1 /*
2 * The Virtio 9p transport driver
3 *
4 * This is a block based transport driver based on the lguest block driver
5 * code.
6 *
7 * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation
8 *
9 * Based on virtio console driver
10 * Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to:
23 * Free Software Foundation
24 * 51 Franklin Street, Fifth Floor
25 * Boston, MA 02111-1301 USA
26 *
27 */
28
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31 #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>
42 #include <linux/highmem.h>
43 #include <linux/slab.h>
44 #include <net/9p/9p.h>
45 #include <linux/parser.h>
46 #include <net/9p/client.h>
47 #include <net/9p/transport.h>
48 #include <linux/scatterlist.h>
49 #include <linux/swap.h>
50 #include <linux/virtio.h>
51 #include <linux/virtio_9p.h>
52 #include "trans_common.h"
53
54 #define VIRTQUEUE_NUM 128
55
56 /* a single mutex to manage channel initialization and attachment */
57 static DEFINE_MUTEX(virtio_9p_lock);
58 static DECLARE_WAIT_QUEUE_HEAD(vp_wq);
59 static atomic_t vp_pinned = ATOMIC_INIT(0);
60
61 /**
62 * struct virtio_chan - per-instance transport information
63 * @inuse: whether the channel is in use
64 * @lock: protects multiple elements within this structure
65 * @client: client instance
66 * @vdev: virtio dev associated with this channel
67 * @vq: virtio queue associated with this channel
68 * @sg: scatter gather list which is used to pack a request (protected?)
69 *
70 * We keep all per-channel information in a structure.
71 * This structure is allocated within the devices dev->mem space.
72 * A pointer to the structure will get put in the transport private.
73 *
74 */
75
76 struct virtio_chan {
77 bool inuse;
78
79 spinlock_t lock;
80
81 struct p9_client *client;
82 struct virtio_device *vdev;
83 struct virtqueue *vq;
84 int ring_bufs_avail;
85 wait_queue_head_t *vc_wq;
86 /* This is global limit. Since we don't have a global structure,
87 * will be placing it in each channel.
88 */
89 unsigned long p9_max_pages;
90 /* Scatterlist: can be too big for stack. */
91 struct scatterlist sg[VIRTQUEUE_NUM];
92 /*
93 * tag name to identify a mount null terminated
94 */
95 char *tag;
96
97 struct list_head chan_list;
98 };
99
100 static struct list_head virtio_chan_list;
101
102 /* How many bytes left in this page. */
rest_of_page(void * data)103 static unsigned int rest_of_page(void *data)
104 {
105 return PAGE_SIZE - offset_in_page(data);
106 }
107
108 /**
109 * p9_virtio_close - reclaim resources of a channel
110 * @client: client instance
111 *
112 * This reclaims a channel by freeing its resources and
113 * reseting its inuse flag.
114 *
115 */
116
p9_virtio_close(struct p9_client * client)117 static void p9_virtio_close(struct p9_client *client)
118 {
119 struct virtio_chan *chan = client->trans;
120
121 mutex_lock(&virtio_9p_lock);
122 if (chan)
123 chan->inuse = false;
124 mutex_unlock(&virtio_9p_lock);
125 }
126
127 /**
128 * req_done - callback which signals activity from the server
129 * @vq: virtio queue activity was received on
130 *
131 * This notifies us that the server has triggered some activity
132 * on the virtio channel - most likely a response to request we
133 * sent. Figure out which requests now have responses and wake up
134 * those threads.
135 *
136 * Bugs: could do with some additional sanity checking, but appears to work.
137 *
138 */
139
req_done(struct virtqueue * vq)140 static void req_done(struct virtqueue *vq)
141 {
142 struct virtio_chan *chan = vq->vdev->priv;
143 unsigned int len;
144 struct p9_req_t *req;
145 bool need_wakeup = false;
146 unsigned long flags;
147
148 p9_debug(P9_DEBUG_TRANS, ": request done\n");
149
150 spin_lock_irqsave(&chan->lock, flags);
151 while ((req = virtqueue_get_buf(chan->vq, &len)) != NULL) {
152 if (!chan->ring_bufs_avail) {
153 chan->ring_bufs_avail = 1;
154 need_wakeup = true;
155 }
156
157 if (len) {
158 req->rc->size = len;
159 p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
160 }
161 }
162 spin_unlock_irqrestore(&chan->lock, flags);
163 /* Wakeup if anyone waiting for VirtIO ring space. */
164 if (need_wakeup)
165 wake_up(chan->vc_wq);
166 }
167
168 /**
169 * pack_sg_list - pack a scatter gather list from a linear buffer
170 * @sg: scatter/gather list to pack into
171 * @start: which segment of the sg_list to start at
172 * @limit: maximum segment to pack data to
173 * @data: data to pack into scatter/gather list
174 * @count: amount of data to pack into the scatter/gather list
175 *
176 * sg_lists have multiple segments of various sizes. This will pack
177 * arbitrary data into an existing scatter gather list, segmenting the
178 * data as necessary within constraints.
179 *
180 */
181
pack_sg_list(struct scatterlist * sg,int start,int limit,char * data,int count)182 static int pack_sg_list(struct scatterlist *sg, int start,
183 int limit, char *data, int count)
184 {
185 int s;
186 int index = start;
187
188 while (count) {
189 s = rest_of_page(data);
190 if (s > count)
191 s = count;
192 BUG_ON(index >= limit);
193 /* Make sure we don't terminate early. */
194 sg_unmark_end(&sg[index]);
195 sg_set_buf(&sg[index++], data, s);
196 count -= s;
197 data += s;
198 }
199 if (index-start)
200 sg_mark_end(&sg[index - 1]);
201 return index-start;
202 }
203
204 /* We don't currently allow canceling of virtio requests */
p9_virtio_cancel(struct p9_client * client,struct p9_req_t * req)205 static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
206 {
207 return 1;
208 }
209
210 /**
211 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
212 * this takes a list of pages.
213 * @sg: scatter/gather list to pack into
214 * @start: which segment of the sg_list to start at
215 * @pdata: a list of pages to add into sg.
216 * @nr_pages: number of pages to pack into the scatter/gather list
217 * @offs: amount of data in the beginning of first page _not_ to pack
218 * @count: amount of data to pack into the scatter/gather list
219 */
220 static int
pack_sg_list_p(struct scatterlist * sg,int start,int limit,struct page ** pdata,int nr_pages,size_t offs,int count)221 pack_sg_list_p(struct scatterlist *sg, int start, int limit,
222 struct page **pdata, int nr_pages, size_t offs, int count)
223 {
224 int i = 0, s;
225 int data_off = offs;
226 int index = start;
227
228 BUG_ON(nr_pages > (limit - start));
229 /*
230 * if the first page doesn't start at
231 * page boundary find the offset
232 */
233 while (nr_pages) {
234 s = PAGE_SIZE - data_off;
235 if (s > count)
236 s = count;
237 BUG_ON(index >= limit);
238 /* Make sure we don't terminate early. */
239 sg_unmark_end(&sg[index]);
240 sg_set_page(&sg[index++], pdata[i++], s, data_off);
241 data_off = 0;
242 count -= s;
243 nr_pages--;
244 }
245
246 if (index-start)
247 sg_mark_end(&sg[index - 1]);
248 return index - start;
249 }
250
251 /**
252 * p9_virtio_request - issue a request
253 * @client: client instance issuing the request
254 * @req: request to be issued
255 *
256 */
257
258 static int
p9_virtio_request(struct p9_client * client,struct p9_req_t * req)259 p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
260 {
261 int err;
262 int in, out, out_sgs, in_sgs;
263 unsigned long flags;
264 struct virtio_chan *chan = client->trans;
265 struct scatterlist *sgs[2];
266
267 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");
268
269 req->status = REQ_STATUS_SENT;
270 req_retry:
271 spin_lock_irqsave(&chan->lock, flags);
272
273 out_sgs = in_sgs = 0;
274 /* Handle out VirtIO ring buffers */
275 out = pack_sg_list(chan->sg, 0,
276 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
277 if (out)
278 sgs[out_sgs++] = chan->sg;
279
280 in = pack_sg_list(chan->sg, out,
281 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
282 if (in)
283 sgs[out_sgs + in_sgs++] = chan->sg + out;
284
285 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,
286 GFP_ATOMIC);
287 if (err < 0) {
288 if (err == -ENOSPC) {
289 chan->ring_bufs_avail = 0;
290 spin_unlock_irqrestore(&chan->lock, flags);
291 err = wait_event_killable(*chan->vc_wq,
292 chan->ring_bufs_avail);
293 if (err == -ERESTARTSYS)
294 return err;
295
296 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
297 goto req_retry;
298 } else {
299 spin_unlock_irqrestore(&chan->lock, flags);
300 p9_debug(P9_DEBUG_TRANS,
301 "virtio rpc add_sgs returned failure\n");
302 return -EIO;
303 }
304 }
305 virtqueue_kick(chan->vq);
306 spin_unlock_irqrestore(&chan->lock, flags);
307
308 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
309 return 0;
310 }
311
p9_get_mapped_pages(struct virtio_chan * chan,struct page *** pages,struct iov_iter * data,int count,size_t * offs,int * need_drop)312 static int p9_get_mapped_pages(struct virtio_chan *chan,
313 struct page ***pages,
314 struct iov_iter *data,
315 int count,
316 size_t *offs,
317 int *need_drop)
318 {
319 int nr_pages;
320 int err;
321
322 if (!iov_iter_count(data))
323 return 0;
324
325 if (!(data->type & ITER_KVEC)) {
326 int n;
327 /*
328 * We allow only p9_max_pages pinned. We wait for the
329 * Other zc request to finish here
330 */
331 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
332 err = wait_event_killable(vp_wq,
333 (atomic_read(&vp_pinned) < chan->p9_max_pages));
334 if (err == -ERESTARTSYS)
335 return err;
336 }
337 n = iov_iter_get_pages_alloc(data, pages, count, offs);
338 if (n < 0)
339 return n;
340 *need_drop = 1;
341 nr_pages = DIV_ROUND_UP(n + *offs, PAGE_SIZE);
342 atomic_add(nr_pages, &vp_pinned);
343 return n;
344 } else {
345 /* kernel buffer, no need to pin pages */
346 int index;
347 size_t len;
348 void *p;
349
350 /* we'd already checked that it's non-empty */
351 while (1) {
352 len = iov_iter_single_seg_count(data);
353 if (likely(len)) {
354 p = data->kvec->iov_base + data->iov_offset;
355 break;
356 }
357 iov_iter_advance(data, 0);
358 }
359 if (len > count)
360 len = count;
361
362 nr_pages = DIV_ROUND_UP((unsigned long)p + len, PAGE_SIZE) -
363 (unsigned long)p / PAGE_SIZE;
364
365 *pages = kmalloc_array(nr_pages, sizeof(struct page *),
366 GFP_NOFS);
367 if (!*pages)
368 return -ENOMEM;
369
370 *need_drop = 0;
371 p -= (*offs = offset_in_page(p));
372 for (index = 0; index < nr_pages; index++) {
373 if (is_vmalloc_addr(p))
374 (*pages)[index] = vmalloc_to_page(p);
375 else
376 (*pages)[index] = kmap_to_page(p);
377 p += PAGE_SIZE;
378 }
379 return len;
380 }
381 }
382
383 /**
384 * p9_virtio_zc_request - issue a zero copy request
385 * @client: client instance issuing the request
386 * @req: request to be issued
387 * @uidata: user buffer that should be used for zero copy read
388 * @uodata: user buffer that should be used for zero copy write
389 * @inlen: read buffer size
390 * @outlen: write buffer size
391 * @in_hdr_len: reader header size, This is the size of response protocol data
392 *
393 */
394 static int
p9_virtio_zc_request(struct p9_client * client,struct p9_req_t * req,struct iov_iter * uidata,struct iov_iter * uodata,int inlen,int outlen,int in_hdr_len)395 p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
396 struct iov_iter *uidata, struct iov_iter *uodata,
397 int inlen, int outlen, int in_hdr_len)
398 {
399 int in, out, err, out_sgs, in_sgs;
400 unsigned long flags;
401 int in_nr_pages = 0, out_nr_pages = 0;
402 struct page **in_pages = NULL, **out_pages = NULL;
403 struct virtio_chan *chan = client->trans;
404 struct scatterlist *sgs[4];
405 size_t offs;
406 int need_drop = 0;
407
408 p9_debug(P9_DEBUG_TRANS, "virtio request\n");
409
410 if (uodata) {
411 __le32 sz;
412 int n = p9_get_mapped_pages(chan, &out_pages, uodata,
413 outlen, &offs, &need_drop);
414 if (n < 0)
415 return n;
416 out_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
417 if (n != outlen) {
418 __le32 v = cpu_to_le32(n);
419 memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
420 outlen = n;
421 }
422 /* The size field of the message must include the length of the
423 * header and the length of the data. We didn't actually know
424 * the length of the data until this point so add it in now.
425 */
426 sz = cpu_to_le32(req->tc->size + outlen);
427 memcpy(&req->tc->sdata[0], &sz, sizeof(sz));
428 } else if (uidata) {
429 int n = p9_get_mapped_pages(chan, &in_pages, uidata,
430 inlen, &offs, &need_drop);
431 if (n < 0)
432 return n;
433 in_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
434 if (n != inlen) {
435 __le32 v = cpu_to_le32(n);
436 memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
437 inlen = n;
438 }
439 }
440 req->status = REQ_STATUS_SENT;
441 req_retry_pinned:
442 spin_lock_irqsave(&chan->lock, flags);
443
444 out_sgs = in_sgs = 0;
445
446 /* out data */
447 out = pack_sg_list(chan->sg, 0,
448 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
449
450 if (out)
451 sgs[out_sgs++] = chan->sg;
452
453 if (out_pages) {
454 sgs[out_sgs++] = chan->sg + out;
455 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
456 out_pages, out_nr_pages, offs, outlen);
457 }
458
459 /*
460 * Take care of in data
461 * For example TREAD have 11.
462 * 11 is the read/write header = PDU Header(7) + IO Size (4).
463 * Arrange in such a way that server places header in the
464 * alloced memory and payload onto the user buffer.
465 */
466 in = pack_sg_list(chan->sg, out,
467 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
468 if (in)
469 sgs[out_sgs + in_sgs++] = chan->sg + out;
470
471 if (in_pages) {
472 sgs[out_sgs + in_sgs++] = chan->sg + out + in;
473 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
474 in_pages, in_nr_pages, offs, inlen);
475 }
476
477 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
478 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,
479 GFP_ATOMIC);
480 if (err < 0) {
481 if (err == -ENOSPC) {
482 chan->ring_bufs_avail = 0;
483 spin_unlock_irqrestore(&chan->lock, flags);
484 err = wait_event_killable(*chan->vc_wq,
485 chan->ring_bufs_avail);
486 if (err == -ERESTARTSYS)
487 goto err_out;
488
489 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
490 goto req_retry_pinned;
491 } else {
492 spin_unlock_irqrestore(&chan->lock, flags);
493 p9_debug(P9_DEBUG_TRANS,
494 "virtio rpc add_sgs returned failure\n");
495 err = -EIO;
496 goto err_out;
497 }
498 }
499 virtqueue_kick(chan->vq);
500 spin_unlock_irqrestore(&chan->lock, flags);
501 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
502 err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
503 /*
504 * Non kernel buffers are pinned, unpin them
505 */
506 err_out:
507 if (need_drop) {
508 if (in_pages) {
509 p9_release_pages(in_pages, in_nr_pages);
510 atomic_sub(in_nr_pages, &vp_pinned);
511 }
512 if (out_pages) {
513 p9_release_pages(out_pages, out_nr_pages);
514 atomic_sub(out_nr_pages, &vp_pinned);
515 }
516 /* wakeup anybody waiting for slots to pin pages */
517 wake_up(&vp_wq);
518 }
519 kvfree(in_pages);
520 kvfree(out_pages);
521 return err;
522 }
523
p9_mount_tag_show(struct device * dev,struct device_attribute * attr,char * buf)524 static ssize_t p9_mount_tag_show(struct device *dev,
525 struct device_attribute *attr, char *buf)
526 {
527 struct virtio_chan *chan;
528 struct virtio_device *vdev;
529 int tag_len;
530
531 vdev = dev_to_virtio(dev);
532 chan = vdev->priv;
533 tag_len = strlen(chan->tag);
534
535 memcpy(buf, chan->tag, tag_len + 1);
536
537 return tag_len + 1;
538 }
539
540 static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
541
542 /**
543 * p9_virtio_probe - probe for existence of 9P virtio channels
544 * @vdev: virtio device to probe
545 *
546 * This probes for existing virtio channels.
547 *
548 */
549
p9_virtio_probe(struct virtio_device * vdev)550 static int p9_virtio_probe(struct virtio_device *vdev)
551 {
552 __u16 tag_len;
553 char *tag;
554 int err;
555 struct virtio_chan *chan;
556
557 if (!vdev->config->get) {
558 dev_err(&vdev->dev, "%s failure: config access disabled\n",
559 __func__);
560 return -EINVAL;
561 }
562
563 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
564 if (!chan) {
565 pr_err("Failed to allocate virtio 9P channel\n");
566 err = -ENOMEM;
567 goto fail;
568 }
569
570 chan->vdev = vdev;
571
572 /* We expect one virtqueue, for requests. */
573 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
574 if (IS_ERR(chan->vq)) {
575 err = PTR_ERR(chan->vq);
576 goto out_free_chan;
577 }
578 chan->vq->vdev->priv = chan;
579 spin_lock_init(&chan->lock);
580
581 sg_init_table(chan->sg, VIRTQUEUE_NUM);
582
583 chan->inuse = false;
584 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
585 virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len);
586 } else {
587 err = -EINVAL;
588 goto out_free_vq;
589 }
590 tag = kzalloc(tag_len + 1, GFP_KERNEL);
591 if (!tag) {
592 err = -ENOMEM;
593 goto out_free_vq;
594 }
595
596 virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag),
597 tag, tag_len);
598 chan->tag = tag;
599 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
600 if (err) {
601 goto out_free_tag;
602 }
603 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
604 if (!chan->vc_wq) {
605 err = -ENOMEM;
606 goto out_free_tag;
607 }
608 init_waitqueue_head(chan->vc_wq);
609 chan->ring_bufs_avail = 1;
610 /* Ceiling limit to avoid denial of service attacks */
611 chan->p9_max_pages = nr_free_buffer_pages()/4;
612
613 virtio_device_ready(vdev);
614
615 mutex_lock(&virtio_9p_lock);
616 list_add_tail(&chan->chan_list, &virtio_chan_list);
617 mutex_unlock(&virtio_9p_lock);
618
619 /* Let udev rules use the new mount_tag attribute. */
620 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
621
622 return 0;
623
624 out_free_tag:
625 kfree(tag);
626 out_free_vq:
627 vdev->config->del_vqs(vdev);
628 out_free_chan:
629 kfree(chan);
630 fail:
631 return err;
632 }
633
634
635 /**
636 * p9_virtio_create - allocate a new virtio channel
637 * @client: client instance invoking this transport
638 * @devname: string identifying the channel to connect to (unused)
639 * @args: args passed from sys_mount() for per-transport options (unused)
640 *
641 * This sets up a transport channel for 9p communication. Right now
642 * we only match the first available channel, but eventually we couldlook up
643 * alternate channels by matching devname versus a virtio_config entry.
644 * We use a simple reference count mechanism to ensure that only a single
645 * mount has a channel open at a time.
646 *
647 */
648
649 static int
p9_virtio_create(struct p9_client * client,const char * devname,char * args)650 p9_virtio_create(struct p9_client *client, const char *devname, char *args)
651 {
652 struct virtio_chan *chan;
653 int ret = -ENOENT;
654 int found = 0;
655
656 if (devname == NULL)
657 return -EINVAL;
658
659 mutex_lock(&virtio_9p_lock);
660 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
661 if (!strcmp(devname, chan->tag)) {
662 if (!chan->inuse) {
663 chan->inuse = true;
664 found = 1;
665 break;
666 }
667 ret = -EBUSY;
668 }
669 }
670 mutex_unlock(&virtio_9p_lock);
671
672 if (!found) {
673 pr_err("no channels available for device %s\n", devname);
674 return ret;
675 }
676
677 client->trans = (void *)chan;
678 client->status = Connected;
679 chan->client = client;
680
681 return 0;
682 }
683
684 /**
685 * p9_virtio_remove - clean up resources associated with a virtio device
686 * @vdev: virtio device to remove
687 *
688 */
689
p9_virtio_remove(struct virtio_device * vdev)690 static void p9_virtio_remove(struct virtio_device *vdev)
691 {
692 struct virtio_chan *chan = vdev->priv;
693 unsigned long warning_time;
694
695 mutex_lock(&virtio_9p_lock);
696
697 /* Remove self from list so we don't get new users. */
698 list_del(&chan->chan_list);
699 warning_time = jiffies;
700
701 /* Wait for existing users to close. */
702 while (chan->inuse) {
703 mutex_unlock(&virtio_9p_lock);
704 msleep(250);
705 if (time_after(jiffies, warning_time + 10 * HZ)) {
706 dev_emerg(&vdev->dev,
707 "p9_virtio_remove: waiting for device in use.\n");
708 warning_time = jiffies;
709 }
710 mutex_lock(&virtio_9p_lock);
711 }
712
713 mutex_unlock(&virtio_9p_lock);
714
715 vdev->config->reset(vdev);
716 vdev->config->del_vqs(vdev);
717
718 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
719 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
720 kfree(chan->tag);
721 kfree(chan->vc_wq);
722 kfree(chan);
723
724 }
725
726 static struct virtio_device_id id_table[] = {
727 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
728 { 0 },
729 };
730
731 static unsigned int features[] = {
732 VIRTIO_9P_MOUNT_TAG,
733 };
734
735 /* The standard "struct lguest_driver": */
736 static struct virtio_driver p9_virtio_drv = {
737 .feature_table = features,
738 .feature_table_size = ARRAY_SIZE(features),
739 .driver.name = KBUILD_MODNAME,
740 .driver.owner = THIS_MODULE,
741 .id_table = id_table,
742 .probe = p9_virtio_probe,
743 .remove = p9_virtio_remove,
744 };
745
746 static struct p9_trans_module p9_virtio_trans = {
747 .name = "virtio",
748 .create = p9_virtio_create,
749 .close = p9_virtio_close,
750 .request = p9_virtio_request,
751 .zc_request = p9_virtio_zc_request,
752 .cancel = p9_virtio_cancel,
753 /*
754 * We leave one entry for input and one entry for response
755 * headers. We also skip one more entry to accomodate, address
756 * that are not at page boundary, that can result in an extra
757 * page in zero copy.
758 */
759 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
760 .def = 1,
761 .owner = THIS_MODULE,
762 };
763
764 /* The standard init function */
p9_virtio_init(void)765 static int __init p9_virtio_init(void)
766 {
767 INIT_LIST_HEAD(&virtio_chan_list);
768
769 v9fs_register_trans(&p9_virtio_trans);
770 return register_virtio_driver(&p9_virtio_drv);
771 }
772
p9_virtio_cleanup(void)773 static void __exit p9_virtio_cleanup(void)
774 {
775 unregister_virtio_driver(&p9_virtio_drv);
776 v9fs_unregister_trans(&p9_virtio_trans);
777 }
778
779 module_init(p9_virtio_init);
780 module_exit(p9_virtio_cleanup);
781
782 MODULE_DEVICE_TABLE(virtio, id_table);
783 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
784 MODULE_DESCRIPTION("Virtio 9p Transport");
785 MODULE_LICENSE("GPL");
786
