xref: /linux/drivers/net/virtio_net.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
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 	/* enable config space updates */
127 	bool config_enable;
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 	/* Lock for config space updates */
139 	struct mutex config_lock;
140 
141 	/* Does the affinity hint is set for virtqueues? */
142 	bool affinity_hint_set;
143 
144 	/* CPU hot plug notifier */
145 	struct notifier_block nb;
146 };
147 
148 struct skb_vnet_hdr {
149 	union {
150 		struct virtio_net_hdr hdr;
151 		struct virtio_net_hdr_mrg_rxbuf mhdr;
152 	};
153 };
154 
155 struct padded_vnet_hdr {
156 	struct virtio_net_hdr hdr;
157 	/*
158 	 * virtio_net_hdr should be in a separated sg buffer because of a
159 	 * QEMU bug, and data sg buffer shares same page with this header sg.
160 	 * This padding makes next sg 16 byte aligned after virtio_net_hdr.
161 	 */
162 	char padding[6];
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 skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
189 {
190 	return (struct skb_vnet_hdr *)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 receive_queue *rq,
251 				   struct page *page, unsigned int offset,
252 				   unsigned int len, unsigned int truesize)
253 {
254 	struct virtnet_info *vi = rq->vq->vdev->priv;
255 	struct sk_buff *skb;
256 	struct skb_vnet_hdr *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 = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
264 	if (unlikely(!skb))
265 		return NULL;
266 
267 	hdr = skb_vnet_hdr(skb);
268 
269 	if (vi->mergeable_rx_bufs) {
270 		hdr_len = sizeof hdr->mhdr;
271 		hdr_padded_len = sizeof hdr->mhdr;
272 	} else {
273 		hdr_len = sizeof hdr->hdr;
274 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
275 	}
276 
277 	memcpy(hdr, p, hdr_len);
278 
279 	len -= hdr_len;
280 	offset += hdr_padded_len;
281 	p += hdr_padded_len;
282 
283 	copy = len;
284 	if (copy > skb_tailroom(skb))
285 		copy = skb_tailroom(skb);
286 	memcpy(skb_put(skb, copy), p, copy);
287 
288 	len -= copy;
289 	offset += copy;
290 
291 	if (vi->mergeable_rx_bufs) {
292 		if (len)
293 			skb_add_rx_frag(skb, 0, page, offset, len, truesize);
294 		else
295 			put_page(page);
296 		return skb;
297 	}
298 
299 	/*
300 	 * Verify that we can indeed put this data into a skb.
301 	 * This is here to handle cases when the device erroneously
302 	 * tries to receive more than is possible. This is usually
303 	 * the case of a broken device.
304 	 */
305 	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
306 		net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
307 		dev_kfree_skb(skb);
308 		return NULL;
309 	}
310 	BUG_ON(offset >= PAGE_SIZE);
311 	while (len) {
312 		unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
313 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
314 				frag_size, truesize);
315 		len -= frag_size;
316 		page = (struct page *)page->private;
317 		offset = 0;
318 	}
319 
320 	if (page)
321 		give_pages(rq, page);
322 
323 	return skb;
324 }
325 
326 static struct sk_buff *receive_small(void *buf, unsigned int len)
327 {
328 	struct sk_buff * skb = buf;
329 
330 	len -= sizeof(struct virtio_net_hdr);
331 	skb_trim(skb, len);
332 
333 	return skb;
334 }
335 
336 static struct sk_buff *receive_big(struct net_device *dev,
337 				   struct receive_queue *rq,
338 				   void *buf,
339 				   unsigned int len)
340 {
341 	struct page *page = buf;
342 	struct sk_buff *skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
343 
344 	if (unlikely(!skb))
345 		goto err;
346 
347 	return skb;
348 
349 err:
350 	dev->stats.rx_dropped++;
351 	give_pages(rq, page);
352 	return NULL;
353 }
354 
355 static struct sk_buff *receive_mergeable(struct net_device *dev,
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 skb_vnet_hdr *hdr = buf;
362 	int num_buf = hdr->mhdr.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(rq, page, offset, len, truesize);
368 	struct sk_buff *curr_skb = head_skb;
369 
370 	if (unlikely(!curr_skb))
371 		goto err_skb;
372 	while (--num_buf) {
373 		int num_skb_frags;
374 
375 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
376 		if (unlikely(!ctx)) {
377 			pr_debug("%s: rx error: %d buffers out of %d missing\n",
378 				 dev->name, num_buf, hdr->mhdr.num_buffers);
379 			dev->stats.rx_length_errors++;
380 			goto err_buf;
381 		}
382 
383 		buf = mergeable_ctx_to_buf_address(ctx);
384 		page = virt_to_head_page(buf);
385 
386 		num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
387 		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
388 			struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
389 
390 			if (unlikely(!nskb))
391 				goto err_skb;
392 			if (curr_skb == head_skb)
393 				skb_shinfo(curr_skb)->frag_list = nskb;
394 			else
395 				curr_skb->next = nskb;
396 			curr_skb = nskb;
397 			head_skb->truesize += nskb->truesize;
398 			num_skb_frags = 0;
399 		}
400 		truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
401 		if (curr_skb != head_skb) {
402 			head_skb->data_len += len;
403 			head_skb->len += len;
404 			head_skb->truesize += truesize;
405 		}
406 		offset = buf - page_address(page);
407 		if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
408 			put_page(page);
409 			skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
410 					     len, truesize);
411 		} else {
412 			skb_add_rx_frag(curr_skb, num_skb_frags, page,
413 					offset, len, truesize);
414 		}
415 	}
416 
417 	ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);
418 	return head_skb;
419 
420 err_skb:
421 	put_page(page);
422 	while (--num_buf) {
423 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
424 		if (unlikely(!ctx)) {
425 			pr_debug("%s: rx error: %d buffers missing\n",
426 				 dev->name, num_buf);
427 			dev->stats.rx_length_errors++;
428 			break;
429 		}
430 		page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
431 		put_page(page);
432 	}
433 err_buf:
434 	dev->stats.rx_dropped++;
435 	dev_kfree_skb(head_skb);
436 	return NULL;
437 }
438 
439 static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
440 {
441 	struct virtnet_info *vi = rq->vq->vdev->priv;
442 	struct net_device *dev = vi->dev;
443 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
444 	struct sk_buff *skb;
445 	struct skb_vnet_hdr *hdr;
446 
447 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
448 		pr_debug("%s: short packet %i\n", dev->name, len);
449 		dev->stats.rx_length_errors++;
450 		if (vi->mergeable_rx_bufs) {
451 			unsigned long ctx = (unsigned long)buf;
452 			void *base = mergeable_ctx_to_buf_address(ctx);
453 			put_page(virt_to_head_page(base));
454 		} else if (vi->big_packets) {
455 			give_pages(rq, buf);
456 		} else {
457 			dev_kfree_skb(buf);
458 		}
459 		return;
460 	}
461 
462 	if (vi->mergeable_rx_bufs)
463 		skb = receive_mergeable(dev, rq, (unsigned long)buf, len);
464 	else if (vi->big_packets)
465 		skb = receive_big(dev, rq, buf, len);
466 	else
467 		skb = receive_small(buf, len);
468 
469 	if (unlikely(!skb))
470 		return;
471 
472 	hdr = skb_vnet_hdr(skb);
473 
474 	u64_stats_update_begin(&stats->rx_syncp);
475 	stats->rx_bytes += skb->len;
476 	stats->rx_packets++;
477 	u64_stats_update_end(&stats->rx_syncp);
478 
479 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
480 		pr_debug("Needs csum!\n");
481 		if (!skb_partial_csum_set(skb,
482 					  hdr->hdr.csum_start,
483 					  hdr->hdr.csum_offset))
484 			goto frame_err;
485 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
486 		skb->ip_summed = CHECKSUM_UNNECESSARY;
487 	}
488 
489 	skb->protocol = eth_type_trans(skb, dev);
490 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
491 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
492 
493 	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
494 		pr_debug("GSO!\n");
495 		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
496 		case VIRTIO_NET_HDR_GSO_TCPV4:
497 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
498 			break;
499 		case VIRTIO_NET_HDR_GSO_UDP:
500 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
501 			break;
502 		case VIRTIO_NET_HDR_GSO_TCPV6:
503 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
504 			break;
505 		default:
506 			net_warn_ratelimited("%s: bad gso type %u.\n",
507 					     dev->name, hdr->hdr.gso_type);
508 			goto frame_err;
509 		}
510 
511 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
512 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
513 
514 		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
515 		if (skb_shinfo(skb)->gso_size == 0) {
516 			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
517 			goto frame_err;
518 		}
519 
520 		/* Header must be checked, and gso_segs computed. */
521 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
522 		skb_shinfo(skb)->gso_segs = 0;
523 	}
524 
525 	skb_mark_napi_id(skb, &rq->napi);
526 
527 	netif_receive_skb(skb);
528 	return;
529 
530 frame_err:
531 	dev->stats.rx_frame_errors++;
532 	dev_kfree_skb(skb);
533 }
534 
535 static int add_recvbuf_small(struct receive_queue *rq, gfp_t gfp)
536 {
537 	struct virtnet_info *vi = rq->vq->vdev->priv;
538 	struct sk_buff *skb;
539 	struct skb_vnet_hdr *hdr;
540 	int err;
541 
542 	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
543 	if (unlikely(!skb))
544 		return -ENOMEM;
545 
546 	skb_put(skb, GOOD_PACKET_LEN);
547 
548 	hdr = skb_vnet_hdr(skb);
549 	sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
550 
551 	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
552 
553 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
554 	if (err < 0)
555 		dev_kfree_skb(skb);
556 
557 	return err;
558 }
559 
560 static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
561 {
562 	struct page *first, *list = NULL;
563 	char *p;
564 	int i, err, offset;
565 
566 	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
567 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
568 		first = get_a_page(rq, gfp);
569 		if (!first) {
570 			if (list)
571 				give_pages(rq, list);
572 			return -ENOMEM;
573 		}
574 		sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
575 
576 		/* chain new page in list head to match sg */
577 		first->private = (unsigned long)list;
578 		list = first;
579 	}
580 
581 	first = get_a_page(rq, gfp);
582 	if (!first) {
583 		give_pages(rq, list);
584 		return -ENOMEM;
585 	}
586 	p = page_address(first);
587 
588 	/* rq->sg[0], rq->sg[1] share the same page */
589 	/* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */
590 	sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr));
591 
592 	/* rq->sg[1] for data packet, from offset */
593 	offset = sizeof(struct padded_vnet_hdr);
594 	sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
595 
596 	/* chain first in list head */
597 	first->private = (unsigned long)list;
598 	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
599 				  first, gfp);
600 	if (err < 0)
601 		give_pages(rq, first);
602 
603 	return err;
604 }
605 
606 static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
607 {
608 	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
609 	unsigned int len;
610 
611 	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
612 			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
613 	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
614 }
615 
616 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
617 {
618 	struct page_frag *alloc_frag = &rq->alloc_frag;
619 	char *buf;
620 	unsigned long ctx;
621 	int err;
622 	unsigned int len, hole;
623 
624 	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
625 	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
626 		return -ENOMEM;
627 
628 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
629 	ctx = mergeable_buf_to_ctx(buf, len);
630 	get_page(alloc_frag->page);
631 	alloc_frag->offset += len;
632 	hole = alloc_frag->size - alloc_frag->offset;
633 	if (hole < len) {
634 		/* To avoid internal fragmentation, if there is very likely not
635 		 * enough space for another buffer, add the remaining space to
636 		 * the current buffer. This extra space is not included in
637 		 * the truesize stored in ctx.
638 		 */
639 		len += hole;
640 		alloc_frag->offset += hole;
641 	}
642 
643 	sg_init_one(rq->sg, buf, len);
644 	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
645 	if (err < 0)
646 		put_page(virt_to_head_page(buf));
647 
648 	return err;
649 }
650 
651 /*
652  * Returns false if we couldn't fill entirely (OOM).
653  *
654  * Normally run in the receive path, but can also be run from ndo_open
655  * before we're receiving packets, or from refill_work which is
656  * careful to disable receiving (using napi_disable).
657  */
658 static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
659 {
660 	struct virtnet_info *vi = rq->vq->vdev->priv;
661 	int err;
662 	bool oom;
663 
664 	gfp |= __GFP_COLD;
665 	do {
666 		if (vi->mergeable_rx_bufs)
667 			err = add_recvbuf_mergeable(rq, gfp);
668 		else if (vi->big_packets)
669 			err = add_recvbuf_big(rq, gfp);
670 		else
671 			err = add_recvbuf_small(rq, gfp);
672 
673 		oom = err == -ENOMEM;
674 		if (err)
675 			break;
676 	} while (rq->vq->num_free);
677 	virtqueue_kick(rq->vq);
678 	return !oom;
679 }
680 
681 static void skb_recv_done(struct virtqueue *rvq)
682 {
683 	struct virtnet_info *vi = rvq->vdev->priv;
684 	struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
685 
686 	/* Schedule NAPI, Suppress further interrupts if successful. */
687 	if (napi_schedule_prep(&rq->napi)) {
688 		virtqueue_disable_cb(rvq);
689 		__napi_schedule(&rq->napi);
690 	}
691 }
692 
693 static void virtnet_napi_enable(struct receive_queue *rq)
694 {
695 	napi_enable(&rq->napi);
696 
697 	/* If all buffers were filled by other side before we napi_enabled, we
698 	 * won't get another interrupt, so process any outstanding packets
699 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
700 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
701 	if (napi_schedule_prep(&rq->napi)) {
702 		virtqueue_disable_cb(rq->vq);
703 		local_bh_disable();
704 		__napi_schedule(&rq->napi);
705 		local_bh_enable();
706 	}
707 }
708 
709 static void refill_work(struct work_struct *work)
710 {
711 	struct virtnet_info *vi =
712 		container_of(work, struct virtnet_info, refill.work);
713 	bool still_empty;
714 	int i;
715 
716 	for (i = 0; i < vi->curr_queue_pairs; i++) {
717 		struct receive_queue *rq = &vi->rq[i];
718 
719 		napi_disable(&rq->napi);
720 		still_empty = !try_fill_recv(rq, GFP_KERNEL);
721 		virtnet_napi_enable(rq);
722 
723 		/* In theory, this can happen: if we don't get any buffers in
724 		 * we will *never* try to fill again.
725 		 */
726 		if (still_empty)
727 			schedule_delayed_work(&vi->refill, HZ/2);
728 	}
729 }
730 
731 static int virtnet_receive(struct receive_queue *rq, int budget)
732 {
733 	struct virtnet_info *vi = rq->vq->vdev->priv;
734 	unsigned int len, received = 0;
735 	void *buf;
736 
737 	while (received < budget &&
738 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
739 		receive_buf(rq, buf, len);
740 		received++;
741 	}
742 
743 	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
744 		if (!try_fill_recv(rq, GFP_ATOMIC))
745 			schedule_delayed_work(&vi->refill, 0);
746 	}
747 
748 	return received;
749 }
750 
751 static int virtnet_poll(struct napi_struct *napi, int budget)
752 {
753 	struct receive_queue *rq =
754 		container_of(napi, struct receive_queue, napi);
755 	unsigned int r, received = 0;
756 
757 again:
758 	received += virtnet_receive(rq, budget - received);
759 
760 	/* Out of packets? */
761 	if (received < budget) {
762 		r = virtqueue_enable_cb_prepare(rq->vq);
763 		napi_complete(napi);
764 		if (unlikely(virtqueue_poll(rq->vq, r)) &&
765 		    napi_schedule_prep(napi)) {
766 			virtqueue_disable_cb(rq->vq);
767 			__napi_schedule(napi);
768 			goto again;
769 		}
770 	}
771 
772 	return received;
773 }
774 
775 #ifdef CONFIG_NET_RX_BUSY_POLL
776 /* must be called with local_bh_disable()d */
777 static int virtnet_busy_poll(struct napi_struct *napi)
778 {
779 	struct receive_queue *rq =
780 		container_of(napi, struct receive_queue, napi);
781 	struct virtnet_info *vi = rq->vq->vdev->priv;
782 	int r, received = 0, budget = 4;
783 
784 	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
785 		return LL_FLUSH_FAILED;
786 
787 	if (!napi_schedule_prep(napi))
788 		return LL_FLUSH_BUSY;
789 
790 	virtqueue_disable_cb(rq->vq);
791 
792 again:
793 	received += virtnet_receive(rq, budget);
794 
795 	r = virtqueue_enable_cb_prepare(rq->vq);
796 	clear_bit(NAPI_STATE_SCHED, &napi->state);
797 	if (unlikely(virtqueue_poll(rq->vq, r)) &&
798 	    napi_schedule_prep(napi)) {
799 		virtqueue_disable_cb(rq->vq);
800 		if (received < budget) {
801 			budget -= received;
802 			goto again;
803 		} else {
804 			__napi_schedule(napi);
805 		}
806 	}
807 
808 	return received;
809 }
810 #endif	/* CONFIG_NET_RX_BUSY_POLL */
811 
812 static int virtnet_open(struct net_device *dev)
813 {
814 	struct virtnet_info *vi = netdev_priv(dev);
815 	int i;
816 
817 	for (i = 0; i < vi->max_queue_pairs; i++) {
818 		if (i < vi->curr_queue_pairs)
819 			/* Make sure we have some buffers: if oom use wq. */
820 			if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
821 				schedule_delayed_work(&vi->refill, 0);
822 		virtnet_napi_enable(&vi->rq[i]);
823 	}
824 
825 	return 0;
826 }
827 
828 static void free_old_xmit_skbs(struct send_queue *sq)
829 {
830 	struct sk_buff *skb;
831 	unsigned int len;
832 	struct virtnet_info *vi = sq->vq->vdev->priv;
833 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
834 
835 	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
836 		pr_debug("Sent skb %p\n", skb);
837 
838 		u64_stats_update_begin(&stats->tx_syncp);
839 		stats->tx_bytes += skb->len;
840 		stats->tx_packets++;
841 		u64_stats_update_end(&stats->tx_syncp);
842 
843 		dev_kfree_skb_any(skb);
844 	}
845 }
846 
847 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
848 {
849 	struct skb_vnet_hdr *hdr;
850 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
851 	struct virtnet_info *vi = sq->vq->vdev->priv;
852 	unsigned num_sg;
853 	unsigned hdr_len;
854 	bool can_push;
855 
856 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
857 	if (vi->mergeable_rx_bufs)
858 		hdr_len = sizeof hdr->mhdr;
859 	else
860 		hdr_len = sizeof hdr->hdr;
861 
862 	can_push = vi->any_header_sg &&
863 		!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
864 		!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
865 	/* Even if we can, don't push here yet as this would skew
866 	 * csum_start offset below. */
867 	if (can_push)
868 		hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len);
869 	else
870 		hdr = skb_vnet_hdr(skb);
871 
872 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
873 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
874 		hdr->hdr.csum_start = skb_checksum_start_offset(skb);
875 		hdr->hdr.csum_offset = skb->csum_offset;
876 	} else {
877 		hdr->hdr.flags = 0;
878 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
879 	}
880 
881 	if (skb_is_gso(skb)) {
882 		hdr->hdr.hdr_len = skb_headlen(skb);
883 		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
884 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
885 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
886 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
887 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
888 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
889 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
890 		else
891 			BUG();
892 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
893 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
894 	} else {
895 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
896 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
897 	}
898 
899 	if (vi->mergeable_rx_bufs)
900 		hdr->mhdr.num_buffers = 0;
901 
902 	if (can_push) {
903 		__skb_push(skb, hdr_len);
904 		num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
905 		/* Pull header back to avoid skew in tx bytes calculations. */
906 		__skb_pull(skb, hdr_len);
907 	} else {
908 		sg_set_buf(sq->sg, hdr, hdr_len);
909 		num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
910 	}
911 	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
912 }
913 
914 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
915 {
916 	struct virtnet_info *vi = netdev_priv(dev);
917 	int qnum = skb_get_queue_mapping(skb);
918 	struct send_queue *sq = &vi->sq[qnum];
919 	int err;
920 
921 	/* Free up any pending old buffers before queueing new ones. */
922 	free_old_xmit_skbs(sq);
923 
924 	/* Try to transmit */
925 	err = xmit_skb(sq, skb);
926 
927 	/* This should not happen! */
928 	if (unlikely(err)) {
929 		dev->stats.tx_fifo_errors++;
930 		if (net_ratelimit())
931 			dev_warn(&dev->dev,
932 				 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
933 		dev->stats.tx_dropped++;
934 		dev_kfree_skb_any(skb);
935 		return NETDEV_TX_OK;
936 	}
937 	virtqueue_kick(sq->vq);
938 
939 	/* Don't wait up for transmitted skbs to be freed. */
940 	skb_orphan(skb);
941 	nf_reset(skb);
942 
943 	/* Apparently nice girls don't return TX_BUSY; stop the queue
944 	 * before it gets out of hand.  Naturally, this wastes entries. */
945 	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
946 		netif_stop_subqueue(dev, qnum);
947 		if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
948 			/* More just got used, free them then recheck. */
949 			free_old_xmit_skbs(sq);
950 			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
951 				netif_start_subqueue(dev, qnum);
952 				virtqueue_disable_cb(sq->vq);
953 			}
954 		}
955 	}
956 
957 	return NETDEV_TX_OK;
958 }
959 
960 /*
961  * Send command via the control virtqueue and check status.  Commands
962  * supported by the hypervisor, as indicated by feature bits, should
963  * never fail unless improperly formatted.
964  */
965 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
966 				 struct scatterlist *out)
967 {
968 	struct scatterlist *sgs[4], hdr, stat;
969 	struct virtio_net_ctrl_hdr ctrl;
970 	virtio_net_ctrl_ack status = ~0;
971 	unsigned out_num = 0, tmp;
972 
973 	/* Caller should know better */
974 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
975 
976 	ctrl.class = class;
977 	ctrl.cmd = cmd;
978 	/* Add header */
979 	sg_init_one(&hdr, &ctrl, sizeof(ctrl));
980 	sgs[out_num++] = &hdr;
981 
982 	if (out)
983 		sgs[out_num++] = out;
984 
985 	/* Add return status. */
986 	sg_init_one(&stat, &status, sizeof(status));
987 	sgs[out_num] = &stat;
988 
989 	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
990 	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
991 
992 	if (unlikely(!virtqueue_kick(vi->cvq)))
993 		return status == VIRTIO_NET_OK;
994 
995 	/* Spin for a response, the kick causes an ioport write, trapping
996 	 * into the hypervisor, so the request should be handled immediately.
997 	 */
998 	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
999 	       !virtqueue_is_broken(vi->cvq))
1000 		cpu_relax();
1001 
1002 	return status == VIRTIO_NET_OK;
1003 }
1004 
1005 static int virtnet_set_mac_address(struct net_device *dev, void *p)
1006 {
1007 	struct virtnet_info *vi = netdev_priv(dev);
1008 	struct virtio_device *vdev = vi->vdev;
1009 	int ret;
1010 	struct sockaddr *addr = p;
1011 	struct scatterlist sg;
1012 
1013 	ret = eth_prepare_mac_addr_change(dev, p);
1014 	if (ret)
1015 		return ret;
1016 
1017 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
1018 		sg_init_one(&sg, addr->sa_data, dev->addr_len);
1019 		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1020 					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
1021 			dev_warn(&vdev->dev,
1022 				 "Failed to set mac address by vq command.\n");
1023 			return -EINVAL;
1024 		}
1025 	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
1026 		unsigned int i;
1027 
1028 		/* Naturally, this has an atomicity problem. */
1029 		for (i = 0; i < dev->addr_len; i++)
1030 			virtio_cwrite8(vdev,
1031 				       offsetof(struct virtio_net_config, mac) +
1032 				       i, addr->sa_data[i]);
1033 	}
1034 
1035 	eth_commit_mac_addr_change(dev, p);
1036 
1037 	return 0;
1038 }
1039 
1040 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
1041 					       struct rtnl_link_stats64 *tot)
1042 {
1043 	struct virtnet_info *vi = netdev_priv(dev);
1044 	int cpu;
1045 	unsigned int start;
1046 
1047 	for_each_possible_cpu(cpu) {
1048 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
1049 		u64 tpackets, tbytes, rpackets, rbytes;
1050 
1051 		do {
1052 			start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
1053 			tpackets = stats->tx_packets;
1054 			tbytes   = stats->tx_bytes;
1055 		} while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
1056 
1057 		do {
1058 			start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
1059 			rpackets = stats->rx_packets;
1060 			rbytes   = stats->rx_bytes;
1061 		} while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
1062 
1063 		tot->rx_packets += rpackets;
1064 		tot->tx_packets += tpackets;
1065 		tot->rx_bytes   += rbytes;
1066 		tot->tx_bytes   += tbytes;
1067 	}
1068 
1069 	tot->tx_dropped = dev->stats.tx_dropped;
1070 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
1071 	tot->rx_dropped = dev->stats.rx_dropped;
1072 	tot->rx_length_errors = dev->stats.rx_length_errors;
1073 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
1074 
1075 	return tot;
1076 }
1077 
1078 #ifdef CONFIG_NET_POLL_CONTROLLER
1079 static void virtnet_netpoll(struct net_device *dev)
1080 {
1081 	struct virtnet_info *vi = netdev_priv(dev);
1082 	int i;
1083 
1084 	for (i = 0; i < vi->curr_queue_pairs; i++)
1085 		napi_schedule(&vi->rq[i].napi);
1086 }
1087 #endif
1088 
1089 static void virtnet_ack_link_announce(struct virtnet_info *vi)
1090 {
1091 	rtnl_lock();
1092 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
1093 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
1094 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
1095 	rtnl_unlock();
1096 }
1097 
1098 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
1099 {
1100 	struct scatterlist sg;
1101 	struct virtio_net_ctrl_mq s;
1102 	struct net_device *dev = vi->dev;
1103 
1104 	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
1105 		return 0;
1106 
1107 	s.virtqueue_pairs = queue_pairs;
1108 	sg_init_one(&sg, &s, sizeof(s));
1109 
1110 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
1111 				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
1112 		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
1113 			 queue_pairs);
1114 		return -EINVAL;
1115 	} else {
1116 		vi->curr_queue_pairs = queue_pairs;
1117 		/* virtnet_open() will refill when device is going to up. */
1118 		if (dev->flags & IFF_UP)
1119 			schedule_delayed_work(&vi->refill, 0);
1120 	}
1121 
1122 	return 0;
1123 }
1124 
1125 static int virtnet_close(struct net_device *dev)
1126 {
1127 	struct virtnet_info *vi = netdev_priv(dev);
1128 	int i;
1129 
1130 	/* Make sure refill_work doesn't re-enable napi! */
1131 	cancel_delayed_work_sync(&vi->refill);
1132 
1133 	for (i = 0; i < vi->max_queue_pairs; i++)
1134 		napi_disable(&vi->rq[i].napi);
1135 
1136 	return 0;
1137 }
1138 
1139 static void virtnet_set_rx_mode(struct net_device *dev)
1140 {
1141 	struct virtnet_info *vi = netdev_priv(dev);
1142 	struct scatterlist sg[2];
1143 	u8 promisc, allmulti;
1144 	struct virtio_net_ctrl_mac *mac_data;
1145 	struct netdev_hw_addr *ha;
1146 	int uc_count;
1147 	int mc_count;
1148 	void *buf;
1149 	int i;
1150 
1151 	/* We can't dynamically set ndo_set_rx_mode, so return gracefully */
1152 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
1153 		return;
1154 
1155 	promisc = ((dev->flags & IFF_PROMISC) != 0);
1156 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
1157 
1158 	sg_init_one(sg, &promisc, sizeof(promisc));
1159 
1160 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1161 				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
1162 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
1163 			 promisc ? "en" : "dis");
1164 
1165 	sg_init_one(sg, &allmulti, sizeof(allmulti));
1166 
1167 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
1168 				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
1169 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
1170 			 allmulti ? "en" : "dis");
1171 
1172 	uc_count = netdev_uc_count(dev);
1173 	mc_count = netdev_mc_count(dev);
1174 	/* MAC filter - use one buffer for both lists */
1175 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
1176 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
1177 	mac_data = buf;
1178 	if (!buf)
1179 		return;
1180 
1181 	sg_init_table(sg, 2);
1182 
1183 	/* Store the unicast list and count in the front of the buffer */
1184 	mac_data->entries = uc_count;
1185 	i = 0;
1186 	netdev_for_each_uc_addr(ha, dev)
1187 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1188 
1189 	sg_set_buf(&sg[0], mac_data,
1190 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
1191 
1192 	/* multicast list and count fill the end */
1193 	mac_data = (void *)&mac_data->macs[uc_count][0];
1194 
1195 	mac_data->entries = mc_count;
1196 	i = 0;
1197 	netdev_for_each_mc_addr(ha, dev)
1198 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
1199 
1200 	sg_set_buf(&sg[1], mac_data,
1201 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
1202 
1203 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
1204 				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
1205 		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
1206 
1207 	kfree(buf);
1208 }
1209 
1210 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
1211 				   __be16 proto, u16 vid)
1212 {
1213 	struct virtnet_info *vi = netdev_priv(dev);
1214 	struct scatterlist sg;
1215 
1216 	sg_init_one(&sg, &vid, sizeof(vid));
1217 
1218 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1219 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
1220 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
1221 	return 0;
1222 }
1223 
1224 static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
1225 				    __be16 proto, u16 vid)
1226 {
1227 	struct virtnet_info *vi = netdev_priv(dev);
1228 	struct scatterlist sg;
1229 
1230 	sg_init_one(&sg, &vid, sizeof(vid));
1231 
1232 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
1233 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
1234 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
1235 	return 0;
1236 }
1237 
1238 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
1239 {
1240 	int i;
1241 
1242 	if (vi->affinity_hint_set) {
1243 		for (i = 0; i < vi->max_queue_pairs; i++) {
1244 			virtqueue_set_affinity(vi->rq[i].vq, -1);
1245 			virtqueue_set_affinity(vi->sq[i].vq, -1);
1246 		}
1247 
1248 		vi->affinity_hint_set = false;
1249 	}
1250 }
1251 
1252 static void virtnet_set_affinity(struct virtnet_info *vi)
1253 {
1254 	int i;
1255 	int cpu;
1256 
1257 	/* In multiqueue mode, when the number of cpu is equal to the number of
1258 	 * queue pairs, we let the queue pairs to be private to one cpu by
1259 	 * setting the affinity hint to eliminate the contention.
1260 	 */
1261 	if (vi->curr_queue_pairs == 1 ||
1262 	    vi->max_queue_pairs != num_online_cpus()) {
1263 		virtnet_clean_affinity(vi, -1);
1264 		return;
1265 	}
1266 
1267 	i = 0;
1268 	for_each_online_cpu(cpu) {
1269 		virtqueue_set_affinity(vi->rq[i].vq, cpu);
1270 		virtqueue_set_affinity(vi->sq[i].vq, cpu);
1271 		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
1272 		i++;
1273 	}
1274 
1275 	vi->affinity_hint_set = true;
1276 }
1277 
1278 static int virtnet_cpu_callback(struct notifier_block *nfb,
1279 			        unsigned long action, void *hcpu)
1280 {
1281 	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
1282 
1283 	switch(action & ~CPU_TASKS_FROZEN) {
1284 	case CPU_ONLINE:
1285 	case CPU_DOWN_FAILED:
1286 	case CPU_DEAD:
1287 		virtnet_set_affinity(vi);
1288 		break;
1289 	case CPU_DOWN_PREPARE:
1290 		virtnet_clean_affinity(vi, (long)hcpu);
1291 		break;
1292 	default:
1293 		break;
1294 	}
1295 
1296 	return NOTIFY_OK;
1297 }
1298 
1299 static void virtnet_get_ringparam(struct net_device *dev,
1300 				struct ethtool_ringparam *ring)
1301 {
1302 	struct virtnet_info *vi = netdev_priv(dev);
1303 
1304 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
1305 	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
1306 	ring->rx_pending = ring->rx_max_pending;
1307 	ring->tx_pending = ring->tx_max_pending;
1308 }
1309 
1310 
1311 static void virtnet_get_drvinfo(struct net_device *dev,
1312 				struct ethtool_drvinfo *info)
1313 {
1314 	struct virtnet_info *vi = netdev_priv(dev);
1315 	struct virtio_device *vdev = vi->vdev;
1316 
1317 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
1318 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
1319 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
1320 
1321 }
1322 
1323 /* TODO: Eliminate OOO packets during switching */
1324 static int virtnet_set_channels(struct net_device *dev,
1325 				struct ethtool_channels *channels)
1326 {
1327 	struct virtnet_info *vi = netdev_priv(dev);
1328 	u16 queue_pairs = channels->combined_count;
1329 	int err;
1330 
1331 	/* We don't support separate rx/tx channels.
1332 	 * We don't allow setting 'other' channels.
1333 	 */
1334 	if (channels->rx_count || channels->tx_count || channels->other_count)
1335 		return -EINVAL;
1336 
1337 	if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
1338 		return -EINVAL;
1339 
1340 	get_online_cpus();
1341 	err = virtnet_set_queues(vi, queue_pairs);
1342 	if (!err) {
1343 		netif_set_real_num_tx_queues(dev, queue_pairs);
1344 		netif_set_real_num_rx_queues(dev, queue_pairs);
1345 
1346 		virtnet_set_affinity(vi);
1347 	}
1348 	put_online_cpus();
1349 
1350 	return err;
1351 }
1352 
1353 static void virtnet_get_channels(struct net_device *dev,
1354 				 struct ethtool_channels *channels)
1355 {
1356 	struct virtnet_info *vi = netdev_priv(dev);
1357 
1358 	channels->combined_count = vi->curr_queue_pairs;
1359 	channels->max_combined = vi->max_queue_pairs;
1360 	channels->max_other = 0;
1361 	channels->rx_count = 0;
1362 	channels->tx_count = 0;
1363 	channels->other_count = 0;
1364 }
1365 
1366 static const struct ethtool_ops virtnet_ethtool_ops = {
1367 	.get_drvinfo = virtnet_get_drvinfo,
1368 	.get_link = ethtool_op_get_link,
1369 	.get_ringparam = virtnet_get_ringparam,
1370 	.set_channels = virtnet_set_channels,
1371 	.get_channels = virtnet_get_channels,
1372 };
1373 
1374 #define MIN_MTU 68
1375 #define MAX_MTU 65535
1376 
1377 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
1378 {
1379 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
1380 		return -EINVAL;
1381 	dev->mtu = new_mtu;
1382 	return 0;
1383 }
1384 
1385 static const struct net_device_ops virtnet_netdev = {
1386 	.ndo_open            = virtnet_open,
1387 	.ndo_stop   	     = virtnet_close,
1388 	.ndo_start_xmit      = start_xmit,
1389 	.ndo_validate_addr   = eth_validate_addr,
1390 	.ndo_set_mac_address = virtnet_set_mac_address,
1391 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
1392 	.ndo_change_mtu	     = virtnet_change_mtu,
1393 	.ndo_get_stats64     = virtnet_stats,
1394 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
1395 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
1396 #ifdef CONFIG_NET_POLL_CONTROLLER
1397 	.ndo_poll_controller = virtnet_netpoll,
1398 #endif
1399 #ifdef CONFIG_NET_RX_BUSY_POLL
1400 	.ndo_busy_poll		= virtnet_busy_poll,
1401 #endif
1402 };
1403 
1404 static void virtnet_config_changed_work(struct work_struct *work)
1405 {
1406 	struct virtnet_info *vi =
1407 		container_of(work, struct virtnet_info, config_work);
1408 	u16 v;
1409 
1410 	mutex_lock(&vi->config_lock);
1411 	if (!vi->config_enable)
1412 		goto done;
1413 
1414 	if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
1415 				 struct virtio_net_config, status, &v) < 0)
1416 		goto done;
1417 
1418 	if (v & VIRTIO_NET_S_ANNOUNCE) {
1419 		netdev_notify_peers(vi->dev);
1420 		virtnet_ack_link_announce(vi);
1421 	}
1422 
1423 	/* Ignore unknown (future) status bits */
1424 	v &= VIRTIO_NET_S_LINK_UP;
1425 
1426 	if (vi->status == v)
1427 		goto done;
1428 
1429 	vi->status = v;
1430 
1431 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1432 		netif_carrier_on(vi->dev);
1433 		netif_tx_wake_all_queues(vi->dev);
1434 	} else {
1435 		netif_carrier_off(vi->dev);
1436 		netif_tx_stop_all_queues(vi->dev);
1437 	}
1438 done:
1439 	mutex_unlock(&vi->config_lock);
1440 }
1441 
1442 static void virtnet_config_changed(struct virtio_device *vdev)
1443 {
1444 	struct virtnet_info *vi = vdev->priv;
1445 
1446 	schedule_work(&vi->config_work);
1447 }
1448 
1449 static void virtnet_free_queues(struct virtnet_info *vi)
1450 {
1451 	int i;
1452 
1453 	for (i = 0; i < vi->max_queue_pairs; i++)
1454 		netif_napi_del(&vi->rq[i].napi);
1455 
1456 	kfree(vi->rq);
1457 	kfree(vi->sq);
1458 }
1459 
1460 static void free_receive_bufs(struct virtnet_info *vi)
1461 {
1462 	int i;
1463 
1464 	for (i = 0; i < vi->max_queue_pairs; i++) {
1465 		while (vi->rq[i].pages)
1466 			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
1467 	}
1468 }
1469 
1470 static void free_receive_page_frags(struct virtnet_info *vi)
1471 {
1472 	int i;
1473 	for (i = 0; i < vi->max_queue_pairs; i++)
1474 		if (vi->rq[i].alloc_frag.page)
1475 			put_page(vi->rq[i].alloc_frag.page);
1476 }
1477 
1478 static void free_unused_bufs(struct virtnet_info *vi)
1479 {
1480 	void *buf;
1481 	int i;
1482 
1483 	for (i = 0; i < vi->max_queue_pairs; i++) {
1484 		struct virtqueue *vq = vi->sq[i].vq;
1485 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
1486 			dev_kfree_skb(buf);
1487 	}
1488 
1489 	for (i = 0; i < vi->max_queue_pairs; i++) {
1490 		struct virtqueue *vq = vi->rq[i].vq;
1491 
1492 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
1493 			if (vi->mergeable_rx_bufs) {
1494 				unsigned long ctx = (unsigned long)buf;
1495 				void *base = mergeable_ctx_to_buf_address(ctx);
1496 				put_page(virt_to_head_page(base));
1497 			} else if (vi->big_packets) {
1498 				give_pages(&vi->rq[i], buf);
1499 			} else {
1500 				dev_kfree_skb(buf);
1501 			}
1502 		}
1503 	}
1504 }
1505 
1506 static void virtnet_del_vqs(struct virtnet_info *vi)
1507 {
1508 	struct virtio_device *vdev = vi->vdev;
1509 
1510 	virtnet_clean_affinity(vi, -1);
1511 
1512 	vdev->config->del_vqs(vdev);
1513 
1514 	virtnet_free_queues(vi);
1515 }
1516 
1517 static int virtnet_find_vqs(struct virtnet_info *vi)
1518 {
1519 	vq_callback_t **callbacks;
1520 	struct virtqueue **vqs;
1521 	int ret = -ENOMEM;
1522 	int i, total_vqs;
1523 	const char **names;
1524 
1525 	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
1526 	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
1527 	 * possible control vq.
1528 	 */
1529 	total_vqs = vi->max_queue_pairs * 2 +
1530 		    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
1531 
1532 	/* Allocate space for find_vqs parameters */
1533 	vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
1534 	if (!vqs)
1535 		goto err_vq;
1536 	callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
1537 	if (!callbacks)
1538 		goto err_callback;
1539 	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
1540 	if (!names)
1541 		goto err_names;
1542 
1543 	/* Parameters for control virtqueue, if any */
1544 	if (vi->has_cvq) {
1545 		callbacks[total_vqs - 1] = NULL;
1546 		names[total_vqs - 1] = "control";
1547 	}
1548 
1549 	/* Allocate/initialize parameters for send/receive virtqueues */
1550 	for (i = 0; i < vi->max_queue_pairs; i++) {
1551 		callbacks[rxq2vq(i)] = skb_recv_done;
1552 		callbacks[txq2vq(i)] = skb_xmit_done;
1553 		sprintf(vi->rq[i].name, "input.%d", i);
1554 		sprintf(vi->sq[i].name, "output.%d", i);
1555 		names[rxq2vq(i)] = vi->rq[i].name;
1556 		names[txq2vq(i)] = vi->sq[i].name;
1557 	}
1558 
1559 	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
1560 					 names);
1561 	if (ret)
1562 		goto err_find;
1563 
1564 	if (vi->has_cvq) {
1565 		vi->cvq = vqs[total_vqs - 1];
1566 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1567 			vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
1568 	}
1569 
1570 	for (i = 0; i < vi->max_queue_pairs; i++) {
1571 		vi->rq[i].vq = vqs[rxq2vq(i)];
1572 		vi->sq[i].vq = vqs[txq2vq(i)];
1573 	}
1574 
1575 	kfree(names);
1576 	kfree(callbacks);
1577 	kfree(vqs);
1578 
1579 	return 0;
1580 
1581 err_find:
1582 	kfree(names);
1583 err_names:
1584 	kfree(callbacks);
1585 err_callback:
1586 	kfree(vqs);
1587 err_vq:
1588 	return ret;
1589 }
1590 
1591 static int virtnet_alloc_queues(struct virtnet_info *vi)
1592 {
1593 	int i;
1594 
1595 	vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
1596 	if (!vi->sq)
1597 		goto err_sq;
1598 	vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
1599 	if (!vi->rq)
1600 		goto err_rq;
1601 
1602 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1603 	for (i = 0; i < vi->max_queue_pairs; i++) {
1604 		vi->rq[i].pages = NULL;
1605 		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
1606 			       napi_weight);
1607 		napi_hash_add(&vi->rq[i].napi);
1608 
1609 		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
1610 		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
1611 		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
1612 	}
1613 
1614 	return 0;
1615 
1616 err_rq:
1617 	kfree(vi->sq);
1618 err_sq:
1619 	return -ENOMEM;
1620 }
1621 
1622 static int init_vqs(struct virtnet_info *vi)
1623 {
1624 	int ret;
1625 
1626 	/* Allocate send & receive queues */
1627 	ret = virtnet_alloc_queues(vi);
1628 	if (ret)
1629 		goto err;
1630 
1631 	ret = virtnet_find_vqs(vi);
1632 	if (ret)
1633 		goto err_free;
1634 
1635 	get_online_cpus();
1636 	virtnet_set_affinity(vi);
1637 	put_online_cpus();
1638 
1639 	return 0;
1640 
1641 err_free:
1642 	virtnet_free_queues(vi);
1643 err:
1644 	return ret;
1645 }
1646 
1647 #ifdef CONFIG_SYSFS
1648 static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
1649 		struct rx_queue_attribute *attribute, char *buf)
1650 {
1651 	struct virtnet_info *vi = netdev_priv(queue->dev);
1652 	unsigned int queue_index = get_netdev_rx_queue_index(queue);
1653 	struct ewma *avg;
1654 
1655 	BUG_ON(queue_index >= vi->max_queue_pairs);
1656 	avg = &vi->rq[queue_index].mrg_avg_pkt_len;
1657 	return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
1658 }
1659 
1660 static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
1661 	__ATTR_RO(mergeable_rx_buffer_size);
1662 
1663 static struct attribute *virtio_net_mrg_rx_attrs[] = {
1664 	&mergeable_rx_buffer_size_attribute.attr,
1665 	NULL
1666 };
1667 
1668 static const struct attribute_group virtio_net_mrg_rx_group = {
1669 	.name = "virtio_net",
1670 	.attrs = virtio_net_mrg_rx_attrs
1671 };
1672 #endif
1673 
1674 static int virtnet_probe(struct virtio_device *vdev)
1675 {
1676 	int i, err;
1677 	struct net_device *dev;
1678 	struct virtnet_info *vi;
1679 	u16 max_queue_pairs;
1680 
1681 	/* Find if host supports multiqueue virtio_net device */
1682 	err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
1683 				   struct virtio_net_config,
1684 				   max_virtqueue_pairs, &max_queue_pairs);
1685 
1686 	/* We need at least 2 queue's */
1687 	if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
1688 	    max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
1689 	    !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1690 		max_queue_pairs = 1;
1691 
1692 	/* Allocate ourselves a network device with room for our info */
1693 	dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
1694 	if (!dev)
1695 		return -ENOMEM;
1696 
1697 	/* Set up network device as normal. */
1698 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
1699 	dev->netdev_ops = &virtnet_netdev;
1700 	dev->features = NETIF_F_HIGHDMA;
1701 
1702 	dev->ethtool_ops = &virtnet_ethtool_ops;
1703 	SET_NETDEV_DEV(dev, &vdev->dev);
1704 
1705 	/* Do we support "hardware" checksums? */
1706 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1707 		/* This opens up the world of extra features. */
1708 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1709 		if (csum)
1710 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1711 
1712 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1713 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1714 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1715 		}
1716 		/* Individual feature bits: what can host handle? */
1717 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1718 			dev->hw_features |= NETIF_F_TSO;
1719 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1720 			dev->hw_features |= NETIF_F_TSO6;
1721 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1722 			dev->hw_features |= NETIF_F_TSO_ECN;
1723 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1724 			dev->hw_features |= NETIF_F_UFO;
1725 
1726 		if (gso)
1727 			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1728 		/* (!csum && gso) case will be fixed by register_netdev() */
1729 	}
1730 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
1731 		dev->features |= NETIF_F_RXCSUM;
1732 
1733 	dev->vlan_features = dev->features;
1734 
1735 	/* Configuration may specify what MAC to use.  Otherwise random. */
1736 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
1737 		virtio_cread_bytes(vdev,
1738 				   offsetof(struct virtio_net_config, mac),
1739 				   dev->dev_addr, dev->addr_len);
1740 	else
1741 		eth_hw_addr_random(dev);
1742 
1743 	/* Set up our device-specific information */
1744 	vi = netdev_priv(dev);
1745 	vi->dev = dev;
1746 	vi->vdev = vdev;
1747 	vdev->priv = vi;
1748 	vi->stats = alloc_percpu(struct virtnet_stats);
1749 	err = -ENOMEM;
1750 	if (vi->stats == NULL)
1751 		goto free;
1752 
1753 	for_each_possible_cpu(i) {
1754 		struct virtnet_stats *virtnet_stats;
1755 		virtnet_stats = per_cpu_ptr(vi->stats, i);
1756 		u64_stats_init(&virtnet_stats->tx_syncp);
1757 		u64_stats_init(&virtnet_stats->rx_syncp);
1758 	}
1759 
1760 	mutex_init(&vi->config_lock);
1761 	vi->config_enable = true;
1762 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1763 
1764 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1765 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1766 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1767 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
1768 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
1769 		vi->big_packets = true;
1770 
1771 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1772 		vi->mergeable_rx_bufs = true;
1773 
1774 	if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
1775 		vi->any_header_sg = true;
1776 
1777 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
1778 		vi->has_cvq = true;
1779 
1780 	if (vi->any_header_sg) {
1781 		if (vi->mergeable_rx_bufs)
1782 			dev->needed_headroom = sizeof(struct virtio_net_hdr_mrg_rxbuf);
1783 		else
1784 			dev->needed_headroom = sizeof(struct virtio_net_hdr);
1785 	}
1786 
1787 	/* Use single tx/rx queue pair as default */
1788 	vi->curr_queue_pairs = 1;
1789 	vi->max_queue_pairs = max_queue_pairs;
1790 
1791 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
1792 	err = init_vqs(vi);
1793 	if (err)
1794 		goto free_stats;
1795 
1796 #ifdef CONFIG_SYSFS
1797 	if (vi->mergeable_rx_bufs)
1798 		dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
1799 #endif
1800 	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
1801 	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
1802 
1803 	err = register_netdev(dev);
1804 	if (err) {
1805 		pr_debug("virtio_net: registering device failed\n");
1806 		goto free_vqs;
1807 	}
1808 
1809 	/* Last of all, set up some receive buffers. */
1810 	for (i = 0; i < vi->curr_queue_pairs; i++) {
1811 		try_fill_recv(&vi->rq[i], GFP_KERNEL);
1812 
1813 		/* If we didn't even get one input buffer, we're useless. */
1814 		if (vi->rq[i].vq->num_free ==
1815 		    virtqueue_get_vring_size(vi->rq[i].vq)) {
1816 			free_unused_bufs(vi);
1817 			err = -ENOMEM;
1818 			goto free_recv_bufs;
1819 		}
1820 	}
1821 
1822 	vi->nb.notifier_call = &virtnet_cpu_callback;
1823 	err = register_hotcpu_notifier(&vi->nb);
1824 	if (err) {
1825 		pr_debug("virtio_net: registering cpu notifier failed\n");
1826 		goto free_recv_bufs;
1827 	}
1828 
1829 	/* Assume link up if device can't report link status,
1830 	   otherwise get link status from config. */
1831 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1832 		netif_carrier_off(dev);
1833 		schedule_work(&vi->config_work);
1834 	} else {
1835 		vi->status = VIRTIO_NET_S_LINK_UP;
1836 		netif_carrier_on(dev);
1837 	}
1838 
1839 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
1840 		 dev->name, max_queue_pairs);
1841 
1842 	return 0;
1843 
1844 free_recv_bufs:
1845 	free_receive_bufs(vi);
1846 	unregister_netdev(dev);
1847 free_vqs:
1848 	cancel_delayed_work_sync(&vi->refill);
1849 	free_receive_page_frags(vi);
1850 	virtnet_del_vqs(vi);
1851 free_stats:
1852 	free_percpu(vi->stats);
1853 free:
1854 	free_netdev(dev);
1855 	return err;
1856 }
1857 
1858 static void remove_vq_common(struct virtnet_info *vi)
1859 {
1860 	vi->vdev->config->reset(vi->vdev);
1861 
1862 	/* Free unused buffers in both send and recv, if any. */
1863 	free_unused_bufs(vi);
1864 
1865 	free_receive_bufs(vi);
1866 
1867 	free_receive_page_frags(vi);
1868 
1869 	virtnet_del_vqs(vi);
1870 }
1871 
1872 static void virtnet_remove(struct virtio_device *vdev)
1873 {
1874 	struct virtnet_info *vi = vdev->priv;
1875 
1876 	unregister_hotcpu_notifier(&vi->nb);
1877 
1878 	/* Prevent config work handler from accessing the device. */
1879 	mutex_lock(&vi->config_lock);
1880 	vi->config_enable = false;
1881 	mutex_unlock(&vi->config_lock);
1882 
1883 	unregister_netdev(vi->dev);
1884 
1885 	remove_vq_common(vi);
1886 
1887 	flush_work(&vi->config_work);
1888 
1889 	free_percpu(vi->stats);
1890 	free_netdev(vi->dev);
1891 }
1892 
1893 #ifdef CONFIG_PM_SLEEP
1894 static int virtnet_freeze(struct virtio_device *vdev)
1895 {
1896 	struct virtnet_info *vi = vdev->priv;
1897 	int i;
1898 
1899 	unregister_hotcpu_notifier(&vi->nb);
1900 
1901 	/* Prevent config work handler from accessing the device */
1902 	mutex_lock(&vi->config_lock);
1903 	vi->config_enable = false;
1904 	mutex_unlock(&vi->config_lock);
1905 
1906 	netif_device_detach(vi->dev);
1907 	cancel_delayed_work_sync(&vi->refill);
1908 
1909 	if (netif_running(vi->dev)) {
1910 		for (i = 0; i < vi->max_queue_pairs; i++) {
1911 			napi_disable(&vi->rq[i].napi);
1912 			napi_hash_del(&vi->rq[i].napi);
1913 			netif_napi_del(&vi->rq[i].napi);
1914 		}
1915 	}
1916 
1917 	remove_vq_common(vi);
1918 
1919 	flush_work(&vi->config_work);
1920 
1921 	return 0;
1922 }
1923 
1924 static int virtnet_restore(struct virtio_device *vdev)
1925 {
1926 	struct virtnet_info *vi = vdev->priv;
1927 	int err, i;
1928 
1929 	err = init_vqs(vi);
1930 	if (err)
1931 		return err;
1932 
1933 	if (netif_running(vi->dev)) {
1934 		for (i = 0; i < vi->curr_queue_pairs; i++)
1935 			if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
1936 				schedule_delayed_work(&vi->refill, 0);
1937 
1938 		for (i = 0; i < vi->max_queue_pairs; i++)
1939 			virtnet_napi_enable(&vi->rq[i]);
1940 	}
1941 
1942 	netif_device_attach(vi->dev);
1943 
1944 	mutex_lock(&vi->config_lock);
1945 	vi->config_enable = true;
1946 	mutex_unlock(&vi->config_lock);
1947 
1948 	rtnl_lock();
1949 	virtnet_set_queues(vi, vi->curr_queue_pairs);
1950 	rtnl_unlock();
1951 
1952 	err = register_hotcpu_notifier(&vi->nb);
1953 	if (err)
1954 		return err;
1955 
1956 	return 0;
1957 }
1958 #endif
1959 
1960 static struct virtio_device_id id_table[] = {
1961 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1962 	{ 0 },
1963 };
1964 
1965 static unsigned int features[] = {
1966 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1967 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1968 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1969 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1970 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1971 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1972 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1973 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
1974 	VIRTIO_NET_F_CTRL_MAC_ADDR,
1975 	VIRTIO_F_ANY_LAYOUT,
1976 };
1977 
1978 static struct virtio_driver virtio_net_driver = {
1979 	.feature_table = features,
1980 	.feature_table_size = ARRAY_SIZE(features),
1981 	.driver.name =	KBUILD_MODNAME,
1982 	.driver.owner =	THIS_MODULE,
1983 	.id_table =	id_table,
1984 	.probe =	virtnet_probe,
1985 	.remove =	virtnet_remove,
1986 	.config_changed = virtnet_config_changed,
1987 #ifdef CONFIG_PM_SLEEP
1988 	.freeze =	virtnet_freeze,
1989 	.restore =	virtnet_restore,
1990 #endif
1991 };
1992 
1993 module_virtio_driver(virtio_net_driver);
1994 
1995 MODULE_DEVICE_TABLE(virtio, id_table);
1996 MODULE_DESCRIPTION("Virtio network driver");
1997 MODULE_LICENSE("GPL");
1998