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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 | |
0e15597e | 60 | * @client: client instance |
ee443996 EVH |
61 | * @vdev: virtio dev associated with this channel |
62 | * @vq: virtio queue associated with this channel | |
ee443996 EVH |
63 | * @sg: scatter gather list which is used to pack a request (protected?) |
64 | * | |
65 | * We keep all per-channel information in a structure. | |
b530cc79 EVH |
66 | * This structure is allocated within the devices dev->mem space. |
67 | * A pointer to the structure will get put in the transport private. | |
ee443996 | 68 | * |
b530cc79 | 69 | */ |
ee443996 | 70 | |
b530cc79 | 71 | static struct virtio_chan { |
ee443996 EVH |
72 | bool initialized; |
73 | bool inuse; | |
b530cc79 | 74 | |
e2735b77 EVH |
75 | spinlock_t lock; |
76 | ||
fea511a6 | 77 | struct p9_client *client; |
b530cc79 | 78 | struct virtio_device *vdev; |
e2735b77 | 79 | struct virtqueue *vq; |
b530cc79 | 80 | |
e2735b77 EVH |
81 | /* Scatterlist: can be too big for stack. */ |
82 | struct scatterlist sg[VIRTQUEUE_NUM]; | |
b530cc79 EVH |
83 | } channels[MAX_9P_CHAN]; |
84 | ||
85 | /* How many bytes left in this page. */ | |
86 | static unsigned int rest_of_page(void *data) | |
87 | { | |
88 | return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); | |
89 | } | |
90 | ||
ee443996 EVH |
91 | /** |
92 | * p9_virtio_close - reclaim resources of a channel | |
0e15597e | 93 | * @client: client instance |
ee443996 EVH |
94 | * |
95 | * This reclaims a channel by freeing its resources and | |
96 | * reseting its inuse flag. | |
97 | * | |
98 | */ | |
99 | ||
8b81ef58 | 100 | static void p9_virtio_close(struct p9_client *client) |
e2735b77 | 101 | { |
8b81ef58 | 102 | struct virtio_chan *chan = client->trans; |
b530cc79 | 103 | |
c1549497 | 104 | mutex_lock(&virtio_9p_lock); |
e2735b77 | 105 | chan->inuse = false; |
c1549497 | 106 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
107 | } |
108 | ||
ee443996 EVH |
109 | /** |
110 | * req_done - callback which signals activity from the server | |
111 | * @vq: virtio queue activity was received on | |
112 | * | |
113 | * This notifies us that the server has triggered some activity | |
114 | * on the virtio channel - most likely a response to request we | |
115 | * sent. Figure out which requests now have responses and wake up | |
116 | * those threads. | |
117 | * | |
118 | * Bugs: could do with some additional sanity checking, but appears to work. | |
119 | * | |
120 | */ | |
121 | ||
e2735b77 | 122 | static void req_done(struct virtqueue *vq) |
b530cc79 | 123 | { |
e2735b77 EVH |
124 | struct virtio_chan *chan = vq->vdev->priv; |
125 | struct p9_fcall *rc; | |
126 | unsigned int len; | |
e2735b77 EVH |
127 | struct p9_req_t *req; |
128 | ||
91b8534f EVH |
129 | P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n"); |
130 | ||
e2735b77 | 131 | while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) { |
91b8534f EVH |
132 | P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc); |
133 | P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); | |
fea511a6 | 134 | req = p9_tag_lookup(chan->client, rc->tag); |
1bab88b2 | 135 | req->status = REQ_STATUS_RCVD; |
91b8534f | 136 | p9_client_cb(chan->client, req); |
e2735b77 | 137 | } |
e2735b77 | 138 | } |
b530cc79 | 139 | |
ee443996 EVH |
140 | /** |
141 | * pack_sg_list - pack a scatter gather list from a linear buffer | |
142 | * @sg: scatter/gather list to pack into | |
143 | * @start: which segment of the sg_list to start at | |
144 | * @limit: maximum segment to pack data to | |
145 | * @data: data to pack into scatter/gather list | |
146 | * @count: amount of data to pack into the scatter/gather list | |
147 | * | |
148 | * sg_lists have multiple segments of various sizes. This will pack | |
149 | * arbitrary data into an existing scatter gather list, segmenting the | |
150 | * data as necessary within constraints. | |
151 | * | |
152 | */ | |
153 | ||
e2735b77 EVH |
154 | static int |
155 | pack_sg_list(struct scatterlist *sg, int start, int limit, char *data, | |
156 | int count) | |
157 | { | |
158 | int s; | |
159 | int index = start; | |
160 | ||
161 | while (count) { | |
162 | s = rest_of_page(data); | |
163 | if (s > count) | |
164 | s = count; | |
165 | sg_set_buf(&sg[index++], data, s); | |
166 | count -= s; | |
167 | data += s; | |
d6584f3a | 168 | BUG_ON(index > limit); |
e2735b77 | 169 | } |
b530cc79 | 170 | |
e2735b77 | 171 | return index-start; |
b530cc79 EVH |
172 | } |
173 | ||
91b8534f EVH |
174 | /* We don't currently allow canceling of virtio requests */ |
175 | static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) | |
176 | { | |
177 | return 1; | |
178 | } | |
179 | ||
ee443996 | 180 | /** |
91b8534f | 181 | * p9_virtio_request - issue a request |
0e15597e AK |
182 | * @client: client instance issuing the request |
183 | * @req: request to be issued | |
ee443996 EVH |
184 | * |
185 | */ | |
186 | ||
e2735b77 | 187 | static int |
91b8534f | 188 | p9_virtio_request(struct p9_client *client, struct p9_req_t *req) |
b530cc79 | 189 | { |
e2735b77 | 190 | int in, out; |
91b8534f EVH |
191 | struct virtio_chan *chan = client->trans; |
192 | char *rdata = (char *)req->rc+sizeof(struct p9_fcall); | |
b530cc79 | 193 | |
91b8534f | 194 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n"); |
b530cc79 | 195 | |
91b8534f EVH |
196 | out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata, |
197 | req->tc->size); | |
198 | in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, | |
199 | client->msize); | |
b530cc79 | 200 | |
e2735b77 | 201 | req->status = REQ_STATUS_SENT; |
b530cc79 | 202 | |
3c1b27d5 | 203 | if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) { |
e2735b77 EVH |
204 | P9_DPRINTK(P9_DEBUG_TRANS, |
205 | "9p debug: virtio rpc add_buf returned failure"); | |
206 | return -EIO; | |
207 | } | |
b530cc79 | 208 | |
e2735b77 | 209 | chan->vq->vq_ops->kick(chan->vq); |
b530cc79 | 210 | |
91b8534f | 211 | P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n"); |
e2735b77 | 212 | return 0; |
b530cc79 EVH |
213 | } |
214 | ||
ee443996 EVH |
215 | /** |
216 | * p9_virtio_probe - probe for existence of 9P virtio channels | |
217 | * @vdev: virtio device to probe | |
218 | * | |
219 | * This probes for existing virtio channels. At present only | |
220 | * a single channel is in use, so in the future more work may need | |
221 | * to be done here. | |
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; | |
229 | int index; | |
230 | ||
c1549497 | 231 | mutex_lock(&virtio_9p_lock); |
b530cc79 EVH |
232 | index = chan_index++; |
233 | chan = &channels[index]; | |
c1549497 | 234 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
235 | |
236 | if (chan_index > MAX_9P_CHAN) { | |
237 | printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n"); | |
238 | BUG(); | |
b530cc79 EVH |
239 | err = -ENOMEM; |
240 | goto fail; | |
241 | } | |
242 | ||
e2735b77 | 243 | chan->vdev = vdev; |
b530cc79 | 244 | |
e2735b77 | 245 | /* We expect one virtqueue, for requests. */ |
d2a7ddda | 246 | chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); |
e2735b77 EVH |
247 | if (IS_ERR(chan->vq)) { |
248 | err = PTR_ERR(chan->vq); | |
249 | goto out_free_vq; | |
b530cc79 | 250 | } |
e2735b77 EVH |
251 | chan->vq->vdev->priv = chan; |
252 | spin_lock_init(&chan->lock); | |
b530cc79 | 253 | |
e2735b77 | 254 | sg_init_table(chan->sg, VIRTQUEUE_NUM); |
b530cc79 | 255 | |
b530cc79 EVH |
256 | chan->inuse = false; |
257 | chan->initialized = true; | |
b530cc79 EVH |
258 | return 0; |
259 | ||
e2735b77 | 260 | out_free_vq: |
d2a7ddda | 261 | vdev->config->del_vqs(vdev); |
b530cc79 | 262 | fail: |
c1549497 | 263 | mutex_lock(&virtio_9p_lock); |
b530cc79 | 264 | chan_index--; |
c1549497 | 265 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
266 | return err; |
267 | } | |
268 | ||
ee443996 EVH |
269 | |
270 | /** | |
271 | * p9_virtio_create - allocate a new virtio channel | |
8b81ef58 | 272 | * @client: client instance invoking this transport |
ee443996 EVH |
273 | * @devname: string identifying the channel to connect to (unused) |
274 | * @args: args passed from sys_mount() for per-transport options (unused) | |
ee443996 EVH |
275 | * |
276 | * This sets up a transport channel for 9p communication. Right now | |
b530cc79 EVH |
277 | * we only match the first available channel, but eventually we couldlook up |
278 | * alternate channels by matching devname versus a virtio_config entry. | |
279 | * We use a simple reference count mechanism to ensure that only a single | |
ee443996 EVH |
280 | * mount has a channel open at a time. |
281 | * | |
282 | * Bugs: doesn't allow identification of a specific channel | |
283 | * to allocate, channels are allocated sequentially. This was | |
284 | * a pragmatic decision to get things rolling, but ideally some | |
285 | * way of identifying the channel to attach to would be nice | |
286 | * if we are going to support multiple channels. | |
287 | * | |
288 | */ | |
289 | ||
8b81ef58 EVH |
290 | static int |
291 | p9_virtio_create(struct p9_client *client, const char *devname, char *args) | |
b530cc79 | 292 | { |
b530cc79 | 293 | struct virtio_chan *chan = channels; |
e2735b77 | 294 | int index = 0; |
b530cc79 | 295 | |
c1549497 | 296 | mutex_lock(&virtio_9p_lock); |
b530cc79 EVH |
297 | while (index < MAX_9P_CHAN) { |
298 | if (chan->initialized && !chan->inuse) { | |
299 | chan->inuse = true; | |
300 | break; | |
301 | } else { | |
302 | index++; | |
303 | chan = &channels[index]; | |
304 | } | |
305 | } | |
c1549497 | 306 | mutex_unlock(&virtio_9p_lock); |
b530cc79 EVH |
307 | |
308 | if (index >= MAX_9P_CHAN) { | |
e2735b77 | 309 | printk(KERN_ERR "9p: no channels available\n"); |
8b81ef58 | 310 | return -ENODEV; |
e2735b77 EVH |
311 | } |
312 | ||
8b81ef58 | 313 | client->trans = (void *)chan; |
562ada61 | 314 | client->status = Connected; |
fea511a6 | 315 | chan->client = client; |
b530cc79 | 316 | |
8b81ef58 | 317 | return 0; |
b530cc79 EVH |
318 | } |
319 | ||
ee443996 EVH |
320 | /** |
321 | * p9_virtio_remove - clean up resources associated with a virtio device | |
322 | * @vdev: virtio device to remove | |
323 | * | |
324 | */ | |
325 | ||
f3933545 EVH |
326 | static void p9_virtio_remove(struct virtio_device *vdev) |
327 | { | |
328 | struct virtio_chan *chan = vdev->priv; | |
329 | ||
330 | BUG_ON(chan->inuse); | |
331 | ||
332 | if (chan->initialized) { | |
d2a7ddda | 333 | vdev->config->del_vqs(vdev); |
f3933545 EVH |
334 | chan->initialized = false; |
335 | } | |
336 | } | |
337 | ||
b530cc79 EVH |
338 | static struct virtio_device_id id_table[] = { |
339 | { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, | |
340 | { 0 }, | |
341 | }; | |
342 | ||
343 | /* The standard "struct lguest_driver": */ | |
344 | static struct virtio_driver p9_virtio_drv = { | |
345 | .driver.name = KBUILD_MODNAME, | |
346 | .driver.owner = THIS_MODULE, | |
347 | .id_table = id_table, | |
348 | .probe = p9_virtio_probe, | |
f3933545 | 349 | .remove = p9_virtio_remove, |
b530cc79 EVH |
350 | }; |
351 | ||
352 | static struct p9_trans_module p9_virtio_trans = { | |
353 | .name = "virtio", | |
354 | .create = p9_virtio_create, | |
8b81ef58 | 355 | .close = p9_virtio_close, |
91b8534f EVH |
356 | .request = p9_virtio_request, |
357 | .cancel = p9_virtio_cancel, | |
e2735b77 | 358 | .maxsize = PAGE_SIZE*16, |
b530cc79 | 359 | .def = 0, |
72029fe8 | 360 | .owner = THIS_MODULE, |
b530cc79 EVH |
361 | }; |
362 | ||
363 | /* The standard init function */ | |
364 | static int __init p9_virtio_init(void) | |
365 | { | |
366 | int count; | |
367 | ||
368 | for (count = 0; count < MAX_9P_CHAN; count++) | |
369 | channels[count].initialized = false; | |
370 | ||
371 | v9fs_register_trans(&p9_virtio_trans); | |
372 | return register_virtio_driver(&p9_virtio_drv); | |
373 | } | |
374 | ||
f3933545 EVH |
375 | static void __exit p9_virtio_cleanup(void) |
376 | { | |
377 | unregister_virtio_driver(&p9_virtio_drv); | |
72029fe8 | 378 | v9fs_unregister_trans(&p9_virtio_trans); |
f3933545 EVH |
379 | } |
380 | ||
b530cc79 | 381 | module_init(p9_virtio_init); |
f3933545 | 382 | module_exit(p9_virtio_cleanup); |
b530cc79 EVH |
383 | |
384 | MODULE_DEVICE_TABLE(virtio, id_table); | |
385 | MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); | |
386 | MODULE_DESCRIPTION("Virtio 9p Transport"); | |
387 | MODULE_LICENSE("GPL"); |