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 EVH |
52 | /* global which tracks highest initialized channel */ |
53 | static int chan_index; | |
54 | ||
ee443996 EVH |
55 | /** |
56 | * struct virtio_chan - per-instance transport information | |
57 | * @initialized: whether the channel is initialized | |
58 | * @inuse: whether the channel is in use | |
59 | * @lock: protects multiple elements within this structure | |
60 | * @vdev: virtio dev associated with this channel | |
61 | * @vq: virtio queue associated with this channel | |
62 | * @tagpool: accounting for tag ids (and request slots) | |
63 | * @reqs: array of request slots | |
64 | * @max_tag: current number of request_slots allocated | |
65 | * @sg: scatter gather list which is used to pack a request (protected?) | |
66 | * | |
67 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
68 | * This structure is allocated within the devices dev->mem space. |
69 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 70 | * |
b530cc79 | 71 | */ |
ee443996 | 72 | |
b530cc79 | 73 | static struct virtio_chan { |
ee443996 EVH |
74 | bool initialized; |
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; |
b530cc79 | 82 | |
e2735b77 EVH |
83 | /* Scatterlist: can be too big for stack. */ |
84 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
b530cc79 EVH |
85 | } channels[MAX_9P_CHAN]; |
86 | ||
87 | /* How many bytes left in this page. */ | |
88 | static unsigned int rest_of_page(void *data) | |
89 | { | |
90 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
91 | } | |
92 | ||
ee443996 EVH |
93 | /** |
94 | * p9_virtio_close - reclaim resources of a channel | |
95 | * @trans: transport state | |
96 | * | |
97 | * This reclaims a channel by freeing its resources and | |
98 | * reseting its inuse flag. | |
99 | * | |
100 | */ | |
101 | ||
8b81ef58 | 102 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 103 | { |
8b81ef58 | 104 | struct virtio_chan *chan = client->trans; |
b530cc79 | 105 | |
c1549497 | 106 | mutex_lock(&virtio_9p_lock); |
e2735b77 | 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); |
91b8534f | 137 | p9_client_cb(chan->client, req); |
e2735b77 | 138 | } |
e2735b77 | 139 | } |
b530cc79 | 140 | |
ee443996 EVH |
141 | /** |
142 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
143 | * @sg: scatter/gather list to pack into | |
144 | * @start: which segment of the sg_list to start at | |
145 | * @limit: maximum segment to pack data to | |
146 | * @data: data to pack into scatter/gather list | |
147 | * @count: amount of data to pack into the scatter/gather list | |
148 | * | |
149 | * sg_lists have multiple segments of various sizes. This will pack | |
150 | * arbitrary data into an existing scatter gather list, segmenting the | |
151 | * data as necessary within constraints. | |
152 | * | |
153 | */ | |
154 | ||
e2735b77 EVH |
155 | static int |
156 | pack_sg_list(struct scatterlist *sg, int start, int limit, char *data, | |
157 | int count) | |
158 | { | |
159 | int s; | |
160 | int index = start; | |
161 | ||
162 | while (count) { | |
163 | s = rest_of_page(data); | |
164 | if (s > count) | |
165 | s = count; | |
166 | sg_set_buf(&sg[index++], data, s); | |
167 | count -= s; | |
168 | data += s; | |
d6584f3a | 169 | BUG_ON(index > limit); |
e2735b77 | 170 | } |
b530cc79 | 171 | |
e2735b77 | 172 | return index-start; |
b530cc79 EVH |
173 | } |
174 | ||
91b8534f EVH |
175 | /* We don't currently allow canceling of virtio requests */ |
176 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
177 | { | |
178 | return 1; | |
179 | } | |
180 | ||
ee443996 | 181 | /** |
91b8534f | 182 | * p9_virtio_request - issue a request |
ee443996 EVH |
183 | * @t: transport state |
184 | * @tc: &p9_fcall request to transmit | |
185 | * @rc: &p9_fcall to put reponse into | |
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 | |
91b8534f | 205 | if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc)) { |
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 | * | |
221 | * This probes for existing virtio channels. At present only | |
222 | * a single channel is in use, so in the future more work may need | |
223 | * to be done here. | |
224 | * | |
225 | */ | |
226 | ||
e2735b77 | 227 | static int p9_virtio_probe(struct virtio_device *vdev) |
b530cc79 EVH |
228 | { |
229 | int err; | |
230 | struct virtio_chan *chan; | |
231 | int index; | |
232 | ||
c1549497 | 233 | mutex_lock(&virtio_9p_lock); |
b530cc79 EVH |
234 | index = chan_index++; |
235 | chan = &channels[index]; | |
c1549497 | 236 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
237 | |
238 | if (chan_index > MAX_9P_CHAN) { | |
239 | printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n"); | |
240 | BUG(); | |
b530cc79 EVH |
241 | err = -ENOMEM; |
242 | goto fail; | |
243 | } | |
244 | ||
e2735b77 | 245 | chan->vdev = vdev; |
b530cc79 | 246 | |
e2735b77 EVH |
247 | /* We expect one virtqueue, for requests. */ |
248 | chan->vq = vdev->config->find_vq(vdev, 0, req_done); | |
249 | if (IS_ERR(chan->vq)) { | |
250 | err = PTR_ERR(chan->vq); | |
251 | goto out_free_vq; | |
b530cc79 | 252 | } |
e2735b77 EVH |
253 | chan->vq->vdev->priv = chan; |
254 | spin_lock_init(&chan->lock); | |
b530cc79 | 255 | |
e2735b77 | 256 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 257 | |
b530cc79 EVH |
258 | chan->inuse = false; |
259 | chan->initialized = true; | |
b530cc79 EVH |
260 | return 0; |
261 | ||
e2735b77 EVH |
262 | out_free_vq: |
263 | vdev->config->del_vq(chan->vq); | |
b530cc79 | 264 | fail: |
c1549497 | 265 | mutex_lock(&virtio_9p_lock); |
b530cc79 | 266 | chan_index--; |
c1549497 | 267 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
268 | return err; |
269 | } | |
270 | ||
ee443996 EVH |
271 | |
272 | /** | |
273 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 274 | * @client: client instance invoking this transport |
ee443996 EVH |
275 | * @devname: string identifying the channel to connect to (unused) |
276 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
277 | * |
278 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
279 | * we only match the first available channel, but eventually we couldlook up |
280 | * alternate channels by matching devname versus a virtio_config entry. | |
281 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
282 | * mount has a channel open at a time. |
283 | * | |
284 | * Bugs: doesn't allow identification of a specific channel | |
285 | * to allocate, channels are allocated sequentially. This was | |
286 | * a pragmatic decision to get things rolling, but ideally some | |
287 | * way of identifying the channel to attach to would be nice | |
288 | * if we are going to support multiple channels. | |
289 | * | |
290 | */ | |
291 | ||
8b81ef58 EVH |
292 | static int |
293 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 294 | { |
b530cc79 | 295 | struct virtio_chan *chan = channels; |
e2735b77 | 296 | int index = 0; |
b530cc79 | 297 | |
c1549497 | 298 | mutex_lock(&virtio_9p_lock); |
b530cc79 EVH |
299 | while (index < MAX_9P_CHAN) { |
300 | if (chan->initialized && !chan->inuse) { | |
301 | chan->inuse = true; | |
302 | break; | |
303 | } else { | |
304 | index++; | |
305 | chan = &channels[index]; | |
306 | } | |
307 | } | |
c1549497 | 308 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
309 | |
310 | if (index >= MAX_9P_CHAN) { | |
e2735b77 | 311 | printk(KERN_ERR "9p: no channels available\n"); |
8b81ef58 | 312 | return -ENODEV; |
e2735b77 EVH |
313 | } |
314 | ||
8b81ef58 | 315 | client->trans = (void *)chan; |
fea511a6 | 316 | chan->client = client; |
b530cc79 | 317 | |
8b81ef58 | 318 | return 0; |
b530cc79 EVH |
319 | } |
320 | ||
ee443996 EVH |
321 | /** |
322 | * p9_virtio_remove - clean up resources associated with a virtio device | |
323 | * @vdev: virtio device to remove | |
324 | * | |
325 | */ | |
326 | ||
f3933545 EVH |
327 | static void p9_virtio_remove(struct virtio_device *vdev) |
328 | { | |
329 | struct virtio_chan *chan = vdev->priv; | |
330 | ||
331 | BUG_ON(chan->inuse); | |
332 | ||
333 | if (chan->initialized) { | |
334 | vdev->config->del_vq(chan->vq); | |
335 | chan->initialized = false; | |
336 | } | |
337 | } | |
338 | ||
b530cc79 EVH |
339 | #define VIRTIO_ID_9P 9 |
340 | ||
341 | static struct virtio_device_id id_table[] = { | |
342 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
343 | { 0 }, | |
344 | }; | |
345 | ||
346 | /* The standard "struct lguest_driver": */ | |
347 | static struct virtio_driver p9_virtio_drv = { | |
348 | .driver.name = KBUILD_MODNAME, | |
349 | .driver.owner = THIS_MODULE, | |
350 | .id_table = id_table, | |
351 | .probe = p9_virtio_probe, | |
f3933545 | 352 | .remove = p9_virtio_remove, |
b530cc79 EVH |
353 | }; |
354 | ||
355 | static struct p9_trans_module p9_virtio_trans = { | |
356 | .name = "virtio", | |
357 | .create = p9_virtio_create, | |
8b81ef58 | 358 | .close = p9_virtio_close, |
91b8534f EVH |
359 | .request = p9_virtio_request, |
360 | .cancel = p9_virtio_cancel, | |
e2735b77 | 361 | .maxsize = PAGE_SIZE*16, |
b530cc79 | 362 | .def = 0, |
72029fe8 | 363 | .owner = THIS_MODULE, |
b530cc79 EVH |
364 | }; |
365 | ||
366 | /* The standard init function */ | |
367 | static int __init p9_virtio_init(void) | |
368 | { | |
369 | int count; | |
370 | ||
371 | for (count = 0; count < MAX_9P_CHAN; count++) | |
372 | channels[count].initialized = false; | |
373 | ||
374 | v9fs_register_trans(&p9_virtio_trans); | |
375 | return register_virtio_driver(&p9_virtio_drv); | |
376 | } | |
377 | ||
f3933545 EVH |
378 | static void __exit p9_virtio_cleanup(void) |
379 | { | |
380 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 381 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
382 | } |
383 | ||
b530cc79 | 384 | module_init(p9_virtio_init); |
f3933545 | 385 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
386 | |
387 | MODULE_DEVICE_TABLE(virtio, id_table); | |
388 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
389 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
390 | MODULE_LICENSE("GPL"); |