blob: 990afab2be1bcc1732167def7eb0336e38509588 [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);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030197 /* Make sure we don't terminate early. */
198 sg_unmark_end(&sg[index]);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600199 sg_set_buf(&sg[index++], data, s);
200 count -= s;
201 data += s;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600202 }
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030203 if (index-start)
204 sg_mark_end(&sg[index - 1]);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600205 return index-start;
206}
207
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500208/* We don't currently allow canceling of virtio requests */
209static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
210{
211 return 1;
212}
213
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600214/**
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800215 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
216 * this takes a list of pages.
217 * @sg: scatter/gather list to pack into
218 * @start: which segment of the sg_list to start at
Ben Hutchings2c530402012-07-10 10:55:09 +0000219 * @pdata: a list of pages to add into sg.
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530220 * @nr_pages: number of pages to pack into the scatter/gather list
221 * @data: data to pack into scatter/gather list
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800222 * @count: amount of data to pack into the scatter/gather list
223 */
224static int
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530225pack_sg_list_p(struct scatterlist *sg, int start, int limit,
226 struct page **pdata, int nr_pages, char *data, int count)
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800227{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530228 int i = 0, s;
229 int data_off;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800230 int index = start;
231
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530232 BUG_ON(nr_pages > (limit - start));
233 /*
234 * if the first page doesn't start at
235 * page boundary find the offset
236 */
237 data_off = offset_in_page(data);
238 while (nr_pages) {
239 s = rest_of_page(data);
240 if (s > count)
241 s = count;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030242 /* Make sure we don't terminate early. */
243 sg_unmark_end(&sg[index]);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530244 sg_set_page(&sg[index++], pdata[i++], s, data_off);
245 data_off = 0;
246 data += s;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800247 count -= s;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530248 nr_pages--;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800249 }
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030250
251 if (index-start)
252 sg_mark_end(&sg[index - 1]);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530253 return index - start;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800254}
255
256/**
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500257 * p9_virtio_request - issue a request
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600258 * @client: client instance issuing the request
259 * @req: request to be issued
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600260 *
261 */
262
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600263static int
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500264p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600265{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530266 int err;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030267 int in, out, out_sgs, in_sgs;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700268 unsigned long flags;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530269 struct virtio_chan *chan = client->trans;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030270 struct scatterlist *sgs[2];
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600271
Joe Perches5d385152011-11-28 10:40:46 -0800272 p9_debug(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;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530275req_retry:
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700276 spin_lock_irqsave(&chan->lock, flags);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800277
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030278 out_sgs = in_sgs = 0;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800279 /* Handle out VirtIO ring buffers */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530280 out = pack_sg_list(chan->sg, 0,
281 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030282 if (out)
283 sgs[out_sgs++] = chan->sg;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800284
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530285 in = pack_sg_list(chan->sg, out,
286 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030287 if (in)
288 sgs[out_sgs + in_sgs++] = chan->sg + out;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600289
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030290 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
Rusty Russellf96fde42012-01-12 15:44:42 +1030291 GFP_ATOMIC);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700292 if (err < 0) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700293 if (err == -ENOSPC) {
294 chan->ring_bufs_avail = 0;
295 spin_unlock_irqrestore(&chan->lock, flags);
296 err = wait_event_interruptible(*chan->vc_wq,
297 chan->ring_bufs_avail);
298 if (err == -ERESTARTSYS)
299 return err;
300
Joe Perches5d385152011-11-28 10:40:46 -0800301 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530302 goto req_retry;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700303 } else {
304 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800305 p9_debug(P9_DEBUG_TRANS,
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030306 "virtio rpc add_sgs returned failure\n");
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700307 return -EIO;
308 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600309 }
Michael S. Tsirkindc3f5e62010-04-13 16:11:50 +0300310 virtqueue_kick(chan->vq);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700311 spin_unlock_irqrestore(&chan->lock, flags);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600312
Joe Perches5d385152011-11-28 10:40:46 -0800313 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600314 return 0;
315}
316
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530317static int p9_get_mapped_pages(struct virtio_chan *chan,
318 struct page **pages, char *data,
319 int nr_pages, int write, int kern_buf)
320{
321 int err;
322 if (!kern_buf) {
323 /*
324 * We allow only p9_max_pages pinned. We wait for the
325 * Other zc request to finish here
326 */
327 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
328 err = wait_event_interruptible(vp_wq,
329 (atomic_read(&vp_pinned) < chan->p9_max_pages));
330 if (err == -ERESTARTSYS)
331 return err;
332 }
333 err = p9_payload_gup(data, &nr_pages, pages, write);
334 if (err < 0)
335 return err;
336 atomic_add(nr_pages, &vp_pinned);
337 } else {
338 /* kernel buffer, no need to pin pages */
339 int s, index = 0;
340 int count = nr_pages;
341 while (nr_pages) {
342 s = rest_of_page(data);
Will Deaconb9cdc882012-10-19 14:03:32 +0100343 pages[index++] = kmap_to_page(data);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530344 data += s;
345 nr_pages--;
346 }
347 nr_pages = count;
348 }
349 return nr_pages;
350}
351
352/**
353 * p9_virtio_zc_request - issue a zero copy request
354 * @client: client instance issuing the request
355 * @req: request to be issued
356 * @uidata: user bffer that should be ued for zero copy read
357 * @uodata: user buffer that shoud be user for zero copy write
358 * @inlen: read buffer size
359 * @olen: write buffer size
360 * @hdrlen: reader header size, This is the size of response protocol data
361 *
362 */
363static int
364p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
365 char *uidata, char *uodata, int inlen,
366 int outlen, int in_hdr_len, int kern_buf)
367{
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030368 int in, out, err, out_sgs, in_sgs;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530369 unsigned long flags;
370 int in_nr_pages = 0, out_nr_pages = 0;
371 struct page **in_pages = NULL, **out_pages = NULL;
372 struct virtio_chan *chan = client->trans;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030373 struct scatterlist *sgs[4];
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530374
Joe Perches5d385152011-11-28 10:40:46 -0800375 p9_debug(P9_DEBUG_TRANS, "virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530376
377 if (uodata) {
378 out_nr_pages = p9_nr_pages(uodata, outlen);
379 out_pages = kmalloc(sizeof(struct page *) * out_nr_pages,
380 GFP_NOFS);
381 if (!out_pages) {
382 err = -ENOMEM;
383 goto err_out;
384 }
385 out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata,
386 out_nr_pages, 0, kern_buf);
387 if (out_nr_pages < 0) {
388 err = out_nr_pages;
389 kfree(out_pages);
390 out_pages = NULL;
391 goto err_out;
392 }
393 }
394 if (uidata) {
395 in_nr_pages = p9_nr_pages(uidata, inlen);
396 in_pages = kmalloc(sizeof(struct page *) * in_nr_pages,
397 GFP_NOFS);
398 if (!in_pages) {
399 err = -ENOMEM;
400 goto err_out;
401 }
402 in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata,
403 in_nr_pages, 1, kern_buf);
404 if (in_nr_pages < 0) {
405 err = in_nr_pages;
406 kfree(in_pages);
407 in_pages = NULL;
408 goto err_out;
409 }
410 }
411 req->status = REQ_STATUS_SENT;
412req_retry_pinned:
413 spin_lock_irqsave(&chan->lock, flags);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030414
415 out_sgs = in_sgs = 0;
416
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530417 /* out data */
418 out = pack_sg_list(chan->sg, 0,
419 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
420
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030421 if (out)
422 sgs[out_sgs++] = chan->sg;
423
424 if (out_pages) {
425 sgs[out_sgs++] = chan->sg + out;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530426 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
427 out_pages, out_nr_pages, uodata, outlen);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030428 }
429
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530430 /*
431 * Take care of in data
432 * For example TREAD have 11.
433 * 11 is the read/write header = PDU Header(7) + IO Size (4).
434 * Arrange in such a way that server places header in the
435 * alloced memory and payload onto the user buffer.
436 */
437 in = pack_sg_list(chan->sg, out,
438 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030439 if (in)
440 sgs[out_sgs + in_sgs++] = chan->sg + out;
441
442 if (in_pages) {
443 sgs[out_sgs + in_sgs++] = chan->sg + out + in;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530444 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
445 in_pages, in_nr_pages, uidata, inlen);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030446 }
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530447
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030448 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
449 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
Rusty Russellf96fde42012-01-12 15:44:42 +1030450 GFP_ATOMIC);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530451 if (err < 0) {
452 if (err == -ENOSPC) {
453 chan->ring_bufs_avail = 0;
454 spin_unlock_irqrestore(&chan->lock, flags);
455 err = wait_event_interruptible(*chan->vc_wq,
456 chan->ring_bufs_avail);
457 if (err == -ERESTARTSYS)
458 goto err_out;
459
Joe Perches5d385152011-11-28 10:40:46 -0800460 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530461 goto req_retry_pinned;
462 } else {
463 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800464 p9_debug(P9_DEBUG_TRANS,
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030465 "virtio rpc add_sgs returned failure\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530466 err = -EIO;
467 goto err_out;
468 }
469 }
470 virtqueue_kick(chan->vq);
471 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800472 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530473 err = wait_event_interruptible(*req->wq,
474 req->status >= REQ_STATUS_RCVD);
475 /*
476 * Non kernel buffers are pinned, unpin them
477 */
478err_out:
479 if (!kern_buf) {
480 if (in_pages) {
481 p9_release_pages(in_pages, in_nr_pages);
482 atomic_sub(in_nr_pages, &vp_pinned);
483 }
484 if (out_pages) {
485 p9_release_pages(out_pages, out_nr_pages);
486 atomic_sub(out_nr_pages, &vp_pinned);
487 }
488 /* wakeup anybody waiting for slots to pin pages */
489 wake_up(&vp_wq);
490 }
491 kfree(in_pages);
492 kfree(out_pages);
493 return err;
494}
495
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000496static ssize_t p9_mount_tag_show(struct device *dev,
497 struct device_attribute *attr, char *buf)
498{
499 struct virtio_chan *chan;
500 struct virtio_device *vdev;
501
502 vdev = dev_to_virtio(dev);
503 chan = vdev->priv;
504
505 return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
506}
507
508static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
509
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600510/**
511 * p9_virtio_probe - probe for existence of 9P virtio channels
512 * @vdev: virtio device to probe
513 *
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000514 * This probes for existing virtio channels.
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600515 *
516 */
517
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600518static int p9_virtio_probe(struct virtio_device *vdev)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500519{
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000520 __u16 tag_len;
521 char *tag;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500522 int err;
523 struct virtio_chan *chan;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500524
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000525 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
526 if (!chan) {
Joe Perches5d385152011-11-28 10:40:46 -0800527 pr_err("Failed to allocate virtio 9P channel\n");
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500528 err = -ENOMEM;
529 goto fail;
530 }
531
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600532 chan->vdev = vdev;
533
534 /* We expect one virtqueue, for requests. */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600535 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600536 if (IS_ERR(chan->vq)) {
537 err = PTR_ERR(chan->vq);
538 goto out_free_vq;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500539 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600540 chan->vq->vdev->priv = chan;
541 spin_lock_init(&chan->lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500542
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600543 sg_init_table(chan->sg, VIRTQUEUE_NUM);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500544
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500545 chan->inuse = false;
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000546 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
547 vdev->config->get(vdev,
548 offsetof(struct virtio_9p_config, tag_len),
549 &tag_len, sizeof(tag_len));
550 } else {
551 err = -EINVAL;
552 goto out_free_vq;
553 }
554 tag = kmalloc(tag_len, GFP_KERNEL);
555 if (!tag) {
556 err = -ENOMEM;
557 goto out_free_vq;
558 }
559 vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
560 tag, tag_len);
561 chan->tag = tag;
562 chan->tag_len = tag_len;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000563 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
564 if (err) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700565 goto out_free_tag;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000566 }
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700567 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
568 if (!chan->vc_wq) {
569 err = -ENOMEM;
570 goto out_free_tag;
571 }
572 init_waitqueue_head(chan->vc_wq);
573 chan->ring_bufs_avail = 1;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700574 /* Ceiling limit to avoid denial of service attacks */
575 chan->p9_max_pages = nr_free_buffer_pages()/4;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700576
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000577 mutex_lock(&virtio_9p_lock);
578 list_add_tail(&chan->chan_list, &virtio_chan_list);
579 mutex_unlock(&virtio_9p_lock);
Michael Marineaue0d6cb92013-08-11 00:53:45 -0400580
581 /* Let udev rules use the new mount_tag attribute. */
582 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
583
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500584 return 0;
585
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700586out_free_tag:
587 kfree(tag);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600588out_free_vq:
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600589 vdev->config->del_vqs(vdev);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000590 kfree(chan);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500591fail:
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500592 return err;
593}
594
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600595
596/**
597 * p9_virtio_create - allocate a new virtio channel
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500598 * @client: client instance invoking this transport
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600599 * @devname: string identifying the channel to connect to (unused)
600 * @args: args passed from sys_mount() for per-transport options (unused)
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600601 *
602 * This sets up a transport channel for 9p communication. Right now
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500603 * we only match the first available channel, but eventually we couldlook up
604 * alternate channels by matching devname versus a virtio_config entry.
605 * We use a simple reference count mechanism to ensure that only a single
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600606 * mount has a channel open at a time.
607 *
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600608 */
609
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500610static int
611p9_virtio_create(struct p9_client *client, const char *devname, char *args)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500612{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000613 struct virtio_chan *chan;
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000614 int ret = -ENOENT;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000615 int found = 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500616
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600617 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000618 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
Sven Eckelmann0b204062010-09-27 15:54:44 -0700619 if (!strncmp(devname, chan->tag, chan->tag_len) &&
620 strlen(devname) == chan->tag_len) {
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000621 if (!chan->inuse) {
622 chan->inuse = true;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000623 found = 1;
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000624 break;
625 }
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000626 ret = -EBUSY;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500627 }
628 }
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600629 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500630
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000631 if (!found) {
Joe Perches5d385152011-11-28 10:40:46 -0800632 pr_err("no channels available\n");
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000633 return ret;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500634 }
635
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500636 client->trans = (void *)chan;
Eric Van Hensbergen562ada62010-01-15 18:54:03 -0600637 client->status = Connected;
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -0500638 chan->client = client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500639
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500640 return 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500641}
642
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600643/**
644 * p9_virtio_remove - clean up resources associated with a virtio device
645 * @vdev: virtio device to remove
646 *
647 */
648
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600649static void p9_virtio_remove(struct virtio_device *vdev)
650{
651 struct virtio_chan *chan = vdev->priv;
652
Sasha Levin991ad9e2012-04-13 17:48:36 -0400653 if (chan->inuse)
654 p9_virtio_close(chan->client);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000655 vdev->config->del_vqs(vdev);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600656
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000657 mutex_lock(&virtio_9p_lock);
658 list_del(&chan->chan_list);
659 mutex_unlock(&virtio_9p_lock);
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000660 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
Michael Marineaue0d6cb92013-08-11 00:53:45 -0400661 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000662 kfree(chan->tag);
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700663 kfree(chan->vc_wq);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000664 kfree(chan);
665
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600666}
667
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500668static struct virtio_device_id id_table[] = {
669 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
670 { 0 },
671};
672
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000673static unsigned int features[] = {
674 VIRTIO_9P_MOUNT_TAG,
675};
676
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500677/* The standard "struct lguest_driver": */
678static struct virtio_driver p9_virtio_drv = {
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000679 .feature_table = features,
680 .feature_table_size = ARRAY_SIZE(features),
681 .driver.name = KBUILD_MODNAME,
682 .driver.owner = THIS_MODULE,
683 .id_table = id_table,
684 .probe = p9_virtio_probe,
685 .remove = p9_virtio_remove,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500686};
687
688static struct p9_trans_module p9_virtio_trans = {
689 .name = "virtio",
690 .create = p9_virtio_create,
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500691 .close = p9_virtio_close,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500692 .request = p9_virtio_request,
Arnd Bergmanndc893e12013-03-08 12:43:31 -0800693 .zc_request = p9_virtio_zc_request,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500694 .cancel = p9_virtio_cancel,
Aneesh Kumar K.Vb49d8b52011-08-17 16:56:04 +0000695 /*
696 * We leave one entry for input and one entry for response
697 * headers. We also skip one more entry to accomodate, address
698 * that are not at page boundary, that can result in an extra
699 * page in zero copy.
700 */
701 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500702 .def = 0,
Tejun Heo72029fe2008-09-24 16:22:23 -0500703 .owner = THIS_MODULE,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500704};
705
706/* The standard init function */
707static int __init p9_virtio_init(void)
708{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000709 INIT_LIST_HEAD(&virtio_chan_list);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500710
711 v9fs_register_trans(&p9_virtio_trans);
712 return register_virtio_driver(&p9_virtio_drv);
713}
714
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600715static void __exit p9_virtio_cleanup(void)
716{
717 unregister_virtio_driver(&p9_virtio_drv);
Tejun Heo72029fe2008-09-24 16:22:23 -0500718 v9fs_unregister_trans(&p9_virtio_trans);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600719}
720
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500721module_init(p9_virtio_init);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600722module_exit(p9_virtio_cleanup);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500723
724MODULE_DEVICE_TABLE(virtio, id_table);
725MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
726MODULE_DESCRIPTION("Virtio 9p Transport");
727MODULE_LICENSE("GPL");