_queue *rq, struct page *page)
192 {
193 	struct page *end;
194 
195 	/* Find end of list, sew whole thing into vi->rq.pages. */
196 	for (end = page; end->private; end = (struct page *)end->private);
197 	end->private = (unsigned long)rq->pages;
198 	rq->pages = page;
199 }
200 
201 static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
202 {
203 	struct page *p = rq->pages;
204 
205 	if (p) {
206 		rq->pages = (struct page *)p->private;
207 		/* clear private here, it is used to chain pages */
208 		p->private = 0;
209 	} else
210 		p = alloc_page(gfp_mask);
211 	return p;
212 }
213 
214 static void skb_xmit_done(struct virtqueue *vq)
215 {
216 	struct virtnet_info *vi = vq->vdev->priv;
217 
218 	/* Suppress further interrupts. */
219 	virtqueue_disable_cb(vq);
220 
221 	/* We were probably waiting for more output buffers. */
222 	netif_wake_subqueue(vi->dev, vq2txq(vq));
223 }
224 
225 static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
226 {
227 	unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
228 	return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
229 }
230 
231 static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
232 {
233 	return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
234 
235 }
236 
237 static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
238 {
239 	unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
240 	return (unsigned long)buf | (size - 1);
241 }
242 
243 /* Called from bottom half context */
244 static struct sk_buff *page_to_skb(struct receive_queue *rq,
245 				   struct page *page, unsigned int offset,
246 				   unsigned int len, unsigned int truesize)
247 {
248 	struct virtnet_info *vi = rq->vq->vdev->priv;
249 	struct sk_buff *skb;
250 	struct skb_vnet_hdr *hdr;
251 	unsigned int copy, hdr_len, hdr_padded_len;
252 	char *p;
253 
254 	p = page_address(page) + offset;
255 
256 	/* copy small packet so we can reuse these pages for small data */
257 	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
258 	if (unlikely(!skb))
259 		return NULL;
260 
261 	hdr = skb_vnet_hdr(skb);
262 
263 	if (vi->mergeable_rx_bufs) {
264 		hdr_len = sizeof hdr->mhdr;
265 		hdr_padded_len = sizeof hdr->mhdr;
266 	} else {
267 		hdr_len = sizeof hdr->hdr;
268 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
269 	}
270 
271 	memcpy(hdr, p, hdr_len);
272 
273 	len -= hdr_len;
274 	offset += hdr_padded_len;
275 	p += hdr_padded_len;
276 
277 	copy = len;
278 	if (copy > skb_tailroom(skb))
279 		copy = skb_tailroom(skb);
280 	memcpy(skb_put(skb, copy), p, copy);
281 
282 	len -= copy;
283 	offset += copy;
284 
285 	if (vi->mergeable_rx_bufs) {
286 		if (len)
287 			skb_add_rx_frag(skb, 0, page, offset, len, truesize);
288 		else
289 			put_page(page);
290 		return skb;
291 	}
292 
293 	/*
294 	 * Verify that we can indeed put this data into a skb.
295 	 * This is here to handle cases when the device erroneously
296 	 * tries to receive more than is possible. This is usually
297 	 * the case of a broken device.
298 	 */
299 	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
300 		net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
301 		dev_kfree_skb(skb);
302 		return NULL;
303 	}
304 	BUG_ON(offset >= PAGE_SIZE);
305 	while (len) {
306 		unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
307 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
308 				frag_size, truesize);
309 		len -= frag_size;
310 		page = (struct page *)page->private;
311 		offset = 0;
312 	}
313 
314 	if (page)
315 		give_pages(rq, page);
316 
317 	return skb;
318 }
319 
320 static struct sk_buff *receive_small(void *buf, unsigned int len)
321 {
322 	struct sk_buff * skb = buf;
323 
324 	len -= sizeof(struct virtio_net_hdr);
325 	skb_trim(skb, len);
326 
327 	return skb;
328 }
329 
330 static struct sk_buff *receive_big(struct net_device *dev,
331 				   struct receive_queue *rq,
332 				   void *buf,
333 				   unsigned int len)
334 {
335 	struct page *page = buf;
336 	struct sk_buff *skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
337 
338 	if (unlikely(!skb))
339 		goto err;
340 
341 	return skb;
342 
343 err:
344 	dev->stats.rx_dropped++;
345 	give_pages(rq, page);
346 	return NULL;
347 }
348 
349 static struct sk_buff *receive_mergeable(struct net_device *dev,
350 					 struct receive_queue *rq,
351 					 unsigned long ctx,
352 					 unsigned int len)
353 {
354 	void *buf = mergeable_ctx_to_buf_address(ctx);
355 	struct skb_vnet_hdr *hdr = buf;
356 	int num_buf = hdr->mhdr.num_buffers;
357 	struct page *page = virt_to_head_page(buf);
358 	int offset = buf - page_address(page);
359 	unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
360 
361 	struct sk_buff *head_skb = page_to_skb(rq, page, offset, len, truesize);
362 	struct sk_buff *curr_skb = head_skb;
363 
364 	if (unlikely(!curr_skb))
365 		goto err_skb;
366 	while (--num_buf) {
367 		int num_skb_frags;
368 
369 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
370 		if (unlikely(!ctx)) {
371 			pr_debug("%s: rx error: %d buffers out of %d missing\n",
372 				 dev->name, num_buf, hdr->mhdr.num_buffers);
373 			dev->stats.rx_length_errors++;
374 			goto err_buf;
375 		}
376 
377 		buf = mergeable_ctx_to_buf_address(ctx);
378 		page = virt_to_head_page(buf);
379 
380 		num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
381 		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
382 			struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
383 
384 			if (unlikely(!nskb))
385 				goto err_skb;
386 			if (curr_skb == head_skb)
387 				skb_shinfo(curr_skb)->frag_list = nskb;
388 			else
389 				curr_skb->next = nskb;
390 			curr_skb = nskb;
391 			head_skb->truesize += nskb->truesize;
392 			num_skb_frags = 0;
393 		}
394 		truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
395 		if (curr_skb != head_skb) {
396 			head_skb->data_len += len;
397 			head_skb->len += len;
398 			head_skb->truesize += truesize;
399 		}
400 		offset = buf - page_address(page);
401 		if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
402 			put_page(page);
403 			skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
404 					     len, truesize);
405 		} else {
406 			skb_add_rx_frag(curr_skb, num_skb_frags, page,
407 					offset, len, truesize);
408 		}
409 	}
410 
411 	ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);
412 	return head_skb;
413 
414 err_skb:
415 	put_page(page);
416 	while (--num_buf) {
417 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
418 		if (unlikely(!ctx)) {
419 			pr_debug("%s: rx error: %d buffers missing\n",
420 				 dev->name, num_buf);
421 			dev->stats.rx_length_errors++;
422 			break;
423 		}
424 		page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
425 		put_page(page);
426 	}
427 err_buf:
428 	dev->stats.rx_dropped++;
429 	dev_kfree_skb(head_skb);
430 	return NULL;
431 }
432 
433 static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
434 {
435 	struct virtnet_info *vi = rq->vq->vdev->priv;
436 	struct net_device *dev = vi->dev;
437 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
438 	struct sk_buff *skb;
439 	struct skb_vnet_hdr *hdr;
440 
441 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
442 		pr_debug("%s: short packet %i\n", dev->name, len);
443 		dev->stats.rx_length_errors++;
444 		if (vi->mergeable_rx_bufs) {
445 			unsigned long ctx = (unsigned long)buf;
446 			void *base = mergeable_ctx_to_buf_address(ctx);
447 			put_page(virt_to_head_page(base));
448 		} else if (vi->big_packets) {
449 			give_pages(rq, buf);
450 		} else {
451 			dev_kfree_skb(buf);
452 		}
453 		return;
454 	}
455 
456 	if (vi->mergeable_rx_bufs)
457 		skb = receive_mergeable(dev, rq, (unsigned long)buf, len);
458 	else if (vi->big_packets)
459 		skb = receive_big(dev, rq, buf, len);
460 	else
461 		skb = receive_small(buf, len);
462 
463 	if (unlikely(!skb))
464 		return;
465 
466 	hdr = skb_vnet_hdr(skb);
467 
468 	u64_stats_update_begin(&stats->rx_syncp);
469 	stats->rx_bytes += skb->len;
470 	stats->rx_packets++;
471 	u64_stats_update_end(&stats->rx_syncp);
472 
473 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
474 		pr_debug("Needs csum!\n");
475 		if (!skb_partial_csum_set(skb,
476 					  hdr->hdr.csum_start,
477 					  hdr->hdr.csum_offset))
478 			goto frame_err;
479 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
480 		skb->ip_summed = CHECKSUM_UNNECESSARY;
481 	}
482 
483 	skb->protocol = eth_type_trans(skb, dev);
484 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
485 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
486 
487 	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
488 		pr_debug("GSO!\n");
489 		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
490 		case VIRTIO_NET_HDR_GSO_TCPV4:
491 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
492 			break;
493 		case VIRTIO_NET_HDR_GSO_UDP:
494 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
495 			break;
496 		case VIRTIO_NET_HDR_GSO_TCPV6:
497 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
498 			break;
499 		default:
500 			net_warn_ratelimited("%s: bad gso type %u.\n",
501 					     dev->name, hdr->hdr.gso_type);
502 			goto frame_err;
503 		}
504 
505 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
506 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
507 
508 		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
509 		if (skb_shinfo(skb)->gso_size == 0) {
510 			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
511 			goto frame_err;
512 		}
513 
514 		/* Header must be checked, and gso_segs computed. */
515 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
516 		skb_shinfo(skb)->gso_segs = 0;
517 	}
518 
519 	skb_mark_napi_id(skb, &rq->napi);
520 
521 	netif_receive_skb(skb);
522 	return;
523 
524 frame_err:
525 	dev->stats.rx_frame_errors++;
526 	dev_kfree_skb(skb);
527 }
528 
529 static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
530 {
531 	struct virtnet_info *vi = rq->vq->vdev->priv;
532 	struct sk_buff *skb;
533 	struct skb_vnet_hdr *hdr;
534 	int err;
535 
536 	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
537 	if (unlikely(!skb))
538 		return -ENOMEM;
539 
540 	skb_put(skb, GOOD_PACKET_LEN);
541 
542 	hdr = skb_vnet_hdr(skb);
543 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
544 	sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
545 	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
546 
547 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
548 	if (err < 0)
549 		dev_kfree_skb(skb);
550 
551 	return err;
552 }
553 
554 static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
555 {
556 	struct page *first, *list = NULL;
557 	char *p;
558 	int i, err, offset;
559 
560 	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
561 
562 	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
563 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
564 		first = get_a_page(rq, gfp);
565 		if (!first) {
566 			if (list)
567 				give_pages(rq, list);
568 			return -ENOMEM;
569 		}
570 		sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
571 
572 		/* chain new page in list head to match sg */
573 		first->private = (unsigned long)list;
574 		list = first;
575 	}
576 
577 	first = get_a_page(rq, gfp);
578 	if (!first) {
579 		give_pages(rq, list);
580 		return -ENOMEM;
581 	}
582 	p = page_address(first);
583 
584 	/* rq->sg[0], rq->sg[1] share the same page */
585 	/* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
586 	sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
587 
588 	/* rq->sg[1] for data packet, from offset */
589 	offset = sizeof(struct padded_vnet_hdr);
590 	sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
591 
592 	/* chain first in list head */
593 	first->private = (unsigned long)list;
594 	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
595 				  first, gfp);
596 	if (err < 0)
597 		give_pages(rq, first);
598 
599 	return err;
600 }
601 
602 static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
603 {
604 	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
605 	unsigned int len;
606 
607 	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
608 			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
609 	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
610 }
611 
612 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
613 {
614 	struct page_frag *alloc_frag = &rq->alloc_frag;
615 	char *buf;
616 	unsigned long ctx;
617 	int err;
618 	unsigned int len, hole;
619 
620 	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
621 	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
622 		return -ENOMEM;
623 
624 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
625 	ctx = mergeable_buf_to_ctx(buf, len);
626 	get_page(alloc_frag->page);
627 	alloc_frag->offset += len;
628 	hole = alloc_frag->size - alloc_frag->offset;
629 	if (hole < len) {
630 		/* To avoid internal fragmentation, if there is very likely not
631 		 * enough space for another buffer, add the remaining space to
632 		 * the current buffer. This extra space is not included in
633 		 * the truesize stored in ctx.
634 		 */
635 		len += hole;
636 		alloc_frag->offset += hole;
637 	}
638 
639 	sg_init_one(rq->sg, buf, len);
640 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
641 	if (err < 0)
642 		put_page(virt_to_head_page(buf));
643 
644 	return err;
645 }
646 
647 /*
648  * Returns false if we couldn't fill entirely (OOM).
649  *
650  * Normally run in the receive path, but can also be run from ndo_open
651  * before we're receiving packets, or from refill_work which is
652  * careful to disable receiving (using napi_disable).
653  */
654 static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
655 {
656 	struct virtnet_info *vi = rq->vq->vdev->priv;
657 	int err;
658 	bool oom;
659 
660 	gfp |= __GFP_COLD;
661 	do {
662 		if (vi->mergeable_rx_bufs)
663 			err = add_recvbuf_mergeable(rq, gfp);
664 		else if (vi->big_packets)
665 			err = add_recvbuf_big(rq, gfp);
666 		else
667 			err = add_recvbuf_small(rq, gfp);
668 
669 		oom = err == -ENOMEM;
670 		if (err)
671 			break;
672 	} while (rq->vq->num_free);
673 	virtqueue_kick(rq->vq);
674 	return !oom;
675 }
676 
677 static void skb_recv_done(struct virtqueue *rvq)
678 {
679 	struct virtnet_info *vi = rvq->vdev->priv;
680 	struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
681 
682 	/* Schedule NAPI, Suppress further interrupts if successful. */
683 	if (napi_schedule_prep(&rq->napi)) {
684 		virtqueue_disable_cb(rvq);
685 		__napi_schedule(&rq->napi);
686 	}
687 }
688 
689 static void virtnet_napi_enable(struct receive_queue *rq)
690 {
691 	napi_enable(&rq->napi);
692 
693 	/* If all buffers were filled by other side before we napi_enabled, we
694 	 * won't get another interrupt, so process any outstanding packets
695 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
696 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
697 	if (napi_schedule_prep(&rq->napi)) {
698 		virtqueue_disable_cb(rq->vq);
699 		local_bh_disable();
700 		__napi_schedule(&rq->napi);
701 		local_bh_enable();
702 	}
703 }
704 
705 static void refill_work(struct work_struct *work)
706 {
707 	struct virtnet_info *vi =
708 		container_of(work, struct virtnet_info, refill.work);
709 	bool still_empty;
710 	int i;
711 
712 	for (i = 0; i < vi->curr_queue_pairs; i++) {
713 		struct receive_queue *rq = &vi->rq[i];
714 
715 		napi_disable(&rq->napi);
716 		still_empty = !try_fill_recv(rq, GFP_KERNEL);
717 		virtnet_napi_enable(rq);
718 
719 		/* In theory, this can happen: if we don't get any buffers in
720 		 * we will *never* try to fill again.
721 		 */
722 		if (still_empty)
723 			schedule_delayed_work(&vi->refill, HZ/2);
724 	}
725 }
726 
727 static int virtnet_receive(struct receive_queue *rq, int budget)
728 {
729 	struct virtnet_info *vi = rq->vq->vdev->priv;
730 	unsigned int len, received = 0;
731 	void *buf;
732 
733 	while (received < budget &&
734 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
735 		receive_buf(rq, buf, len);
736 		received++;
737 	}
738 
739 	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
740 		if (!try_fill_recv(rq, GFP_ATOMIC))
741 			schedule_delayed_work(&vi->refill, 0);
742 	}
743 
744 	return received;
745 }
746 
747 static int virtnet_poll(struct napi_struct *napi, int budget)
748 {
749 	struct receive_queue *rq =
750 		container_of(napi, struct receive_queue, napi);
751 	unsigned int r, received = 0;
752 
753 again:
754 	received += virtnet_receive(rq, budget - received);
755 
756 	/* Out of packets? */
757 	if (received < budget) {
758 		r = virtqueue_enable_cb_prepare(rq->vq);
759 		napi_complete(napi);
760 		if (unlikely(virtqueue_poll(rq->vq, r)) &&
761 		    napi_schedule_prep(napi)) {
762 			virtqueue_disable_cb(rq->vq);
763 			__napi_schedule(napi);
764 			goto again;
765 		}
766 	}
767 
768 	return received;
769 }
770 
771 #ifdef CONFIG_NET_RX_BUSY_POLL
772 /* must be called with local_bh_disable()d */
773 static int virtnet_busy_poll(struct napi_struct *napi)
774 {
775 	struct receive_queue *rq =
776 		container_of(napi, struct receive_queue, napi);
777 	struct virtnet_info *vi = rq->vq->vdev->priv;
778 	int r, received = 0, budget = 4;
779 
780 	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
781 		return LL_FLUSH_FAILED;
782 
783 	if (!napi_schedule_prep(napi))
784 		return LL_FLUSH_BUSY;
785 
786 	virtqueue_disable_cb(rq->vq);
787 
788 again:
789 	received += virtnet_receive(rq, budget);
790 
791 	r = virtqueue_enable_cb_prepare(rq->vq);
792 	clear_bit(NAPI_STATE_SCHED, &napi->state);
793 	if (unlikely(virtqueue_poll(rq->vq, r)) &&
794 	    napi_schedule_prep(napi)) {
795 		virtqueue_disable_cb(rq->vq);
796 		if (received < budget) {
797 			budget -= received;
798 			goto again;
799 		} else {
800 			__napi_schedule(napi);
801 		}
802 	}
803 
804 	return received;
805 }
806 #endif	/* CONFIG_NET_RX_BUSY_POLL */
807 
808 static int virtnet_open(struct net_device *dev)
809 {
810 	struct virtnet_info *vi = netdev_priv(dev);
811 	int i;
812 
813 	for (i = 0; i < vi->max_queue_pairs; i++) {
814 		if (i < vi->curr_queue_pairs)
815 			/* Make sure we have some buffers: if oom use wq. */
816 			if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
817 				schedule_delayed_work(&vi->refill, 0);
818 		virtnet_napi_enable(&vi->rq[i]);
819 	}
820 
821 	return 0;
822 }
823 
824 static void free_old_xmit_skbs(struct send_queue *sq)
825 {
826 	struct sk_buff *skb;
827 	unsigned int len;
828 	struct virtnet_info *vi = sq->vq->vdev->priv;
829 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
830 
831 	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
832 		pr_debug("Sent skb %p\n", skb);
833 
834 		u64_stats_update_begin(&stats->tx_syncp);
835 		stats->tx_bytes += skb->len;
836 		stats->tx_packets++;
837 		u64_stats_update_end(&stats->tx_syncp);
838 
839 		dev_kfree_skb_any(skb);
840 	}
841 }
842 
843 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
844 {
845 	struct skb_vnet_hdr *hdr;
846 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
847 	struct virtnet_info *vi = sq->vq->vdev->priv;
848 	unsigned num_sg;
849 	unsigned hdr_len;
850 	bool can_push;
851 
852 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
853 	if (vi->mergeable_rx_bufs)
854 		hdr_len = sizeof hdr->mhdr;
855 	else
856 		hdr_len = sizeof hdr->hdr;
857 
858 	can_push = vi->any_header_sg &&
859 		!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
860 		!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
861 	/* Even if we can, don't push here yet as this would skew
862 	 * csum_start offset below. */
863 	if (can_push)
864 		hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len);
865 	else
866 		hdr = skb_vnet_hdr(skb);
867 
868 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
869 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
870 		hdr->hdr.csum_start = skb_checksum_start_offset(skb);
871 		hdr->hdr.csum_offset = skb->csum_offset;
872 	} else {
873 		hdr->hdr.flags = 0;
874 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
875 	}
876 
877 	if (skb_is_gso(skb)) {
878 		hdr->hdr.hdr_len = skb_headlen(skb);
879 		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
880 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
881 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
882 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
883 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
884 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
885 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
886 		else
887 			BUG();
888 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
889 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
890 	} else {
891 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
892 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
893 	}
894 
895 	if (vi->mergeable_rx_bufs)
896 		hdr->mhdr.num_buffers = 0;
897 
898 	sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
899 	if (can_push) {
900 		__skb_push(skb, hdr_len);
901 		num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
902 		/* Pull header back to avoid skew in tx bytes calculations. */
903 		__skb_pull(skb, hdr_len);
904 	} else {
905 		sg_set_buf(sq->sg, hdr, hdr_len);
906 		num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
907 	}
908 	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
909 }
910 
911 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
912 {
913 	struct virtnet_info *vi = netdev_priv(dev);
914 	int qnum = skb_get_queue_mapping(skb);
915 	struct send_queue *sq = &vi->sq[qnum];
916 	int err;
917 	struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
918 	bool kick = !skb->xmit_more;
919 
920 	/* Free up any pending old buffers before queueing new ones. */
921 	free_old_xmit_skbs(sq);
922 
923 	/* Try to transmit */
924 	err = xmit_skb(sq, skb);
925 
926 	/* This should not happen! */
927 	if (unlikely(err)) {
928 		dev->stats.tx_fifo_errors++;
929 		if (net_ratelimit())
930 			dev_warn(&dev->dev,
931 				 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
932 		dev->stats.tx_dropped++;
933 		dev_kfree_skb_any(skb);
934 		return NETDEV_TX_OK;
935 	}
936 
937 	/* Don't wait up for transmitted skbs to be freed. */
938 	skb_orphan(skb);
939 	nf_reset(skb);
940 
941 	/* Apparently nice girls don't return TX_BUSY; stop the queue
942 	 * before it gets out of hand.  Naturally, this wastes entries. */
943 	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
944 		netif_stop_subqueue(dev, qnum);
945 		if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
946 			/* More just got used, free them then recheck. */
947 			free_old_xmit_skbs(sq);
948 			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
949 				netif_start_subqueue(dev, qnum);
950 				virtqueue_disable_cb(sq->vq);
951 			}
952 		}
953 	}
954 
955 	if (kick || netif_xmit_stopped(txq))
956 		virtqueue_kick(sq->vq);
957 
958 	return NETDEV_TX_OK;
959 }
960 
961 /*
962  * Send command via the control virtqueue and check status.  Commands
963  * supported by the hypervisor, as indicated by feature bits, should
964  * never fail unless improperly formatted.
965  */
966 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
967 				 struct scatterlist *out)
968 {
969 	struct scatterlist *sgs[4], hdr, stat;
970 	struct virtio_net_ctrl_hdr ctrl;
971 	virtio_net_ctrl_ack status = ~0;
972 	unsigned out_num = 0, tmp;
973 
974 	/* Caller should know better */
975 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
976 
977 	ctrl.class = class;
978 	ctrl.cmd = cmd;
979 	/* Add header */
980 	sg_init_one(&hdr, &ctrl, sizeof(ctrl));
981 	sgs[out_num++] = &hdr;
982 
983 	if (out)
984 		sgs[out_num++] = out;
985 
986 	/* Add return status. */
987 	sg_init_one(&stat, &status, sizeof(status));
988 	sgs[out_num] = &stat;
989 
990 	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
991 	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
992 
993 	if (unlikely(!virtqueue_kick(vi->cvq)))
994 		return status == VIRTIO_NET_OK;
995 
996 	/* Spin for a response, the kick causes an ioport write, trapping
997 	 * into the hypervisor, so the request should be handled immediately.
998 	 */
999 	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
1000 	       !virtqueue_is_broken(vi->cvq))
1001 		cpu_relax();
1002 
1003 	return status == VIRTIO_NET_OK;
1004 }
1005 
1006 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1007 {
1008 	struct virtnet_info *vi = netdev_priv(dev);
1009 	struct virtio_device *vdev = vi->vdev;
1010 	int ret;
1011 	struct sockaddr *addr = p;
1012 	struct scatterlist sg;
1013 
1014 	ret = eth_prepare_mac_addr_change(dev, p);
1015 	if (ret)
1016 		return ret;
1017 
1018 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1019 		sg_init_one(&sg, addr->sa_data, dev->addr_len);
1020 		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1021 					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1022 			dev_warn(&vdev->dev,
1023 				 "Failed to set mac address by vq command.\n");
1024 			return -EINVAL;
1025 		}
1026 	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
1027 		unsigned int i;
1028 
1029 		/* Naturally, this has an atomicity problem. */
1030 		for (i = 0; i < dev->addr_len; i++)
1031 			virtio_cwrite8(vdev,
1032 				       offsetof(struct virtio_net_config, mac) +
1033 				       i, addr->sa_data[i]);
1034 	}
1035 
1036 	eth_commit_mac_addr_change(dev, p);
1037 
1038 	return 0;
1039 }
1040 
1041 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1042 					       struct rtnl_link_stats64 *tot)
1043 {
1044 	struct virtnet_info *vi = netdev_priv(dev);
1045 	int cpu;
1046 	unsigned int start;
1047 
1048 	for_each_possible_cpu(cpu) {
1049 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1050 		u64 tpackets, tbytes, rpackets, rbytes;
1051 
1052 		do {
1053 			start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1054 			tpackets = stats->tx_packets;
1055 			tbytes   = stats->tx_bytes;
1056 		} while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1057 
1058 		do {
1059 			start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1060 			rpackets = stats->rx_packets;
1061 			rbytes   = stats->rx_bytes;
1062 		} while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1063 
1064 		tot->rx_packets += rpackets;
1065 		tot->tx_packets += tpackets;
1066 		tot->rx_bytes   += rbytes;
1067 		tot->tx_bytes   += tbytes;
1068 	}
1069 
1070 	tot->tx_dropped = dev->stats.tx_dropped;
1071 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1072 	tot->rx_dropped = dev->stats.rx_dropped;
1073 	tot->rx_length_errors = dev->stats.rx_length_errors;
1074 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
1075 
1076 	return tot;
1077 }
1078 
1079 #ifdef CONFIG_NET_POLL_CONTROLLER
1080 static void virtnet_netpoll(struct net_device *dev)
1081 {
1082 	struct virtnet_info *vi = netdev_priv(dev);
1083 	int i;
1084 
1085 	for (i = 0; i < vi->curr_queue_pairs; i++)
1086 		napi_schedule(&vi->rq[i].napi);
1087 }
1088 #endif
1089 
1090 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1091 {
1092 	rtnl_lock();
1093 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1094 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1095 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1096 	rtnl_unlock();
1097 }
1098 
1099 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1100 {
1101 	struct scatterlist sg;
1102 	struct virtio_net_ctrl_mq s;
1103 	struct net_device *dev = vi->dev;
1104 
1105 	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1106 		return 0;
1107 
1108 	s.virtqueue_pairs = queue_pairs;
1109 	sg_init_one(&sg, &s, sizeof(s));
1110 
1111 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1112 				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1113 		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1114 			 queue_pairs);
1115 		return -EINVAL;
1116 	} else {
1117 		vi->curr_queue_pairs = queue_pairs;
1118 		/* virtnet_open() will refill when device is going to up. */
1119 		if (dev->flags & IFF_UP)
1120 			schedule_delayed_work(&vi->refill, 0);
1121 	}
1122 
1123 	return 0;
1124 }
1125 
1126 static int virtnet_close(struct net_device *dev)
1127 {
1128 	struct virtnet_info *vi = netdev_priv(dev);
1129 	int i;
1130 
1131 	/* Make sure refill_work doesn't re-enable napi! */
1132 	cancel_delayed_work_sync(&vi->refill);
1133 
1134 	for (i = 0; i < vi->max_queue_pairs; i++)
1135 		napi_disable(&vi->rq[i].napi);
1136 
1137 	return 0;
1138 }
1139 
1140 static void virtnet_set_rx_mode(struct net_device *dev)
1141 {
1142 	struct virtnet_info *vi = netdev_priv(dev);
1143 	struct scatterlist sg[2];
1144 	u8 promisc, allmulti;
1145 	struct virtio_net_ctrl_mac *mac_data;
1146 	struct netdev_hw_addr *ha;
1147 	int uc_count;
1148 	int mc_count;
1149 	void *buf;
1150 	int i;
1151 
1152 	/* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1153 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1154 		return;
1155 
1156 	promisc = ((dev->flags & IFF_PROMISC) != 0);
1157 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1158 
1159 	sg_init_one(sg, &promisc, sizeof(promisc));
1160 
1161 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1162 				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
1163 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1164 			 promisc ? "en" : "dis");
1165 
1166 	sg_init_one(sg, &allmulti, sizeof(allmulti));
1167 
1168 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1169 				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1170 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1171 			 allmulti ? "en" : "dis");
1172 
1173 	uc_count = netdev_uc_count(dev);
1174 	mc_count = netdev_mc_count(dev);
1175 	/* MAC filter - use one buffer for both lists */
1176 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1177 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1178 	mac_data = buf;
1179 	if (!buf)
1180 		return;
1181 
1182 	sg_init_table(sg, 2);
1183 
1184 	/* Store the unicast list and count in the front of the buffer */
1185 	mac_data->entries = uc_count;
1186 	i = 0;
1187 	netdev_for_each_uc_addr(ha, dev)
1188 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1189 
1190 	sg_set_buf(&sg[0], mac_data,
1191 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1192 
1193 	/* multicast list and count fill the end */
1194 	mac_data = (void *)&mac_data->macs[uc_count][0];
1195 
1196 	mac_data->entries = mc_count;
1197 	i = 0;
1198 	netdev_for_each_mc_addr(ha, dev)
1199 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1200 
1201 	sg_set_buf(&sg[1], mac_data,
1202 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1203 
1204 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1205 				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1206 		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1207 
1208 	kfree(buf);
1209 }
1210 
1211 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1212 				   __be16 proto, u16 vid)
1213 {
1214 	struct virtnet_info *vi = netdev_priv(dev);
1215 	struct scatterlist sg;
1216 
1217 	sg_init_one(&sg, &vid, sizeof(vid));
1218 
1219 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1220 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1221 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1222 	return 0;
1223 }
1224 
1225 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1226 				    __be16 proto, u16 vid)
1227 {
1228 	struct virtnet_info *vi = netdev_priv(dev);
1229 	struct scatterlist sg;
1230 
1231 	sg_init_one(&sg, &vid, sizeof(vid));
1232 
1233 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1234 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1235 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1236 	return 0;
1237 }
1238 
1239 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1240 {
1241 	int i;
1242 
1243 	if (vi->affinity_hint_set) {
1244 		for (i = 0; i < vi->max_queue_pairs; i++) {
1245 			virtqueue_set_affinity(vi->rq[i].vq, -1);
1246 			virtqueue_set_affinity(vi->sq[i].vq, -1);
1247 		}
1248 
1249 		vi->affinity_hint_set = false;
1250 	}
1251 }
1252 
1253 static void virtnet_set_affinity(struct virtnet_info *vi)
1254 {
1255 	int i;
1256 	int cpu;
1257 
1258 	/* In multiqueue mode, when the number of cpu is equal to the number of
1259 	 * queue pairs, we let the queue pairs to be private to one cpu by
1260 	 * setting the affinity hint to eliminate the contention.
1261 	 */
1262 	if (vi->curr_queue_pairs == 1 ||
1263 	    vi->max_queue_pairs != num_online_cpus()) {
1264 		virtnet_clean_affinity(vi, -1);
1265 		return;
1266 	}
1267 
1268 	i = 0;
1269 	for_each_online_cpu(cpu) {
1270 		virtqueue_set_affinity(vi->rq[i].vq, cpu);
1271 		virtqueue_set_affinity(vi->sq[i].vq, cpu);
1272 		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1273 		i++;
1274 	}
1275 
1276 	vi->affinity_hint_set = true;
1277 }
1278 
1279 static int virtnet_cpu_callback(struct notifier_block *nfb,
1280 			        unsigned long action, void *hcpu)
1281 {
1282 	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1283 
1284 	switch(action & ~CPU_TASKS_FROZEN) {
1285 	case CPU_ONLINE:
1286 	case CPU_DOWN_FAILED:
1287 	case CPU_DEAD:
1288 		virtnet_set_affinity(vi);
1289 		break;
1290 	case CPU_DOWN_PREPARE:
1291 		virtnet_clean_affinity(vi, (long)hcpu);
1292 		break;
1293 	default:
1294 		break;
1295 	}
1296 
1297 	return NOTIFY_OK;
1298 }
1299 
1300 static void virtnet_get_ringparam(struct net_device *dev,
1301 				struct ethtool_ringparam *ring)
1302 {
1303 	struct virtnet_info *vi = netdev_priv(dev);
1304 
1305 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1306 	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1307 	ring->rx_pending = ring->rx_max_pending;
1308 	ring->tx_pending = ring->tx_max_pending;
1309 }
1310 
1311 
1312 static void virtnet_get_drvinfo(struct net_device *dev,
1313 				struct ethtool_drvinfo *info)
1314 {
1315 	struct virtnet_info *vi = netdev_priv(dev);
1316 	struct virtio_device *vdev = vi->vdev;
1317 
1318 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1319 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1320 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1321 
1322 }
1323 
1324 /* TODO: Eliminate OOO packets during switching */
1325 static int virtnet_set_channels(struct net_device *dev,
1326 				struct ethtool_channels *channels)
1327 {
1328 	struct virtnet_info *vi = netdev_priv(dev);
1329 	u16 queue_pairs = channels->combined_count;
1330 	int err;
1331 
1332 	/* We don't support separate rx/tx channels.
1333 	 * We don't allow setting 'other' channels.
1334 	 */
1335 	if (channels->rx_count || channels->tx_count || channels->other_count)
1336 		return -EINVAL;
1337 
1338 	if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1339 		return -EINVAL;
1340 
1341 	get_online_cpus();
1342 	err = virtnet_set_queues(vi, queue_pairs);
1343 	if (!err) {
1344 		netif_set_real_num_tx_queues(dev, queue_pairs);
1345 		netif_set_real_num_rx_queues(dev, queue_pairs);
1346 
1347 		virtnet_set_affinity(vi);
1348 	}
1349 	put_online_cpus();
1350 
1351 	return err;
1352 }
1353 
1354 static void virtnet_get_channels(struct net_device *dev,
1355 				 struct ethtool_channels *channels)
1356 {
1357 	struct virtnet_info *vi = netdev_priv(dev);
1358 
1359 	channels->combined_count = vi->curr_queue_pairs;
1360 	channels->max_combined = vi->max_queue_pairs;
1361 	channels->max_other = 0;
1362 	channels->rx_count = 0;
1363 	channels->tx_count = 0;
1364 	channels->other_count = 0;
1365 }
1366 
1367 static const struct ethtool_ops virtnet_ethtool_ops = {
1368 	.get_drvinfo = virtnet_get_drvinfo,
1369 	.get_link = ethtool_op_get_link,
1370 	.get_ringparam = virtnet_get_ringparam,
1371 	.set_channels = virtnet_set_channels,
1372 	.get_channels = virtnet_get_channels,
1373 };
1374 
1375 #define MIN_MTU 68
1376 #define MAX_MTU 65535
1377 
1378 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1379 {
1380 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1381 		return -EINVAL;
1382 	dev->mtu = new_mtu;
1383 	return 0;
1384 }
1385 
1386 static const struct net_device_ops virtnet_netdev = {
1387 	.ndo_open            = virtnet_open,
1388 	.ndo_stop   	     = virtnet_close,
1389 	.ndo_start_xmit      = start_xmit,
1390 	.ndo_validate_addr   = eth_validate_addr,
1391 	.ndo_set_mac_address = virtnet_set_mac_address,
1392 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
1393 	.ndo_change_mtu	     = virtnet_change_mtu,
1394 	.ndo_get_stats64     = virtnet_stats,
1395 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1396 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1397 #ifdef CONFIG_NET_POLL_CONTROLLER
1398 	.ndo_poll_controller = virtnet_netpoll,
1399 #endif
1400 #ifdef CONFIG_NET_RX_BUSY_POLL
1401 	.ndo_busy_poll		= virtnet_busy_poll,
1402 #endif
1403 };
1404 
1405 static void virtnet_config_changed_work(struct work_struct *work)
1406 {
1407 	struct virtnet_info *vi =
1408 		container_of(work, struct virtnet_info, config_work);
1409 	u16 v;
1410 
1411 	if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1412 				 struct virtio_net_config, status, &v) < 0)
1413 		return;
1414 
1415 	if (v & VIRTIO_NET_S_ANNOUNCE) {
1416 		netdev_notify_peers(vi->dev);
1417 		virtnet_ack_link_announce(vi);
1418 	}
1419 
1420 	/* Ignore unknown (future) status bits */
1421 	v &= VIRTIO_NET_S_LINK_UP;
1422 
1423 	if (vi->status == v)
1424 		return;
1425 
1426 	vi->status = v;
1427 
1428 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1429 		netif_carrier_on(vi->dev);
1430 		netif_tx_wake_all_queues(vi->dev);
1431 	} else {
1432 		netif_carrier_off(vi->dev);
1433 		netif_tx_stop_all_queues(vi->dev);
1434 	}
1435 }
1436 
1437 static void virtnet_config_changed(struct virtio_device *vdev)
1438 {
1439 	struct virtnet_info *vi = vdev->priv;
1440 
1441 	schedule_work(&vi->config_work);
1442 }
1443 
1444 static void virtnet_free_queues(struct virtnet_info *vi)
1445 {
1446 	int i;
1447 
1448 	for (i = 0; i < vi->max_queue_pairs; i++)
1449 		netif_napi_del(&vi->rq[i].napi);
1450 
1451 	kfree(vi->rq);
1452 	kfree(vi->sq);
1453 }
1454 
1455 static void free_receive_bufs(struct virtnet_info *vi)
1456 {
1457 	int i;
1458 
1459 	for (i = 0; i < vi->max_queue_pairs; i++) {
1460 		while (vi->rq[i].pages)
1461 			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1462 	}
1463 }
1464 
1465 static void free_receive_page_frags(struct virtnet_info *vi)
1466 {
1467 	int i;
1468 	for (i = 0; i < vi->max_queue_pairs; i++)
1469 		if (vi->rq[i].alloc_frag.page)
1470 			put_page(vi->rq[i].alloc_frag.page);
1471 }
1472 
1473 static void free_unused_bufs(struct virtnet_info *vi)
1474 {
1475 	void *buf;
1476 	int i;
1477 
1478 	for (i = 0; i < vi->max_queue_pairs; i++) {
1479 		struct virtqueue *vq = vi->sq[i].vq;
1480 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1481 			dev_kfree_skb(buf);
1482 	}
1483 
1484 	for (i = 0; i < vi->max_queue_pairs; i++) {
1485 		struct virtqueue *vq = vi->rq[i].vq;
1486 
1487 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1488 			if (vi->mergeable_rx_bufs) {
1489 				unsigned long ctx = (unsigned long)buf;
1490 				void *base = mergeable_ctx_to_buf_address(ctx);
1491 				put_page(virt_to_head_page(base));
1492 			} else if (vi->big_packets) {
1493 				give_pages(&vi->rq[i], buf);
1494 			} else {
1495 				dev_kfree_skb(buf);
1496 			}
1497 		}
1498 	}
1499 }
1500 
1501 static void virtnet_del_vqs(struct virtnet_info *vi)
1502 {
1503 	struct virtio_device *vdev = vi->vdev;
1504 
1505 	virtnet_clean_affinity(vi, -1);
1506 
1507 	vdev->config->del_vqs(vdev);
1508 
1509 	virtnet_free_queues(vi);
1510 }
1511 
1512 static int virtnet_find_vqs(struct virtnet_info *vi)
1513 {
1514 	vq_callback_t **callbacks;
1515 	struct virtqueue **vqs;
1516 	int ret = -ENOMEM;
1517 	int i, total_vqs;
1518 	const char **names;
1519 
1520 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1521 	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1522 	 * possible control vq.
1523 	 */
1524 	total_vqs = vi->max_queue_pairs * 2 +
1525 		    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1526 
1527 	/* Allocate space for find_vqs parameters */
1528 	vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1529 	if (!vqs)
1530 		goto err_vq;
1531 	callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1532 	if (!callbacks)
1533 		goto err_callback;
1534 	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1535 	if (!names)
1536 		goto err_names;
1537 
1538 	/* Parameters for control virtqueue, if any */
1539 	if (vi->has_cvq) {
1540 		callbacks[total_vqs - 1] = NULL;
1541 		names[total_vqs - 1] = "control";
1542 	}
1543 
1544 	/* Allocate/initialize parameters for send/receive virtqueues */
1545 	for (i = 0; i < vi->max_queue_pairs; i++) {
1546 		callbacks[rxq2vq(i)] = skb_recv_done;
1547 		callbacks[txq2vq(i)] = skb_xmit_done;
1548 		sprintf(vi->rq[i].name, "input.%d", i);
1549 		sprintf(vi->sq[i].name, "output.%d", i);
1550 		names[rxq2vq(i)] = vi->rq[i].name;
1551 		names[txq2vq(i)] = vi->sq[i].name;
1552 	}
1553 
1554 	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1555 					 names);
1556 	if (ret)
1557 		goto err_find;
1558 
1559 	if (vi->has_cvq) {
1560 		vi->cvq = vqs[total_vqs - 1];
1561 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1562 			vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1563 	}
1564 
1565 	for (i = 0; i < vi->max_queue_pairs; i++) {
1566 		vi->rq[i].vq = vqs[rxq2vq(i)];
1567 		vi->sq[i].vq = vqs[txq2vq(i)];
1568 	}
1569 
1570 	kfree(names);
1571 	kfree(callbacks);
1572 	kfree(vqs);
1573 
1574 	return 0;
1575 
1576 err_find:
1577 	kfree(names);
1578 err_names:
1579 	kfree(callbacks);
1580 err_callback:
1581 	kfree(vqs);
1582 err_vq:
1583 	return ret;
1584 }
1585 
1586 static int virtnet_alloc_queues(struct virtnet_info *vi)
1587 {
1588 	int i;
1589 
1590 	vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1591 	if (!vi->sq)
1592 		goto err_sq;
1593 	vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1594 	if (!vi->rq)
1595 		goto err_rq;
1596 
1597 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1598 	for (i = 0; i < vi->max_queue_pairs; i++) {
1599 		vi->rq[i].pages = NULL;
1600 		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1601 			       napi_weight);
1602 		napi_hash_add(&vi->rq[i].napi);
1603 
1604 		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1605 		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
1606 		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1607 	}
1608 
1609 	return 0;
1610 
1611 err_rq:
1612 	kfree(vi->sq);
1613 err_sq:
1614 	return -ENOMEM;
1615 }
1616 
1617 static int init_vqs(struct virtnet_info *vi)
1618 {
1619 	int ret;
1620 
1621 	/* Allocate send & receive queues */
1622 	ret = virtnet_alloc_queues(vi);
1623 	if (ret)
1624 		goto err;
1625 
1626 	ret = virtnet_find_vqs(vi);
1627 	if (ret)
1628 		goto err_free;
1629 
1630 	get_online_cpus();
1631 	virtnet_set_affinity(vi);
1632 	put_online_cpus();
1633 
1634 	return 0;
1635 
1636 err_free:
1637 	virtnet_free_queues(vi);
1638 err:
1639 	return ret;
1640 }
1641 
1642 #ifdef CONFIG_SYSFS
1643 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1644 		struct rx_queue_attribute *attribute, char *buf)
1645 {
1646 	struct virtnet_info *vi = netdev_priv(queue->dev);
1647 	unsigned int queue_index = get_netdev_rx_queue_index(queue);
1648 	struct ewma *avg;
1649 
1650 	BUG_ON(queue_index >= vi->max_queue_pairs);
1651 	avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1652 	return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1653 }
1654 
1655 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1656 	__ATTR_RO(mergeable_rx_buffer_size);
1657 
1658 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1659 	&mergeable_rx_buffer_size_attribute.attr,
1660 	NULL
1661 };
1662 
1663 static const struct attribute_group virtio_net_mrg_rx_group = {
1664 	.name = "virtio_net",
1665 	.attrs = virtio_net_mrg_rx_attrs
1666 };
1667 #endif
1668 
1669 static int virtnet_probe(struct virtio_device *vdev)
1670 {
1671 	int i, err;
1672 	struct net_device *dev;
1673 	struct virtnet_info *vi;
1674 	u16 max_queue_pairs;
1675 
1676 	/* Find if host supports multiqueue virtio_net device */
1677 	err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1678 				   struct virtio_net_config,
1679 				   max_virtqueue_pairs, &max_queue_pairs);
1680 
1681 	/* We need at least 2 queue's */
1682 	if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1683 	    max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1684 	    !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1685 		max_queue_pairs = 1;
1686 
1687 	/* Allocate ourselves a network device with room for our info */
1688 	dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1689 	if (!dev)
1690 		return -ENOMEM;
1691 
1692 	/* Set up network device as normal. */
1693 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1694 	dev->netdev_ops = &virtnet_netdev;
1695 	dev->features = NETIF_F_HIGHDMA;
1696 
1697 	dev->ethtool_ops = &virtnet_ethtool_ops;
1698 	SET_NETDEV_DEV(dev, &vdev->dev);
1699 
1700 	/* Do we support "hardware" checksums? */
1701 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1702 		/* This opens up the world of extra features. */
1703 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1704 		if (csum)
1705 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1706 
1707 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1708 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1709 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1710 		}
1711 		/* Individual feature bits: what can host handle? */
1712 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1713 			dev->hw_features |= NETIF_F_TSO;
1714 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1715 			dev->hw_features |= NETIF_F_TSO6;
1716 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1717 			dev->hw_features |= NETIF_F_TSO_ECN;
1718 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1719 			dev->hw_features |= NETIF_F_UFO;
1720 
1721 		if (gso)
1722 			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1723 		/* (!csum && gso) case will be fixed by register_netdev() */
1724 	}
1725 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1726 		dev->features |= NETIF_F_RXCSUM;
1727 
1728 	dev->vlan_features = dev->features;
1729 
1730 	/* Configuration may specify what MAC to use.  Otherwise random. */
1731 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1732 		virtio_cread_bytes(vdev,
1733 				   offsetof(struct virtio_net_config, mac),
1734 				   dev->dev_addr, dev->addr_len);
1735 	else
1736 		eth_hw_addr_random(dev);
1737 
1738 	/* Set up our device-specific information */
1739 	vi = netdev_priv(dev);
1740 	vi->dev = dev;
1741 	vi->vdev = vdev;
1742 	vdev->priv = vi;
1743 	vi->stats = alloc_percpu(struct virtnet_stats);
1744 	err = -ENOMEM;
1745 	if (vi->stats == NULL)
1746 		goto free;
1747 
1748 	for_each_possible_cpu(i) {
1749 		struct virtnet_stats *virtnet_stats;
1750 		virtnet_stats = per_cpu_ptr(vi->stats, i);
1751 		u64_stats_init(&virtnet_stats->tx_syncp);
1752 		u64_stats_init(&virtnet_stats->rx_syncp);
1753 	}
1754 
1755 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1756 
1757 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1758 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1759 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1760 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1761 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1762 		vi->big_packets = true;
1763 
1764 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1765 		vi->mergeable_rx_bufs = true;
1766 
1767 	if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1768 		vi->any_header_sg = true;
1769 
1770 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1771 		vi->has_cvq = true;
1772 
1773 	if (vi->any_header_sg) {
1774 		if (vi->mergeable_rx_bufs)
1775 			dev->needed_headroom = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1776 		else
1777 			dev->needed_headroom = sizeof(struct virtio_net_hdr);
1778 	}
1779 
1780 	/* Use single tx/rx queue pair as default */
1781 	vi->curr_queue_pairs = 1;
1782 	vi->max_queue_pairs = max_queue_pairs;
1783 
1784 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1785 	err = init_vqs(vi);
1786 	if (err)
1787 		goto free_stats;
1788 
1789 #ifdef CONFIG_SYSFS
1790 	if (vi->mergeable_rx_bufs)
1791 		dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1792 #endif
1793 	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1794 	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1795 
1796 	err = register_netdev(dev);
1797 	if (err) {
1798 		pr_debug("virtio_net: registering device failed\n");
1799 		goto free_vqs;
1800 	}
1801 
1802 	virtio_device_ready(vdev);
1803 
1804 	/* Last of all, set up some receive buffers. */
1805 	for (i = 0; i < vi->curr_queue_pairs; i++) {
1806 		try_fill_recv(&vi->rq[i], GFP_KERNEL);
1807 
1808 		/* If we didn't even get one input buffer, we're useless. */
1809 		if (vi->rq[i].vq->num_free ==
1810 		    virtqueue_get_vring_size(vi->rq[i].vq)) {
1811 			free_unused_bufs(vi);
1812 			err = -ENOMEM;
1813 			goto free_recv_bufs;
1814 		}
1815 	}
1816 
1817 	vi->nb.notifier_call = &virtnet_cpu_callback;
1818 	err = register_hotcpu_notifier(&vi->nb);
1819 	if (err) {
1820 		pr_debug("virtio_net: registering cpu notifier failed\n");
1821 		goto free_recv_bufs;
1822 	}
1823 
1824 	/* Assume link up if device can't report link status,
1825 	   otherwise get link status from config. */
1826 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1827 		netif_carrier_off(dev);
1828 		schedule_work(&vi->config_work);
1829 	} else {
1830 		vi->status = VIRTIO_NET_S_LINK_UP;
1831 		netif_carrier_on(dev);
1832 	}
1833 
1834 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1835 		 dev->name, max_queue_pairs);
1836 
1837 	return 0;
1838 
1839 free_recv_bufs:
1840 	vi->vdev->config->reset(vdev);
1841 
1842 	free_receive_bufs(vi);
1843 	unregister_netdev(dev);
1844 free_vqs:
1845 	cancel_delayed_work_sync(&vi->refill);
1846 	free_receive_page_frags(vi);
1847 	virtnet_del_vqs(vi);
1848 free_stats:
1849 	free_percpu(vi->stats);
1850 free:
1851 	free_netdev(dev);
1852 	return err;
1853 }
1854 
1855 static void remove_vq_common(struct virtnet_info *vi)
1856 {
1857 	vi->vdev->config->reset(vi->vdev);
1858 
1859 	/* Free unused buffers in both send and recv, if any. */
1860 	free_unused_bufs(vi);
1861 
1862 	free_receive_bufs(vi);
1863 
1864 	free_receive_page_frags(vi);
1865 
1866 	virtnet_del_vqs(vi);
1867 }
1868 
1869 static void virtnet_remove(struct virtio_device *vdev)
1870 {
1871 	struct virtnet_info *vi = vdev->priv;
1872 
1873 	unregister_hotcpu_notifier(&vi->nb);
1874 
1875 	/* Make sure no work handler is accessing the device. */
1876 	flush_work(&vi->config_work);
1877 
1878 	unregister_netdev(vi->dev);
1879 
1880 	remove_vq_common(vi);
1881 
1882 	free_percpu(vi->stats);
1883 	free_netdev(vi->dev);
1884 }
1885 
1886 #ifdef CONFIG_PM_SLEEP
1887 static int virtnet_freeze(struct virtio_device *vdev)
1888 {
1889 	struct virtnet_info *vi = vdev->priv;
1890 	int i;
1891 
1892 	unregister_hotcpu_notifier(&vi->nb);
1893 
1894 	/* Make sure no work handler is accessing the device */
1895 	flush_work(&vi->config_work);
1896 
1897 	netif_device_detach(vi->dev);
1898 	cancel_delayed_work_sync(&vi->refill);
1899 
1900 	if (netif_running(vi->dev)) {
1901 		for (i = 0; i < vi->max_queue_pairs; i++) {
1902 			napi_disable(&vi->rq[i].napi);
1903 			napi_hash_del(&vi->rq[i].napi);
1904 			netif_napi_del(&vi->rq[i].napi);
1905 		}
1906 	}
1907 
1908 	remove_vq_common(vi);
1909 
1910 	return 0;
1911 }
1912 
1913 static int virtnet_restore(struct virtio_device *vdev)
1914 {
1915 	struct virtnet_info *vi = vdev->priv;
1916 	int err, i;
1917 
1918 	err = init_vqs(vi);
1919 	if (err)
1920 		return err;
1921 
1922 	virtio_device_ready(vdev);
1923 
1924 	if (netif_running(vi->dev)) {
1925 		for (i = 0; i < vi->curr_queue_pairs; i++)
1926 			if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1927 				schedule_delayed_work(&vi->refill, 0);
1928 
1929 		for (i = 0; i < vi->max_queue_pairs; i++)
1930 			virtnet_napi_enable(&vi->rq[i]);
1931 	}
1932 
1933 	netif_device_attach(vi->dev);
1934 
1935 	rtnl_lock();
1936 	virtnet_set_queues(vi, vi->curr_queue_pairs);
1937 	rtnl_unlock();
1938 
1939 	err = register_hotcpu_notifier(&vi->nb);
1940 	if (err)
1941 		return err;
1942 
1943 	return 0;
1944 }
1945 #endif
1946 
1947 static struct virtio_device_id id_table[] = {
1948 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1949 	{ 0 },
1950 };
1951 
1952 static unsigned int features[] = {
1953 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1954 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1955 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1956 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1957 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1958 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1959 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1960 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
1961 	VIRTIO_NET_F_CTRL_MAC_ADDR,
1962 	VIRTIO_F_ANY_LAYOUT,
1963 };
1964 
1965 static struct virtio_driver virtio_net_driver = {
1966 	.feature_table = features,
1967 	.feature_table_size = ARRAY_SIZE(features),
1968 	.driver.name =	KBUILD_MODNAME,
1969 	.driver.owner =	THIS_MODULE,
1970 	.id_table =	id_table,
1971 	.probe =	virtnet_probe,
1972 	.remove =	virtnet_remove,
1973 	.config_changed = virtnet_config_changed,
1974 #ifdef CONFIG_PM_SLEEP
1975 	.freeze =	virtnet_freeze,
1976 	.restore =	virtnet_restore,
1977 #endif
1978 };
1979 
1980 module_virtio_driver(virtio_net_driver);
1981 
1982 MODULE_DEVICE_TABLE(virtio, id_table);
1983 MODULE_DESCRIPTION("Virtio network driver");
1984 MODULE_LICENSE("GPL");
1985