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sched: make early bootup sched_clock() use safer
[wrt350n-kernel.git] / drivers / net / virtio_net.c
blobfdc23678117bdd31157a13c6d428d2c1951dc778
1 /* A simple 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/module.h>
23 #include <linux/virtio.h>
24 #include <linux/virtio_net.h>
25 #include <linux/scatterlist.h>
26
27 static int napi_weight = 128;
28 module_param(napi_weight, int, 0444);
29
30 static int csum = 1, gso = 1;
31 module_param(csum, bool, 0444);
32 module_param(gso, bool, 0444);
33
34 /* FIXME: MTU in config. */
35 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
36
37 struct virtnet_info
38 {
39 struct virtio_device *vdev;
40 struct virtqueue *rvq, *svq;
41 struct net_device *dev;
42 struct napi_struct napi;
43
44 /* Number of input buffers, and max we've ever had. */
45 unsigned int num, max;
46
47 /* Receive & send queues. */
48 struct sk_buff_head recv;
49 struct sk_buff_head send;
50 };
51
52 static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
53 {
54 return (struct virtio_net_hdr *)skb->cb;
55 }
56
57 static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
58 {
59 sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
60 }
61
62 static void skb_xmit_done(struct virtqueue *svq)
63 {
64 struct virtnet_info *vi = svq->vdev->priv;
65
66 /* Suppress further interrupts. */
67 svq->vq_ops->disable_cb(svq);
68 /* We were waiting for more output buffers. */
69 netif_wake_queue(vi->dev);
70 }
71
72 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
73 unsigned len)
74 {
75 struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
76
77 if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
78 pr_debug("%s: short packet %i\n", dev->name, len);
79 dev->stats.rx_length_errors++;
80 goto drop;
81 }
82 len -= sizeof(struct virtio_net_hdr);
83 BUG_ON(len > MAX_PACKET_LEN);
84
85 skb_trim(skb, len);
86 skb->protocol = eth_type_trans(skb, dev);
87 pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
88 ntohs(skb->protocol), skb->len, skb->pkt_type);
89 dev->stats.rx_bytes += skb->len;
90 dev->stats.rx_packets++;
91
92 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
93 pr_debug("Needs csum!\n");
94 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
95 goto frame_err;
96 }
97
98 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
99 pr_debug("GSO!\n");
100 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
101 case VIRTIO_NET_HDR_GSO_TCPV4:
102 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
103 break;
104 case VIRTIO_NET_HDR_GSO_UDP:
105 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
106 break;
107 case VIRTIO_NET_HDR_GSO_TCPV6:
108 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
109 break;
110 default:
111 if (net_ratelimit())
112 printk(KERN_WARNING "%s: bad gso type %u.\n",
113 dev->name, hdr->gso_type);
114 goto frame_err;
115 }
116
117 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
118 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
119
120 skb_shinfo(skb)->gso_size = hdr->gso_size;
121 if (skb_shinfo(skb)->gso_size == 0) {
122 if (net_ratelimit())
123 printk(KERN_WARNING "%s: zero gso size.\n",
124 dev->name);
125 goto frame_err;
126 }
127
128 /* Header must be checked, and gso_segs computed. */
129 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
130 skb_shinfo(skb)->gso_segs = 0;
131 }
132
133 netif_receive_skb(skb);
134 return;
135
136 frame_err:
137 dev->stats.rx_frame_errors++;
138 drop:
139 dev_kfree_skb(skb);
140 }
141
142 static void try_fill_recv(struct virtnet_info *vi)
143 {
144 struct sk_buff *skb;
145 struct scatterlist sg[1+MAX_SKB_FRAGS];
146 int num, err;
147
148 sg_init_table(sg, 1+MAX_SKB_FRAGS);
149 for (;;) {
150 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
151 if (unlikely(!skb))
152 break;
153
154 skb_put(skb, MAX_PACKET_LEN);
155 vnet_hdr_to_sg(sg, skb);
156 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
157 skb_queue_head(&vi->recv, skb);
158
159 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
160 if (err) {
161 skb_unlink(skb, &vi->recv);
162 kfree_skb(skb);
163 break;
164 }
165 vi->num++;
166 }
167 if (unlikely(vi->num > vi->max))
168 vi->max = vi->num;
169 vi->rvq->vq_ops->kick(vi->rvq);
170 }
171
172 static void skb_recv_done(struct virtqueue *rvq)
173 {
174 struct virtnet_info *vi = rvq->vdev->priv;
175 /* Schedule NAPI, Suppress further interrupts if successful. */
176 if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
177 rvq->vq_ops->disable_cb(rvq);
178 __netif_rx_schedule(vi->dev, &vi->napi);
179 }
180 }
181
182 static int virtnet_poll(struct napi_struct *napi, int budget)
183 {
184 struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
185 struct sk_buff *skb = NULL;
186 unsigned int len, received = 0;
187
188 again:
189 while (received < budget &&
190 (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
191 __skb_unlink(skb, &vi->recv);
192 receive_skb(vi->dev, skb, len);
193 vi->num--;
194 received++;
195 }
196
197 /* FIXME: If we oom and completely run out of inbufs, we need
198 * to start a timer trying to fill more. */
199 if (vi->num < vi->max / 2)
200 try_fill_recv(vi);
201
202 /* Out of packets? */
203 if (received < budget) {
204 netif_rx_complete(vi->dev, napi);
205 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
206 && netif_rx_reschedule(vi->dev, napi))
207 goto again;
208 }
209
210 return received;
211 }
212
213 static void free_old_xmit_skbs(struct virtnet_info *vi)
214 {
215 struct sk_buff *skb;
216 unsigned int len;
217
218 while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
219 pr_debug("Sent skb %p\n", skb);
220 __skb_unlink(skb, &vi->send);
221 vi->dev->stats.tx_bytes += len;
222 vi->dev->stats.tx_packets++;
223 kfree_skb(skb);
224 }
225 }
226
227 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
228 {
229 struct virtnet_info *vi = netdev_priv(dev);
230 int num, err;
231 struct scatterlist sg[1+MAX_SKB_FRAGS];
232 struct virtio_net_hdr *hdr;
233 const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
234 DECLARE_MAC_BUF(mac);
235
236 sg_init_table(sg, 1+MAX_SKB_FRAGS);
237
238 pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
239
240 /* Encode metadata header at front. */
241 hdr = skb_vnet_hdr(skb);
242 if (skb->ip_summed == CHECKSUM_PARTIAL) {
243 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
244 hdr->csum_start = skb->csum_start - skb_headroom(skb);
245 hdr->csum_offset = skb->csum_offset;
246 } else {
247 hdr->flags = 0;
248 hdr->csum_offset = hdr->csum_start = 0;
249 }
250
251 if (skb_is_gso(skb)) {
252 hdr->hdr_len = skb_transport_header(skb) - skb->data;
253 hdr->gso_size = skb_shinfo(skb)->gso_size;
254 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
255 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
256 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
257 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
258 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
259 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
260 else
261 BUG();
262 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
263 hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
264 } else {
265 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
266 hdr->gso_size = hdr->hdr_len = 0;
267 }
268
269 vnet_hdr_to_sg(sg, skb);
270 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
271 __skb_queue_head(&vi->send, skb);
272
273 again:
274 /* Free up any pending old buffers before queueing new ones. */
275 free_old_xmit_skbs(vi);
276 err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
277 if (err) {
278 pr_debug("%s: virtio not prepared to send\n", dev->name);
279 netif_stop_queue(dev);
280
281 /* Activate callback for using skbs: if this fails it
282 * means some were used in the meantime. */
283 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
284 printk("Unlikely: restart svq failed\n");
285 netif_start_queue(dev);
286 goto again;
287 }
288 __skb_unlink(skb, &vi->send);
289
290 return NETDEV_TX_BUSY;
291 }
292 vi->svq->vq_ops->kick(vi->svq);
293
294 return 0;
295 }
296
297 static int virtnet_open(struct net_device *dev)
298 {
299 struct virtnet_info *vi = netdev_priv(dev);
300
301 napi_enable(&vi->napi);
302
303 /* If all buffers were filled by other side before we napi_enabled, we
304 * won't get another interrupt, so process any outstanding packets
305 * now. virtnet_poll wants re-enable the queue, so we disable here.
306 * We synchronize against interrupts via NAPI_STATE_SCHED */
307 if (netif_rx_schedule_prep(dev, &vi->napi)) {
308 vi->rvq->vq_ops->disable_cb(vi->rvq);
309 __netif_rx_schedule(dev, &vi->napi);
310 }
311 return 0;
312 }
313
314 static int virtnet_close(struct net_device *dev)
315 {
316 struct virtnet_info *vi = netdev_priv(dev);
317
318 napi_disable(&vi->napi);
319
320 return 0;
321 }
322
323 static int virtnet_probe(struct virtio_device *vdev)
324 {
325 int err;
326 struct net_device *dev;
327 struct virtnet_info *vi;
328
329 /* Allocate ourselves a network device with room for our info */
330 dev = alloc_etherdev(sizeof(struct virtnet_info));
331 if (!dev)
332 return -ENOMEM;
333
334 /* Set up network device as normal. */
335 dev->open = virtnet_open;
336 dev->stop = virtnet_close;
337 dev->hard_start_xmit = start_xmit;
338 dev->features = NETIF_F_HIGHDMA;
339 SET_NETDEV_DEV(dev, &vdev->dev);
340
341 /* Do we support "hardware" checksums? */
342 if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
343 /* This opens up the world of extra features. */
344 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
345 if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
346 dev->features |= NETIF_F_TSO | NETIF_F_UFO
347 | NETIF_F_TSO_ECN | NETIF_F_TSO6;
348 }
349 }
350
351 /* Configuration may specify what MAC to use. Otherwise random. */
352 if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
353 vdev->config->get(vdev,
354 offsetof(struct virtio_net_config, mac),
355 dev->dev_addr, dev->addr_len);
356 } else
357 random_ether_addr(dev->dev_addr);
358
359 /* Set up our device-specific information */
360 vi = netdev_priv(dev);
361 netif_napi_add(dev, &vi->napi, virtnet_poll, napi_weight);
362 vi->dev = dev;
363 vi->vdev = vdev;
364
365 /* We expect two virtqueues, receive then send. */
366 vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
367 if (IS_ERR(vi->rvq)) {
368 err = PTR_ERR(vi->rvq);
369 goto free;
370 }
371
372 vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
373 if (IS_ERR(vi->svq)) {
374 err = PTR_ERR(vi->svq);
375 goto free_recv;
376 }
377
378 /* Initialize our empty receive and send queues. */
379 skb_queue_head_init(&vi->recv);
380 skb_queue_head_init(&vi->send);
381
382 err = register_netdev(dev);
383 if (err) {
384 pr_debug("virtio_net: registering device failed\n");
385 goto free_send;
386 }
387
388 /* Last of all, set up some receive buffers. */
389 try_fill_recv(vi);
390
391 /* If we didn't even get one input buffer, we're useless. */
392 if (vi->num == 0) {
393 err = -ENOMEM;
394 goto unregister;
395 }
396
397 pr_debug("virtnet: registered device %s\n", dev->name);
398 vdev->priv = vi;
399 return 0;
400
401 unregister:
402 unregister_netdev(dev);
403 free_send:
404 vdev->config->del_vq(vi->svq);
405 free_recv:
406 vdev->config->del_vq(vi->rvq);
407 free:
408 free_netdev(dev);
409 return err;
410 }
411
412 static void virtnet_remove(struct virtio_device *vdev)
413 {
414 struct virtnet_info *vi = vdev->priv;
415 struct sk_buff *skb;
416
417 /* Stop all the virtqueues. */
418 vdev->config->reset(vdev);
419
420 /* Free our skbs in send and recv queues, if any. */
421 while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
422 kfree_skb(skb);
423 vi->num--;
424 }
425 while ((skb = __skb_dequeue(&vi->send)) != NULL)
426 kfree_skb(skb);
427
428 BUG_ON(vi->num != 0);
429
430 vdev->config->del_vq(vi->svq);
431 vdev->config->del_vq(vi->rvq);
432 unregister_netdev(vi->dev);
433 free_netdev(vi->dev);
434 }
435
436 static struct virtio_device_id id_table[] = {
437 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
438 { 0 },
439 };
440
441 static struct virtio_driver virtio_net = {
442 .driver.name = KBUILD_MODNAME,
443 .driver.owner = THIS_MODULE,
444 .id_table = id_table,
445 .probe = virtnet_probe,
446 .remove = __devexit_p(virtnet_remove),
447 };
448
449 static int __init init(void)
450 {
451 return register_virtio_driver(&virtio_net);
452 }
453
454 static void __exit fini(void)
455 {
456 unregister_virtio_driver(&virtio_net);
457 }
458 module_init(init);
459 module_exit(fini);
460
461 MODULE_DEVICE_TABLE(virtio, id_table);
462 MODULE_DESCRIPTION("Virtio network driver");
463 MODULE_LICENSE("GPL");
WRT350N Kernel Patches