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Eric Van Hensbergenb530cc72007-10-23 13:47:31 -05001/*
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -05002 * The Virtio 9p transport driver
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -05003 *
Eric Van Hensbergene2735b72008-02-06 19:25:58 -06004 * This is a block based transport driver based on the lguest block driver
5 * code.
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -05006 *
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -05007 * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -05008 *
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090040#include <linux/slab.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050041#include <net/9p/9p.h>
42#include <linux/parser.h>
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -050043#include <net/9p/client.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050044#include <net/9p/transport.h>
45#include <linux/scatterlist.h>
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070046#include <linux/swap.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050047#include <linux/virtio.h>
48#include <linux/virtio_9p.h>
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -080049#include "trans_common.h"
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050050
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060051#define VIRTQUEUE_NUM 128
52
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050053/* a single mutex to manage channel initialization and attachment */
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -060054static DEFINE_MUTEX(virtio_9p_lock);
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070055static DECLARE_WAIT_QUEUE_HEAD(vp_wq);
56static atomic_t vp_pinned = ATOMIC_INIT(0);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050057
Eric Van Hensbergenee443992008-03-05 07:08:09 -060058/**
59 * struct virtio_chan - per-instance transport information
60 * @initialized: whether the channel is initialized
61 * @inuse: whether the channel is in use
62 * @lock: protects multiple elements within this structure
Abhishek Kulkarni0e155972009-07-19 13:41:55 -060063 * @client: client instance
Eric Van Hensbergenee443992008-03-05 07:08:09 -060064 * @vdev: virtio dev associated with this channel
65 * @vq: virtio queue associated with this channel
Eric Van Hensbergenee443992008-03-05 07:08:09 -060066 * @sg: scatter gather list which is used to pack a request (protected?)
67 *
68 * We keep all per-channel information in a structure.
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050069 * This structure is allocated within the devices dev->mem space.
70 * A pointer to the structure will get put in the transport private.
Eric Van Hensbergenee443992008-03-05 07:08:09 -060071 *
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050072 */
Eric Van Hensbergenee443992008-03-05 07:08:09 -060073
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +000074struct virtio_chan {
Eric Van Hensbergenee443992008-03-05 07:08:09 -060075 bool inuse;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050076
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060077 spinlock_t lock;
78
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -050079 struct p9_client *client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050080 struct virtio_device *vdev;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060081 struct virtqueue *vq;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -070082 int ring_bufs_avail;
83 wait_queue_head_t *vc_wq;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070084 /* This is global limit. Since we don't have a global structure,
85 * will be placing it in each channel.
86 */
87 int p9_max_pages;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060088 /* Scatterlist: can be too big for stack. */
89 struct scatterlist sg[VIRTQUEUE_NUM];
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +000090
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +000091 int tag_len;
92 /*
93 * tag name to identify a mount Non-null terminated
94 */
95 char *tag;
96
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +000097 struct list_head chan_list;
98};
99
100static struct list_head virtio_chan_list;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500101
102/* How many bytes left in this page. */
103static unsigned int rest_of_page(void *data)
104{
105 return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
106}
107
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600108/**
109 * p9_virtio_close - reclaim resources of a channel
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600110 * @client: client instance
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600111 *
112 * This reclaims a channel by freeing its resources and
113 * reseting its inuse flag.
114 *
115 */
116
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500117static void p9_virtio_close(struct p9_client *client)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500118{
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500119 struct virtio_chan *chan = client->trans;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500120
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600121 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.Vfb786102010-02-08 11:50:32 +0000122 if (chan)
123 chan->inuse = false;
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600124 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500125}
126
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600127/**
128 * req_done - callback which signals activity from the server
129 * @vq: virtio queue activity was received on
130 *
131 * This notifies us that the server has triggered some activity
132 * on the virtio channel - most likely a response to request we
133 * sent. Figure out which requests now have responses and wake up
134 * those threads.
135 *
136 * Bugs: could do with some additional sanity checking, but appears to work.
137 *
138 */
139
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600140static void req_done(struct virtqueue *vq)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500141{
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600142 struct virtio_chan *chan = vq->vdev->priv;
143 struct p9_fcall *rc;
144 unsigned int len;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600145 struct p9_req_t *req;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700146 unsigned long flags;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500147
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500148 P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
149
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700150 while (1) {
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700151 spin_lock_irqsave(&chan->lock, flags);
152 rc = virtqueue_get_buf(chan->vq, &len);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700153
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700154 if (rc == NULL) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700155 spin_unlock_irqrestore(&chan->lock, flags);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700156 break;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700157 }
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700158
159 chan->ring_bufs_avail = 1;
160 spin_unlock_irqrestore(&chan->lock, flags);
161 /* Wakeup if anyone waiting for VirtIO ring space. */
162 wake_up(chan->vc_wq);
163 P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
164 P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
165 req = p9_tag_lookup(chan->client, rc->tag);
166 if (req->tc->private) {
167 struct trans_rpage_info *rp = req->tc->private;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700168 int p = rp->rp_nr_pages;
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700169 /*Release pages */
170 p9_release_req_pages(rp);
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700171 atomic_sub(p, &vp_pinned);
172 wake_up(&vp_wq);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700173 if (rp->rp_alloc)
174 kfree(rp);
175 req->tc->private = NULL;
176 }
177 req->status = REQ_STATUS_RCVD;
178 p9_client_cb(chan->client, req);
179 }
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500180}
181
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600182/**
183 * pack_sg_list - pack a scatter gather list from a linear buffer
184 * @sg: scatter/gather list to pack into
185 * @start: which segment of the sg_list to start at
186 * @limit: maximum segment to pack data to
187 * @data: data to pack into scatter/gather list
188 * @count: amount of data to pack into the scatter/gather list
189 *
190 * sg_lists have multiple segments of various sizes. This will pack
191 * arbitrary data into an existing scatter gather list, segmenting the
192 * data as necessary within constraints.
193 *
194 */
195
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600196static int
197pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
198 int count)
199{
200 int s;
201 int index = start;
202
203 while (count) {
204 s = rest_of_page(data);
205 if (s > count)
206 s = count;
207 sg_set_buf(&sg[index++], data, s);
208 count -= s;
209 data += s;
Julia Lawalld6584f32008-02-17 18:42:53 -0800210 BUG_ON(index > limit);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600211 }
212
213 return index-start;
214}
215
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500216/* We don't currently allow canceling of virtio requests */
217static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
218{
219 return 1;
220}
221
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600222/**
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800223 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
224 * this takes a list of pages.
225 * @sg: scatter/gather list to pack into
226 * @start: which segment of the sg_list to start at
227 * @pdata_off: Offset into the first page
228 * @**pdata: a list of pages to add into sg.
229 * @count: amount of data to pack into the scatter/gather list
230 */
231static int
232pack_sg_list_p(struct scatterlist *sg, int start, int limit, size_t pdata_off,
233 struct page **pdata, int count)
234{
235 int s;
236 int i = 0;
237 int index = start;
238
239 if (pdata_off) {
240 s = min((int)(PAGE_SIZE - pdata_off), count);
241 sg_set_page(&sg[index++], pdata[i++], s, pdata_off);
242 count -= s;
243 }
244
245 while (count) {
246 BUG_ON(index > limit);
247 s = min((int)PAGE_SIZE, count);
248 sg_set_page(&sg[index++], pdata[i++], s, 0);
249 count -= s;
250 }
251 return index-start;
252}
253
254/**
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500255 * p9_virtio_request - issue a request
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600256 * @client: client instance issuing the request
257 * @req: request to be issued
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600258 *
259 */
260
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600261static int
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500262p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600263{
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800264 int in, out, inp, outp;
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500265 struct virtio_chan *chan = client->trans;
266 char *rdata = (char *)req->rc+sizeof(struct p9_fcall);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700267 unsigned long flags;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800268 size_t pdata_off = 0;
269 struct trans_rpage_info *rpinfo = NULL;
270 int err, pdata_len = 0;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600271
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500272 P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600273
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700274 req->status = REQ_STATUS_SENT;
275
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800276 if (req->tc->pbuf_size && (req->tc->pubuf && P9_IS_USER_CONTEXT)) {
277 int nr_pages = p9_nr_pages(req);
278 int rpinfo_size = sizeof(struct trans_rpage_info) +
279 sizeof(struct page *) * nr_pages;
280
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700281 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
282 err = wait_event_interruptible(vp_wq,
283 atomic_read(&vp_pinned) < chan->p9_max_pages);
284 if (err == -ERESTARTSYS)
285 return err;
286 P9_DPRINTK(P9_DEBUG_TRANS, "9p: May gup pages now.\n");
287 }
288
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800289 if (rpinfo_size <= (req->tc->capacity - req->tc->size)) {
290 /* We can use sdata */
291 req->tc->private = req->tc->sdata + req->tc->size;
292 rpinfo = (struct trans_rpage_info *)req->tc->private;
293 rpinfo->rp_alloc = 0;
294 } else {
295 req->tc->private = kmalloc(rpinfo_size, GFP_NOFS);
296 if (!req->tc->private) {
297 P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: "
298 "private kmalloc returned NULL");
299 return -ENOMEM;
300 }
301 rpinfo = (struct trans_rpage_info *)req->tc->private;
302 rpinfo->rp_alloc = 1;
303 }
304
305 err = p9_payload_gup(req, &pdata_off, &pdata_len, nr_pages,
306 req->tc->id == P9_TREAD ? 1 : 0);
307 if (err < 0) {
308 if (rpinfo->rp_alloc)
309 kfree(rpinfo);
310 return err;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700311 } else {
312 atomic_add(rpinfo->rp_nr_pages, &vp_pinned);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800313 }
314 }
315
Venkateswararao Jujjuri (JV)316ad552011-03-14 14:22:41 -0700316req_retry_pinned:
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700317 spin_lock_irqsave(&chan->lock, flags);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800318
319 /* Handle out VirtIO ring buffers */
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500320 out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata,
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800321 req->tc->size);
322
323 if (req->tc->pbuf_size && (req->tc->id == P9_TWRITE)) {
324 /* We have additional write payload buffer to take care */
325 if (req->tc->pubuf && P9_IS_USER_CONTEXT) {
326 outp = pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
327 pdata_off, rpinfo->rp_data, pdata_len);
328 } else {
Aneesh Kumar K.Vbd8c8ad2011-03-24 23:14:46 +0530329 char *pbuf;
330 if (req->tc->pubuf)
331 pbuf = (__force char *) req->tc->pubuf;
332 else
333 pbuf = req->tc->pkbuf;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800334 outp = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, pbuf,
335 req->tc->pbuf_size);
336 }
337 out += outp;
338 }
339
340 /* Handle in VirtIO ring buffers */
341 if (req->tc->pbuf_size &&
342 ((req->tc->id == P9_TREAD) || (req->tc->id == P9_TREADDIR))) {
343 /*
344 * Take care of additional Read payload.
345 * 11 is the read/write header = PDU Header(7) + IO Size (4).
346 * Arrange in such a way that server places header in the
347 * alloced memory and payload onto the user buffer.
348 */
349 inp = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata, 11);
350 /*
351 * Running executables in the filesystem may result in
352 * a read request with kernel buffer as opposed to user buffer.
353 */
354 if (req->tc->pubuf && P9_IS_USER_CONTEXT) {
355 in = pack_sg_list_p(chan->sg, out+inp, VIRTQUEUE_NUM,
356 pdata_off, rpinfo->rp_data, pdata_len);
357 } else {
Aneesh Kumar K.Vbd8c8ad2011-03-24 23:14:46 +0530358 char *pbuf;
359 if (req->tc->pubuf)
360 pbuf = (__force char *) req->tc->pubuf;
361 else
362 pbuf = req->tc->pkbuf;
363
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800364 in = pack_sg_list(chan->sg, out+inp, VIRTQUEUE_NUM,
365 pbuf, req->tc->pbuf_size);
366 }
367 in += inp;
368 } else {
369 in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM, rdata,
jvrao114e6f32011-06-30 23:18:39 +0000370 req->rc->capacity);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800371 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600372
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700373 err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc);
374 if (err < 0) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700375 if (err == -ENOSPC) {
376 chan->ring_bufs_avail = 0;
377 spin_unlock_irqrestore(&chan->lock, flags);
378 err = wait_event_interruptible(*chan->vc_wq,
379 chan->ring_bufs_avail);
380 if (err == -ERESTARTSYS)
381 return err;
382
383 P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n");
Venkateswararao Jujjuri (JV)316ad552011-03-14 14:22:41 -0700384 goto req_retry_pinned;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700385 } else {
386 spin_unlock_irqrestore(&chan->lock, flags);
387 P9_DPRINTK(P9_DEBUG_TRANS,
388 "9p debug: "
389 "virtio rpc add_buf returned failure");
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800390 if (rpinfo && rpinfo->rp_alloc)
391 kfree(rpinfo);
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700392 return -EIO;
393 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600394 }
395
Michael S. Tsirkindc3f5e62010-04-13 16:11:50 +0300396 virtqueue_kick(chan->vq);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700397 spin_unlock_irqrestore(&chan->lock, flags);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600398
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500399 P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600400 return 0;
401}
402
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000403static ssize_t p9_mount_tag_show(struct device *dev,
404 struct device_attribute *attr, char *buf)
405{
406 struct virtio_chan *chan;
407 struct virtio_device *vdev;
408
409 vdev = dev_to_virtio(dev);
410 chan = vdev->priv;
411
412 return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
413}
414
415static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
416
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600417/**
418 * p9_virtio_probe - probe for existence of 9P virtio channels
419 * @vdev: virtio device to probe
420 *
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000421 * This probes for existing virtio channels.
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600422 *
423 */
424
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600425static int p9_virtio_probe(struct virtio_device *vdev)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500426{
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000427 __u16 tag_len;
428 char *tag;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500429 int err;
430 struct virtio_chan *chan;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500431
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000432 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
433 if (!chan) {
434 printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n");
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500435 err = -ENOMEM;
436 goto fail;
437 }
438
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600439 chan->vdev = vdev;
440
441 /* We expect one virtqueue, for requests. */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600442 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600443 if (IS_ERR(chan->vq)) {
444 err = PTR_ERR(chan->vq);
445 goto out_free_vq;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500446 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600447 chan->vq->vdev->priv = chan;
448 spin_lock_init(&chan->lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500449
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600450 sg_init_table(chan->sg, VIRTQUEUE_NUM);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500451
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500452 chan->inuse = false;
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000453 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
454 vdev->config->get(vdev,
455 offsetof(struct virtio_9p_config, tag_len),
456 &tag_len, sizeof(tag_len));
457 } else {
458 err = -EINVAL;
459 goto out_free_vq;
460 }
461 tag = kmalloc(tag_len, GFP_KERNEL);
462 if (!tag) {
463 err = -ENOMEM;
464 goto out_free_vq;
465 }
466 vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
467 tag, tag_len);
468 chan->tag = tag;
469 chan->tag_len = tag_len;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000470 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
471 if (err) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700472 goto out_free_tag;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000473 }
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700474 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
475 if (!chan->vc_wq) {
476 err = -ENOMEM;
477 goto out_free_tag;
478 }
479 init_waitqueue_head(chan->vc_wq);
480 chan->ring_bufs_avail = 1;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700481 /* Ceiling limit to avoid denial of service attacks */
482 chan->p9_max_pages = nr_free_buffer_pages()/4;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700483
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000484 mutex_lock(&virtio_9p_lock);
485 list_add_tail(&chan->chan_list, &virtio_chan_list);
486 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500487 return 0;
488
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700489out_free_tag:
490 kfree(tag);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600491out_free_vq:
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600492 vdev->config->del_vqs(vdev);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000493 kfree(chan);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500494fail:
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500495 return err;
496}
497
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600498
499/**
500 * p9_virtio_create - allocate a new virtio channel
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500501 * @client: client instance invoking this transport
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600502 * @devname: string identifying the channel to connect to (unused)
503 * @args: args passed from sys_mount() for per-transport options (unused)
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600504 *
505 * This sets up a transport channel for 9p communication. Right now
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500506 * we only match the first available channel, but eventually we couldlook up
507 * alternate channels by matching devname versus a virtio_config entry.
508 * We use a simple reference count mechanism to ensure that only a single
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600509 * mount has a channel open at a time.
510 *
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600511 */
512
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500513static int
514p9_virtio_create(struct p9_client *client, const char *devname, char *args)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500515{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000516 struct virtio_chan *chan;
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000517 int ret = -ENOENT;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000518 int found = 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500519
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600520 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000521 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
Sven Eckelmann0b204062010-09-27 15:54:44 -0700522 if (!strncmp(devname, chan->tag, chan->tag_len) &&
523 strlen(devname) == chan->tag_len) {
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000524 if (!chan->inuse) {
525 chan->inuse = true;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000526 found = 1;
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000527 break;
528 }
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000529 ret = -EBUSY;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500530 }
531 }
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600532 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500533
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000534 if (!found) {
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600535 printk(KERN_ERR "9p: no channels available\n");
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000536 return ret;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500537 }
538
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500539 client->trans = (void *)chan;
Eric Van Hensbergen562ada62010-01-15 18:54:03 -0600540 client->status = Connected;
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -0500541 chan->client = client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500542
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500543 return 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500544}
545
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600546/**
547 * p9_virtio_remove - clean up resources associated with a virtio device
548 * @vdev: virtio device to remove
549 *
550 */
551
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600552static void p9_virtio_remove(struct virtio_device *vdev)
553{
554 struct virtio_chan *chan = vdev->priv;
555
556 BUG_ON(chan->inuse);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000557 vdev->config->del_vqs(vdev);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600558
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000559 mutex_lock(&virtio_9p_lock);
560 list_del(&chan->chan_list);
561 mutex_unlock(&virtio_9p_lock);
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000562 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000563 kfree(chan->tag);
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700564 kfree(chan->vc_wq);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000565 kfree(chan);
566
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600567}
568
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500569static struct virtio_device_id id_table[] = {
570 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
571 { 0 },
572};
573
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000574static unsigned int features[] = {
575 VIRTIO_9P_MOUNT_TAG,
576};
577
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500578/* The standard "struct lguest_driver": */
579static struct virtio_driver p9_virtio_drv = {
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000580 .feature_table = features,
581 .feature_table_size = ARRAY_SIZE(features),
582 .driver.name = KBUILD_MODNAME,
583 .driver.owner = THIS_MODULE,
584 .id_table = id_table,
585 .probe = p9_virtio_probe,
586 .remove = p9_virtio_remove,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500587};
588
589static struct p9_trans_module p9_virtio_trans = {
590 .name = "virtio",
591 .create = p9_virtio_create,
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500592 .close = p9_virtio_close,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500593 .request = p9_virtio_request,
594 .cancel = p9_virtio_cancel,
jvrao7f781672011-06-30 23:18:41 +0000595 .maxsize = PAGE_SIZE*VIRTQUEUE_NUM,
Venkateswararao Jujjuri (JV)6f69c392011-02-06 12:08:01 -0800596 .pref = P9_TRANS_PREF_PAYLOAD_SEP,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500597 .def = 0,
Tejun Heo72029fe2008-09-24 16:22:23 -0500598 .owner = THIS_MODULE,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500599};
600
601/* The standard init function */
602static int __init p9_virtio_init(void)
603{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000604 INIT_LIST_HEAD(&virtio_chan_list);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500605
606 v9fs_register_trans(&p9_virtio_trans);
607 return register_virtio_driver(&p9_virtio_drv);
608}
609
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600610static void __exit p9_virtio_cleanup(void)
611{
612 unregister_virtio_driver(&p9_virtio_drv);
Tejun Heo72029fe2008-09-24 16:22:23 -0500613 v9fs_unregister_trans(&p9_virtio_trans);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600614}
615
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500616module_init(p9_virtio_init);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600617module_exit(p9_virtio_cleanup);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500618
619MODULE_DEVICE_TABLE(virtio, id_table);
620MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
621MODULE_DESCRIPTION("Virtio 9p Transport");
622MODULE_LICENSE("GPL");