blob: de2e950a0a7a8724a06618b45334e0c544278f70 [file] [log] [blame]
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
Joe Perches5d385152011-11-28 10:40:46 -080029#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050031#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>
Will Deaconb9cdc882012-10-19 14:03:32 +010042#include <linux/highmem.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090043#include <linux/slab.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050044#include <net/9p/9p.h>
45#include <linux/parser.h>
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -050046#include <net/9p/client.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050047#include <net/9p/transport.h>
48#include <linux/scatterlist.h>
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070049#include <linux/swap.h>
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050050#include <linux/virtio.h>
51#include <linux/virtio_9p.h>
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -080052#include "trans_common.h"
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050053
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060054#define VIRTQUEUE_NUM 128
55
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050056/* a single mutex to manage channel initialization and attachment */
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -060057static DEFINE_MUTEX(virtio_9p_lock);
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070058static DECLARE_WAIT_QUEUE_HEAD(vp_wq);
59static atomic_t vp_pinned = ATOMIC_INIT(0);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050060
Eric Van Hensbergenee443992008-03-05 07:08:09 -060061/**
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
Abhishek Kulkarni0e155972009-07-19 13:41:55 -060066 * @client: client instance
Eric Van Hensbergenee443992008-03-05 07:08:09 -060067 * @vdev: virtio dev associated with this channel
68 * @vq: virtio queue associated with this channel
Eric Van Hensbergenee443992008-03-05 07:08:09 -060069 * @sg: scatter gather list which is used to pack a request (protected?)
70 *
71 * We keep all per-channel information in a structure.
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050072 * This structure is allocated within the devices dev->mem space.
73 * A pointer to the structure will get put in the transport private.
Eric Van Hensbergenee443992008-03-05 07:08:09 -060074 *
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050075 */
Eric Van Hensbergenee443992008-03-05 07:08:09 -060076
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +000077struct virtio_chan {
Eric Van Hensbergenee443992008-03-05 07:08:09 -060078 bool inuse;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050079
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060080 spinlock_t lock;
81
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -050082 struct p9_client *client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -050083 struct virtio_device *vdev;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060084 struct virtqueue *vq;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -070085 int ring_bufs_avail;
86 wait_queue_head_t *vc_wq;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -070087 /* This is global limit. Since we don't have a global structure,
88 * will be placing it in each channel.
89 */
Zhang Yanfei7293bfb2013-02-22 16:35:49 -080090 unsigned long p9_max_pages;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -060091 /* Scatterlist: can be too big for stack. */
92 struct scatterlist sg[VIRTQUEUE_NUM];
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +000093
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +000094 int tag_len;
95 /*
96 * tag name to identify a mount Non-null terminated
97 */
98 char *tag;
99
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000100 struct list_head chan_list;
101};
102
103static struct list_head virtio_chan_list;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500104
105/* How many bytes left in this page. */
106static unsigned int rest_of_page(void *data)
107{
108 return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
109}
110
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600111/**
112 * p9_virtio_close - reclaim resources of a channel
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600113 * @client: client instance
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600114 *
115 * This reclaims a channel by freeing its resources and
116 * reseting its inuse flag.
117 *
118 */
119
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500120static void p9_virtio_close(struct p9_client *client)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500121{
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500122 struct virtio_chan *chan = client->trans;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500123
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600124 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.Vfb786102010-02-08 11:50:32 +0000125 if (chan)
126 chan->inuse = false;
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600127 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500128}
129
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600130/**
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
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600143static void req_done(struct virtqueue *vq)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500144{
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600145 struct virtio_chan *chan = vq->vdev->priv;
146 struct p9_fcall *rc;
147 unsigned int len;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600148 struct p9_req_t *req;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700149 unsigned long flags;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500150
Joe Perches5d385152011-11-28 10:40:46 -0800151 p9_debug(P9_DEBUG_TRANS, ": request done\n");
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500152
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700153 while (1) {
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700154 spin_lock_irqsave(&chan->lock, flags);
155 rc = virtqueue_get_buf(chan->vq, &len);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700156 if (rc == NULL) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700157 spin_unlock_irqrestore(&chan->lock, flags);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700158 break;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700159 }
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700160 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);
Joe Perches5d385152011-11-28 10:40:46 -0800164 p9_debug(P9_DEBUG_TRANS, ": rc %p\n", rc);
165 p9_debug(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700166 req = p9_tag_lookup(chan->client, rc->tag);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700167 req->status = REQ_STATUS_RCVD;
168 p9_client_cb(chan->client, req);
169 }
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500170}
171
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600172/**
173 * pack_sg_list - pack a scatter gather list from a linear buffer
174 * @sg: scatter/gather list to pack into
175 * @start: which segment of the sg_list to start at
176 * @limit: maximum segment to pack data to
177 * @data: data to pack into scatter/gather list
178 * @count: amount of data to pack into the scatter/gather list
179 *
180 * sg_lists have multiple segments of various sizes. This will pack
181 * arbitrary data into an existing scatter gather list, segmenting the
182 * data as necessary within constraints.
183 *
184 */
185
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530186static int pack_sg_list(struct scatterlist *sg, int start,
187 int limit, char *data, int count)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600188{
189 int s;
190 int index = start;
191
192 while (count) {
193 s = rest_of_page(data);
194 if (s > count)
195 s = count;
Sasha Levin5fcb08b2012-06-11 10:18:13 -0500196 BUG_ON(index > limit);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600197 sg_set_buf(&sg[index++], data, s);
198 count -= s;
199 data += s;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600200 }
201
202 return index-start;
203}
204
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500205/* We don't currently allow canceling of virtio requests */
206static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
207{
208 return 1;
209}
210
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600211/**
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800212 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
213 * this takes a list of pages.
214 * @sg: scatter/gather list to pack into
215 * @start: which segment of the sg_list to start at
Ben Hutchings2c530402012-07-10 10:55:09 +0000216 * @pdata: a list of pages to add into sg.
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530217 * @nr_pages: number of pages to pack into the scatter/gather list
218 * @data: data to pack into scatter/gather list
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800219 * @count: amount of data to pack into the scatter/gather list
220 */
221static int
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530222pack_sg_list_p(struct scatterlist *sg, int start, int limit,
223 struct page **pdata, int nr_pages, char *data, int count)
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800224{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530225 int i = 0, s;
226 int data_off;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800227 int index = start;
228
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530229 BUG_ON(nr_pages > (limit - start));
230 /*
231 * if the first page doesn't start at
232 * page boundary find the offset
233 */
234 data_off = offset_in_page(data);
235 while (nr_pages) {
236 s = rest_of_page(data);
237 if (s > count)
238 s = count;
239 sg_set_page(&sg[index++], pdata[i++], s, data_off);
240 data_off = 0;
241 data += s;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800242 count -= s;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530243 nr_pages--;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800244 }
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530245 return index - start;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800246}
247
248/**
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500249 * p9_virtio_request - issue a request
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600250 * @client: client instance issuing the request
251 * @req: request to be issued
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600252 *
253 */
254
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600255static int
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500256p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600257{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530258 int err;
259 int in, out;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700260 unsigned long flags;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530261 struct virtio_chan *chan = client->trans;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600262
Joe Perches5d385152011-11-28 10:40:46 -0800263 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600264
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700265 req->status = REQ_STATUS_SENT;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530266req_retry:
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700267 spin_lock_irqsave(&chan->lock, flags);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800268
269 /* Handle out VirtIO ring buffers */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530270 out = pack_sg_list(chan->sg, 0,
271 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800272
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530273 in = pack_sg_list(chan->sg, out,
274 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600275
Rusty Russellf96fde42012-01-12 15:44:42 +1030276 err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc,
277 GFP_ATOMIC);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700278 if (err < 0) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700279 if (err == -ENOSPC) {
280 chan->ring_bufs_avail = 0;
281 spin_unlock_irqrestore(&chan->lock, flags);
282 err = wait_event_interruptible(*chan->vc_wq,
283 chan->ring_bufs_avail);
284 if (err == -ERESTARTSYS)
285 return err;
286
Joe Perches5d385152011-11-28 10:40:46 -0800287 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530288 goto req_retry;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700289 } else {
290 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800291 p9_debug(P9_DEBUG_TRANS,
292 "virtio rpc add_buf returned failure\n");
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700293 return -EIO;
294 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600295 }
Michael S. Tsirkindc3f5e62010-04-13 16:11:50 +0300296 virtqueue_kick(chan->vq);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700297 spin_unlock_irqrestore(&chan->lock, flags);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600298
Joe Perches5d385152011-11-28 10:40:46 -0800299 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600300 return 0;
301}
302
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530303static int p9_get_mapped_pages(struct virtio_chan *chan,
304 struct page **pages, char *data,
305 int nr_pages, int write, int kern_buf)
306{
307 int err;
308 if (!kern_buf) {
309 /*
310 * We allow only p9_max_pages pinned. We wait for the
311 * Other zc request to finish here
312 */
313 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
314 err = wait_event_interruptible(vp_wq,
315 (atomic_read(&vp_pinned) < chan->p9_max_pages));
316 if (err == -ERESTARTSYS)
317 return err;
318 }
319 err = p9_payload_gup(data, &nr_pages, pages, write);
320 if (err < 0)
321 return err;
322 atomic_add(nr_pages, &vp_pinned);
323 } else {
324 /* kernel buffer, no need to pin pages */
325 int s, index = 0;
326 int count = nr_pages;
327 while (nr_pages) {
328 s = rest_of_page(data);
Will Deaconb9cdc882012-10-19 14:03:32 +0100329 pages[index++] = kmap_to_page(data);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530330 data += s;
331 nr_pages--;
332 }
333 nr_pages = count;
334 }
335 return nr_pages;
336}
337
338/**
339 * p9_virtio_zc_request - issue a zero copy request
340 * @client: client instance issuing the request
341 * @req: request to be issued
342 * @uidata: user bffer that should be ued for zero copy read
343 * @uodata: user buffer that shoud be user for zero copy write
344 * @inlen: read buffer size
345 * @olen: write buffer size
346 * @hdrlen: reader header size, This is the size of response protocol data
347 *
348 */
349static int
350p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
351 char *uidata, char *uodata, int inlen,
352 int outlen, int in_hdr_len, int kern_buf)
353{
354 int in, out, err;
355 unsigned long flags;
356 int in_nr_pages = 0, out_nr_pages = 0;
357 struct page **in_pages = NULL, **out_pages = NULL;
358 struct virtio_chan *chan = client->trans;
359
Joe Perches5d385152011-11-28 10:40:46 -0800360 p9_debug(P9_DEBUG_TRANS, "virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530361
362 if (uodata) {
363 out_nr_pages = p9_nr_pages(uodata, outlen);
364 out_pages = kmalloc(sizeof(struct page *) * out_nr_pages,
365 GFP_NOFS);
366 if (!out_pages) {
367 err = -ENOMEM;
368 goto err_out;
369 }
370 out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata,
371 out_nr_pages, 0, kern_buf);
372 if (out_nr_pages < 0) {
373 err = out_nr_pages;
374 kfree(out_pages);
375 out_pages = NULL;
376 goto err_out;
377 }
378 }
379 if (uidata) {
380 in_nr_pages = p9_nr_pages(uidata, inlen);
381 in_pages = kmalloc(sizeof(struct page *) * in_nr_pages,
382 GFP_NOFS);
383 if (!in_pages) {
384 err = -ENOMEM;
385 goto err_out;
386 }
387 in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata,
388 in_nr_pages, 1, kern_buf);
389 if (in_nr_pages < 0) {
390 err = in_nr_pages;
391 kfree(in_pages);
392 in_pages = NULL;
393 goto err_out;
394 }
395 }
396 req->status = REQ_STATUS_SENT;
397req_retry_pinned:
398 spin_lock_irqsave(&chan->lock, flags);
399 /* out data */
400 out = pack_sg_list(chan->sg, 0,
401 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
402
403 if (out_pages)
404 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
405 out_pages, out_nr_pages, uodata, outlen);
406 /*
407 * Take care of in data
408 * For example TREAD have 11.
409 * 11 is the read/write header = PDU Header(7) + IO Size (4).
410 * Arrange in such a way that server places header in the
411 * alloced memory and payload onto the user buffer.
412 */
413 in = pack_sg_list(chan->sg, out,
414 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
415 if (in_pages)
416 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
417 in_pages, in_nr_pages, uidata, inlen);
418
Rusty Russellf96fde42012-01-12 15:44:42 +1030419 err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc,
420 GFP_ATOMIC);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530421 if (err < 0) {
422 if (err == -ENOSPC) {
423 chan->ring_bufs_avail = 0;
424 spin_unlock_irqrestore(&chan->lock, flags);
425 err = wait_event_interruptible(*chan->vc_wq,
426 chan->ring_bufs_avail);
427 if (err == -ERESTARTSYS)
428 goto err_out;
429
Joe Perches5d385152011-11-28 10:40:46 -0800430 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530431 goto req_retry_pinned;
432 } else {
433 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800434 p9_debug(P9_DEBUG_TRANS,
435 "virtio rpc add_buf returned failure\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530436 err = -EIO;
437 goto err_out;
438 }
439 }
440 virtqueue_kick(chan->vq);
441 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800442 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530443 err = wait_event_interruptible(*req->wq,
444 req->status >= REQ_STATUS_RCVD);
445 /*
446 * Non kernel buffers are pinned, unpin them
447 */
448err_out:
449 if (!kern_buf) {
450 if (in_pages) {
451 p9_release_pages(in_pages, in_nr_pages);
452 atomic_sub(in_nr_pages, &vp_pinned);
453 }
454 if (out_pages) {
455 p9_release_pages(out_pages, out_nr_pages);
456 atomic_sub(out_nr_pages, &vp_pinned);
457 }
458 /* wakeup anybody waiting for slots to pin pages */
459 wake_up(&vp_wq);
460 }
461 kfree(in_pages);
462 kfree(out_pages);
463 return err;
464}
465
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000466static ssize_t p9_mount_tag_show(struct device *dev,
467 struct device_attribute *attr, char *buf)
468{
469 struct virtio_chan *chan;
470 struct virtio_device *vdev;
471
472 vdev = dev_to_virtio(dev);
473 chan = vdev->priv;
474
475 return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
476}
477
478static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
479
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600480/**
481 * p9_virtio_probe - probe for existence of 9P virtio channels
482 * @vdev: virtio device to probe
483 *
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000484 * This probes for existing virtio channels.
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600485 *
486 */
487
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600488static int p9_virtio_probe(struct virtio_device *vdev)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500489{
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000490 __u16 tag_len;
491 char *tag;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500492 int err;
493 struct virtio_chan *chan;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500494
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000495 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
496 if (!chan) {
Joe Perches5d385152011-11-28 10:40:46 -0800497 pr_err("Failed to allocate virtio 9P channel\n");
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500498 err = -ENOMEM;
499 goto fail;
500 }
501
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600502 chan->vdev = vdev;
503
504 /* We expect one virtqueue, for requests. */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600505 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600506 if (IS_ERR(chan->vq)) {
507 err = PTR_ERR(chan->vq);
508 goto out_free_vq;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500509 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600510 chan->vq->vdev->priv = chan;
511 spin_lock_init(&chan->lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500512
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600513 sg_init_table(chan->sg, VIRTQUEUE_NUM);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500514
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500515 chan->inuse = false;
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000516 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
517 vdev->config->get(vdev,
518 offsetof(struct virtio_9p_config, tag_len),
519 &tag_len, sizeof(tag_len));
520 } else {
521 err = -EINVAL;
522 goto out_free_vq;
523 }
524 tag = kmalloc(tag_len, GFP_KERNEL);
525 if (!tag) {
526 err = -ENOMEM;
527 goto out_free_vq;
528 }
529 vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
530 tag, tag_len);
531 chan->tag = tag;
532 chan->tag_len = tag_len;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000533 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
534 if (err) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700535 goto out_free_tag;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000536 }
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700537 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
538 if (!chan->vc_wq) {
539 err = -ENOMEM;
540 goto out_free_tag;
541 }
542 init_waitqueue_head(chan->vc_wq);
543 chan->ring_bufs_avail = 1;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700544 /* Ceiling limit to avoid denial of service attacks */
545 chan->p9_max_pages = nr_free_buffer_pages()/4;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700546
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000547 mutex_lock(&virtio_9p_lock);
548 list_add_tail(&chan->chan_list, &virtio_chan_list);
549 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500550 return 0;
551
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700552out_free_tag:
553 kfree(tag);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600554out_free_vq:
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600555 vdev->config->del_vqs(vdev);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000556 kfree(chan);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500557fail:
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500558 return err;
559}
560
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600561
562/**
563 * p9_virtio_create - allocate a new virtio channel
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500564 * @client: client instance invoking this transport
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600565 * @devname: string identifying the channel to connect to (unused)
566 * @args: args passed from sys_mount() for per-transport options (unused)
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600567 *
568 * This sets up a transport channel for 9p communication. Right now
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500569 * we only match the first available channel, but eventually we couldlook up
570 * alternate channels by matching devname versus a virtio_config entry.
571 * We use a simple reference count mechanism to ensure that only a single
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600572 * mount has a channel open at a time.
573 *
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600574 */
575
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500576static int
577p9_virtio_create(struct p9_client *client, const char *devname, char *args)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500578{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000579 struct virtio_chan *chan;
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000580 int ret = -ENOENT;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000581 int found = 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500582
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600583 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000584 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
Sven Eckelmann0b204062010-09-27 15:54:44 -0700585 if (!strncmp(devname, chan->tag, chan->tag_len) &&
586 strlen(devname) == chan->tag_len) {
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000587 if (!chan->inuse) {
588 chan->inuse = true;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000589 found = 1;
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000590 break;
591 }
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000592 ret = -EBUSY;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500593 }
594 }
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600595 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500596
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000597 if (!found) {
Joe Perches5d385152011-11-28 10:40:46 -0800598 pr_err("no channels available\n");
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000599 return ret;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500600 }
601
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500602 client->trans = (void *)chan;
Eric Van Hensbergen562ada62010-01-15 18:54:03 -0600603 client->status = Connected;
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -0500604 chan->client = client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500605
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500606 return 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500607}
608
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600609/**
610 * p9_virtio_remove - clean up resources associated with a virtio device
611 * @vdev: virtio device to remove
612 *
613 */
614
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600615static void p9_virtio_remove(struct virtio_device *vdev)
616{
617 struct virtio_chan *chan = vdev->priv;
618
Sasha Levin991ad9e2012-04-13 17:48:36 -0400619 if (chan->inuse)
620 p9_virtio_close(chan->client);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000621 vdev->config->del_vqs(vdev);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600622
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000623 mutex_lock(&virtio_9p_lock);
624 list_del(&chan->chan_list);
625 mutex_unlock(&virtio_9p_lock);
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000626 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000627 kfree(chan->tag);
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700628 kfree(chan->vc_wq);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000629 kfree(chan);
630
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600631}
632
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500633static struct virtio_device_id id_table[] = {
634 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
635 { 0 },
636};
637
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000638static unsigned int features[] = {
639 VIRTIO_9P_MOUNT_TAG,
640};
641
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500642/* The standard "struct lguest_driver": */
643static struct virtio_driver p9_virtio_drv = {
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000644 .feature_table = features,
645 .feature_table_size = ARRAY_SIZE(features),
646 .driver.name = KBUILD_MODNAME,
647 .driver.owner = THIS_MODULE,
648 .id_table = id_table,
649 .probe = p9_virtio_probe,
650 .remove = p9_virtio_remove,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500651};
652
653static struct p9_trans_module p9_virtio_trans = {
654 .name = "virtio",
655 .create = p9_virtio_create,
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500656 .close = p9_virtio_close,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500657 .request = p9_virtio_request,
Arnd Bergmanndc893e12013-03-08 12:43:31 -0800658 .zc_request = p9_virtio_zc_request,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500659 .cancel = p9_virtio_cancel,
Aneesh Kumar K.Vb49d8b52011-08-17 16:56:04 +0000660 /*
661 * We leave one entry for input and one entry for response
662 * headers. We also skip one more entry to accomodate, address
663 * that are not at page boundary, that can result in an extra
664 * page in zero copy.
665 */
666 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500667 .def = 0,
Tejun Heo72029fe2008-09-24 16:22:23 -0500668 .owner = THIS_MODULE,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500669};
670
671/* The standard init function */
672static int __init p9_virtio_init(void)
673{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000674 INIT_LIST_HEAD(&virtio_chan_list);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500675
676 v9fs_register_trans(&p9_virtio_trans);
677 return register_virtio_driver(&p9_virtio_drv);
678}
679
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600680static void __exit p9_virtio_cleanup(void)
681{
682 unregister_virtio_driver(&p9_virtio_drv);
Tejun Heo72029fe2008-09-24 16:22:23 -0500683 v9fs_unregister_trans(&p9_virtio_trans);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600684}
685
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500686module_init(p9_virtio_init);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600687module_exit(p9_virtio_cleanup);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500688
689MODULE_DEVICE_TABLE(virtio, id_table);
690MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
691MODULE_DESCRIPTION("Virtio 9p Transport");
692MODULE_LICENSE("GPL");