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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 | ||
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); |
2b6e72ed | 167 | p9_client_cb(chan->client, req, REQ_STATUS_RCVD); |
a01a9840 | 168 | } |
e2735b77 | 169 | } |
b530cc79 | 170 | |
ee443996 EVH |
171 | /** |
172 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
173 | * @sg: scatter/gather list to pack into | |
174 | * @start: which segment of the sg_list to start at | |
175 | * @limit: maximum segment to pack data to | |
176 | * @data: data to pack into scatter/gather list | |
177 | * @count: amount of data to pack into the scatter/gather list | |
178 | * | |
179 | * sg_lists have multiple segments of various sizes. This will pack | |
180 | * arbitrary data into an existing scatter gather list, segmenting the | |
181 | * data as necessary within constraints. | |
182 | * | |
183 | */ | |
184 | ||
abfa034e AK |
185 | static int pack_sg_list(struct scatterlist *sg, int start, |
186 | int limit, char *data, int count) | |
e2735b77 EVH |
187 | { |
188 | int s; | |
189 | int index = start; | |
190 | ||
191 | while (count) { | |
192 | s = rest_of_page(data); | |
193 | if (s > count) | |
194 | s = count; | |
5fcb08be | 195 | BUG_ON(index > limit); |
0b36f1ad RR |
196 | /* Make sure we don't terminate early. */ |
197 | sg_unmark_end(&sg[index]); | |
e2735b77 EVH |
198 | sg_set_buf(&sg[index++], data, s); |
199 | count -= s; | |
200 | data += s; | |
e2735b77 | 201 | } |
0b36f1ad RR |
202 | if (index-start) |
203 | sg_mark_end(&sg[index - 1]); | |
e2735b77 | 204 | return index-start; |
b530cc79 EVH |
205 | } |
206 | ||
91b8534f EVH |
207 | /* We don't currently allow canceling of virtio requests */ |
208 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
209 | { | |
210 | return 1; | |
211 | } | |
212 | ||
4038866d VJJ |
213 | /** |
214 | * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, | |
215 | * this takes a list of pages. | |
216 | * @sg: scatter/gather list to pack into | |
217 | * @start: which segment of the sg_list to start at | |
2c53040f | 218 | * @pdata: a list of pages to add into sg. |
abfa034e AK |
219 | * @nr_pages: number of pages to pack into the scatter/gather list |
220 | * @data: data to pack into scatter/gather list | |
4038866d VJJ |
221 | * @count: amount of data to pack into the scatter/gather list |
222 | */ | |
223 | static int | |
abfa034e AK |
224 | pack_sg_list_p(struct scatterlist *sg, int start, int limit, |
225 | struct page **pdata, int nr_pages, char *data, int count) | |
4038866d | 226 | { |
abfa034e AK |
227 | int i = 0, s; |
228 | int data_off; | |
4038866d VJJ |
229 | int index = start; |
230 | ||
abfa034e AK |
231 | BUG_ON(nr_pages > (limit - start)); |
232 | /* | |
233 | * if the first page doesn't start at | |
234 | * page boundary find the offset | |
235 | */ | |
236 | data_off = offset_in_page(data); | |
237 | while (nr_pages) { | |
238 | s = rest_of_page(data); | |
239 | if (s > count) | |
240 | s = count; | |
0b36f1ad RR |
241 | /* Make sure we don't terminate early. */ |
242 | sg_unmark_end(&sg[index]); | |
abfa034e AK |
243 | sg_set_page(&sg[index++], pdata[i++], s, data_off); |
244 | data_off = 0; | |
245 | data += s; | |
4038866d | 246 | count -= s; |
abfa034e | 247 | nr_pages--; |
4038866d | 248 | } |
0b36f1ad RR |
249 | |
250 | if (index-start) | |
251 | sg_mark_end(&sg[index - 1]); | |
abfa034e | 252 | return index - start; |
4038866d VJJ |
253 | } |
254 | ||
ee443996 | 255 | /** |
91b8534f | 256 | * p9_virtio_request - issue a request |
0e15597e AK |
257 | * @client: client instance issuing the request |
258 | * @req: request to be issued | |
ee443996 EVH |
259 | * |
260 | */ | |
261 | ||
e2735b77 | 262 | static int |
91b8534f | 263 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 264 | { |
abfa034e | 265 | int err; |
0b36f1ad | 266 | int in, out, out_sgs, in_sgs; |
419b3956 | 267 | unsigned long flags; |
abfa034e | 268 | struct virtio_chan *chan = client->trans; |
0b36f1ad | 269 | struct scatterlist *sgs[2]; |
b530cc79 | 270 | |
5d385153 | 271 | p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 272 | |
419b3956 | 273 | req->status = REQ_STATUS_SENT; |
abfa034e AK |
274 | req_retry: |
275 | spin_lock_irqsave(&chan->lock, flags); | |
276 | ||
0b36f1ad | 277 | out_sgs = in_sgs = 0; |
abfa034e AK |
278 | /* Handle out VirtIO ring buffers */ |
279 | out = pack_sg_list(chan->sg, 0, | |
280 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
0b36f1ad RR |
281 | if (out) |
282 | sgs[out_sgs++] = chan->sg; | |
419b3956 | 283 | |
abfa034e AK |
284 | in = pack_sg_list(chan->sg, out, |
285 | VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity); | |
0b36f1ad RR |
286 | if (in) |
287 | sgs[out_sgs + in_sgs++] = chan->sg + out; | |
4038866d | 288 | |
0b36f1ad | 289 | err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, |
f96fde41 | 290 | GFP_ATOMIC); |
abfa034e AK |
291 | if (err < 0) { |
292 | if (err == -ENOSPC) { | |
293 | chan->ring_bufs_avail = 0; | |
294 | spin_unlock_irqrestore(&chan->lock, flags); | |
295 | err = wait_event_interruptible(*chan->vc_wq, | |
296 | chan->ring_bufs_avail); | |
68da9ba4 VJJ |
297 | if (err == -ERESTARTSYS) |
298 | return err; | |
68da9ba4 | 299 | |
5d385153 | 300 | p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); |
abfa034e | 301 | goto req_retry; |
4038866d | 302 | } else { |
abfa034e | 303 | spin_unlock_irqrestore(&chan->lock, flags); |
5d385153 | 304 | p9_debug(P9_DEBUG_TRANS, |
0b36f1ad | 305 | "virtio rpc add_sgs returned failure\n"); |
abfa034e | 306 | return -EIO; |
4038866d | 307 | } |
abfa034e AK |
308 | } |
309 | virtqueue_kick(chan->vq); | |
310 | spin_unlock_irqrestore(&chan->lock, flags); | |
4038866d | 311 | |
5d385153 | 312 | p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); |
abfa034e AK |
313 | return 0; |
314 | } | |
315 | ||
316 | static int p9_get_mapped_pages(struct virtio_chan *chan, | |
317 | struct page **pages, char *data, | |
318 | int nr_pages, int write, int kern_buf) | |
319 | { | |
320 | int err; | |
321 | if (!kern_buf) { | |
322 | /* | |
323 | * We allow only p9_max_pages pinned. We wait for the | |
324 | * Other zc request to finish here | |
325 | */ | |
326 | if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { | |
327 | err = wait_event_interruptible(vp_wq, | |
328 | (atomic_read(&vp_pinned) < chan->p9_max_pages)); | |
329 | if (err == -ERESTARTSYS) | |
330 | return err; | |
331 | } | |
332 | err = p9_payload_gup(data, &nr_pages, pages, write); | |
333 | if (err < 0) | |
4038866d | 334 | return err; |
abfa034e AK |
335 | atomic_add(nr_pages, &vp_pinned); |
336 | } else { | |
337 | /* kernel buffer, no need to pin pages */ | |
338 | int s, index = 0; | |
339 | int count = nr_pages; | |
340 | while (nr_pages) { | |
341 | s = rest_of_page(data); | |
b6f52ae2 RY |
342 | if (is_vmalloc_addr(data)) |
343 | pages[index++] = vmalloc_to_page(data); | |
344 | else | |
345 | pages[index++] = kmap_to_page(data); | |
abfa034e AK |
346 | data += s; |
347 | nr_pages--; | |
4038866d | 348 | } |
abfa034e | 349 | nr_pages = count; |
4038866d | 350 | } |
abfa034e AK |
351 | return nr_pages; |
352 | } | |
4038866d | 353 | |
abfa034e AK |
354 | /** |
355 | * p9_virtio_zc_request - issue a zero copy request | |
356 | * @client: client instance issuing the request | |
357 | * @req: request to be issued | |
358 | * @uidata: user bffer that should be ued for zero copy read | |
359 | * @uodata: user buffer that shoud be user for zero copy write | |
360 | * @inlen: read buffer size | |
361 | * @olen: write buffer size | |
362 | * @hdrlen: reader header size, This is the size of response protocol data | |
363 | * | |
364 | */ | |
365 | static int | |
366 | p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, | |
367 | char *uidata, char *uodata, int inlen, | |
368 | int outlen, int in_hdr_len, int kern_buf) | |
369 | { | |
0b36f1ad | 370 | int in, out, err, out_sgs, in_sgs; |
abfa034e AK |
371 | unsigned long flags; |
372 | int in_nr_pages = 0, out_nr_pages = 0; | |
373 | struct page **in_pages = NULL, **out_pages = NULL; | |
374 | struct virtio_chan *chan = client->trans; | |
0b36f1ad | 375 | struct scatterlist *sgs[4]; |
4038866d | 376 | |
5d385153 | 377 | p9_debug(P9_DEBUG_TRANS, "virtio request\n"); |
abfa034e AK |
378 | |
379 | if (uodata) { | |
380 | out_nr_pages = p9_nr_pages(uodata, outlen); | |
381 | out_pages = kmalloc(sizeof(struct page *) * out_nr_pages, | |
382 | GFP_NOFS); | |
383 | if (!out_pages) { | |
384 | err = -ENOMEM; | |
385 | goto err_out; | |
386 | } | |
387 | out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata, | |
388 | out_nr_pages, 0, kern_buf); | |
389 | if (out_nr_pages < 0) { | |
390 | err = out_nr_pages; | |
391 | kfree(out_pages); | |
392 | out_pages = NULL; | |
393 | goto err_out; | |
4038866d | 394 | } |
4038866d | 395 | } |
abfa034e AK |
396 | if (uidata) { |
397 | in_nr_pages = p9_nr_pages(uidata, inlen); | |
398 | in_pages = kmalloc(sizeof(struct page *) * in_nr_pages, | |
399 | GFP_NOFS); | |
400 | if (!in_pages) { | |
401 | err = -ENOMEM; | |
402 | goto err_out; | |
403 | } | |
404 | in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata, | |
405 | in_nr_pages, 1, kern_buf); | |
406 | if (in_nr_pages < 0) { | |
407 | err = in_nr_pages; | |
408 | kfree(in_pages); | |
409 | in_pages = NULL; | |
410 | goto err_out; | |
4038866d | 411 | } |
4038866d | 412 | } |
abfa034e AK |
413 | req->status = REQ_STATUS_SENT; |
414 | req_retry_pinned: | |
415 | spin_lock_irqsave(&chan->lock, flags); | |
0b36f1ad RR |
416 | |
417 | out_sgs = in_sgs = 0; | |
418 | ||
abfa034e AK |
419 | /* out data */ |
420 | out = pack_sg_list(chan->sg, 0, | |
421 | VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); | |
422 | ||
0b36f1ad RR |
423 | if (out) |
424 | sgs[out_sgs++] = chan->sg; | |
425 | ||
426 | if (out_pages) { | |
427 | sgs[out_sgs++] = chan->sg + out; | |
abfa034e AK |
428 | out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, |
429 | out_pages, out_nr_pages, uodata, outlen); | |
0b36f1ad RR |
430 | } |
431 | ||
abfa034e AK |
432 | /* |
433 | * Take care of in data | |
434 | * For example TREAD have 11. | |
435 | * 11 is the read/write header = PDU Header(7) + IO Size (4). | |
436 | * Arrange in such a way that server places header in the | |
437 | * alloced memory and payload onto the user buffer. | |
438 | */ | |
439 | in = pack_sg_list(chan->sg, out, | |
440 | VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len); | |
0b36f1ad RR |
441 | if (in) |
442 | sgs[out_sgs + in_sgs++] = chan->sg + out; | |
443 | ||
444 | if (in_pages) { | |
445 | sgs[out_sgs + in_sgs++] = chan->sg + out + in; | |
abfa034e AK |
446 | in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM, |
447 | in_pages, in_nr_pages, uidata, inlen); | |
0b36f1ad | 448 | } |
b530cc79 | 449 | |
0b36f1ad RR |
450 | BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs)); |
451 | err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, | |
f96fde41 | 452 | GFP_ATOMIC); |
419b3956 | 453 | if (err < 0) { |
52f44e0d VJJ |
454 | if (err == -ENOSPC) { |
455 | chan->ring_bufs_avail = 0; | |
456 | spin_unlock_irqrestore(&chan->lock, flags); | |
457 | err = wait_event_interruptible(*chan->vc_wq, | |
abfa034e | 458 | chan->ring_bufs_avail); |
52f44e0d | 459 | if (err == -ERESTARTSYS) |
abfa034e | 460 | goto err_out; |
52f44e0d | 461 | |
5d385153 | 462 | p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); |
316ad550 | 463 | goto req_retry_pinned; |
52f44e0d VJJ |
464 | } else { |
465 | spin_unlock_irqrestore(&chan->lock, flags); | |
5d385153 | 466 | p9_debug(P9_DEBUG_TRANS, |
0b36f1ad | 467 | "virtio rpc add_sgs returned failure\n"); |
abfa034e AK |
468 | err = -EIO; |
469 | goto err_out; | |
52f44e0d | 470 | } |
e2735b77 | 471 | } |
dc3f5e68 | 472 | virtqueue_kick(chan->vq); |
419b3956 | 473 | spin_unlock_irqrestore(&chan->lock, flags); |
5d385153 | 474 | p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); |
abfa034e AK |
475 | err = wait_event_interruptible(*req->wq, |
476 | req->status >= REQ_STATUS_RCVD); | |
477 | /* | |
478 | * Non kernel buffers are pinned, unpin them | |
479 | */ | |
480 | err_out: | |
481 | if (!kern_buf) { | |
482 | if (in_pages) { | |
483 | p9_release_pages(in_pages, in_nr_pages); | |
484 | atomic_sub(in_nr_pages, &vp_pinned); | |
485 | } | |
486 | if (out_pages) { | |
487 | p9_release_pages(out_pages, out_nr_pages); | |
488 | atomic_sub(out_nr_pages, &vp_pinned); | |
489 | } | |
490 | /* wakeup anybody waiting for slots to pin pages */ | |
491 | wake_up(&vp_wq); | |
492 | } | |
493 | kfree(in_pages); | |
494 | kfree(out_pages); | |
495 | return err; | |
b530cc79 EVH |
496 | } |
497 | ||
86c84373 AK |
498 | static ssize_t p9_mount_tag_show(struct device *dev, |
499 | struct device_attribute *attr, char *buf) | |
500 | { | |
501 | struct virtio_chan *chan; | |
502 | struct virtio_device *vdev; | |
503 | ||
504 | vdev = dev_to_virtio(dev); | |
505 | chan = vdev->priv; | |
506 | ||
507 | return snprintf(buf, chan->tag_len + 1, "%s", chan->tag); | |
508 | } | |
509 | ||
510 | static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); | |
511 | ||
ee443996 EVH |
512 | /** |
513 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
514 | * @vdev: virtio device to probe | |
515 | * | |
37c1209d | 516 | * This probes for existing virtio channels. |
ee443996 EVH |
517 | * |
518 | */ | |
519 | ||
e2735b77 | 520 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 | 521 | { |
97ee9b02 AK |
522 | __u16 tag_len; |
523 | char *tag; | |
b530cc79 EVH |
524 | int err; |
525 | struct virtio_chan *chan; | |
b530cc79 | 526 | |
7754f53e MT |
527 | if (!vdev->config->get) { |
528 | dev_err(&vdev->dev, "%s failure: config access disabled\n", | |
529 | __func__); | |
530 | return -EINVAL; | |
531 | } | |
532 | ||
37c1209d AK |
533 | chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); |
534 | if (!chan) { | |
5d385153 | 535 | pr_err("Failed to allocate virtio 9P channel\n"); |
b530cc79 EVH |
536 | err = -ENOMEM; |
537 | goto fail; | |
538 | } | |
539 | ||
e2735b77 | 540 | chan->vdev = vdev; |
b530cc79 | 541 | |
e2735b77 | 542 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 543 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
544 | if (IS_ERR(chan->vq)) { |
545 | err = PTR_ERR(chan->vq); | |
546 | goto out_free_vq; | |
b530cc79 | 547 | } |
e2735b77 EVH |
548 | chan->vq->vdev->priv = chan; |
549 | spin_lock_init(&chan->lock); | |
b530cc79 | 550 | |
e2735b77 | 551 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 552 | |
b530cc79 | 553 | chan->inuse = false; |
97ee9b02 | 554 | if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { |
855e0c52 | 555 | virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len); |
97ee9b02 AK |
556 | } else { |
557 | err = -EINVAL; | |
558 | goto out_free_vq; | |
559 | } | |
560 | tag = kmalloc(tag_len, GFP_KERNEL); | |
561 | if (!tag) { | |
562 | err = -ENOMEM; | |
563 | goto out_free_vq; | |
564 | } | |
855e0c52 RR |
565 | |
566 | virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag), | |
567 | tag, tag_len); | |
97ee9b02 AK |
568 | chan->tag = tag; |
569 | chan->tag_len = tag_len; | |
86c84373 AK |
570 | err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
571 | if (err) { | |
52f44e0d | 572 | goto out_free_tag; |
86c84373 | 573 | } |
52f44e0d VJJ |
574 | chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); |
575 | if (!chan->vc_wq) { | |
576 | err = -ENOMEM; | |
577 | goto out_free_tag; | |
578 | } | |
579 | init_waitqueue_head(chan->vc_wq); | |
580 | chan->ring_bufs_avail = 1; | |
68da9ba4 VJJ |
581 | /* Ceiling limit to avoid denial of service attacks */ |
582 | chan->p9_max_pages = nr_free_buffer_pages()/4; | |
52f44e0d | 583 | |
64b4cc39 MT |
584 | virtio_device_ready(vdev); |
585 | ||
37c1209d AK |
586 | mutex_lock(&virtio_9p_lock); |
587 | list_add_tail(&chan->chan_list, &virtio_chan_list); | |
588 | mutex_unlock(&virtio_9p_lock); | |
e0d6cb9c MM |
589 | |
590 | /* Let udev rules use the new mount_tag attribute. */ | |
591 | kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); | |
592 | ||
b530cc79 EVH |
593 | return 0; |
594 | ||
52f44e0d VJJ |
595 | out_free_tag: |
596 | kfree(tag); | |
e2735b77 | 597 | out_free_vq: |
d2a7ddda | 598 | vdev->config->del_vqs(vdev); |
37c1209d | 599 | kfree(chan); |
b530cc79 | 600 | fail: |
b530cc79 EVH |
601 | return err; |
602 | } | |
603 | ||
ee443996 EVH |
604 | |
605 | /** | |
606 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 607 | * @client: client instance invoking this transport |
ee443996 EVH |
608 | * @devname: string identifying the channel to connect to (unused) |
609 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
610 | * |
611 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
612 | * we only match the first available channel, but eventually we couldlook up |
613 | * alternate channels by matching devname versus a virtio_config entry. | |
614 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
615 | * mount has a channel open at a time. |
616 | * | |
ee443996 EVH |
617 | */ |
618 | ||
8b81ef58 EVH |
619 | static int |
620 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 621 | { |
37c1209d | 622 | struct virtio_chan *chan; |
c1a7c226 | 623 | int ret = -ENOENT; |
37c1209d | 624 | int found = 0; |
b530cc79 | 625 | |
c1549497 | 626 | mutex_lock(&virtio_9p_lock); |
37c1209d | 627 | list_for_each_entry(chan, &virtio_chan_list, chan_list) { |
0b20406c SE |
628 | if (!strncmp(devname, chan->tag, chan->tag_len) && |
629 | strlen(devname) == chan->tag_len) { | |
f75580c4 AK |
630 | if (!chan->inuse) { |
631 | chan->inuse = true; | |
37c1209d | 632 | found = 1; |
f75580c4 AK |
633 | break; |
634 | } | |
c1a7c226 | 635 | ret = -EBUSY; |
b530cc79 EVH |
636 | } |
637 | } | |
c1549497 | 638 | mutex_unlock(&virtio_9p_lock); |
b530cc79 | 639 | |
37c1209d | 640 | if (!found) { |
5d385153 | 641 | pr_err("no channels available\n"); |
c1a7c226 | 642 | return ret; |
e2735b77 EVH |
643 | } |
644 | ||
8b81ef58 | 645 | client->trans = (void *)chan; |
562ada61 | 646 | client->status = Connected; |
fea511a6 | 647 | chan->client = client; |
b530cc79 | 648 | |
8b81ef58 | 649 | return 0; |
b530cc79 EVH |
650 | } |
651 | ||
ee443996 EVH |
652 | /** |
653 | * p9_virtio_remove - clean up resources associated with a virtio device | |
654 | * @vdev: virtio device to remove | |
655 | * | |
656 | */ | |
657 | ||
f3933545 EVH |
658 | static void p9_virtio_remove(struct virtio_device *vdev) |
659 | { | |
660 | struct virtio_chan *chan = vdev->priv; | |
661 | ||
991ad9ec SL |
662 | if (chan->inuse) |
663 | p9_virtio_close(chan->client); | |
37c1209d AK |
664 | vdev->config->del_vqs(vdev); |
665 | ||
666 | mutex_lock(&virtio_9p_lock); | |
667 | list_del(&chan->chan_list); | |
668 | mutex_unlock(&virtio_9p_lock); | |
86c84373 | 669 | sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); |
e0d6cb9c | 670 | kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); |
97ee9b02 | 671 | kfree(chan->tag); |
52f44e0d | 672 | kfree(chan->vc_wq); |
37c1209d | 673 | kfree(chan); |
f3933545 | 674 | |
f3933545 EVH |
675 | } |
676 | ||
b530cc79 EVH |
677 | static struct virtio_device_id id_table[] = { |
678 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
679 | { 0 }, | |
680 | }; | |
681 | ||
97ee9b02 AK |
682 | static unsigned int features[] = { |
683 | VIRTIO_9P_MOUNT_TAG, | |
684 | }; | |
685 | ||
b530cc79 EVH |
686 | /* The standard "struct lguest_driver": */ |
687 | static struct virtio_driver p9_virtio_drv = { | |
97ee9b02 AK |
688 | .feature_table = features, |
689 | .feature_table_size = ARRAY_SIZE(features), | |
690 | .driver.name = KBUILD_MODNAME, | |
691 | .driver.owner = THIS_MODULE, | |
692 | .id_table = id_table, | |
693 | .probe = p9_virtio_probe, | |
694 | .remove = p9_virtio_remove, | |
b530cc79 EVH |
695 | }; |
696 | ||
697 | static struct p9_trans_module p9_virtio_trans = { | |
698 | .name = "virtio", | |
699 | .create = p9_virtio_create, | |
8b81ef58 | 700 | .close = p9_virtio_close, |
91b8534f | 701 | .request = p9_virtio_request, |
dc893e19 | 702 | .zc_request = p9_virtio_zc_request, |
91b8534f | 703 | .cancel = p9_virtio_cancel, |
b49d8b5d AK |
704 | /* |
705 | * We leave one entry for input and one entry for response | |
706 | * headers. We also skip one more entry to accomodate, address | |
707 | * that are not at page boundary, that can result in an extra | |
708 | * page in zero copy. | |
709 | */ | |
710 | .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), | |
f94741fd | 711 | .def = 1, |
72029fe8 | 712 | .owner = THIS_MODULE, |
b530cc79 EVH |
713 | }; |
714 | ||
715 | /* The standard init function */ | |
716 | static int __init p9_virtio_init(void) | |
717 | { | |
37c1209d | 718 | INIT_LIST_HEAD(&virtio_chan_list); |
b530cc79 EVH |
719 | |
720 | v9fs_register_trans(&p9_virtio_trans); | |
721 | return register_virtio_driver(&p9_virtio_drv); | |
722 | } | |
723 | ||
f3933545 EVH |
724 | static void __exit p9_virtio_cleanup(void) |
725 | { | |
726 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 727 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
728 | } |
729 | ||
b530cc79 | 730 | module_init(p9_virtio_init); |
f3933545 | 731 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
732 | |
733 | MODULE_DEVICE_TABLE(virtio, id_table); | |
734 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
735 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
736 | MODULE_LICENSE("GPL"); |