xref: /linux/drivers/net/virtio_net.c (revision a508da6cc0093171833efb8376b00473f24221b9)
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, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19 //#define DEBUG
20 #include <linux/netdevice.h>
21 #include <linux/etherdevice.h>
22 #include <linux/ethtool.h>
23 #include <linux/module.h>
24 #include <linux/virtio.h>
25 #include <linux/virtio_net.h>
26 #include <linux/scatterlist.h>
27 #include <linux/if_vlan.h>
28 #include <linux/slab.h>
29 
30 static int napi_weight = 128;
31 module_param(napi_weight, int, 0444);
32 
33 static bool csum = true, gso = true;
34 module_param(csum, bool, 0444);
35 module_param(gso, bool, 0444);
36 
37 /* FIXME: MTU in config. */
38 #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
39 #define GOOD_COPY_LEN	128
40 
41 #define VIRTNET_SEND_COMMAND_SG_MAX    2
42 #define VIRTNET_DRIVER_VERSION "1.0.0"
43 
44 struct virtnet_stats {
45 	struct u64_stats_sync syncp;
46 	u64 tx_bytes;
47 	u64 tx_packets;
48 
49 	u64 rx_bytes;
50 	u64 rx_packets;
51 };
52 
53 struct virtnet_info {
54 	struct virtio_device *vdev;
55 	struct virtqueue *rvq, *svq, *cvq;
56 	struct net_device *dev;
57 	struct napi_struct napi;
58 	unsigned int status;
59 
60 	/* Number of input buffers, and max we've ever had. */
61 	unsigned int num, max;
62 
63 	/* I like... big packets and I cannot lie! */
64 	bool big_packets;
65 
66 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
67 	bool mergeable_rx_bufs;
68 
69 	/* enable config space updates */
70 	bool config_enable;
71 
72 	/* Active statistics */
73 	struct virtnet_stats __percpu *stats;
74 
75 	/* Work struct for refilling if we run low on memory. */
76 	struct delayed_work refill;
77 
78 	/* Work struct for config space updates */
79 	struct work_struct config_work;
80 
81 	/* Lock for config space updates */
82 	struct mutex config_lock;
83 
84 	/* Chain pages by the private ptr. */
85 	struct page *pages;
86 
87 	/* fragments + linear part + virtio header */
88 	struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
89 	struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
90 };
91 
92 struct skb_vnet_hdr {
93 	union {
94 		struct virtio_net_hdr hdr;
95 		struct virtio_net_hdr_mrg_rxbuf mhdr;
96 	};
97 	unsigned int num_sg;
98 };
99 
100 struct padded_vnet_hdr {
101 	struct virtio_net_hdr hdr;
102 	/*
103 	 * virtio_net_hdr should be in a separated sg buffer because of a
104 	 * QEMU bug, and data sg buffer shares same page with this header sg.
105 	 * This padding makes next sg 16 byte aligned after virtio_net_hdr.
106 	 */
107 	char padding[6];
108 };
109 
110 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
111 {
112 	return (struct skb_vnet_hdr *)skb->cb;
113 }
114 
115 /*
116  * private is used to chain pages for big packets, put the whole
117  * most recent used list in the beginning for reuse
118  */
119 static void give_pages(struct virtnet_info *vi, struct page *page)
120 {
121 	struct page *end;
122 
123 	/* Find end of list, sew whole thing into vi->pages. */
124 	for (end = page; end->private; end = (struct page *)end->private);
125 	end->private = (unsigned long)vi->pages;
126 	vi->pages = page;
127 }
128 
129 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
130 {
131 	struct page *p = vi->pages;
132 
133 	if (p) {
134 		vi->pages = (struct page *)p->private;
135 		/* clear private here, it is used to chain pages */
136 		p->private = 0;
137 	} else
138 		p = alloc_page(gfp_mask);
139 	return p;
140 }
141 
142 static void skb_xmit_done(struct virtqueue *svq)
143 {
144 	struct virtnet_info *vi = svq->vdev->priv;
145 
146 	/* Suppress further interrupts. */
147 	virtqueue_disable_cb(svq);
148 
149 	/* We were probably waiting for more output buffers. */
150 	netif_wake_queue(vi->dev);
151 }
152 
153 static void set_skb_frag(struct sk_buff *skb, struct page *page,
154 			 unsigned int offset, unsigned int *len)
155 {
156 	int size = min((unsigned)PAGE_SIZE - offset, *len);
157 	int i = skb_shinfo(skb)->nr_frags;
158 
159 	__skb_fill_page_desc(skb, i, page, offset, size);
160 
161 	skb->data_len += size;
162 	skb->len += size;
163 	skb->truesize += PAGE_SIZE;
164 	skb_shinfo(skb)->nr_frags++;
165 	*len -= size;
166 }
167 
168 /* Called from bottom half context */
169 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
170 				   struct page *page, unsigned int len)
171 {
172 	struct sk_buff *skb;
173 	struct skb_vnet_hdr *hdr;
174 	unsigned int copy, hdr_len, offset;
175 	char *p;
176 
177 	p = page_address(page);
178 
179 	/* copy small packet so we can reuse these pages for small data */
180 	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
181 	if (unlikely(!skb))
182 		return NULL;
183 
184 	hdr = skb_vnet_hdr(skb);
185 
186 	if (vi->mergeable_rx_bufs) {
187 		hdr_len = sizeof hdr->mhdr;
188 		offset = hdr_len;
189 	} else {
190 		hdr_len = sizeof hdr->hdr;
191 		offset = sizeof(struct padded_vnet_hdr);
192 	}
193 
194 	memcpy(hdr, p, hdr_len);
195 
196 	len -= hdr_len;
197 	p += offset;
198 
199 	copy = len;
200 	if (copy > skb_tailroom(skb))
201 		copy = skb_tailroom(skb);
202 	memcpy(skb_put(skb, copy), p, copy);
203 
204 	len -= copy;
205 	offset += copy;
206 
207 	/*
208 	 * Verify that we can indeed put this data into a skb.
209 	 * This is here to handle cases when the device erroneously
210 	 * tries to receive more than is possible. This is usually
211 	 * the case of a broken device.
212 	 */
213 	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
214 		if (net_ratelimit())
215 			pr_debug("%s: too much data\n", skb->dev->name);
216 		dev_kfree_skb(skb);
217 		return NULL;
218 	}
219 
220 	while (len) {
221 		set_skb_frag(skb, page, offset, &len);
222 		page = (struct page *)page->private;
223 		offset = 0;
224 	}
225 
226 	if (page)
227 		give_pages(vi, page);
228 
229 	return skb;
230 }
231 
232 static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
233 {
234 	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
235 	struct page *page;
236 	int num_buf, i, len;
237 
238 	num_buf = hdr->mhdr.num_buffers;
239 	while (--num_buf) {
240 		i = skb_shinfo(skb)->nr_frags;
241 		if (i >= MAX_SKB_FRAGS) {
242 			pr_debug("%s: packet too long\n", skb->dev->name);
243 			skb->dev->stats.rx_length_errors++;
244 			return -EINVAL;
245 		}
246 		page = virtqueue_get_buf(vi->rvq, &len);
247 		if (!page) {
248 			pr_debug("%s: rx error: %d buffers missing\n",
249 				 skb->dev->name, hdr->mhdr.num_buffers);
250 			skb->dev->stats.rx_length_errors++;
251 			return -EINVAL;
252 		}
253 
254 		if (len > PAGE_SIZE)
255 			len = PAGE_SIZE;
256 
257 		set_skb_frag(skb, page, 0, &len);
258 
259 		--vi->num;
260 	}
261 	return 0;
262 }
263 
264 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
265 {
266 	struct virtnet_info *vi = netdev_priv(dev);
267 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
268 	struct sk_buff *skb;
269 	struct page *page;
270 	struct skb_vnet_hdr *hdr;
271 
272 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
273 		pr_debug("%s: short packet %i\n", dev->name, len);
274 		dev->stats.rx_length_errors++;
275 		if (vi->mergeable_rx_bufs || vi->big_packets)
276 			give_pages(vi, buf);
277 		else
278 			dev_kfree_skb(buf);
279 		return;
280 	}
281 
282 	if (!vi->mergeable_rx_bufs && !vi->big_packets) {
283 		skb = buf;
284 		len -= sizeof(struct virtio_net_hdr);
285 		skb_trim(skb, len);
286 	} else {
287 		page = buf;
288 		skb = page_to_skb(vi, page, len);
289 		if (unlikely(!skb)) {
290 			dev->stats.rx_dropped++;
291 			give_pages(vi, page);
292 			return;
293 		}
294 		if (vi->mergeable_rx_bufs)
295 			if (receive_mergeable(vi, skb)) {
296 				dev_kfree_skb(skb);
297 				return;
298 			}
299 	}
300 
301 	hdr = skb_vnet_hdr(skb);
302 
303 	u64_stats_update_begin(&stats->syncp);
304 	stats->rx_bytes += skb->len;
305 	stats->rx_packets++;
306 	u64_stats_update_end(&stats->syncp);
307 
308 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
309 		pr_debug("Needs csum!\n");
310 		if (!skb_partial_csum_set(skb,
311 					  hdr->hdr.csum_start,
312 					  hdr->hdr.csum_offset))
313 			goto frame_err;
314 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
315 		skb->ip_summed = CHECKSUM_UNNECESSARY;
316 	}
317 
318 	skb->protocol = eth_type_trans(skb, dev);
319 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
320 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
321 
322 	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
323 		pr_debug("GSO!\n");
324 		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
325 		case VIRTIO_NET_HDR_GSO_TCPV4:
326 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
327 			break;
328 		case VIRTIO_NET_HDR_GSO_UDP:
329 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
330 			break;
331 		case VIRTIO_NET_HDR_GSO_TCPV6:
332 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
333 			break;
334 		default:
335 			if (net_ratelimit())
336 				printk(KERN_WARNING "%s: bad gso type %u.\n",
337 				       dev->name, hdr->hdr.gso_type);
338 			goto frame_err;
339 		}
340 
341 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
342 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
343 
344 		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
345 		if (skb_shinfo(skb)->gso_size == 0) {
346 			if (net_ratelimit())
347 				printk(KERN_WARNING "%s: zero gso size.\n",
348 				       dev->name);
349 			goto frame_err;
350 		}
351 
352 		/* Header must be checked, and gso_segs computed. */
353 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
354 		skb_shinfo(skb)->gso_segs = 0;
355 	}
356 
357 	netif_receive_skb(skb);
358 	return;
359 
360 frame_err:
361 	dev->stats.rx_frame_errors++;
362 	dev_kfree_skb(skb);
363 }
364 
365 static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
366 {
367 	struct sk_buff *skb;
368 	struct skb_vnet_hdr *hdr;
369 	int err;
370 
371 	skb = __netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN, gfp);
372 	if (unlikely(!skb))
373 		return -ENOMEM;
374 
375 	skb_put(skb, MAX_PACKET_LEN);
376 
377 	hdr = skb_vnet_hdr(skb);
378 	sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
379 
380 	skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
381 
382 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 2, skb, gfp);
383 	if (err < 0)
384 		dev_kfree_skb(skb);
385 
386 	return err;
387 }
388 
389 static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
390 {
391 	struct page *first, *list = NULL;
392 	char *p;
393 	int i, err, offset;
394 
395 	/* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
396 	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
397 		first = get_a_page(vi, gfp);
398 		if (!first) {
399 			if (list)
400 				give_pages(vi, list);
401 			return -ENOMEM;
402 		}
403 		sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
404 
405 		/* chain new page in list head to match sg */
406 		first->private = (unsigned long)list;
407 		list = first;
408 	}
409 
410 	first = get_a_page(vi, gfp);
411 	if (!first) {
412 		give_pages(vi, list);
413 		return -ENOMEM;
414 	}
415 	p = page_address(first);
416 
417 	/* vi->rx_sg[0], vi->rx_sg[1] share the same page */
418 	/* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
419 	sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
420 
421 	/* vi->rx_sg[1] for data packet, from offset */
422 	offset = sizeof(struct padded_vnet_hdr);
423 	sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
424 
425 	/* chain first in list head */
426 	first->private = (unsigned long)list;
427 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
428 				first, gfp);
429 	if (err < 0)
430 		give_pages(vi, first);
431 
432 	return err;
433 }
434 
435 static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
436 {
437 	struct page *page;
438 	int err;
439 
440 	page = get_a_page(vi, gfp);
441 	if (!page)
442 		return -ENOMEM;
443 
444 	sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
445 
446 	err = virtqueue_add_buf(vi->rvq, vi->rx_sg, 0, 1, page, gfp);
447 	if (err < 0)
448 		give_pages(vi, page);
449 
450 	return err;
451 }
452 
453 /*
454  * Returns false if we couldn't fill entirely (OOM).
455  *
456  * Normally run in the receive path, but can also be run from ndo_open
457  * before we're receiving packets, or from refill_work which is
458  * careful to disable receiving (using napi_disable).
459  */
460 static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
461 {
462 	int err;
463 	bool oom;
464 
465 	do {
466 		if (vi->mergeable_rx_bufs)
467 			err = add_recvbuf_mergeable(vi, gfp);
468 		else if (vi->big_packets)
469 			err = add_recvbuf_big(vi, gfp);
470 		else
471 			err = add_recvbuf_small(vi, gfp);
472 
473 		oom = err == -ENOMEM;
474 		if (err < 0)
475 			break;
476 		++vi->num;
477 	} while (err > 0);
478 	if (unlikely(vi->num > vi->max))
479 		vi->max = vi->num;
480 	virtqueue_kick(vi->rvq);
481 	return !oom;
482 }
483 
484 static void skb_recv_done(struct virtqueue *rvq)
485 {
486 	struct virtnet_info *vi = rvq->vdev->priv;
487 	/* Schedule NAPI, Suppress further interrupts if successful. */
488 	if (napi_schedule_prep(&vi->napi)) {
489 		virtqueue_disable_cb(rvq);
490 		__napi_schedule(&vi->napi);
491 	}
492 }
493 
494 static void virtnet_napi_enable(struct virtnet_info *vi)
495 {
496 	napi_enable(&vi->napi);
497 
498 	/* If all buffers were filled by other side before we napi_enabled, we
499 	 * won't get another interrupt, so process any outstanding packets
500 	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
501 	 * We synchronize against interrupts via NAPI_STATE_SCHED */
502 	if (napi_schedule_prep(&vi->napi)) {
503 		virtqueue_disable_cb(vi->rvq);
504 		__napi_schedule(&vi->napi);
505 	}
506 }
507 
508 static void refill_work(struct work_struct *work)
509 {
510 	struct virtnet_info *vi;
511 	bool still_empty;
512 
513 	vi = container_of(work, struct virtnet_info, refill.work);
514 	napi_disable(&vi->napi);
515 	still_empty = !try_fill_recv(vi, GFP_KERNEL);
516 	virtnet_napi_enable(vi);
517 
518 	/* In theory, this can happen: if we don't get any buffers in
519 	 * we will *never* try to fill again. */
520 	if (still_empty)
521 		queue_delayed_work(system_nrt_wq, &vi->refill, HZ/2);
522 }
523 
524 static int virtnet_poll(struct napi_struct *napi, int budget)
525 {
526 	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
527 	void *buf;
528 	unsigned int len, received = 0;
529 
530 again:
531 	while (received < budget &&
532 	       (buf = virtqueue_get_buf(vi->rvq, &len)) != NULL) {
533 		receive_buf(vi->dev, buf, len);
534 		--vi->num;
535 		received++;
536 	}
537 
538 	if (vi->num < vi->max / 2) {
539 		if (!try_fill_recv(vi, GFP_ATOMIC))
540 			queue_delayed_work(system_nrt_wq, &vi->refill, 0);
541 	}
542 
543 	/* Out of packets? */
544 	if (received < budget) {
545 		napi_complete(napi);
546 		if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
547 		    napi_schedule_prep(napi)) {
548 			virtqueue_disable_cb(vi->rvq);
549 			__napi_schedule(napi);
550 			goto again;
551 		}
552 	}
553 
554 	return received;
555 }
556 
557 static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
558 {
559 	struct sk_buff *skb;
560 	unsigned int len, tot_sgs = 0;
561 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
562 
563 	while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
564 		pr_debug("Sent skb %p\n", skb);
565 
566 		u64_stats_update_begin(&stats->syncp);
567 		stats->tx_bytes += skb->len;
568 		stats->tx_packets++;
569 		u64_stats_update_end(&stats->syncp);
570 
571 		tot_sgs += skb_vnet_hdr(skb)->num_sg;
572 		dev_kfree_skb_any(skb);
573 	}
574 	return tot_sgs;
575 }
576 
577 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
578 {
579 	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
580 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
581 
582 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
583 
584 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
585 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
586 		hdr->hdr.csum_start = skb_checksum_start_offset(skb);
587 		hdr->hdr.csum_offset = skb->csum_offset;
588 	} else {
589 		hdr->hdr.flags = 0;
590 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
591 	}
592 
593 	if (skb_is_gso(skb)) {
594 		hdr->hdr.hdr_len = skb_headlen(skb);
595 		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
596 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
597 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
598 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
599 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
600 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
601 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
602 		else
603 			BUG();
604 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
605 			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
606 	} else {
607 		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
608 		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
609 	}
610 
611 	hdr->mhdr.num_buffers = 0;
612 
613 	/* Encode metadata header at front. */
614 	if (vi->mergeable_rx_bufs)
615 		sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
616 	else
617 		sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
618 
619 	hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
620 	return virtqueue_add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
621 				 0, skb, GFP_ATOMIC);
622 }
623 
624 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
625 {
626 	struct virtnet_info *vi = netdev_priv(dev);
627 	int capacity;
628 
629 	/* Free up any pending old buffers before queueing new ones. */
630 	free_old_xmit_skbs(vi);
631 
632 	/* Try to transmit */
633 	capacity = xmit_skb(vi, skb);
634 
635 	/* This can happen with OOM and indirect buffers. */
636 	if (unlikely(capacity < 0)) {
637 		if (likely(capacity == -ENOMEM)) {
638 			if (net_ratelimit())
639 				dev_warn(&dev->dev,
640 					 "TX queue failure: out of memory\n");
641 		} else {
642 			dev->stats.tx_fifo_errors++;
643 			if (net_ratelimit())
644 				dev_warn(&dev->dev,
645 					 "Unexpected TX queue failure: %d\n",
646 					 capacity);
647 		}
648 		dev->stats.tx_dropped++;
649 		kfree_skb(skb);
650 		return NETDEV_TX_OK;
651 	}
652 	virtqueue_kick(vi->svq);
653 
654 	/* Don't wait up for transmitted skbs to be freed. */
655 	skb_orphan(skb);
656 	nf_reset(skb);
657 
658 	/* Apparently nice girls don't return TX_BUSY; stop the queue
659 	 * before it gets out of hand.  Naturally, this wastes entries. */
660 	if (capacity < 2+MAX_SKB_FRAGS) {
661 		netif_stop_queue(dev);
662 		if (unlikely(!virtqueue_enable_cb_delayed(vi->svq))) {
663 			/* More just got used, free them then recheck. */
664 			capacity += free_old_xmit_skbs(vi);
665 			if (capacity >= 2+MAX_SKB_FRAGS) {
666 				netif_start_queue(dev);
667 				virtqueue_disable_cb(vi->svq);
668 			}
669 		}
670 	}
671 
672 	return NETDEV_TX_OK;
673 }
674 
675 static int virtnet_set_mac_address(struct net_device *dev, void *p)
676 {
677 	struct virtnet_info *vi = netdev_priv(dev);
678 	struct virtio_device *vdev = vi->vdev;
679 	int ret;
680 
681 	ret = eth_mac_addr(dev, p);
682 	if (ret)
683 		return ret;
684 
685 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
686 		vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
687 		                  dev->dev_addr, dev->addr_len);
688 
689 	return 0;
690 }
691 
692 static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
693 					       struct rtnl_link_stats64 *tot)
694 {
695 	struct virtnet_info *vi = netdev_priv(dev);
696 	int cpu;
697 	unsigned int start;
698 
699 	for_each_possible_cpu(cpu) {
700 		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
701 		u64 tpackets, tbytes, rpackets, rbytes;
702 
703 		do {
704 			start = u64_stats_fetch_begin(&stats->syncp);
705 			tpackets = stats->tx_packets;
706 			tbytes   = stats->tx_bytes;
707 			rpackets = stats->rx_packets;
708 			rbytes   = stats->rx_bytes;
709 		} while (u64_stats_fetch_retry(&stats->syncp, start));
710 
711 		tot->rx_packets += rpackets;
712 		tot->tx_packets += tpackets;
713 		tot->rx_bytes   += rbytes;
714 		tot->tx_bytes   += tbytes;
715 	}
716 
717 	tot->tx_dropped = dev->stats.tx_dropped;
718 	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
719 	tot->rx_dropped = dev->stats.rx_dropped;
720 	tot->rx_length_errors = dev->stats.rx_length_errors;
721 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
722 
723 	return tot;
724 }
725 
726 #ifdef CONFIG_NET_POLL_CONTROLLER
727 static void virtnet_netpoll(struct net_device *dev)
728 {
729 	struct virtnet_info *vi = netdev_priv(dev);
730 
731 	napi_schedule(&vi->napi);
732 }
733 #endif
734 
735 static int virtnet_open(struct net_device *dev)
736 {
737 	struct virtnet_info *vi = netdev_priv(dev);
738 
739 	/* Make sure we have some buffers: if oom use wq. */
740 	if (!try_fill_recv(vi, GFP_KERNEL))
741 		queue_delayed_work(system_nrt_wq, &vi->refill, 0);
742 
743 	virtnet_napi_enable(vi);
744 	return 0;
745 }
746 
747 /*
748  * Send command via the control virtqueue and check status.  Commands
749  * supported by the hypervisor, as indicated by feature bits, should
750  * never fail unless improperly formated.
751  */
752 static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
753 				 struct scatterlist *data, int out, int in)
754 {
755 	struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
756 	struct virtio_net_ctrl_hdr ctrl;
757 	virtio_net_ctrl_ack status = ~0;
758 	unsigned int tmp;
759 	int i;
760 
761 	/* Caller should know better */
762 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
763 		(out + in > VIRTNET_SEND_COMMAND_SG_MAX));
764 
765 	out++; /* Add header */
766 	in++; /* Add return status */
767 
768 	ctrl.class = class;
769 	ctrl.cmd = cmd;
770 
771 	sg_init_table(sg, out + in);
772 
773 	sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
774 	for_each_sg(data, s, out + in - 2, i)
775 		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
776 	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
777 
778 	BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
779 
780 	virtqueue_kick(vi->cvq);
781 
782 	/*
783 	 * Spin for a response, the kick causes an ioport write, trapping
784 	 * into the hypervisor, so the request should be handled immediately.
785 	 */
786 	while (!virtqueue_get_buf(vi->cvq, &tmp))
787 		cpu_relax();
788 
789 	return status == VIRTIO_NET_OK;
790 }
791 
792 static void virtnet_ack_link_announce(struct virtnet_info *vi)
793 {
794 	rtnl_lock();
795 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
796 				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
797 				  0, 0))
798 		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
799 	rtnl_unlock();
800 }
801 
802 static int virtnet_close(struct net_device *dev)
803 {
804 	struct virtnet_info *vi = netdev_priv(dev);
805 
806 	/* Make sure refill_work doesn't re-enable napi! */
807 	cancel_delayed_work_sync(&vi->refill);
808 	napi_disable(&vi->napi);
809 
810 	return 0;
811 }
812 
813 static void virtnet_set_rx_mode(struct net_device *dev)
814 {
815 	struct virtnet_info *vi = netdev_priv(dev);
816 	struct scatterlist sg[2];
817 	u8 promisc, allmulti;
818 	struct virtio_net_ctrl_mac *mac_data;
819 	struct netdev_hw_addr *ha;
820 	int uc_count;
821 	int mc_count;
822 	void *buf;
823 	int i;
824 
825 	/* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
826 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
827 		return;
828 
829 	promisc = ((dev->flags & IFF_PROMISC) != 0);
830 	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
831 
832 	sg_init_one(sg, &promisc, sizeof(promisc));
833 
834 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
835 				  VIRTIO_NET_CTRL_RX_PROMISC,
836 				  sg, 1, 0))
837 		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
838 			 promisc ? "en" : "dis");
839 
840 	sg_init_one(sg, &allmulti, sizeof(allmulti));
841 
842 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
843 				  VIRTIO_NET_CTRL_RX_ALLMULTI,
844 				  sg, 1, 0))
845 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
846 			 allmulti ? "en" : "dis");
847 
848 	uc_count = netdev_uc_count(dev);
849 	mc_count = netdev_mc_count(dev);
850 	/* MAC filter - use one buffer for both lists */
851 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
852 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
853 	mac_data = buf;
854 	if (!buf) {
855 		dev_warn(&dev->dev, "No memory for MAC address buffer\n");
856 		return;
857 	}
858 
859 	sg_init_table(sg, 2);
860 
861 	/* Store the unicast list and count in the front of the buffer */
862 	mac_data->entries = uc_count;
863 	i = 0;
864 	netdev_for_each_uc_addr(ha, dev)
865 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
866 
867 	sg_set_buf(&sg[0], mac_data,
868 		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
869 
870 	/* multicast list and count fill the end */
871 	mac_data = (void *)&mac_data->macs[uc_count][0];
872 
873 	mac_data->entries = mc_count;
874 	i = 0;
875 	netdev_for_each_mc_addr(ha, dev)
876 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
877 
878 	sg_set_buf(&sg[1], mac_data,
879 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
880 
881 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
882 				  VIRTIO_NET_CTRL_MAC_TABLE_SET,
883 				  sg, 2, 0))
884 		dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
885 
886 	kfree(buf);
887 }
888 
889 static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
890 {
891 	struct virtnet_info *vi = netdev_priv(dev);
892 	struct scatterlist sg;
893 
894 	sg_init_one(&sg, &vid, sizeof(vid));
895 
896 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
897 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
898 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
899 	return 0;
900 }
901 
902 static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
903 {
904 	struct virtnet_info *vi = netdev_priv(dev);
905 	struct scatterlist sg;
906 
907 	sg_init_one(&sg, &vid, sizeof(vid));
908 
909 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
910 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
911 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
912 	return 0;
913 }
914 
915 static void virtnet_get_ringparam(struct net_device *dev,
916 				struct ethtool_ringparam *ring)
917 {
918 	struct virtnet_info *vi = netdev_priv(dev);
919 
920 	ring->rx_max_pending = virtqueue_get_vring_size(vi->rvq);
921 	ring->tx_max_pending = virtqueue_get_vring_size(vi->svq);
922 	ring->rx_pending = ring->rx_max_pending;
923 	ring->tx_pending = ring->tx_max_pending;
924 
925 }
926 
927 
928 static void virtnet_get_drvinfo(struct net_device *dev,
929 				struct ethtool_drvinfo *info)
930 {
931 	struct virtnet_info *vi = netdev_priv(dev);
932 	struct virtio_device *vdev = vi->vdev;
933 
934 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
935 	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
936 	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
937 
938 }
939 
940 static const struct ethtool_ops virtnet_ethtool_ops = {
941 	.get_drvinfo = virtnet_get_drvinfo,
942 	.get_link = ethtool_op_get_link,
943 	.get_ringparam = virtnet_get_ringparam,
944 };
945 
946 #define MIN_MTU 68
947 #define MAX_MTU 65535
948 
949 static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
950 {
951 	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
952 		return -EINVAL;
953 	dev->mtu = new_mtu;
954 	return 0;
955 }
956 
957 static const struct net_device_ops virtnet_netdev = {
958 	.ndo_open            = virtnet_open,
959 	.ndo_stop   	     = virtnet_close,
960 	.ndo_start_xmit      = start_xmit,
961 	.ndo_validate_addr   = eth_validate_addr,
962 	.ndo_set_mac_address = virtnet_set_mac_address,
963 	.ndo_set_rx_mode     = virtnet_set_rx_mode,
964 	.ndo_change_mtu	     = virtnet_change_mtu,
965 	.ndo_get_stats64     = virtnet_stats,
966 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
967 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
968 #ifdef CONFIG_NET_POLL_CONTROLLER
969 	.ndo_poll_controller = virtnet_netpoll,
970 #endif
971 };
972 
973 static void virtnet_config_changed_work(struct work_struct *work)
974 {
975 	struct virtnet_info *vi =
976 		container_of(work, struct virtnet_info, config_work);
977 	u16 v;
978 
979 	mutex_lock(&vi->config_lock);
980 	if (!vi->config_enable)
981 		goto done;
982 
983 	if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
984 			      offsetof(struct virtio_net_config, status),
985 			      &v) < 0)
986 		goto done;
987 
988 	if (v & VIRTIO_NET_S_ANNOUNCE) {
989 		netif_notify_peers(vi->dev);
990 		virtnet_ack_link_announce(vi);
991 	}
992 
993 	/* Ignore unknown (future) status bits */
994 	v &= VIRTIO_NET_S_LINK_UP;
995 
996 	if (vi->status == v)
997 		goto done;
998 
999 	vi->status = v;
1000 
1001 	if (vi->status & VIRTIO_NET_S_LINK_UP) {
1002 		netif_carrier_on(vi->dev);
1003 		netif_wake_queue(vi->dev);
1004 	} else {
1005 		netif_carrier_off(vi->dev);
1006 		netif_stop_queue(vi->dev);
1007 	}
1008 done:
1009 	mutex_unlock(&vi->config_lock);
1010 }
1011 
1012 static void virtnet_config_changed(struct virtio_device *vdev)
1013 {
1014 	struct virtnet_info *vi = vdev->priv;
1015 
1016 	queue_work(system_nrt_wq, &vi->config_work);
1017 }
1018 
1019 static int init_vqs(struct virtnet_info *vi)
1020 {
1021 	struct virtqueue *vqs[3];
1022 	vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
1023 	const char *names[] = { "input", "output", "control" };
1024 	int nvqs, err;
1025 
1026 	/* We expect two virtqueues, receive then send,
1027 	 * and optionally control. */
1028 	nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
1029 
1030 	err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
1031 	if (err)
1032 		return err;
1033 
1034 	vi->rvq = vqs[0];
1035 	vi->svq = vqs[1];
1036 
1037 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
1038 		vi->cvq = vqs[2];
1039 
1040 		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
1041 			vi->dev->features |= NETIF_F_HW_VLAN_FILTER;
1042 	}
1043 	return 0;
1044 }
1045 
1046 static int virtnet_probe(struct virtio_device *vdev)
1047 {
1048 	int err;
1049 	struct net_device *dev;
1050 	struct virtnet_info *vi;
1051 
1052 	/* Allocate ourselves a network device with room for our info */
1053 	dev = alloc_etherdev(sizeof(struct virtnet_info));
1054 	if (!dev)
1055 		return -ENOMEM;
1056 
1057 	/* Set up network device as normal. */
1058 	dev->priv_flags |= IFF_UNICAST_FLT;
1059 	dev->netdev_ops = &virtnet_netdev;
1060 	dev->features = NETIF_F_HIGHDMA;
1061 
1062 	SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
1063 	SET_NETDEV_DEV(dev, &vdev->dev);
1064 
1065 	/* Do we support "hardware" checksums? */
1066 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
1067 		/* This opens up the world of extra features. */
1068 		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1069 		if (csum)
1070 			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1071 
1072 		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
1073 			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
1074 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
1075 		}
1076 		/* Individual feature bits: what can host handle? */
1077 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
1078 			dev->hw_features |= NETIF_F_TSO;
1079 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
1080 			dev->hw_features |= NETIF_F_TSO6;
1081 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
1082 			dev->hw_features |= NETIF_F_TSO_ECN;
1083 		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
1084 			dev->hw_features |= NETIF_F_UFO;
1085 
1086 		if (gso)
1087 			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
1088 		/* (!csum && gso) case will be fixed by register_netdev() */
1089 	}
1090 
1091 	/* Configuration may specify what MAC to use.  Otherwise random. */
1092 	if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
1093 				  offsetof(struct virtio_net_config, mac),
1094 				  dev->dev_addr, dev->addr_len) < 0)
1095 		eth_hw_addr_random(dev);
1096 
1097 	/* Set up our device-specific information */
1098 	vi = netdev_priv(dev);
1099 	netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
1100 	vi->dev = dev;
1101 	vi->vdev = vdev;
1102 	vdev->priv = vi;
1103 	vi->pages = NULL;
1104 	vi->stats = alloc_percpu(struct virtnet_stats);
1105 	err = -ENOMEM;
1106 	if (vi->stats == NULL)
1107 		goto free;
1108 
1109 	INIT_DELAYED_WORK(&vi->refill, refill_work);
1110 	mutex_init(&vi->config_lock);
1111 	vi->config_enable = true;
1112 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
1113 	sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
1114 	sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
1115 
1116 	/* If we can receive ANY GSO packets, we must allocate large ones. */
1117 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
1118 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
1119 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
1120 		vi->big_packets = true;
1121 
1122 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
1123 		vi->mergeable_rx_bufs = true;
1124 
1125 	err = init_vqs(vi);
1126 	if (err)
1127 		goto free_stats;
1128 
1129 	err = register_netdev(dev);
1130 	if (err) {
1131 		pr_debug("virtio_net: registering device failed\n");
1132 		goto free_vqs;
1133 	}
1134 
1135 	/* Last of all, set up some receive buffers. */
1136 	try_fill_recv(vi, GFP_KERNEL);
1137 
1138 	/* If we didn't even get one input buffer, we're useless. */
1139 	if (vi->num == 0) {
1140 		err = -ENOMEM;
1141 		goto unregister;
1142 	}
1143 
1144 	/* Assume link up if device can't report link status,
1145 	   otherwise get link status from config. */
1146 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
1147 		netif_carrier_off(dev);
1148 		queue_work(system_nrt_wq, &vi->config_work);
1149 	} else {
1150 		vi->status = VIRTIO_NET_S_LINK_UP;
1151 		netif_carrier_on(dev);
1152 	}
1153 
1154 	pr_debug("virtnet: registered device %s\n", dev->name);
1155 	return 0;
1156 
1157 unregister:
1158 	unregister_netdev(dev);
1159 free_vqs:
1160 	vdev->config->del_vqs(vdev);
1161 free_stats:
1162 	free_percpu(vi->stats);
1163 free:
1164 	free_netdev(dev);
1165 	return err;
1166 }
1167 
1168 static void free_unused_bufs(struct virtnet_info *vi)
1169 {
1170 	void *buf;
1171 	while (1) {
1172 		buf = virtqueue_detach_unused_buf(vi->svq);
1173 		if (!buf)
1174 			break;
1175 		dev_kfree_skb(buf);
1176 	}
1177 	while (1) {
1178 		buf = virtqueue_detach_unused_buf(vi->rvq);
1179 		if (!buf)
1180 			break;
1181 		if (vi->mergeable_rx_bufs || vi->big_packets)
1182 			give_pages(vi, buf);
1183 		else
1184 			dev_kfree_skb(buf);
1185 		--vi->num;
1186 	}
1187 	BUG_ON(vi->num != 0);
1188 }
1189 
1190 static void remove_vq_common(struct virtnet_info *vi)
1191 {
1192 	vi->vdev->config->reset(vi->vdev);
1193 
1194 	/* Free unused buffers in both send and recv, if any. */
1195 	free_unused_bufs(vi);
1196 
1197 	vi->vdev->config->del_vqs(vi->vdev);
1198 
1199 	while (vi->pages)
1200 		__free_pages(get_a_page(vi, GFP_KERNEL), 0);
1201 }
1202 
1203 static void __devexit virtnet_remove(struct virtio_device *vdev)
1204 {
1205 	struct virtnet_info *vi = vdev->priv;
1206 
1207 	/* Prevent config work handler from accessing the device. */
1208 	mutex_lock(&vi->config_lock);
1209 	vi->config_enable = false;
1210 	mutex_unlock(&vi->config_lock);
1211 
1212 	unregister_netdev(vi->dev);
1213 
1214 	remove_vq_common(vi);
1215 
1216 	flush_work(&vi->config_work);
1217 
1218 	free_percpu(vi->stats);
1219 	free_netdev(vi->dev);
1220 }
1221 
1222 #ifdef CONFIG_PM
1223 static int virtnet_freeze(struct virtio_device *vdev)
1224 {
1225 	struct virtnet_info *vi = vdev->priv;
1226 
1227 	/* Prevent config work handler from accessing the device */
1228 	mutex_lock(&vi->config_lock);
1229 	vi->config_enable = false;
1230 	mutex_unlock(&vi->config_lock);
1231 
1232 	virtqueue_disable_cb(vi->rvq);
1233 	virtqueue_disable_cb(vi->svq);
1234 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ))
1235 		virtqueue_disable_cb(vi->cvq);
1236 
1237 	netif_device_detach(vi->dev);
1238 	cancel_delayed_work_sync(&vi->refill);
1239 
1240 	if (netif_running(vi->dev))
1241 		napi_disable(&vi->napi);
1242 
1243 	remove_vq_common(vi);
1244 
1245 	flush_work(&vi->config_work);
1246 
1247 	return 0;
1248 }
1249 
1250 static int virtnet_restore(struct virtio_device *vdev)
1251 {
1252 	struct virtnet_info *vi = vdev->priv;
1253 	int err;
1254 
1255 	err = init_vqs(vi);
1256 	if (err)
1257 		return err;
1258 
1259 	if (netif_running(vi->dev))
1260 		virtnet_napi_enable(vi);
1261 
1262 	netif_device_attach(vi->dev);
1263 
1264 	if (!try_fill_recv(vi, GFP_KERNEL))
1265 		queue_delayed_work(system_nrt_wq, &vi->refill, 0);
1266 
1267 	mutex_lock(&vi->config_lock);
1268 	vi->config_enable = true;
1269 	mutex_unlock(&vi->config_lock);
1270 
1271 	return 0;
1272 }
1273 #endif
1274 
1275 static struct virtio_device_id id_table[] = {
1276 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
1277 	{ 0 },
1278 };
1279 
1280 static unsigned int features[] = {
1281 	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
1282 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
1283 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
1284 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
1285 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
1286 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
1287 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
1288 	VIRTIO_NET_F_GUEST_ANNOUNCE,
1289 };
1290 
1291 static struct virtio_driver virtio_net_driver = {
1292 	.feature_table = features,
1293 	.feature_table_size = ARRAY_SIZE(features),
1294 	.driver.name =	KBUILD_MODNAME,
1295 	.driver.owner =	THIS_MODULE,
1296 	.id_table =	id_table,
1297 	.probe =	virtnet_probe,
1298 	.remove =	__devexit_p(virtnet_remove),
1299 	.config_changed = virtnet_config_changed,
1300 #ifdef CONFIG_PM
1301 	.freeze =	virtnet_freeze,
1302 	.restore =	virtnet_restore,
1303 #endif
1304 };
1305 
1306 static int __init init(void)
1307 {
1308 	return register_virtio_driver(&virtio_net_driver);
1309 }
1310 
1311 static void __exit fini(void)
1312 {
1313 	unregister_virtio_driver(&virtio_net_driver);
1314 }
1315 module_init(init);
1316 module_exit(fini);
1317 
1318 MODULE_DEVICE_TABLE(virtio, id_table);
1319 MODULE_DESCRIPTION("Virtio network driver");
1320 MODULE_LICENSE("GPL");
1321