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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
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);
Dominique Martinet2b6e72e2014-01-17 18:31:00 +0100167 p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
Venkateswararao Jujjuri (JV)a01a9842011-03-14 14:12:49 -0700168 }
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500169}
170
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600171/**
172 * pack_sg_list - pack a scatter gather list from a linear buffer
173 * @sg: scatter/gather list to pack into
174 * @start: which segment of the sg_list to start at
175 * @limit: maximum segment to pack data to
176 * @data: data to pack into scatter/gather list
177 * @count: amount of data to pack into the scatter/gather list
178 *
179 * sg_lists have multiple segments of various sizes. This will pack
180 * arbitrary data into an existing scatter gather list, segmenting the
181 * data as necessary within constraints.
182 *
183 */
184
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530185static int pack_sg_list(struct scatterlist *sg, int start,
186 int limit, char *data, int count)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600187{
188 int s;
189 int index = start;
190
191 while (count) {
192 s = rest_of_page(data);
193 if (s > count)
194 s = count;
Sasha Levin5fcb08b2012-06-11 10:18:13 -0500195 BUG_ON(index > limit);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030196 /* Make sure we don't terminate early. */
197 sg_unmark_end(&sg[index]);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600198 sg_set_buf(&sg[index++], data, s);
199 count -= s;
200 data += s;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600201 }
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030202 if (index-start)
203 sg_mark_end(&sg[index - 1]);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600204 return index-start;
205}
206
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500207/* We don't currently allow canceling of virtio requests */
208static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
209{
210 return 1;
211}
212
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600213/**
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800214 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
215 * this takes a list of pages.
216 * @sg: scatter/gather list to pack into
217 * @start: which segment of the sg_list to start at
Ben Hutchings2c530402012-07-10 10:55:09 +0000218 * @pdata: a list of pages to add into sg.
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530219 * @nr_pages: number of pages to pack into the scatter/gather list
220 * @data: data to pack into scatter/gather list
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800221 * @count: amount of data to pack into the scatter/gather list
222 */
223static int
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530224pack_sg_list_p(struct scatterlist *sg, int start, int limit,
225 struct page **pdata, int nr_pages, char *data, int count)
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800226{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530227 int i = 0, s;
228 int data_off;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800229 int index = start;
230
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530231 BUG_ON(nr_pages > (limit - start));
232 /*
233 * if the first page doesn't start at
234 * page boundary find the offset
235 */
236 data_off = offset_in_page(data);
237 while (nr_pages) {
238 s = rest_of_page(data);
239 if (s > count)
240 s = count;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030241 /* Make sure we don't terminate early. */
242 sg_unmark_end(&sg[index]);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530243 sg_set_page(&sg[index++], pdata[i++], s, data_off);
244 data_off = 0;
245 data += s;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800246 count -= s;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530247 nr_pages--;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800248 }
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030249
250 if (index-start)
251 sg_mark_end(&sg[index - 1]);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530252 return index - start;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800253}
254
255/**
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500256 * p9_virtio_request - issue a request
Abhishek Kulkarni0e155972009-07-19 13:41:55 -0600257 * @client: client instance issuing the request
258 * @req: request to be issued
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600259 *
260 */
261
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600262static int
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500263p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600264{
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530265 int err;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030266 int in, out, out_sgs, in_sgs;
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700267 unsigned long flags;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530268 struct virtio_chan *chan = client->trans;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030269 struct scatterlist *sgs[2];
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600270
Joe Perches5d385152011-11-28 10:40:46 -0800271 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600272
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700273 req->status = REQ_STATUS_SENT;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530274req_retry:
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700275 spin_lock_irqsave(&chan->lock, flags);
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800276
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030277 out_sgs = in_sgs = 0;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800278 /* Handle out VirtIO ring buffers */
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530279 out = pack_sg_list(chan->sg, 0,
280 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030281 if (out)
282 sgs[out_sgs++] = chan->sg;
Venkateswararao Jujjuri (JV)40388662011-01-28 15:22:36 -0800283
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530284 in = pack_sg_list(chan->sg, out,
285 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030286 if (in)
287 sgs[out_sgs + in_sgs++] = chan->sg + out;
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600288
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030289 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
Rusty Russellf96fde42012-01-12 15:44:42 +1030290 GFP_ATOMIC);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700291 if (err < 0) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700292 if (err == -ENOSPC) {
293 chan->ring_bufs_avail = 0;
294 spin_unlock_irqrestore(&chan->lock, flags);
295 err = wait_event_interruptible(*chan->vc_wq,
296 chan->ring_bufs_avail);
297 if (err == -ERESTARTSYS)
298 return err;
299
Joe Perches5d385152011-11-28 10:40:46 -0800300 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530301 goto req_retry;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700302 } else {
303 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800304 p9_debug(P9_DEBUG_TRANS,
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030305 "virtio rpc add_sgs returned failure\n");
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700306 return -EIO;
307 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600308 }
Michael S. Tsirkindc3f5e62010-04-13 16:11:50 +0300309 virtqueue_kick(chan->vq);
Venkateswararao Jujjuri (JV)419b3952010-09-29 18:06:54 -0700310 spin_unlock_irqrestore(&chan->lock, flags);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600311
Joe Perches5d385152011-11-28 10:40:46 -0800312 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600313 return 0;
314}
315
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530316static int p9_get_mapped_pages(struct virtio_chan *chan,
317 struct page **pages, char *data,
318 int nr_pages, int write, int kern_buf)
319{
320 int err;
321 if (!kern_buf) {
322 /*
323 * We allow only p9_max_pages pinned. We wait for the
324 * Other zc request to finish here
325 */
326 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
327 err = wait_event_interruptible(vp_wq,
328 (atomic_read(&vp_pinned) < chan->p9_max_pages));
329 if (err == -ERESTARTSYS)
330 return err;
331 }
332 err = p9_payload_gup(data, &nr_pages, pages, write);
333 if (err < 0)
334 return err;
335 atomic_add(nr_pages, &vp_pinned);
336 } else {
337 /* kernel buffer, no need to pin pages */
338 int s, index = 0;
339 int count = nr_pages;
340 while (nr_pages) {
341 s = rest_of_page(data);
Richard Yaob6f52ae2014-02-08 19:32:01 -0500342 if (is_vmalloc_addr(data))
343 pages[index++] = vmalloc_to_page(data);
344 else
345 pages[index++] = kmap_to_page(data);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530346 data += s;
347 nr_pages--;
348 }
349 nr_pages = count;
350 }
351 return nr_pages;
352}
353
354/**
355 * p9_virtio_zc_request - issue a zero copy request
356 * @client: client instance issuing the request
357 * @req: request to be issued
358 * @uidata: user bffer that should be ued for zero copy read
359 * @uodata: user buffer that shoud be user for zero copy write
360 * @inlen: read buffer size
361 * @olen: write buffer size
362 * @hdrlen: reader header size, This is the size of response protocol data
363 *
364 */
365static int
366p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
367 char *uidata, char *uodata, int inlen,
368 int outlen, int in_hdr_len, int kern_buf)
369{
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030370 int in, out, err, out_sgs, in_sgs;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530371 unsigned long flags;
372 int in_nr_pages = 0, out_nr_pages = 0;
373 struct page **in_pages = NULL, **out_pages = NULL;
374 struct virtio_chan *chan = client->trans;
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030375 struct scatterlist *sgs[4];
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530376
Joe Perches5d385152011-11-28 10:40:46 -0800377 p9_debug(P9_DEBUG_TRANS, "virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530378
379 if (uodata) {
380 out_nr_pages = p9_nr_pages(uodata, outlen);
381 out_pages = kmalloc(sizeof(struct page *) * out_nr_pages,
382 GFP_NOFS);
383 if (!out_pages) {
384 err = -ENOMEM;
385 goto err_out;
386 }
387 out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata,
388 out_nr_pages, 0, kern_buf);
389 if (out_nr_pages < 0) {
390 err = out_nr_pages;
391 kfree(out_pages);
392 out_pages = NULL;
393 goto err_out;
394 }
395 }
396 if (uidata) {
397 in_nr_pages = p9_nr_pages(uidata, inlen);
398 in_pages = kmalloc(sizeof(struct page *) * in_nr_pages,
399 GFP_NOFS);
400 if (!in_pages) {
401 err = -ENOMEM;
402 goto err_out;
403 }
404 in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata,
405 in_nr_pages, 1, kern_buf);
406 if (in_nr_pages < 0) {
407 err = in_nr_pages;
408 kfree(in_pages);
409 in_pages = NULL;
410 goto err_out;
411 }
412 }
413 req->status = REQ_STATUS_SENT;
414req_retry_pinned:
415 spin_lock_irqsave(&chan->lock, flags);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030416
417 out_sgs = in_sgs = 0;
418
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530419 /* out data */
420 out = pack_sg_list(chan->sg, 0,
421 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
422
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030423 if (out)
424 sgs[out_sgs++] = chan->sg;
425
426 if (out_pages) {
427 sgs[out_sgs++] = chan->sg + out;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530428 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
429 out_pages, out_nr_pages, uodata, outlen);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030430 }
431
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530432 /*
433 * Take care of in data
434 * For example TREAD have 11.
435 * 11 is the read/write header = PDU Header(7) + IO Size (4).
436 * Arrange in such a way that server places header in the
437 * alloced memory and payload onto the user buffer.
438 */
439 in = pack_sg_list(chan->sg, out,
440 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030441 if (in)
442 sgs[out_sgs + in_sgs++] = chan->sg + out;
443
444 if (in_pages) {
445 sgs[out_sgs + in_sgs++] = chan->sg + out + in;
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530446 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
447 in_pages, in_nr_pages, uidata, inlen);
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030448 }
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530449
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030450 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
451 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
Rusty Russellf96fde42012-01-12 15:44:42 +1030452 GFP_ATOMIC);
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530453 if (err < 0) {
454 if (err == -ENOSPC) {
455 chan->ring_bufs_avail = 0;
456 spin_unlock_irqrestore(&chan->lock, flags);
457 err = wait_event_interruptible(*chan->vc_wq,
458 chan->ring_bufs_avail);
459 if (err == -ERESTARTSYS)
460 goto err_out;
461
Joe Perches5d385152011-11-28 10:40:46 -0800462 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530463 goto req_retry_pinned;
464 } else {
465 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800466 p9_debug(P9_DEBUG_TRANS,
Rusty Russell0b36f1a2013-03-20 15:44:30 +1030467 "virtio rpc add_sgs returned failure\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530468 err = -EIO;
469 goto err_out;
470 }
471 }
472 virtqueue_kick(chan->vq);
473 spin_unlock_irqrestore(&chan->lock, flags);
Joe Perches5d385152011-11-28 10:40:46 -0800474 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
Aneesh Kumar K.Vabfa0342011-08-16 10:50:10 +0530475 err = wait_event_interruptible(*req->wq,
476 req->status >= REQ_STATUS_RCVD);
477 /*
478 * Non kernel buffers are pinned, unpin them
479 */
480err_out:
481 if (!kern_buf) {
482 if (in_pages) {
483 p9_release_pages(in_pages, in_nr_pages);
484 atomic_sub(in_nr_pages, &vp_pinned);
485 }
486 if (out_pages) {
487 p9_release_pages(out_pages, out_nr_pages);
488 atomic_sub(out_nr_pages, &vp_pinned);
489 }
490 /* wakeup anybody waiting for slots to pin pages */
491 wake_up(&vp_wq);
492 }
493 kfree(in_pages);
494 kfree(out_pages);
495 return err;
496}
497
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000498static ssize_t p9_mount_tag_show(struct device *dev,
499 struct device_attribute *attr, char *buf)
500{
501 struct virtio_chan *chan;
502 struct virtio_device *vdev;
503
504 vdev = dev_to_virtio(dev);
505 chan = vdev->priv;
506
507 return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
508}
509
510static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
511
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600512/**
513 * p9_virtio_probe - probe for existence of 9P virtio channels
514 * @vdev: virtio device to probe
515 *
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000516 * This probes for existing virtio channels.
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600517 *
518 */
519
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600520static int p9_virtio_probe(struct virtio_device *vdev)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500521{
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000522 __u16 tag_len;
523 char *tag;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500524 int err;
525 struct virtio_chan *chan;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500526
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000527 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
528 if (!chan) {
Joe Perches5d385152011-11-28 10:40:46 -0800529 pr_err("Failed to allocate virtio 9P channel\n");
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500530 err = -ENOMEM;
531 goto fail;
532 }
533
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600534 chan->vdev = vdev;
535
536 /* We expect one virtqueue, for requests. */
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600537 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600538 if (IS_ERR(chan->vq)) {
539 err = PTR_ERR(chan->vq);
540 goto out_free_vq;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500541 }
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600542 chan->vq->vdev->priv = chan;
543 spin_lock_init(&chan->lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500544
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600545 sg_init_table(chan->sg, VIRTQUEUE_NUM);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500546
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500547 chan->inuse = false;
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000548 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
Rusty Russell855e0c52013-10-14 18:11:51 +1030549 virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000550 } 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 }
Rusty Russell855e0c52013-10-14 18:11:51 +1030559
560 virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag),
561 tag, tag_len);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000562 chan->tag = tag;
563 chan->tag_len = tag_len;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000564 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
565 if (err) {
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700566 goto out_free_tag;
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000567 }
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700568 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
569 if (!chan->vc_wq) {
570 err = -ENOMEM;
571 goto out_free_tag;
572 }
573 init_waitqueue_head(chan->vc_wq);
574 chan->ring_bufs_avail = 1;
Venkateswararao Jujjuri (JV)68da9ba2011-03-18 15:49:48 -0700575 /* Ceiling limit to avoid denial of service attacks */
576 chan->p9_max_pages = nr_free_buffer_pages()/4;
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700577
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000578 mutex_lock(&virtio_9p_lock);
579 list_add_tail(&chan->chan_list, &virtio_chan_list);
580 mutex_unlock(&virtio_9p_lock);
Michael Marineaue0d6cb92013-08-11 00:53:45 -0400581
582 /* Let udev rules use the new mount_tag attribute. */
583 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
584
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500585 return 0;
586
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700587out_free_tag:
588 kfree(tag);
Eric Van Hensbergene2735b72008-02-06 19:25:58 -0600589out_free_vq:
Michael S. Tsirkind2a7ddd2009-06-12 22:16:36 -0600590 vdev->config->del_vqs(vdev);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000591 kfree(chan);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500592fail:
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500593 return err;
594}
595
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600596
597/**
598 * p9_virtio_create - allocate a new virtio channel
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500599 * @client: client instance invoking this transport
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600600 * @devname: string identifying the channel to connect to (unused)
601 * @args: args passed from sys_mount() for per-transport options (unused)
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600602 *
603 * This sets up a transport channel for 9p communication. Right now
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500604 * we only match the first available channel, but eventually we couldlook up
605 * alternate channels by matching devname versus a virtio_config entry.
606 * We use a simple reference count mechanism to ensure that only a single
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600607 * mount has a channel open at a time.
608 *
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600609 */
610
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500611static int
612p9_virtio_create(struct p9_client *client, const char *devname, char *args)
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500613{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000614 struct virtio_chan *chan;
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000615 int ret = -ENOENT;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000616 int found = 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500617
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600618 mutex_lock(&virtio_9p_lock);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000619 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
Sven Eckelmann0b204062010-09-27 15:54:44 -0700620 if (!strncmp(devname, chan->tag, chan->tag_len) &&
621 strlen(devname) == chan->tag_len) {
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000622 if (!chan->inuse) {
623 chan->inuse = true;
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000624 found = 1;
Aneesh Kumar K.Vf75580c2010-02-15 17:27:00 +0000625 break;
626 }
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000627 ret = -EBUSY;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500628 }
629 }
Josef 'Jeff' Sipekc1549492008-03-07 11:39:13 -0600630 mutex_unlock(&virtio_9p_lock);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500631
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000632 if (!found) {
Joe Perches5d385152011-11-28 10:40:46 -0800633 pr_err("no channels available\n");
Aneesh Kumar K.Vc1a7c222010-02-15 17:27:02 +0000634 return ret;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500635 }
636
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500637 client->trans = (void *)chan;
Eric Van Hensbergen562ada62010-01-15 18:54:03 -0600638 client->status = Connected;
Eric Van Hensbergenfea511a2008-10-13 18:45:23 -0500639 chan->client = client;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500640
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500641 return 0;
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500642}
643
Eric Van Hensbergenee443992008-03-05 07:08:09 -0600644/**
645 * p9_virtio_remove - clean up resources associated with a virtio device
646 * @vdev: virtio device to remove
647 *
648 */
649
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600650static void p9_virtio_remove(struct virtio_device *vdev)
651{
652 struct virtio_chan *chan = vdev->priv;
653
Sasha Levin991ad9e2012-04-13 17:48:36 -0400654 if (chan->inuse)
655 p9_virtio_close(chan->client);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000656 vdev->config->del_vqs(vdev);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600657
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000658 mutex_lock(&virtio_9p_lock);
659 list_del(&chan->chan_list);
660 mutex_unlock(&virtio_9p_lock);
Aneesh Kumar K.V86c84372010-03-06 04:44:15 +0000661 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
Michael Marineaue0d6cb92013-08-11 00:53:45 -0400662 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000663 kfree(chan->tag);
Venkateswararao Jujjuri (JV)52f44e02010-09-29 18:33:41 -0700664 kfree(chan->vc_wq);
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000665 kfree(chan);
666
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600667}
668
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500669static struct virtio_device_id id_table[] = {
670 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
671 { 0 },
672};
673
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000674static unsigned int features[] = {
675 VIRTIO_9P_MOUNT_TAG,
676};
677
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500678/* The standard "struct lguest_driver": */
679static struct virtio_driver p9_virtio_drv = {
Aneesh Kumar K.V97ee9b02010-03-06 04:44:14 +0000680 .feature_table = features,
681 .feature_table_size = ARRAY_SIZE(features),
682 .driver.name = KBUILD_MODNAME,
683 .driver.owner = THIS_MODULE,
684 .id_table = id_table,
685 .probe = p9_virtio_probe,
686 .remove = p9_virtio_remove,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500687};
688
689static struct p9_trans_module p9_virtio_trans = {
690 .name = "virtio",
691 .create = p9_virtio_create,
Eric Van Hensbergen8b81ef52008-10-13 18:45:25 -0500692 .close = p9_virtio_close,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500693 .request = p9_virtio_request,
Arnd Bergmanndc893e12013-03-08 12:43:31 -0800694 .zc_request = p9_virtio_zc_request,
Eric Van Hensbergen91b85342008-10-13 18:45:21 -0500695 .cancel = p9_virtio_cancel,
Aneesh Kumar K.Vb49d8b52011-08-17 16:56:04 +0000696 /*
697 * We leave one entry for input and one entry for response
698 * headers. We also skip one more entry to accomodate, address
699 * that are not at page boundary, that can result in an extra
700 * page in zero copy.
701 */
702 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
Eric Van Hensbergenf94741f2013-11-12 10:20:03 -0600703 .def = 1,
Tejun Heo72029fe2008-09-24 16:22:23 -0500704 .owner = THIS_MODULE,
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500705};
706
707/* The standard init function */
708static int __init p9_virtio_init(void)
709{
Aneesh Kumar K.V37c1209d42010-02-15 17:27:01 +0000710 INIT_LIST_HEAD(&virtio_chan_list);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500711
712 v9fs_register_trans(&p9_virtio_trans);
713 return register_virtio_driver(&p9_virtio_drv);
714}
715
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600716static void __exit p9_virtio_cleanup(void)
717{
718 unregister_virtio_driver(&p9_virtio_drv);
Tejun Heo72029fe2008-09-24 16:22:23 -0500719 v9fs_unregister_trans(&p9_virtio_trans);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600720}
721
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500722module_init(p9_virtio_init);
Eric Van Hensbergenf3933542008-02-06 19:25:04 -0600723module_exit(p9_virtio_cleanup);
Eric Van Hensbergenb530cc72007-10-23 13:47:31 -0500724
725MODULE_DEVICE_TABLE(virtio, id_table);
726MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
727MODULE_DESCRIPTION("Virtio 9p Transport");
728MODULE_LICENSE("GPL");