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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 | ||
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> | |
40 | #include <net/9p/9p.h> | |
41 | #include <linux/parser.h> | |
8b81ef58 | 42 | #include <net/9p/client.h> |
b530cc79 EVH |
43 | #include <net/9p/transport.h> |
44 | #include <linux/scatterlist.h> | |
45 | #include <linux/virtio.h> | |
46 | #include <linux/virtio_9p.h> | |
47 | ||
e2735b77 EVH |
48 | #define VIRTQUEUE_NUM 128 |
49 | ||
b530cc79 | 50 | /* a single mutex to manage channel initialization and attachment */ |
c1549497 | 51 | static DEFINE_MUTEX(virtio_9p_lock); |
b530cc79 | 52 | |
ee443996 EVH |
53 | /** |
54 | * struct virtio_chan - per-instance transport information | |
55 | * @initialized: whether the channel is initialized | |
56 | * @inuse: whether the channel is in use | |
57 | * @lock: protects multiple elements within this structure | |
0e15597e | 58 | * @client: client instance |
ee443996 EVH |
59 | * @vdev: virtio dev associated with this channel |
60 | * @vq: virtio queue associated with this channel | |
ee443996 EVH |
61 | * @sg: scatter gather list which is used to pack a request (protected?) |
62 | * | |
63 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
64 | * This structure is allocated within the devices dev->mem space. |
65 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 66 | * |
b530cc79 | 67 | */ |
ee443996 | 68 | |
37c1209d | 69 | struct virtio_chan { |
ee443996 | 70 | bool inuse; |
b530cc79 | 71 | |
e2735b77 EVH |
72 | spinlock_t lock; |
73 | ||
fea511a6 | 74 | struct p9_client *client; |
b530cc79 | 75 | struct virtio_device *vdev; |
e2735b77 | 76 | struct virtqueue *vq; |
b530cc79 | 77 | |
e2735b77 EVH |
78 | /* Scatterlist: can be too big for stack. */ |
79 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
37c1209d AK |
80 | |
81 | struct list_head chan_list; | |
82 | }; | |
83 | ||
84 | static struct list_head virtio_chan_list; | |
b530cc79 EVH |
85 | |
86 | /* How many bytes left in this page. */ | |
87 | static unsigned int rest_of_page(void *data) | |
88 | { | |
89 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
90 | } | |
91 | ||
ee443996 EVH |
92 | /** |
93 | * p9_virtio_close - reclaim resources of a channel | |
0e15597e | 94 | * @client: client instance |
ee443996 EVH |
95 | * |
96 | * This reclaims a channel by freeing its resources and | |
97 | * reseting its inuse flag. | |
98 | * | |
99 | */ | |
100 | ||
8b81ef58 | 101 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 102 | { |
8b81ef58 | 103 | struct virtio_chan *chan = client->trans; |
b530cc79 | 104 | |
c1549497 | 105 | mutex_lock(&virtio_9p_lock); |
fb786100 AK |
106 | if (chan) |
107 | chan->inuse = false; | |
c1549497 | 108 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
109 | } |
110 | ||
ee443996 EVH |
111 | /** |
112 | * req_done - callback which signals activity from the server | |
113 | * @vq: virtio queue activity was received on | |
114 | * | |
115 | * This notifies us that the server has triggered some activity | |
116 | * on the virtio channel - most likely a response to request we | |
117 | * sent. Figure out which requests now have responses and wake up | |
118 | * those threads. | |
119 | * | |
120 | * Bugs: could do with some additional sanity checking, but appears to work. | |
121 | * | |
122 | */ | |
123 | ||
e2735b77 | 124 | static void req_done(struct virtqueue *vq) |
b530cc79 | 125 | { |
e2735b77 EVH |
126 | struct virtio_chan *chan = vq->vdev->priv; |
127 | struct p9_fcall *rc; | |
128 | unsigned int len; | |
e2735b77 EVH |
129 | struct p9_req_t *req; |
130 | ||
91b8534f EVH |
131 | P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n"); |
132 | ||
e2735b77 | 133 | while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) { |
91b8534f EVH |
134 | P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc); |
135 | P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); | |
fea511a6 | 136 | req = p9_tag_lookup(chan->client, rc->tag); |
1bab88b2 | 137 | req->status = REQ_STATUS_RCVD; |
91b8534f | 138 | p9_client_cb(chan->client, req); |
e2735b77 | 139 | } |
e2735b77 | 140 | } |
b530cc79 | 141 | |
ee443996 EVH |
142 | /** |
143 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
144 | * @sg: scatter/gather list to pack into | |
145 | * @start: which segment of the sg_list to start at | |
146 | * @limit: maximum segment to pack data to | |
147 | * @data: data to pack into scatter/gather list | |
148 | * @count: amount of data to pack into the scatter/gather list | |
149 | * | |
150 | * sg_lists have multiple segments of various sizes. This will pack | |
151 | * arbitrary data into an existing scatter gather list, segmenting the | |
152 | * data as necessary within constraints. | |
153 | * | |
154 | */ | |
155 | ||
e2735b77 EVH |
156 | static int |
157 | pack_sg_list(struct scatterlist *sg, int start, int limit, char *data, | |
158 | int count) | |
159 | { | |
160 | int s; | |
161 | int index = start; | |
162 | ||
163 | while (count) { | |
164 | s = rest_of_page(data); | |
165 | if (s > count) | |
166 | s = count; | |
167 | sg_set_buf(&sg[index++], data, s); | |
168 | count -= s; | |
169 | data += s; | |
d6584f3a | 170 | BUG_ON(index > limit); |
e2735b77 | 171 | } |
b530cc79 | 172 | |
e2735b77 | 173 | return index-start; |
b530cc79 EVH |
174 | } |
175 | ||
91b8534f EVH |
176 | /* We don't currently allow canceling of virtio requests */ |
177 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
178 | { | |
179 | return 1; | |
180 | } | |
181 | ||
ee443996 | 182 | /** |
91b8534f | 183 | * p9_virtio_request - issue a request |
0e15597e AK |
184 | * @client: client instance issuing the request |
185 | * @req: request to be issued | |
ee443996 EVH |
186 | * |
187 | */ | |
188 | ||
e2735b77 | 189 | static int |
91b8534f | 190 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 191 | { |
e2735b77 | 192 | int in, out; |
91b8534f EVH |
193 | struct virtio_chan *chan = client->trans; |
194 | char *rdata = (char *)req->rc+sizeof(struct p9_fcall); | |
b530cc79 | 195 | |
91b8534f | 196 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 197 | |
91b8534f EVH |
198 | out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata, |
199 | req->tc->size); | |
200 | in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, | |
201 | client->msize); | |
b530cc79 | 202 | |
e2735b77 | 203 | req->status = REQ_STATUS_SENT; |
b530cc79 | 204 | |
3c1b27d5 | 205 | if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) { |
e2735b77 EVH |
206 | P9_DPRINTK(P9_DEBUG_TRANS, |
207 | "9p debug: virtio rpc add_buf returned failure"); | |
208 | return -EIO; | |
209 | } | |
b530cc79 | 210 | |
e2735b77 | 211 | chan->vq->vq_ops->kick(chan->vq); |
b530cc79 | 212 | |
91b8534f | 213 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n"); |
e2735b77 | 214 | return 0; |
b530cc79 EVH |
215 | } |
216 | ||
ee443996 EVH |
217 | /** |
218 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
219 | * @vdev: virtio device to probe | |
220 | * | |
37c1209d | 221 | * This probes for existing virtio channels. |
ee443996 EVH |
222 | * |
223 | */ | |
224 | ||
e2735b77 | 225 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 EVH |
226 | { |
227 | int err; | |
228 | struct virtio_chan *chan; | |
b530cc79 | 229 | |
37c1209d AK |
230 | chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); |
231 | if (!chan) { | |
232 | printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n"); | |
b530cc79 EVH |
233 | err = -ENOMEM; |
234 | goto fail; | |
235 | } | |
236 | ||
e2735b77 | 237 | chan->vdev = vdev; |
b530cc79 | 238 | |
e2735b77 | 239 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 240 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
241 | if (IS_ERR(chan->vq)) { |
242 | err = PTR_ERR(chan->vq); | |
243 | goto out_free_vq; | |
b530cc79 | 244 | } |
e2735b77 EVH |
245 | chan->vq->vdev->priv = chan; |
246 | spin_lock_init(&chan->lock); | |
b530cc79 | 247 | |
e2735b77 | 248 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 249 | |
b530cc79 | 250 | chan->inuse = false; |
37c1209d AK |
251 | mutex_lock(&virtio_9p_lock); |
252 | list_add_tail(&chan->chan_list, &virtio_chan_list); | |
253 | mutex_unlock(&virtio_9p_lock); | |
b530cc79 EVH |
254 | return 0; |
255 | ||
e2735b77 | 256 | out_free_vq: |
d2a7ddda | 257 | vdev->config->del_vqs(vdev); |
37c1209d | 258 | kfree(chan); |
b530cc79 | 259 | fail: |
b530cc79 EVH |
260 | return err; |
261 | } | |
262 | ||
ee443996 EVH |
263 | |
264 | /** | |
265 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 266 | * @client: client instance invoking this transport |
ee443996 EVH |
267 | * @devname: string identifying the channel to connect to (unused) |
268 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
269 | * |
270 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
271 | * we only match the first available channel, but eventually we couldlook up |
272 | * alternate channels by matching devname versus a virtio_config entry. | |
273 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
274 | * mount has a channel open at a time. |
275 | * | |
ee443996 EVH |
276 | */ |
277 | ||
8b81ef58 EVH |
278 | static int |
279 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 280 | { |
37c1209d AK |
281 | struct virtio_chan *chan; |
282 | int found = 0; | |
b530cc79 | 283 | |
c1549497 | 284 | mutex_lock(&virtio_9p_lock); |
37c1209d AK |
285 | list_for_each_entry(chan, &virtio_chan_list, chan_list) { |
286 | if (!strcmp(devname, dev_name(&chan->vdev->dev))) { | |
f75580c4 AK |
287 | if (!chan->inuse) { |
288 | chan->inuse = true; | |
37c1209d | 289 | found = 1; |
f75580c4 AK |
290 | break; |
291 | } | |
b530cc79 EVH |
292 | } |
293 | } | |
c1549497 | 294 | mutex_unlock(&virtio_9p_lock); |
b530cc79 | 295 | |
37c1209d | 296 | if (!found) { |
e2735b77 | 297 | printk(KERN_ERR "9p: no channels available\n"); |
8b81ef58 | 298 | return -ENODEV; |
e2735b77 EVH |
299 | } |
300 | ||
8b81ef58 | 301 | client->trans = (void *)chan; |
562ada61 | 302 | client->status = Connected; |
fea511a6 | 303 | chan->client = client; |
b530cc79 | 304 | |
8b81ef58 | 305 | return 0; |
b530cc79 EVH |
306 | } |
307 | ||
ee443996 EVH |
308 | /** |
309 | * p9_virtio_remove - clean up resources associated with a virtio device | |
310 | * @vdev: virtio device to remove | |
311 | * | |
312 | */ | |
313 | ||
f3933545 EVH |
314 | static void p9_virtio_remove(struct virtio_device *vdev) |
315 | { | |
316 | struct virtio_chan *chan = vdev->priv; | |
317 | ||
318 | BUG_ON(chan->inuse); | |
37c1209d AK |
319 | vdev->config->del_vqs(vdev); |
320 | ||
321 | mutex_lock(&virtio_9p_lock); | |
322 | list_del(&chan->chan_list); | |
323 | mutex_unlock(&virtio_9p_lock); | |
324 | kfree(chan); | |
f3933545 | 325 | |
f3933545 EVH |
326 | } |
327 | ||
b530cc79 EVH |
328 | static struct virtio_device_id id_table[] = { |
329 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
330 | { 0 }, | |
331 | }; | |
332 | ||
333 | /* The standard "struct lguest_driver": */ | |
334 | static struct virtio_driver p9_virtio_drv = { | |
335 | .driver.name = KBUILD_MODNAME, | |
336 | .driver.owner = THIS_MODULE, | |
337 | .id_table = id_table, | |
338 | .probe = p9_virtio_probe, | |
f3933545 | 339 | .remove = p9_virtio_remove, |
b530cc79 EVH |
340 | }; |
341 | ||
342 | static struct p9_trans_module p9_virtio_trans = { | |
343 | .name = "virtio", | |
344 | .create = p9_virtio_create, | |
8b81ef58 | 345 | .close = p9_virtio_close, |
91b8534f EVH |
346 | .request = p9_virtio_request, |
347 | .cancel = p9_virtio_cancel, | |
e2735b77 | 348 | .maxsize = PAGE_SIZE*16, |
b530cc79 | 349 | .def = 0, |
72029fe8 | 350 | .owner = THIS_MODULE, |
b530cc79 EVH |
351 | }; |
352 | ||
353 | /* The standard init function */ | |
354 | static int __init p9_virtio_init(void) | |
355 | { | |
37c1209d | 356 | INIT_LIST_HEAD(&virtio_chan_list); |
b530cc79 EVH |
357 | |
358 | v9fs_register_trans(&p9_virtio_trans); | |
359 | return register_virtio_driver(&p9_virtio_drv); | |
360 | } | |
361 | ||
f3933545 EVH |
362 | static void __exit p9_virtio_cleanup(void) |
363 | { | |
364 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 365 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
366 | } |
367 | ||
b530cc79 | 368 | module_init(p9_virtio_init); |
f3933545 | 369 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
370 | |
371 | MODULE_DEVICE_TABLE(virtio, id_table); | |
372 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
373 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
374 | MODULE_LICENSE("GPL"); |