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 | ||
5d385153 JP |
29 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
30 | ||
b530cc79 EVH |
31 | #include <linux/in.h> |
32 | #include <linux/module.h> | |
33 | #include <linux/net.h> | |
34 | #include <linux/ipv6.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/kernel.h> | |
37 | #include <linux/un.h> | |
38 | #include <linux/uaccess.h> | |
39 | #include <linux/inet.h> | |
40 | #include <linux/idr.h> | |
41 | #include <linux/file.h> | |
b9cdc88d | 42 | #include <linux/highmem.h> |
5a0e3ad6 | 43 | #include <linux/slab.h> |
b530cc79 EVH |
44 | #include <net/9p/9p.h> |
45 | #include <linux/parser.h> | |
8b81ef58 | 46 | #include <net/9p/client.h> |
b530cc79 EVH |
47 | #include <net/9p/transport.h> |
48 | #include <linux/scatterlist.h> | |
68da9ba4 | 49 | #include <linux/swap.h> |
b530cc79 EVH |
50 | #include <linux/virtio.h> |
51 | #include <linux/virtio_9p.h> | |
4038866d | 52 | #include "trans_common.h" |
b530cc79 | 53 | |
e2735b77 EVH |
54 | #define VIRTQUEUE_NUM 128 |
55 | ||
b530cc79 | 56 | /* a single mutex to manage channel initialization and attachment */ |
c1549497 | 57 | static DEFINE_MUTEX(virtio_9p_lock); |
68da9ba4 VJJ |
58 | static DECLARE_WAIT_QUEUE_HEAD(vp_wq); |
59 | static atomic_t vp_pinned = ATOMIC_INIT(0); | |
b530cc79 | 60 | |
ee443996 EVH |
61 | /** |
62 | * struct virtio_chan - per-instance transport information | |
63 | * @initialized: whether the channel is initialized | |
64 | * @inuse: whether the channel is in use | |
65 | * @lock: protects multiple elements within this structure | |
0e15597e | 66 | * @client: client instance |
ee443996 EVH |
67 | * @vdev: virtio dev associated with this channel |
68 | * @vq: virtio queue associated with this channel | |
ee443996 EVH |
69 | * @sg: scatter gather list which is used to pack a request (protected?) |
70 | * | |
71 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
72 | * This structure is allocated within the devices dev->mem space. |
73 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 74 | * |
b530cc79 | 75 | */ |
ee443996 | 76 | |
37c1209d | 77 | struct virtio_chan { |
ee443996 | 78 | bool inuse; |
b530cc79 | 79 | |
e2735b77 EVH |
80 | spinlock_t lock; |
81 | ||
fea511a6 | 82 | struct p9_client *client; |
b530cc79 | 83 | struct virtio_device *vdev; |
e2735b77 | 84 | struct virtqueue *vq; |
52f44e0d VJJ |
85 | int ring_bufs_avail; |
86 | wait_queue_head_t *vc_wq; | |
68da9ba4 VJJ |
87 | /* This is global limit. Since we don't have a global structure, |
88 | * will be placing it in each channel. | |
89 | */ | |
7293bfba | 90 | unsigned long p9_max_pages; |
e2735b77 EVH |
91 | /* Scatterlist: can be too big for stack. */ |
92 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
37c1209d | 93 | |
97ee9b02 AK |
94 | int tag_len; |
95 | /* | |
96 | * tag name to identify a mount Non-null terminated | |
97 | */ | |
98 | char *tag; | |
99 | ||
37c1209d AK |
100 | struct list_head chan_list; |
101 | }; | |
102 | ||
103 | static struct list_head virtio_chan_list; | |
b530cc79 EVH |
104 | |
105 | /* How many bytes left in this page. */ | |
106 | static unsigned int rest_of_page(void *data) | |
107 | { | |
108 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
109 | } | |
110 | ||
ee443996 EVH |
111 | /** |
112 | * p9_virtio_close - reclaim resources of a channel | |
0e15597e | 113 | * @client: client instance |
ee443996 EVH |
114 | * |
115 | * This reclaims a channel by freeing its resources and | |
116 | * reseting its inuse flag. | |
117 | * | |
118 | */ | |
119 | ||
8b81ef58 | 120 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 121 | { |
8b81ef58 | 122 | struct virtio_chan *chan = client->trans; |
b530cc79 | 123 | |
c1549497 | 124 | mutex_lock(&virtio_9p_lock); |
fb786100 AK |
125 | if (chan) |
126 | chan->inuse = false; | |
c1549497 | 127 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
128 | } |
129 | ||
ee443996 EVH |
130 | /** |
131 | * req_done - callback which signals activity from the server | |
132 | * @vq: virtio queue activity was received on | |
133 | * | |
134 | * This notifies us that the server has triggered some activity | |
135 | * on the virtio channel - most likely a response to request we | |
136 | * sent. Figure out which requests now have responses and wake up | |
137 | * those threads. | |
138 | * | |
139 | * Bugs: could do with some additional sanity checking, but appears to work. | |
140 | * | |
141 | */ | |
142 | ||
e2735b77 | 143 | static void req_done(struct virtqueue *vq) |
b530cc79 | 144 | { |
e2735b77 EVH |
145 | struct virtio_chan *chan = vq->vdev->priv; |
146 | struct p9_fcall *rc; | |
147 | unsigned int len; | |
e2735b77 | 148 | struct p9_req_t *req; |
419b3956 | 149 | unsigned long flags; |
e2735b77 | 150 | |
5d385153 | 151 | p9_debug(P9_DEBUG_TRANS, ": request done\n"); |
91b8534f | 152 | |
a01a9840 | 153 | while (1) { |
419b3956 VJJ |
154 | spin_lock_irqsave(&chan->lock, flags); |
155 | rc = virtqueue_get_buf(chan->vq, &len); | |
a01a9840 | 156 | if (rc == NULL) { |
52f44e0d | 157 | spin_unlock_irqrestore(&chan->lock, flags); |
a01a9840 VJJ |
158 | break; |
159 | } | |
a01a9840 VJJ |
160 | chan->ring_bufs_avail = 1; |
161 | spin_unlock_irqrestore(&chan->lock, flags); | |
162 | /* Wakeup if anyone waiting for VirtIO ring space. */ | |
163 | wake_up(chan->vc_wq); | |
5d385153 JP |
164 | p9_debug(P9_DEBUG_TRANS, ": rc %p\n", rc); |
165 | p9_debug(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); | |
a01a9840 | 166 | req = p9_tag_lookup(chan->client, rc->tag); |
a01a9840 VJJ |
167 | req->status = REQ_STATUS_RCVD; |
168 | p9_client_cb(chan->client, req); | |
169 | } | |
e2735b77 | 170 | } |
b530cc79 | 171 | |
ee443996 EVH |
172 | /** |
173 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
174 | * @sg: scatter/gather list to pack into | |
175 | * @start: which segment of the sg_list to start at | |
176 | * @limit: maximum segment to pack data to | |
177 | * @data: data to pack into scatter/gather list | |
178 | * @count: amount of data to pack into the scatter/gather list | |
179 | * | |
180 | * sg_lists have multiple segments of various sizes. This will pack | |
181 | * arbitrary data into an existing scatter gather list, segmenting the | |
182 | * data as necessary within constraints. | |
183 | * | |
184 | */ | |
185 | ||
abfa034e AK |
186 | static int pack_sg_list(struct scatterlist *sg, int start, |
187 | int limit, char *data, int count) | |
e2735b77 EVH |
188 | { |
189 | int s; | |
190 | int index = start; | |
191 | ||
192 | while (count) { | |
193 | s = rest_of_page(data); | |
194 | if (s > count) | |
195 | s = count; | |
5fcb08be | 196 | BUG_ON(index > limit); |
0b36f1ad RR |
197 | /* Make sure we don't terminate early. */ |
198 | sg_unmark_end(&sg[index]); | |
e2735b77 EVH |
199 | sg_set_buf(&sg[index++], data, s); |
200 | count -= s; | |
201 | data += s; | |
e2735b77 | 202 | } |
0b36f1ad RR |
203 | if (index-start) |
204 | sg_mark_end(&sg[index - 1]); | |
e2735b77 | 205 | return index-start; |
b530cc79 EVH |
206 | } |
207 | ||
91b8534f EVH |
208 | /* We don't currently allow canceling of virtio requests */ |
209 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
210 | { | |
211 | return 1; | |
212 | } | |
213 | ||
4038866d VJJ |
214 | /** |
215 | * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, | |
216 | * this takes a list of pages. | |
217 | * @sg: scatter/gather list to pack into | |
218 | * @start: which segment of the sg_list to start at | |
2c53040f | 219 | * @pdata: a list of pages to add into sg. |
abfa034e AK |
220 | * @nr_pages: number of pages to pack into the scatter/gather list |
221 | * @data: data to pack into scatter/gather list | |
4038866d VJJ |
222 | * @count: amount of data to pack into the scatter/gather list |
223 | */ | |
224 | static int | |
abfa034e AK |
225 | pack_sg_list_p(struct scatterlist *sg, int start, int limit, |
226 | struct page **pdata, int nr_pages, char *data, int count) | |
4038866d | 227 | { |
abfa034e AK |
228 | int i = 0, s; |
229 | int data_off; | |
4038866d VJJ |
230 | int index = start; |
231 | ||
abfa034e AK |
232 | BUG_ON(nr_pages > (limit - start)); |
233 | /* | |
234 | * if the first page doesn't start at | |
235 | * page boundary find the offset | |
236 | */ | |
237 | data_off = offset_in_page(data); | |
238 | while (nr_pages) { | |
239 | s = rest_of_page(data); | |
240 | if (s > count) | |
241 | s = count; | |
0b36f1ad RR |
242 | /* Make sure we don't terminate early. */ |
243 | sg_unmark_end(&sg[index]); | |
abfa034e AK |
244 | sg_set_page(&sg[index++], pdata[i++], s, data_off); |
245 | data_off = 0; | |
246 | data += s; | |
4038866d | 247 | count -= s; |
abfa034e | 248 | nr_pages--; |
4038866d | 249 | } |
0b36f1ad RR |
250 | |
251 | if (index-start) | |
252 | sg_mark_end(&sg[index - 1]); | |
abfa034e | 253 | return index - start; |
4038866d VJJ |
254 | } |
255 | ||
ee443996 | 256 | /** |
91b8534f | 257 | * p9_virtio_request - issue a request |
0e15597e AK |
258 | * @client: client instance issuing the request |
259 | * @req: request to be issued | |
ee443996 EVH |
260 | * |
261 | */ | |
262 | ||
e2735b77 | 263 | static int |
91b8534f | 264 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 265 | { |
abfa034e | 266 | int err; |
0b36f1ad | 267 | int in, out, out_sgs, in_sgs; |
419b3956 | 268 | unsigned long flags; |
abfa034e | 269 | struct virtio_chan *chan = client->trans; |
0b36f1ad | 270 | struct scatterlist *sgs[2]; |
b530cc79 | 271 | |
5d385153 | 272 | p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 273 | |
419b3956 | 274 | req->status = REQ_STATUS_SENT; |
abfa034e AK |
275 | req_retry: |
276 | spin_lock_irqsave(&chan->lock, flags); | |
277 | ||
0b36f1ad | 278 | out_sgs = in_sgs = 0; |
abfa034e AK |
279 | /* Handle out VirtIO ring buffers */ |
280 | out = pack_sg_list(chan->sg, 0, | |
281 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
0b36f1ad RR |
282 | if (out) |
283 | sgs[out_sgs++] = chan->sg; | |
419b3956 | 284 | |
abfa034e AK |
285 | in = pack_sg_list(chan->sg, out, |
286 | VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity); | |
0b36f1ad RR |
287 | if (in) |
288 | sgs[out_sgs + in_sgs++] = chan->sg + out; | |
4038866d | 289 | |
0b36f1ad | 290 | err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, |
f96fde41 | 291 | GFP_ATOMIC); |
abfa034e AK |
292 | if (err < 0) { |
293 | if (err == -ENOSPC) { | |
294 | chan->ring_bufs_avail = 0; | |
295 | spin_unlock_irqrestore(&chan->lock, flags); | |
296 | err = wait_event_interruptible(*chan->vc_wq, | |
297 | chan->ring_bufs_avail); | |
68da9ba4 VJJ |
298 | if (err == -ERESTARTSYS) |
299 | return err; | |
68da9ba4 | 300 | |
5d385153 | 301 | p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); |
abfa034e | 302 | goto req_retry; |
4038866d | 303 | } else { |
abfa034e | 304 | spin_unlock_irqrestore(&chan->lock, flags); |
5d385153 | 305 | p9_debug(P9_DEBUG_TRANS, |
0b36f1ad | 306 | "virtio rpc add_sgs returned failure\n"); |
abfa034e | 307 | return -EIO; |
4038866d | 308 | } |
abfa034e AK |
309 | } |
310 | virtqueue_kick(chan->vq); | |
311 | spin_unlock_irqrestore(&chan->lock, flags); | |
4038866d | 312 | |
5d385153 | 313 | p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); |
abfa034e AK |
314 | return 0; |
315 | } | |
316 | ||
317 | static int p9_get_mapped_pages(struct virtio_chan *chan, | |
318 | struct page **pages, char *data, | |
319 | int nr_pages, int write, int kern_buf) | |
320 | { | |
321 | int err; | |
322 | if (!kern_buf) { | |
323 | /* | |
324 | * We allow only p9_max_pages pinned. We wait for the | |
325 | * Other zc request to finish here | |
326 | */ | |
327 | if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { | |
328 | err = wait_event_interruptible(vp_wq, | |
329 | (atomic_read(&vp_pinned) < chan->p9_max_pages)); | |
330 | if (err == -ERESTARTSYS) | |
331 | return err; | |
332 | } | |
333 | err = p9_payload_gup(data, &nr_pages, pages, write); | |
334 | if (err < 0) | |
4038866d | 335 | return err; |
abfa034e AK |
336 | atomic_add(nr_pages, &vp_pinned); |
337 | } else { | |
338 | /* kernel buffer, no need to pin pages */ | |
339 | int s, index = 0; | |
340 | int count = nr_pages; | |
341 | while (nr_pages) { | |
342 | s = rest_of_page(data); | |
b9cdc88d | 343 | pages[index++] = kmap_to_page(data); |
abfa034e AK |
344 | data += s; |
345 | nr_pages--; | |
4038866d | 346 | } |
abfa034e | 347 | nr_pages = count; |
4038866d | 348 | } |
abfa034e AK |
349 | return nr_pages; |
350 | } | |
4038866d | 351 | |
abfa034e AK |
352 | /** |
353 | * p9_virtio_zc_request - issue a zero copy request | |
354 | * @client: client instance issuing the request | |
355 | * @req: request to be issued | |
356 | * @uidata: user bffer that should be ued for zero copy read | |
357 | * @uodata: user buffer that shoud be user for zero copy write | |
358 | * @inlen: read buffer size | |
359 | * @olen: write buffer size | |
360 | * @hdrlen: reader header size, This is the size of response protocol data | |
361 | * | |
362 | */ | |
363 | static int | |
364 | p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, | |
365 | char *uidata, char *uodata, int inlen, | |
366 | int outlen, int in_hdr_len, int kern_buf) | |
367 | { | |
0b36f1ad | 368 | int in, out, err, out_sgs, in_sgs; |
abfa034e AK |
369 | unsigned long flags; |
370 | int in_nr_pages = 0, out_nr_pages = 0; | |
371 | struct page **in_pages = NULL, **out_pages = NULL; | |
372 | struct virtio_chan *chan = client->trans; | |
0b36f1ad | 373 | struct scatterlist *sgs[4]; |
4038866d | 374 | |
5d385153 | 375 | p9_debug(P9_DEBUG_TRANS, "virtio request\n"); |
abfa034e AK |
376 | |
377 | if (uodata) { | |
378 | out_nr_pages = p9_nr_pages(uodata, outlen); | |
379 | out_pages = kmalloc(sizeof(struct page *) * out_nr_pages, | |
380 | GFP_NOFS); | |
381 | if (!out_pages) { | |
382 | err = -ENOMEM; | |
383 | goto err_out; | |
384 | } | |
385 | out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata, | |
386 | out_nr_pages, 0, kern_buf); | |
387 | if (out_nr_pages < 0) { | |
388 | err = out_nr_pages; | |
389 | kfree(out_pages); | |
390 | out_pages = NULL; | |
391 | goto err_out; | |
4038866d | 392 | } |
4038866d | 393 | } |
abfa034e AK |
394 | if (uidata) { |
395 | in_nr_pages = p9_nr_pages(uidata, inlen); | |
396 | in_pages = kmalloc(sizeof(struct page *) * in_nr_pages, | |
397 | GFP_NOFS); | |
398 | if (!in_pages) { | |
399 | err = -ENOMEM; | |
400 | goto err_out; | |
401 | } | |
402 | in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata, | |
403 | in_nr_pages, 1, kern_buf); | |
404 | if (in_nr_pages < 0) { | |
405 | err = in_nr_pages; | |
406 | kfree(in_pages); | |
407 | in_pages = NULL; | |
408 | goto err_out; | |
4038866d | 409 | } |
4038866d | 410 | } |
abfa034e AK |
411 | req->status = REQ_STATUS_SENT; |
412 | req_retry_pinned: | |
413 | spin_lock_irqsave(&chan->lock, flags); | |
0b36f1ad RR |
414 | |
415 | out_sgs = in_sgs = 0; | |
416 | ||
abfa034e AK |
417 | /* out data */ |
418 | out = pack_sg_list(chan->sg, 0, | |
419 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
420 | ||
0b36f1ad RR |
421 | if (out) |
422 | sgs[out_sgs++] = chan->sg; | |
423 | ||
424 | if (out_pages) { | |
425 | sgs[out_sgs++] = chan->sg + out; | |
abfa034e AK |
426 | out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, |
427 | out_pages, out_nr_pages, uodata, outlen); | |
0b36f1ad RR |
428 | } |
429 | ||
abfa034e AK |
430 | /* |
431 | * Take care of in data | |
432 | * For example TREAD have 11. | |
433 | * 11 is the read/write header = PDU Header(7) + IO Size (4). | |
434 | * Arrange in such a way that server places header in the | |
435 | * alloced memory and payload onto the user buffer. | |
436 | */ | |
437 | in = pack_sg_list(chan->sg, out, | |
438 | VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len); | |
0b36f1ad RR |
439 | if (in) |
440 | sgs[out_sgs + in_sgs++] = chan->sg + out; | |
441 | ||
442 | if (in_pages) { | |
443 | sgs[out_sgs + in_sgs++] = chan->sg + out + in; | |
abfa034e AK |
444 | in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM, |
445 | in_pages, in_nr_pages, uidata, inlen); | |
0b36f1ad | 446 | } |
b530cc79 | 447 | |
0b36f1ad RR |
448 | BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs)); |
449 | err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, | |
f96fde41 | 450 | GFP_ATOMIC); |
419b3956 | 451 | if (err < 0) { |
52f44e0d VJJ |
452 | if (err == -ENOSPC) { |
453 | chan->ring_bufs_avail = 0; | |
454 | spin_unlock_irqrestore(&chan->lock, flags); | |
455 | err = wait_event_interruptible(*chan->vc_wq, | |
abfa034e | 456 | chan->ring_bufs_avail); |
52f44e0d | 457 | if (err == -ERESTARTSYS) |
abfa034e | 458 | goto err_out; |
52f44e0d | 459 | |
5d385153 | 460 | p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); |
316ad550 | 461 | goto req_retry_pinned; |
52f44e0d VJJ |
462 | } else { |
463 | spin_unlock_irqrestore(&chan->lock, flags); | |
5d385153 | 464 | p9_debug(P9_DEBUG_TRANS, |
0b36f1ad | 465 | "virtio rpc add_sgs returned failure\n"); |
abfa034e AK |
466 | err = -EIO; |
467 | goto err_out; | |
52f44e0d | 468 | } |
e2735b77 | 469 | } |
dc3f5e68 | 470 | virtqueue_kick(chan->vq); |
419b3956 | 471 | spin_unlock_irqrestore(&chan->lock, flags); |
5d385153 | 472 | p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); |
abfa034e AK |
473 | err = wait_event_interruptible(*req->wq, |
474 | req->status >= REQ_STATUS_RCVD); | |
475 | /* | |
476 | * Non kernel buffers are pinned, unpin them | |
477 | */ | |
478 | err_out: | |
479 | if (!kern_buf) { | |
480 | if (in_pages) { | |
481 | p9_release_pages(in_pages, in_nr_pages); | |
482 | atomic_sub(in_nr_pages, &vp_pinned); | |
483 | } | |
484 | if (out_pages) { | |
485 | p9_release_pages(out_pages, out_nr_pages); | |
486 | atomic_sub(out_nr_pages, &vp_pinned); | |
487 | } | |
488 | /* wakeup anybody waiting for slots to pin pages */ | |
489 | wake_up(&vp_wq); | |
490 | } | |
491 | kfree(in_pages); | |
492 | kfree(out_pages); | |
493 | return err; | |
b530cc79 EVH |
494 | } |
495 | ||
86c84373 AK |
496 | static ssize_t p9_mount_tag_show(struct device *dev, |
497 | struct device_attribute *attr, char *buf) | |
498 | { | |
499 | struct virtio_chan *chan; | |
500 | struct virtio_device *vdev; | |
501 | ||
502 | vdev = dev_to_virtio(dev); | |
503 | chan = vdev->priv; | |
504 | ||
505 | return snprintf(buf, chan->tag_len + 1, "%s", chan->tag); | |
506 | } | |
507 | ||
508 | static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); | |
509 | ||
ee443996 EVH |
510 | /** |
511 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
512 | * @vdev: virtio device to probe | |
513 | * | |
37c1209d | 514 | * This probes for existing virtio channels. |
ee443996 EVH |
515 | * |
516 | */ | |
517 | ||
e2735b77 | 518 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 | 519 | { |
97ee9b02 AK |
520 | __u16 tag_len; |
521 | char *tag; | |
b530cc79 EVH |
522 | int err; |
523 | struct virtio_chan *chan; | |
b530cc79 | 524 | |
37c1209d AK |
525 | chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); |
526 | if (!chan) { | |
5d385153 | 527 | pr_err("Failed to allocate virtio 9P channel\n"); |
b530cc79 EVH |
528 | err = -ENOMEM; |
529 | goto fail; | |
530 | } | |
531 | ||
e2735b77 | 532 | chan->vdev = vdev; |
b530cc79 | 533 | |
e2735b77 | 534 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 535 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
536 | if (IS_ERR(chan->vq)) { |
537 | err = PTR_ERR(chan->vq); | |
538 | goto out_free_vq; | |
b530cc79 | 539 | } |
e2735b77 EVH |
540 | chan->vq->vdev->priv = chan; |
541 | spin_lock_init(&chan->lock); | |
b530cc79 | 542 | |
e2735b77 | 543 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 544 | |
b530cc79 | 545 | chan->inuse = false; |
97ee9b02 AK |
546 | if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { |
547 | vdev->config->get(vdev, | |
548 | offsetof(struct virtio_9p_config, tag_len), | |
549 | &tag_len, sizeof(tag_len)); | |
550 | } else { | |
551 | err = -EINVAL; | |
552 | goto out_free_vq; | |
553 | } | |
554 | tag = kmalloc(tag_len, GFP_KERNEL); | |
555 | if (!tag) { | |
556 | err = -ENOMEM; | |
557 | goto out_free_vq; | |
558 | } | |
559 | vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag), | |
560 | tag, tag_len); | |
561 | chan->tag = tag; | |
562 | chan->tag_len = tag_len; | |
86c84373 AK |
563 | err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
564 | if (err) { | |
52f44e0d | 565 | goto out_free_tag; |
86c84373 | 566 | } |
52f44e0d VJJ |
567 | chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); |
568 | if (!chan->vc_wq) { | |
569 | err = -ENOMEM; | |
570 | goto out_free_tag; | |
571 | } | |
572 | init_waitqueue_head(chan->vc_wq); | |
573 | chan->ring_bufs_avail = 1; | |
68da9ba4 VJJ |
574 | /* Ceiling limit to avoid denial of service attacks */ |
575 | chan->p9_max_pages = nr_free_buffer_pages()/4; | |
52f44e0d | 576 | |
37c1209d AK |
577 | mutex_lock(&virtio_9p_lock); |
578 | list_add_tail(&chan->chan_list, &virtio_chan_list); | |
579 | mutex_unlock(&virtio_9p_lock); | |
b530cc79 EVH |
580 | return 0; |
581 | ||
52f44e0d VJJ |
582 | out_free_tag: |
583 | kfree(tag); | |
e2735b77 | 584 | out_free_vq: |
d2a7ddda | 585 | vdev->config->del_vqs(vdev); |
37c1209d | 586 | kfree(chan); |
b530cc79 | 587 | fail: |
b530cc79 EVH |
588 | return err; |
589 | } | |
590 | ||
ee443996 EVH |
591 | |
592 | /** | |
593 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 594 | * @client: client instance invoking this transport |
ee443996 EVH |
595 | * @devname: string identifying the channel to connect to (unused) |
596 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
597 | * |
598 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
599 | * we only match the first available channel, but eventually we couldlook up |
600 | * alternate channels by matching devname versus a virtio_config entry. | |
601 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
602 | * mount has a channel open at a time. |
603 | * | |
ee443996 EVH |
604 | */ |
605 | ||
8b81ef58 EVH |
606 | static int |
607 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 608 | { |
37c1209d | 609 | struct virtio_chan *chan; |
c1a7c226 | 610 | int ret = -ENOENT; |
37c1209d | 611 | int found = 0; |
b530cc79 | 612 | |
c1549497 | 613 | mutex_lock(&virtio_9p_lock); |
37c1209d | 614 | list_for_each_entry(chan, &virtio_chan_list, chan_list) { |
0b20406c SE |
615 | if (!strncmp(devname, chan->tag, chan->tag_len) && |
616 | strlen(devname) == chan->tag_len) { | |
f75580c4 AK |
617 | if (!chan->inuse) { |
618 | chan->inuse = true; | |
37c1209d | 619 | found = 1; |
f75580c4 AK |
620 | break; |
621 | } | |
c1a7c226 | 622 | ret = -EBUSY; |
b530cc79 EVH |
623 | } |
624 | } | |
c1549497 | 625 | mutex_unlock(&virtio_9p_lock); |
b530cc79 | 626 | |
37c1209d | 627 | if (!found) { |
5d385153 | 628 | pr_err("no channels available\n"); |
c1a7c226 | 629 | return ret; |
e2735b77 EVH |
630 | } |
631 | ||
8b81ef58 | 632 | client->trans = (void *)chan; |
562ada61 | 633 | client->status = Connected; |
fea511a6 | 634 | chan->client = client; |
b530cc79 | 635 | |
8b81ef58 | 636 | return 0; |
b530cc79 EVH |
637 | } |
638 | ||
ee443996 EVH |
639 | /** |
640 | * p9_virtio_remove - clean up resources associated with a virtio device | |
641 | * @vdev: virtio device to remove | |
642 | * | |
643 | */ | |
644 | ||
f3933545 EVH |
645 | static void p9_virtio_remove(struct virtio_device *vdev) |
646 | { | |
647 | struct virtio_chan *chan = vdev->priv; | |
648 | ||
991ad9ec SL |
649 | if (chan->inuse) |
650 | p9_virtio_close(chan->client); | |
37c1209d AK |
651 | vdev->config->del_vqs(vdev); |
652 | ||
653 | mutex_lock(&virtio_9p_lock); | |
654 | list_del(&chan->chan_list); | |
655 | mutex_unlock(&virtio_9p_lock); | |
86c84373 | 656 | sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
97ee9b02 | 657 | kfree(chan->tag); |
52f44e0d | 658 | kfree(chan->vc_wq); |
37c1209d | 659 | kfree(chan); |
f3933545 | 660 | |
f3933545 EVH |
661 | } |
662 | ||
b530cc79 EVH |
663 | static struct virtio_device_id id_table[] = { |
664 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
665 | { 0 }, | |
666 | }; | |
667 | ||
97ee9b02 AK |
668 | static unsigned int features[] = { |
669 | VIRTIO_9P_MOUNT_TAG, | |
670 | }; | |
671 | ||
b530cc79 EVH |
672 | /* The standard "struct lguest_driver": */ |
673 | static struct virtio_driver p9_virtio_drv = { | |
97ee9b02 AK |
674 | .feature_table = features, |
675 | .feature_table_size = ARRAY_SIZE(features), | |
676 | .driver.name = KBUILD_MODNAME, | |
677 | .driver.owner = THIS_MODULE, | |
678 | .id_table = id_table, | |
679 | .probe = p9_virtio_probe, | |
680 | .remove = p9_virtio_remove, | |
b530cc79 EVH |
681 | }; |
682 | ||
683 | static struct p9_trans_module p9_virtio_trans = { | |
684 | .name = "virtio", | |
685 | .create = p9_virtio_create, | |
8b81ef58 | 686 | .close = p9_virtio_close, |
91b8534f | 687 | .request = p9_virtio_request, |
dc893e19 | 688 | .zc_request = p9_virtio_zc_request, |
91b8534f | 689 | .cancel = p9_virtio_cancel, |
b49d8b5d AK |
690 | /* |
691 | * We leave one entry for input and one entry for response | |
692 | * headers. We also skip one more entry to accomodate, address | |
693 | * that are not at page boundary, that can result in an extra | |
694 | * page in zero copy. | |
695 | */ | |
696 | .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), | |
b530cc79 | 697 | .def = 0, |
72029fe8 | 698 | .owner = THIS_MODULE, |
b530cc79 EVH |
699 | }; |
700 | ||
701 | /* The standard init function */ | |
702 | static int __init p9_virtio_init(void) | |
703 | { | |
37c1209d | 704 | INIT_LIST_HEAD(&virtio_chan_list); |
b530cc79 EVH |
705 | |
706 | v9fs_register_trans(&p9_virtio_trans); | |
707 | return register_virtio_driver(&p9_virtio_drv); | |
708 | } | |
709 | ||
f3933545 EVH |
710 | static void __exit p9_virtio_cleanup(void) |
711 | { | |
712 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 713 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
714 | } |
715 | ||
b530cc79 | 716 | module_init(p9_virtio_init); |
f3933545 | 717 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
718 | |
719 | MODULE_DEVICE_TABLE(virtio, id_table); | |
720 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
721 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
722 | MODULE_LICENSE("GPL"); |