Commit | Line | Data |
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b530cc79 | 1 | /* |
fea511a6 | 2 | * The Virtio 9p transport driver |
b530cc79 | 3 | * |
e2735b77 EVH |
4 | * This is a block based transport driver based on the lguest block driver |
5 | * code. | |
b530cc79 | 6 | * |
fea511a6 | 7 | * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation |
b530cc79 EVH |
8 | * |
9 | * Based on virtio console driver | |
10 | * Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2 | |
14 | * as published by the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program; if not, write to: | |
23 | * Free Software Foundation | |
24 | * 51 Franklin Street, Fifth Floor | |
25 | * Boston, MA 02111-1301 USA | |
26 | * | |
27 | */ | |
28 | ||
29 | #include <linux/in.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/net.h> | |
32 | #include <linux/ipv6.h> | |
33 | #include <linux/errno.h> | |
34 | #include <linux/kernel.h> | |
35 | #include <linux/un.h> | |
36 | #include <linux/uaccess.h> | |
37 | #include <linux/inet.h> | |
38 | #include <linux/idr.h> | |
39 | #include <linux/file.h> | |
5a0e3ad6 | 40 | #include <linux/slab.h> |
b530cc79 EVH |
41 | #include <net/9p/9p.h> |
42 | #include <linux/parser.h> | |
8b81ef58 | 43 | #include <net/9p/client.h> |
b530cc79 EVH |
44 | #include <net/9p/transport.h> |
45 | #include <linux/scatterlist.h> | |
46 | #include <linux/virtio.h> | |
47 | #include <linux/virtio_9p.h> | |
48 | ||
e2735b77 EVH |
49 | #define VIRTQUEUE_NUM 128 |
50 | ||
b530cc79 | 51 | /* a single mutex to manage channel initialization and attachment */ |
c1549497 | 52 | static DEFINE_MUTEX(virtio_9p_lock); |
b530cc79 | 53 | |
ee443996 EVH |
54 | /** |
55 | * struct virtio_chan - per-instance transport information | |
56 | * @initialized: whether the channel is initialized | |
57 | * @inuse: whether the channel is in use | |
58 | * @lock: protects multiple elements within this structure | |
0e15597e | 59 | * @client: client instance |
ee443996 EVH |
60 | * @vdev: virtio dev associated with this channel |
61 | * @vq: virtio queue associated with this channel | |
ee443996 EVH |
62 | * @sg: scatter gather list which is used to pack a request (protected?) |
63 | * | |
64 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
65 | * This structure is allocated within the devices dev->mem space. |
66 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 67 | * |
b530cc79 | 68 | */ |
ee443996 | 69 | |
37c1209d | 70 | struct virtio_chan { |
ee443996 | 71 | bool inuse; |
b530cc79 | 72 | |
e2735b77 EVH |
73 | spinlock_t lock; |
74 | ||
fea511a6 | 75 | struct p9_client *client; |
b530cc79 | 76 | struct virtio_device *vdev; |
e2735b77 | 77 | struct virtqueue *vq; |
52f44e0d VJJ |
78 | int ring_bufs_avail; |
79 | wait_queue_head_t *vc_wq; | |
b530cc79 | 80 | |
e2735b77 EVH |
81 | /* Scatterlist: can be too big for stack. */ |
82 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
37c1209d | 83 | |
97ee9b02 AK |
84 | int tag_len; |
85 | /* | |
86 | * tag name to identify a mount Non-null terminated | |
87 | */ | |
88 | char *tag; | |
89 | ||
37c1209d AK |
90 | struct list_head chan_list; |
91 | }; | |
92 | ||
93 | static struct list_head virtio_chan_list; | |
b530cc79 EVH |
94 | |
95 | /* How many bytes left in this page. */ | |
96 | static unsigned int rest_of_page(void *data) | |
97 | { | |
98 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
99 | } | |
100 | ||
ee443996 EVH |
101 | /** |
102 | * p9_virtio_close - reclaim resources of a channel | |
0e15597e | 103 | * @client: client instance |
ee443996 EVH |
104 | * |
105 | * This reclaims a channel by freeing its resources and | |
106 | * reseting its inuse flag. | |
107 | * | |
108 | */ | |
109 | ||
8b81ef58 | 110 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 111 | { |
8b81ef58 | 112 | struct virtio_chan *chan = client->trans; |
b530cc79 | 113 | |
c1549497 | 114 | mutex_lock(&virtio_9p_lock); |
fb786100 AK |
115 | if (chan) |
116 | chan->inuse = false; | |
c1549497 | 117 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
118 | } |
119 | ||
ee443996 EVH |
120 | /** |
121 | * req_done - callback which signals activity from the server | |
122 | * @vq: virtio queue activity was received on | |
123 | * | |
124 | * This notifies us that the server has triggered some activity | |
125 | * on the virtio channel - most likely a response to request we | |
126 | * sent. Figure out which requests now have responses and wake up | |
127 | * those threads. | |
128 | * | |
129 | * Bugs: could do with some additional sanity checking, but appears to work. | |
130 | * | |
131 | */ | |
132 | ||
e2735b77 | 133 | static void req_done(struct virtqueue *vq) |
b530cc79 | 134 | { |
e2735b77 EVH |
135 | struct virtio_chan *chan = vq->vdev->priv; |
136 | struct p9_fcall *rc; | |
137 | unsigned int len; | |
e2735b77 | 138 | struct p9_req_t *req; |
419b3956 | 139 | unsigned long flags; |
e2735b77 | 140 | |
91b8534f EVH |
141 | P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n"); |
142 | ||
419b3956 VJJ |
143 | do { |
144 | spin_lock_irqsave(&chan->lock, flags); | |
145 | rc = virtqueue_get_buf(chan->vq, &len); | |
419b3956 VJJ |
146 | |
147 | if (rc != NULL) { | |
52f44e0d VJJ |
148 | if (!chan->ring_bufs_avail) { |
149 | chan->ring_bufs_avail = 1; | |
150 | wake_up(chan->vc_wq); | |
151 | } | |
152 | spin_unlock_irqrestore(&chan->lock, flags); | |
419b3956 VJJ |
153 | P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc); |
154 | P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", | |
155 | rc->tag); | |
156 | req = p9_tag_lookup(chan->client, rc->tag); | |
157 | req->status = REQ_STATUS_RCVD; | |
158 | p9_client_cb(chan->client, req); | |
52f44e0d VJJ |
159 | } else { |
160 | spin_unlock_irqrestore(&chan->lock, flags); | |
419b3956 VJJ |
161 | } |
162 | } while (rc != NULL); | |
e2735b77 | 163 | } |
b530cc79 | 164 | |
ee443996 EVH |
165 | /** |
166 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
167 | * @sg: scatter/gather list to pack into | |
168 | * @start: which segment of the sg_list to start at | |
169 | * @limit: maximum segment to pack data to | |
170 | * @data: data to pack into scatter/gather list | |
171 | * @count: amount of data to pack into the scatter/gather list | |
172 | * | |
173 | * sg_lists have multiple segments of various sizes. This will pack | |
174 | * arbitrary data into an existing scatter gather list, segmenting the | |
175 | * data as necessary within constraints. | |
176 | * | |
177 | */ | |
178 | ||
e2735b77 EVH |
179 | static int |
180 | pack_sg_list(struct scatterlist *sg, int start, int limit, char *data, | |
181 | int count) | |
182 | { | |
183 | int s; | |
184 | int index = start; | |
185 | ||
186 | while (count) { | |
187 | s = rest_of_page(data); | |
188 | if (s > count) | |
189 | s = count; | |
190 | sg_set_buf(&sg[index++], data, s); | |
191 | count -= s; | |
192 | data += s; | |
d6584f3a | 193 | BUG_ON(index > limit); |
e2735b77 | 194 | } |
b530cc79 | 195 | |
e2735b77 | 196 | return index-start; |
b530cc79 EVH |
197 | } |
198 | ||
91b8534f EVH |
199 | /* We don't currently allow canceling of virtio requests */ |
200 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
201 | { | |
202 | return 1; | |
203 | } | |
204 | ||
ee443996 | 205 | /** |
91b8534f | 206 | * p9_virtio_request - issue a request |
0e15597e AK |
207 | * @client: client instance issuing the request |
208 | * @req: request to be issued | |
ee443996 EVH |
209 | * |
210 | */ | |
211 | ||
e2735b77 | 212 | static int |
91b8534f | 213 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 214 | { |
e2735b77 | 215 | int in, out; |
91b8534f EVH |
216 | struct virtio_chan *chan = client->trans; |
217 | char *rdata = (char *)req->rc+sizeof(struct p9_fcall); | |
419b3956 VJJ |
218 | unsigned long flags; |
219 | int err; | |
b530cc79 | 220 | |
91b8534f | 221 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 222 | |
52f44e0d | 223 | req_retry: |
419b3956 VJJ |
224 | req->status = REQ_STATUS_SENT; |
225 | ||
226 | spin_lock_irqsave(&chan->lock, flags); | |
91b8534f EVH |
227 | out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata, |
228 | req->tc->size); | |
229 | in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, | |
230 | client->msize); | |
b530cc79 | 231 | |
419b3956 VJJ |
232 | err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc); |
233 | if (err < 0) { | |
52f44e0d VJJ |
234 | if (err == -ENOSPC) { |
235 | chan->ring_bufs_avail = 0; | |
236 | spin_unlock_irqrestore(&chan->lock, flags); | |
237 | err = wait_event_interruptible(*chan->vc_wq, | |
238 | chan->ring_bufs_avail); | |
239 | if (err == -ERESTARTSYS) | |
240 | return err; | |
241 | ||
242 | P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n"); | |
243 | goto req_retry; | |
244 | } else { | |
245 | spin_unlock_irqrestore(&chan->lock, flags); | |
246 | P9_DPRINTK(P9_DEBUG_TRANS, | |
247 | "9p debug: " | |
248 | "virtio rpc add_buf returned failure"); | |
249 | return -EIO; | |
250 | } | |
e2735b77 | 251 | } |
b530cc79 | 252 | |
dc3f5e68 | 253 | virtqueue_kick(chan->vq); |
419b3956 | 254 | spin_unlock_irqrestore(&chan->lock, flags); |
b530cc79 | 255 | |
91b8534f | 256 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n"); |
e2735b77 | 257 | return 0; |
b530cc79 EVH |
258 | } |
259 | ||
86c84373 AK |
260 | static ssize_t p9_mount_tag_show(struct device *dev, |
261 | struct device_attribute *attr, char *buf) | |
262 | { | |
263 | struct virtio_chan *chan; | |
264 | struct virtio_device *vdev; | |
265 | ||
266 | vdev = dev_to_virtio(dev); | |
267 | chan = vdev->priv; | |
268 | ||
269 | return snprintf(buf, chan->tag_len + 1, "%s", chan->tag); | |
270 | } | |
271 | ||
272 | static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); | |
273 | ||
ee443996 EVH |
274 | /** |
275 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
276 | * @vdev: virtio device to probe | |
277 | * | |
37c1209d | 278 | * This probes for existing virtio channels. |
ee443996 EVH |
279 | * |
280 | */ | |
281 | ||
e2735b77 | 282 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 | 283 | { |
97ee9b02 AK |
284 | __u16 tag_len; |
285 | char *tag; | |
b530cc79 EVH |
286 | int err; |
287 | struct virtio_chan *chan; | |
b530cc79 | 288 | |
37c1209d AK |
289 | chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); |
290 | if (!chan) { | |
291 | printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n"); | |
b530cc79 EVH |
292 | err = -ENOMEM; |
293 | goto fail; | |
294 | } | |
295 | ||
e2735b77 | 296 | chan->vdev = vdev; |
b530cc79 | 297 | |
e2735b77 | 298 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 299 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
300 | if (IS_ERR(chan->vq)) { |
301 | err = PTR_ERR(chan->vq); | |
302 | goto out_free_vq; | |
b530cc79 | 303 | } |
e2735b77 EVH |
304 | chan->vq->vdev->priv = chan; |
305 | spin_lock_init(&chan->lock); | |
b530cc79 | 306 | |
e2735b77 | 307 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 308 | |
b530cc79 | 309 | chan->inuse = false; |
97ee9b02 AK |
310 | if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { |
311 | vdev->config->get(vdev, | |
312 | offsetof(struct virtio_9p_config, tag_len), | |
313 | &tag_len, sizeof(tag_len)); | |
314 | } else { | |
315 | err = -EINVAL; | |
316 | goto out_free_vq; | |
317 | } | |
318 | tag = kmalloc(tag_len, GFP_KERNEL); | |
319 | if (!tag) { | |
320 | err = -ENOMEM; | |
321 | goto out_free_vq; | |
322 | } | |
323 | vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag), | |
324 | tag, tag_len); | |
325 | chan->tag = tag; | |
326 | chan->tag_len = tag_len; | |
86c84373 AK |
327 | err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
328 | if (err) { | |
52f44e0d | 329 | goto out_free_tag; |
86c84373 | 330 | } |
52f44e0d VJJ |
331 | chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); |
332 | if (!chan->vc_wq) { | |
333 | err = -ENOMEM; | |
334 | goto out_free_tag; | |
335 | } | |
336 | init_waitqueue_head(chan->vc_wq); | |
337 | chan->ring_bufs_avail = 1; | |
338 | ||
37c1209d AK |
339 | mutex_lock(&virtio_9p_lock); |
340 | list_add_tail(&chan->chan_list, &virtio_chan_list); | |
341 | mutex_unlock(&virtio_9p_lock); | |
b530cc79 EVH |
342 | return 0; |
343 | ||
52f44e0d VJJ |
344 | out_free_tag: |
345 | kfree(tag); | |
e2735b77 | 346 | out_free_vq: |
d2a7ddda | 347 | vdev->config->del_vqs(vdev); |
37c1209d | 348 | kfree(chan); |
b530cc79 | 349 | fail: |
b530cc79 EVH |
350 | return err; |
351 | } | |
352 | ||
ee443996 EVH |
353 | |
354 | /** | |
355 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 356 | * @client: client instance invoking this transport |
ee443996 EVH |
357 | * @devname: string identifying the channel to connect to (unused) |
358 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
359 | * |
360 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
361 | * we only match the first available channel, but eventually we couldlook up |
362 | * alternate channels by matching devname versus a virtio_config entry. | |
363 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
364 | * mount has a channel open at a time. |
365 | * | |
ee443996 EVH |
366 | */ |
367 | ||
8b81ef58 EVH |
368 | static int |
369 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 370 | { |
37c1209d | 371 | struct virtio_chan *chan; |
c1a7c226 | 372 | int ret = -ENOENT; |
37c1209d | 373 | int found = 0; |
b530cc79 | 374 | |
c1549497 | 375 | mutex_lock(&virtio_9p_lock); |
37c1209d | 376 | list_for_each_entry(chan, &virtio_chan_list, chan_list) { |
0b20406c SE |
377 | if (!strncmp(devname, chan->tag, chan->tag_len) && |
378 | strlen(devname) == chan->tag_len) { | |
f75580c4 AK |
379 | if (!chan->inuse) { |
380 | chan->inuse = true; | |
37c1209d | 381 | found = 1; |
f75580c4 AK |
382 | break; |
383 | } | |
c1a7c226 | 384 | ret = -EBUSY; |
b530cc79 EVH |
385 | } |
386 | } | |
c1549497 | 387 | mutex_unlock(&virtio_9p_lock); |
b530cc79 | 388 | |
37c1209d | 389 | if (!found) { |
e2735b77 | 390 | printk(KERN_ERR "9p: no channels available\n"); |
c1a7c226 | 391 | return ret; |
e2735b77 EVH |
392 | } |
393 | ||
8b81ef58 | 394 | client->trans = (void *)chan; |
562ada61 | 395 | client->status = Connected; |
fea511a6 | 396 | chan->client = client; |
b530cc79 | 397 | |
8b81ef58 | 398 | return 0; |
b530cc79 EVH |
399 | } |
400 | ||
ee443996 EVH |
401 | /** |
402 | * p9_virtio_remove - clean up resources associated with a virtio device | |
403 | * @vdev: virtio device to remove | |
404 | * | |
405 | */ | |
406 | ||
f3933545 EVH |
407 | static void p9_virtio_remove(struct virtio_device *vdev) |
408 | { | |
409 | struct virtio_chan *chan = vdev->priv; | |
410 | ||
411 | BUG_ON(chan->inuse); | |
37c1209d AK |
412 | vdev->config->del_vqs(vdev); |
413 | ||
414 | mutex_lock(&virtio_9p_lock); | |
415 | list_del(&chan->chan_list); | |
416 | mutex_unlock(&virtio_9p_lock); | |
86c84373 | 417 | sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
97ee9b02 | 418 | kfree(chan->tag); |
52f44e0d | 419 | kfree(chan->vc_wq); |
37c1209d | 420 | kfree(chan); |
f3933545 | 421 | |
f3933545 EVH |
422 | } |
423 | ||
b530cc79 EVH |
424 | static struct virtio_device_id id_table[] = { |
425 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
426 | { 0 }, | |
427 | }; | |
428 | ||
97ee9b02 AK |
429 | static unsigned int features[] = { |
430 | VIRTIO_9P_MOUNT_TAG, | |
431 | }; | |
432 | ||
b530cc79 EVH |
433 | /* The standard "struct lguest_driver": */ |
434 | static struct virtio_driver p9_virtio_drv = { | |
97ee9b02 AK |
435 | .feature_table = features, |
436 | .feature_table_size = ARRAY_SIZE(features), | |
437 | .driver.name = KBUILD_MODNAME, | |
438 | .driver.owner = THIS_MODULE, | |
439 | .id_table = id_table, | |
440 | .probe = p9_virtio_probe, | |
441 | .remove = p9_virtio_remove, | |
b530cc79 EVH |
442 | }; |
443 | ||
444 | static struct p9_trans_module p9_virtio_trans = { | |
445 | .name = "virtio", | |
446 | .create = p9_virtio_create, | |
8b81ef58 | 447 | .close = p9_virtio_close, |
91b8534f EVH |
448 | .request = p9_virtio_request, |
449 | .cancel = p9_virtio_cancel, | |
e2735b77 | 450 | .maxsize = PAGE_SIZE*16, |
b530cc79 | 451 | .def = 0, |
72029fe8 | 452 | .owner = THIS_MODULE, |
b530cc79 EVH |
453 | }; |
454 | ||
455 | /* The standard init function */ | |
456 | static int __init p9_virtio_init(void) | |
457 | { | |
37c1209d | 458 | INIT_LIST_HEAD(&virtio_chan_list); |
b530cc79 EVH |
459 | |
460 | v9fs_register_trans(&p9_virtio_trans); | |
461 | return register_virtio_driver(&p9_virtio_drv); | |
462 | } | |
463 | ||
f3933545 EVH |
464 | static void __exit p9_virtio_cleanup(void) |
465 | { | |
466 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 467 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
468 | } |
469 | ||
b530cc79 | 470 | module_init(p9_virtio_init); |
f3933545 | 471 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
472 | |
473 | MODULE_DEVICE_TABLE(virtio, id_table); | |
474 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
475 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
476 | MODULE_LICENSE("GPL"); |