Commit | Line | Data |
---|---|---|
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> | |
68da9ba4 | 46 | #include <linux/swap.h> |
b530cc79 EVH |
47 | #include <linux/virtio.h> |
48 | #include <linux/virtio_9p.h> | |
4038866d | 49 | #include "trans_common.h" |
b530cc79 | 50 | |
e2735b77 EVH |
51 | #define VIRTQUEUE_NUM 128 |
52 | ||
b530cc79 | 53 | /* a single mutex to manage channel initialization and attachment */ |
c1549497 | 54 | static DEFINE_MUTEX(virtio_9p_lock); |
68da9ba4 VJJ |
55 | static DECLARE_WAIT_QUEUE_HEAD(vp_wq); |
56 | static atomic_t vp_pinned = ATOMIC_INIT(0); | |
b530cc79 | 57 | |
ee443996 EVH |
58 | /** |
59 | * struct virtio_chan - per-instance transport information | |
60 | * @initialized: whether the channel is initialized | |
61 | * @inuse: whether the channel is in use | |
62 | * @lock: protects multiple elements within this structure | |
0e15597e | 63 | * @client: client instance |
ee443996 EVH |
64 | * @vdev: virtio dev associated with this channel |
65 | * @vq: virtio queue associated with this channel | |
ee443996 EVH |
66 | * @sg: scatter gather list which is used to pack a request (protected?) |
67 | * | |
68 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
69 | * This structure is allocated within the devices dev->mem space. |
70 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 71 | * |
b530cc79 | 72 | */ |
ee443996 | 73 | |
37c1209d | 74 | struct virtio_chan { |
ee443996 | 75 | bool inuse; |
b530cc79 | 76 | |
e2735b77 EVH |
77 | spinlock_t lock; |
78 | ||
fea511a6 | 79 | struct p9_client *client; |
b530cc79 | 80 | struct virtio_device *vdev; |
e2735b77 | 81 | struct virtqueue *vq; |
52f44e0d VJJ |
82 | int ring_bufs_avail; |
83 | wait_queue_head_t *vc_wq; | |
68da9ba4 VJJ |
84 | /* This is global limit. Since we don't have a global structure, |
85 | * will be placing it in each channel. | |
86 | */ | |
87 | int p9_max_pages; | |
e2735b77 EVH |
88 | /* Scatterlist: can be too big for stack. */ |
89 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
37c1209d | 90 | |
97ee9b02 AK |
91 | int tag_len; |
92 | /* | |
93 | * tag name to identify a mount Non-null terminated | |
94 | */ | |
95 | char *tag; | |
96 | ||
37c1209d AK |
97 | struct list_head chan_list; |
98 | }; | |
99 | ||
100 | static struct list_head virtio_chan_list; | |
b530cc79 EVH |
101 | |
102 | /* How many bytes left in this page. */ | |
103 | static unsigned int rest_of_page(void *data) | |
104 | { | |
105 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
106 | } | |
107 | ||
ee443996 EVH |
108 | /** |
109 | * p9_virtio_close - reclaim resources of a channel | |
0e15597e | 110 | * @client: client instance |
ee443996 EVH |
111 | * |
112 | * This reclaims a channel by freeing its resources and | |
113 | * reseting its inuse flag. | |
114 | * | |
115 | */ | |
116 | ||
8b81ef58 | 117 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 118 | { |
8b81ef58 | 119 | struct virtio_chan *chan = client->trans; |
b530cc79 | 120 | |
c1549497 | 121 | mutex_lock(&virtio_9p_lock); |
fb786100 AK |
122 | if (chan) |
123 | chan->inuse = false; | |
c1549497 | 124 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
125 | } |
126 | ||
ee443996 EVH |
127 | /** |
128 | * req_done - callback which signals activity from the server | |
129 | * @vq: virtio queue activity was received on | |
130 | * | |
131 | * This notifies us that the server has triggered some activity | |
132 | * on the virtio channel - most likely a response to request we | |
133 | * sent. Figure out which requests now have responses and wake up | |
134 | * those threads. | |
135 | * | |
136 | * Bugs: could do with some additional sanity checking, but appears to work. | |
137 | * | |
138 | */ | |
139 | ||
e2735b77 | 140 | static void req_done(struct virtqueue *vq) |
b530cc79 | 141 | { |
e2735b77 EVH |
142 | struct virtio_chan *chan = vq->vdev->priv; |
143 | struct p9_fcall *rc; | |
144 | unsigned int len; | |
e2735b77 | 145 | struct p9_req_t *req; |
419b3956 | 146 | unsigned long flags; |
e2735b77 | 147 | |
91b8534f EVH |
148 | P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n"); |
149 | ||
a01a9840 | 150 | while (1) { |
419b3956 VJJ |
151 | spin_lock_irqsave(&chan->lock, flags); |
152 | rc = virtqueue_get_buf(chan->vq, &len); | |
a01a9840 | 153 | if (rc == NULL) { |
52f44e0d | 154 | spin_unlock_irqrestore(&chan->lock, flags); |
a01a9840 VJJ |
155 | break; |
156 | } | |
a01a9840 VJJ |
157 | chan->ring_bufs_avail = 1; |
158 | spin_unlock_irqrestore(&chan->lock, flags); | |
159 | /* Wakeup if anyone waiting for VirtIO ring space. */ | |
160 | wake_up(chan->vc_wq); | |
161 | P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc); | |
162 | P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); | |
163 | req = p9_tag_lookup(chan->client, rc->tag); | |
a01a9840 VJJ |
164 | req->status = REQ_STATUS_RCVD; |
165 | p9_client_cb(chan->client, req); | |
166 | } | |
e2735b77 | 167 | } |
b530cc79 | 168 | |
ee443996 EVH |
169 | /** |
170 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
171 | * @sg: scatter/gather list to pack into | |
172 | * @start: which segment of the sg_list to start at | |
173 | * @limit: maximum segment to pack data to | |
174 | * @data: data to pack into scatter/gather list | |
175 | * @count: amount of data to pack into the scatter/gather list | |
176 | * | |
177 | * sg_lists have multiple segments of various sizes. This will pack | |
178 | * arbitrary data into an existing scatter gather list, segmenting the | |
179 | * data as necessary within constraints. | |
180 | * | |
181 | */ | |
182 | ||
abfa034e AK |
183 | static int pack_sg_list(struct scatterlist *sg, int start, |
184 | int limit, char *data, int count) | |
e2735b77 EVH |
185 | { |
186 | int s; | |
187 | int index = start; | |
188 | ||
189 | while (count) { | |
190 | s = rest_of_page(data); | |
191 | if (s > count) | |
192 | s = count; | |
193 | sg_set_buf(&sg[index++], data, s); | |
194 | count -= s; | |
195 | data += s; | |
d6584f3a | 196 | BUG_ON(index > limit); |
e2735b77 | 197 | } |
b530cc79 | 198 | |
e2735b77 | 199 | return index-start; |
b530cc79 EVH |
200 | } |
201 | ||
91b8534f EVH |
202 | /* We don't currently allow canceling of virtio requests */ |
203 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
204 | { | |
205 | return 1; | |
206 | } | |
207 | ||
4038866d VJJ |
208 | /** |
209 | * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, | |
210 | * this takes a list of pages. | |
211 | * @sg: scatter/gather list to pack into | |
212 | * @start: which segment of the sg_list to start at | |
4038866d | 213 | * @**pdata: a list of pages to add into sg. |
abfa034e AK |
214 | * @nr_pages: number of pages to pack into the scatter/gather list |
215 | * @data: data to pack into scatter/gather list | |
4038866d VJJ |
216 | * @count: amount of data to pack into the scatter/gather list |
217 | */ | |
218 | static int | |
abfa034e AK |
219 | pack_sg_list_p(struct scatterlist *sg, int start, int limit, |
220 | struct page **pdata, int nr_pages, char *data, int count) | |
4038866d | 221 | { |
abfa034e AK |
222 | int i = 0, s; |
223 | int data_off; | |
4038866d VJJ |
224 | int index = start; |
225 | ||
abfa034e AK |
226 | BUG_ON(nr_pages > (limit - start)); |
227 | /* | |
228 | * if the first page doesn't start at | |
229 | * page boundary find the offset | |
230 | */ | |
231 | data_off = offset_in_page(data); | |
232 | while (nr_pages) { | |
233 | s = rest_of_page(data); | |
234 | if (s > count) | |
235 | s = count; | |
236 | sg_set_page(&sg[index++], pdata[i++], s, data_off); | |
237 | data_off = 0; | |
238 | data += s; | |
4038866d | 239 | count -= s; |
abfa034e | 240 | nr_pages--; |
4038866d | 241 | } |
abfa034e | 242 | return index - start; |
4038866d VJJ |
243 | } |
244 | ||
ee443996 | 245 | /** |
91b8534f | 246 | * p9_virtio_request - issue a request |
0e15597e AK |
247 | * @client: client instance issuing the request |
248 | * @req: request to be issued | |
ee443996 EVH |
249 | * |
250 | */ | |
251 | ||
e2735b77 | 252 | static int |
91b8534f | 253 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 254 | { |
abfa034e AK |
255 | int err; |
256 | int in, out; | |
419b3956 | 257 | unsigned long flags; |
abfa034e | 258 | struct virtio_chan *chan = client->trans; |
b530cc79 | 259 | |
91b8534f | 260 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 261 | |
419b3956 | 262 | req->status = REQ_STATUS_SENT; |
abfa034e AK |
263 | req_retry: |
264 | spin_lock_irqsave(&chan->lock, flags); | |
265 | ||
266 | /* Handle out VirtIO ring buffers */ | |
267 | out = pack_sg_list(chan->sg, 0, | |
268 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
419b3956 | 269 | |
abfa034e AK |
270 | in = pack_sg_list(chan->sg, out, |
271 | VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity); | |
4038866d | 272 | |
abfa034e AK |
273 | err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc); |
274 | if (err < 0) { | |
275 | if (err == -ENOSPC) { | |
276 | chan->ring_bufs_avail = 0; | |
277 | spin_unlock_irqrestore(&chan->lock, flags); | |
278 | err = wait_event_interruptible(*chan->vc_wq, | |
279 | chan->ring_bufs_avail); | |
68da9ba4 VJJ |
280 | if (err == -ERESTARTSYS) |
281 | return err; | |
68da9ba4 | 282 | |
abfa034e AK |
283 | P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n"); |
284 | goto req_retry; | |
4038866d | 285 | } else { |
abfa034e AK |
286 | spin_unlock_irqrestore(&chan->lock, flags); |
287 | P9_DPRINTK(P9_DEBUG_TRANS, | |
288 | "9p debug: " | |
289 | "virtio rpc add_buf returned failure"); | |
290 | return -EIO; | |
4038866d | 291 | } |
abfa034e AK |
292 | } |
293 | virtqueue_kick(chan->vq); | |
294 | spin_unlock_irqrestore(&chan->lock, flags); | |
4038866d | 295 | |
abfa034e AK |
296 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n"); |
297 | return 0; | |
298 | } | |
299 | ||
300 | static int p9_get_mapped_pages(struct virtio_chan *chan, | |
301 | struct page **pages, char *data, | |
302 | int nr_pages, int write, int kern_buf) | |
303 | { | |
304 | int err; | |
305 | if (!kern_buf) { | |
306 | /* | |
307 | * We allow only p9_max_pages pinned. We wait for the | |
308 | * Other zc request to finish here | |
309 | */ | |
310 | if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { | |
311 | err = wait_event_interruptible(vp_wq, | |
312 | (atomic_read(&vp_pinned) < chan->p9_max_pages)); | |
313 | if (err == -ERESTARTSYS) | |
314 | return err; | |
315 | } | |
316 | err = p9_payload_gup(data, &nr_pages, pages, write); | |
317 | if (err < 0) | |
4038866d | 318 | return err; |
abfa034e AK |
319 | atomic_add(nr_pages, &vp_pinned); |
320 | } else { | |
321 | /* kernel buffer, no need to pin pages */ | |
322 | int s, index = 0; | |
323 | int count = nr_pages; | |
324 | while (nr_pages) { | |
325 | s = rest_of_page(data); | |
326 | pages[index++] = virt_to_page(data); | |
327 | data += s; | |
328 | nr_pages--; | |
4038866d | 329 | } |
abfa034e | 330 | nr_pages = count; |
4038866d | 331 | } |
abfa034e AK |
332 | return nr_pages; |
333 | } | |
4038866d | 334 | |
abfa034e AK |
335 | /** |
336 | * p9_virtio_zc_request - issue a zero copy request | |
337 | * @client: client instance issuing the request | |
338 | * @req: request to be issued | |
339 | * @uidata: user bffer that should be ued for zero copy read | |
340 | * @uodata: user buffer that shoud be user for zero copy write | |
341 | * @inlen: read buffer size | |
342 | * @olen: write buffer size | |
343 | * @hdrlen: reader header size, This is the size of response protocol data | |
344 | * | |
345 | */ | |
346 | static int | |
347 | p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, | |
348 | char *uidata, char *uodata, int inlen, | |
349 | int outlen, int in_hdr_len, int kern_buf) | |
350 | { | |
351 | int in, out, err; | |
352 | unsigned long flags; | |
353 | int in_nr_pages = 0, out_nr_pages = 0; | |
354 | struct page **in_pages = NULL, **out_pages = NULL; | |
355 | struct virtio_chan *chan = client->trans; | |
4038866d | 356 | |
abfa034e AK |
357 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
358 | ||
359 | if (uodata) { | |
360 | out_nr_pages = p9_nr_pages(uodata, outlen); | |
361 | out_pages = kmalloc(sizeof(struct page *) * out_nr_pages, | |
362 | GFP_NOFS); | |
363 | if (!out_pages) { | |
364 | err = -ENOMEM; | |
365 | goto err_out; | |
366 | } | |
367 | out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata, | |
368 | out_nr_pages, 0, kern_buf); | |
369 | if (out_nr_pages < 0) { | |
370 | err = out_nr_pages; | |
371 | kfree(out_pages); | |
372 | out_pages = NULL; | |
373 | goto err_out; | |
4038866d | 374 | } |
4038866d | 375 | } |
abfa034e AK |
376 | if (uidata) { |
377 | in_nr_pages = p9_nr_pages(uidata, inlen); | |
378 | in_pages = kmalloc(sizeof(struct page *) * in_nr_pages, | |
379 | GFP_NOFS); | |
380 | if (!in_pages) { | |
381 | err = -ENOMEM; | |
382 | goto err_out; | |
383 | } | |
384 | in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata, | |
385 | in_nr_pages, 1, kern_buf); | |
386 | if (in_nr_pages < 0) { | |
387 | err = in_nr_pages; | |
388 | kfree(in_pages); | |
389 | in_pages = NULL; | |
390 | goto err_out; | |
4038866d | 391 | } |
4038866d | 392 | } |
abfa034e AK |
393 | req->status = REQ_STATUS_SENT; |
394 | req_retry_pinned: | |
395 | spin_lock_irqsave(&chan->lock, flags); | |
396 | /* out data */ | |
397 | out = pack_sg_list(chan->sg, 0, | |
398 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
399 | ||
400 | if (out_pages) | |
401 | out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, | |
402 | out_pages, out_nr_pages, uodata, outlen); | |
403 | /* | |
404 | * Take care of in data | |
405 | * For example TREAD have 11. | |
406 | * 11 is the read/write header = PDU Header(7) + IO Size (4). | |
407 | * Arrange in such a way that server places header in the | |
408 | * alloced memory and payload onto the user buffer. | |
409 | */ | |
410 | in = pack_sg_list(chan->sg, out, | |
411 | VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len); | |
412 | if (in_pages) | |
413 | in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM, | |
414 | in_pages, in_nr_pages, uidata, inlen); | |
b530cc79 | 415 | |
419b3956 VJJ |
416 | err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc); |
417 | if (err < 0) { | |
52f44e0d VJJ |
418 | if (err == -ENOSPC) { |
419 | chan->ring_bufs_avail = 0; | |
420 | spin_unlock_irqrestore(&chan->lock, flags); | |
421 | err = wait_event_interruptible(*chan->vc_wq, | |
abfa034e | 422 | chan->ring_bufs_avail); |
52f44e0d | 423 | if (err == -ERESTARTSYS) |
abfa034e | 424 | goto err_out; |
52f44e0d VJJ |
425 | |
426 | P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n"); | |
316ad550 | 427 | goto req_retry_pinned; |
52f44e0d VJJ |
428 | } else { |
429 | spin_unlock_irqrestore(&chan->lock, flags); | |
430 | P9_DPRINTK(P9_DEBUG_TRANS, | |
abfa034e AK |
431 | "9p debug: " |
432 | "virtio rpc add_buf returned failure"); | |
433 | err = -EIO; | |
434 | goto err_out; | |
52f44e0d | 435 | } |
e2735b77 | 436 | } |
dc3f5e68 | 437 | virtqueue_kick(chan->vq); |
419b3956 | 438 | spin_unlock_irqrestore(&chan->lock, flags); |
91b8534f | 439 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n"); |
abfa034e AK |
440 | err = wait_event_interruptible(*req->wq, |
441 | req->status >= REQ_STATUS_RCVD); | |
442 | /* | |
443 | * Non kernel buffers are pinned, unpin them | |
444 | */ | |
445 | err_out: | |
446 | if (!kern_buf) { | |
447 | if (in_pages) { | |
448 | p9_release_pages(in_pages, in_nr_pages); | |
449 | atomic_sub(in_nr_pages, &vp_pinned); | |
450 | } | |
451 | if (out_pages) { | |
452 | p9_release_pages(out_pages, out_nr_pages); | |
453 | atomic_sub(out_nr_pages, &vp_pinned); | |
454 | } | |
455 | /* wakeup anybody waiting for slots to pin pages */ | |
456 | wake_up(&vp_wq); | |
457 | } | |
458 | kfree(in_pages); | |
459 | kfree(out_pages); | |
460 | return err; | |
b530cc79 EVH |
461 | } |
462 | ||
86c84373 AK |
463 | static ssize_t p9_mount_tag_show(struct device *dev, |
464 | struct device_attribute *attr, char *buf) | |
465 | { | |
466 | struct virtio_chan *chan; | |
467 | struct virtio_device *vdev; | |
468 | ||
469 | vdev = dev_to_virtio(dev); | |
470 | chan = vdev->priv; | |
471 | ||
472 | return snprintf(buf, chan->tag_len + 1, "%s", chan->tag); | |
473 | } | |
474 | ||
475 | static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); | |
476 | ||
ee443996 EVH |
477 | /** |
478 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
479 | * @vdev: virtio device to probe | |
480 | * | |
37c1209d | 481 | * This probes for existing virtio channels. |
ee443996 EVH |
482 | * |
483 | */ | |
484 | ||
e2735b77 | 485 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 | 486 | { |
97ee9b02 AK |
487 | __u16 tag_len; |
488 | char *tag; | |
b530cc79 EVH |
489 | int err; |
490 | struct virtio_chan *chan; | |
b530cc79 | 491 | |
37c1209d AK |
492 | chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); |
493 | if (!chan) { | |
494 | printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n"); | |
b530cc79 EVH |
495 | err = -ENOMEM; |
496 | goto fail; | |
497 | } | |
498 | ||
e2735b77 | 499 | chan->vdev = vdev; |
b530cc79 | 500 | |
e2735b77 | 501 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 502 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
503 | if (IS_ERR(chan->vq)) { |
504 | err = PTR_ERR(chan->vq); | |
505 | goto out_free_vq; | |
b530cc79 | 506 | } |
e2735b77 EVH |
507 | chan->vq->vdev->priv = chan; |
508 | spin_lock_init(&chan->lock); | |
b530cc79 | 509 | |
e2735b77 | 510 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 511 | |
b530cc79 | 512 | chan->inuse = false; |
97ee9b02 AK |
513 | if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { |
514 | vdev->config->get(vdev, | |
515 | offsetof(struct virtio_9p_config, tag_len), | |
516 | &tag_len, sizeof(tag_len)); | |
517 | } else { | |
518 | err = -EINVAL; | |
519 | goto out_free_vq; | |
520 | } | |
521 | tag = kmalloc(tag_len, GFP_KERNEL); | |
522 | if (!tag) { | |
523 | err = -ENOMEM; | |
524 | goto out_free_vq; | |
525 | } | |
526 | vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag), | |
527 | tag, tag_len); | |
528 | chan->tag = tag; | |
529 | chan->tag_len = tag_len; | |
86c84373 AK |
530 | err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
531 | if (err) { | |
52f44e0d | 532 | goto out_free_tag; |
86c84373 | 533 | } |
52f44e0d VJJ |
534 | chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); |
535 | if (!chan->vc_wq) { | |
536 | err = -ENOMEM; | |
537 | goto out_free_tag; | |
538 | } | |
539 | init_waitqueue_head(chan->vc_wq); | |
540 | chan->ring_bufs_avail = 1; | |
68da9ba4 VJJ |
541 | /* Ceiling limit to avoid denial of service attacks */ |
542 | chan->p9_max_pages = nr_free_buffer_pages()/4; | |
52f44e0d | 543 | |
37c1209d AK |
544 | mutex_lock(&virtio_9p_lock); |
545 | list_add_tail(&chan->chan_list, &virtio_chan_list); | |
546 | mutex_unlock(&virtio_9p_lock); | |
b530cc79 EVH |
547 | return 0; |
548 | ||
52f44e0d VJJ |
549 | out_free_tag: |
550 | kfree(tag); | |
e2735b77 | 551 | out_free_vq: |
d2a7ddda | 552 | vdev->config->del_vqs(vdev); |
37c1209d | 553 | kfree(chan); |
b530cc79 | 554 | fail: |
b530cc79 EVH |
555 | return err; |
556 | } | |
557 | ||
ee443996 EVH |
558 | |
559 | /** | |
560 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 561 | * @client: client instance invoking this transport |
ee443996 EVH |
562 | * @devname: string identifying the channel to connect to (unused) |
563 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
564 | * |
565 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
566 | * we only match the first available channel, but eventually we couldlook up |
567 | * alternate channels by matching devname versus a virtio_config entry. | |
568 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
569 | * mount has a channel open at a time. |
570 | * | |
ee443996 EVH |
571 | */ |
572 | ||
8b81ef58 EVH |
573 | static int |
574 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 575 | { |
37c1209d | 576 | struct virtio_chan *chan; |
c1a7c226 | 577 | int ret = -ENOENT; |
37c1209d | 578 | int found = 0; |
b530cc79 | 579 | |
c1549497 | 580 | mutex_lock(&virtio_9p_lock); |
37c1209d | 581 | list_for_each_entry(chan, &virtio_chan_list, chan_list) { |
0b20406c SE |
582 | if (!strncmp(devname, chan->tag, chan->tag_len) && |
583 | strlen(devname) == chan->tag_len) { | |
f75580c4 AK |
584 | if (!chan->inuse) { |
585 | chan->inuse = true; | |
37c1209d | 586 | found = 1; |
f75580c4 AK |
587 | break; |
588 | } | |
c1a7c226 | 589 | ret = -EBUSY; |
b530cc79 EVH |
590 | } |
591 | } | |
c1549497 | 592 | mutex_unlock(&virtio_9p_lock); |
b530cc79 | 593 | |
37c1209d | 594 | if (!found) { |
e2735b77 | 595 | printk(KERN_ERR "9p: no channels available\n"); |
c1a7c226 | 596 | return ret; |
e2735b77 EVH |
597 | } |
598 | ||
8b81ef58 | 599 | client->trans = (void *)chan; |
562ada61 | 600 | client->status = Connected; |
fea511a6 | 601 | chan->client = client; |
b530cc79 | 602 | |
8b81ef58 | 603 | return 0; |
b530cc79 EVH |
604 | } |
605 | ||
ee443996 EVH |
606 | /** |
607 | * p9_virtio_remove - clean up resources associated with a virtio device | |
608 | * @vdev: virtio device to remove | |
609 | * | |
610 | */ | |
611 | ||
f3933545 EVH |
612 | static void p9_virtio_remove(struct virtio_device *vdev) |
613 | { | |
614 | struct virtio_chan *chan = vdev->priv; | |
615 | ||
616 | BUG_ON(chan->inuse); | |
37c1209d AK |
617 | vdev->config->del_vqs(vdev); |
618 | ||
619 | mutex_lock(&virtio_9p_lock); | |
620 | list_del(&chan->chan_list); | |
621 | mutex_unlock(&virtio_9p_lock); | |
86c84373 | 622 | sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
97ee9b02 | 623 | kfree(chan->tag); |
52f44e0d | 624 | kfree(chan->vc_wq); |
37c1209d | 625 | kfree(chan); |
f3933545 | 626 | |
f3933545 EVH |
627 | } |
628 | ||
b530cc79 EVH |
629 | static struct virtio_device_id id_table[] = { |
630 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
631 | { 0 }, | |
632 | }; | |
633 | ||
97ee9b02 AK |
634 | static unsigned int features[] = { |
635 | VIRTIO_9P_MOUNT_TAG, | |
636 | }; | |
637 | ||
b530cc79 EVH |
638 | /* The standard "struct lguest_driver": */ |
639 | static struct virtio_driver p9_virtio_drv = { | |
97ee9b02 AK |
640 | .feature_table = features, |
641 | .feature_table_size = ARRAY_SIZE(features), | |
642 | .driver.name = KBUILD_MODNAME, | |
643 | .driver.owner = THIS_MODULE, | |
644 | .id_table = id_table, | |
645 | .probe = p9_virtio_probe, | |
646 | .remove = p9_virtio_remove, | |
b530cc79 EVH |
647 | }; |
648 | ||
649 | static struct p9_trans_module p9_virtio_trans = { | |
650 | .name = "virtio", | |
651 | .create = p9_virtio_create, | |
8b81ef58 | 652 | .close = p9_virtio_close, |
91b8534f | 653 | .request = p9_virtio_request, |
abfa034e | 654 | .zc_request = p9_virtio_zc_request, |
91b8534f | 655 | .cancel = p9_virtio_cancel, |
b49d8b5d AK |
656 | /* |
657 | * We leave one entry for input and one entry for response | |
658 | * headers. We also skip one more entry to accomodate, address | |
659 | * that are not at page boundary, that can result in an extra | |
660 | * page in zero copy. | |
661 | */ | |
662 | .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), | |
b530cc79 | 663 | .def = 0, |
72029fe8 | 664 | .owner = THIS_MODULE, |
b530cc79 EVH |
665 | }; |
666 | ||
667 | /* The standard init function */ | |
668 | static int __init p9_virtio_init(void) | |
669 | { | |
37c1209d | 670 | INIT_LIST_HEAD(&virtio_chan_list); |
b530cc79 EVH |
671 | |
672 | v9fs_register_trans(&p9_virtio_trans); | |
673 | return register_virtio_driver(&p9_virtio_drv); | |
674 | } | |
675 | ||
f3933545 EVH |
676 | static void __exit p9_virtio_cleanup(void) |
677 | { | |
678 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 679 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
680 | } |
681 | ||
b530cc79 | 682 | module_init(p9_virtio_init); |
f3933545 | 683 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
684 | |
685 | MODULE_DEVICE_TABLE(virtio, id_table); | |
686 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
687 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
688 | MODULE_LICENSE("GPL"); |