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13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/in.h>
17#include <linux/module.h>
18#include <linux/net.h>
19#include <linux/ipv6.h>
20#include <linux/errno.h>
21#include <linux/kernel.h>
22#include <linux/un.h>
23#include <linux/uaccess.h>
24#include <linux/inet.h>
25#include <linux/idr.h>
26#include <linux/file.h>
27#include <linux/highmem.h>
28#include <linux/slab.h>
29#include <net/9p/9p.h>
30#include <linux/parser.h>
31#include <net/9p/client.h>
32#include <net/9p/transport.h>
33#include <linux/scatterlist.h>
34#include <linux/swap.h>
35#include <linux/virtio.h>
36#include <linux/virtio_9p.h>
37#include "trans_common.h"
38
39#define VIRTQUEUE_NUM 128
40
41
42static DEFINE_MUTEX(virtio_9p_lock);
43static DECLARE_WAIT_QUEUE_HEAD(vp_wq);
44static atomic_t vp_pinned = ATOMIC_INIT(0);
45
46
47
48
49
50
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63
64
65struct virtio_chan {
66 bool inuse;
67
68 spinlock_t lock;
69
70 struct p9_client *client;
71 struct virtio_device *vdev;
72 struct virtqueue *vq;
73 int ring_bufs_avail;
74 wait_queue_head_t *vc_wq;
75
76
77
78 unsigned long p9_max_pages;
79
80 struct scatterlist sg[VIRTQUEUE_NUM];
81
82
83
84 char *tag;
85
86 struct list_head chan_list;
87};
88
89static struct list_head virtio_chan_list;
90
91
92static unsigned int rest_of_page(void *data)
93{
94 return PAGE_SIZE - offset_in_page(data);
95}
96
97
98
99
100
101
102
103
104
105
106static void p9_virtio_close(struct p9_client *client)
107{
108 struct virtio_chan *chan = client->trans;
109
110 mutex_lock(&virtio_9p_lock);
111 if (chan)
112 chan->inuse = false;
113 mutex_unlock(&virtio_9p_lock);
114}
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129static void req_done(struct virtqueue *vq)
130{
131 struct virtio_chan *chan = vq->vdev->priv;
132 unsigned int len;
133 struct p9_req_t *req;
134 bool need_wakeup = false;
135 unsigned long flags;
136
137 p9_debug(P9_DEBUG_TRANS, ": request done\n");
138
139 spin_lock_irqsave(&chan->lock, flags);
140 while ((req = virtqueue_get_buf(chan->vq, &len)) != NULL) {
141 if (!chan->ring_bufs_avail) {
142 chan->ring_bufs_avail = 1;
143 need_wakeup = true;
144 }
145
146 if (len) {
147 req->rc.size = len;
148 p9_client_cb(chan->client, req, REQ_STATUS_RCVD);
149 }
150 }
151 spin_unlock_irqrestore(&chan->lock, flags);
152
153 if (need_wakeup)
154 wake_up(chan->vc_wq);
155}
156
157
158
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161
162
163
164
165
166
167
168
169
170
171static int pack_sg_list(struct scatterlist *sg, int start,
172 int limit, char *data, int count)
173{
174 int s;
175 int index = start;
176
177 while (count) {
178 s = rest_of_page(data);
179 if (s > count)
180 s = count;
181 BUG_ON(index >= limit);
182
183 sg_unmark_end(&sg[index]);
184 sg_set_buf(&sg[index++], data, s);
185 count -= s;
186 data += s;
187 }
188 if (index-start)
189 sg_mark_end(&sg[index - 1]);
190 return index-start;
191}
192
193
194static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
195{
196 return 1;
197}
198
199
200static int p9_virtio_cancelled(struct p9_client *client, struct p9_req_t *req)
201{
202 p9_req_put(req);
203 return 0;
204}
205
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214
215
216
217static int
218pack_sg_list_p(struct scatterlist *sg, int start, int limit,
219 struct page **pdata, int nr_pages, size_t offs, int count)
220{
221 int i = 0, s;
222 int data_off = offs;
223 int index = start;
224
225 BUG_ON(nr_pages > (limit - start));
226
227
228
229
230 while (nr_pages) {
231 s = PAGE_SIZE - data_off;
232 if (s > count)
233 s = count;
234 BUG_ON(index >= limit);
235
236 sg_unmark_end(&sg[index]);
237 sg_set_page(&sg[index++], pdata[i++], s, data_off);
238 data_off = 0;
239 count -= s;
240 nr_pages--;
241 }
242
243 if (index-start)
244 sg_mark_end(&sg[index - 1]);
245 return index - start;
246}
247
248
249
250
251
252
253
254
255static int
256p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
257{
258 int err;
259 int in, out, out_sgs, in_sgs;
260 unsigned long flags;
261 struct virtio_chan *chan = client->trans;
262 struct scatterlist *sgs[2];
263
264 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");
265
266 req->status = REQ_STATUS_SENT;
267req_retry:
268 spin_lock_irqsave(&chan->lock, flags);
269
270 out_sgs = in_sgs = 0;
271
272 out = pack_sg_list(chan->sg, 0,
273 VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);
274 if (out)
275 sgs[out_sgs++] = chan->sg;
276
277 in = pack_sg_list(chan->sg, out,
278 VIRTQUEUE_NUM, req->rc.sdata, req->rc.capacity);
279 if (in)
280 sgs[out_sgs + in_sgs++] = chan->sg + out;
281
282 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,
283 GFP_ATOMIC);
284 if (err < 0) {
285 if (err == -ENOSPC) {
286 chan->ring_bufs_avail = 0;
287 spin_unlock_irqrestore(&chan->lock, flags);
288 err = wait_event_killable(*chan->vc_wq,
289 chan->ring_bufs_avail);
290 if (err == -ERESTARTSYS)
291 return err;
292
293 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
294 goto req_retry;
295 } else {
296 spin_unlock_irqrestore(&chan->lock, flags);
297 p9_debug(P9_DEBUG_TRANS,
298 "virtio rpc add_sgs returned failure\n");
299 return -EIO;
300 }
301 }
302 virtqueue_kick(chan->vq);
303 spin_unlock_irqrestore(&chan->lock, flags);
304
305 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
306 return 0;
307}
308
309static int p9_get_mapped_pages(struct virtio_chan *chan,
310 struct page ***pages,
311 struct iov_iter *data,
312 int count,
313 size_t *offs,
314 int *need_drop)
315{
316 int nr_pages;
317 int err;
318
319 if (!iov_iter_count(data))
320 return 0;
321
322 if (!iov_iter_is_kvec(data)) {
323 int n;
324
325
326
327
328 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {
329 err = wait_event_killable(vp_wq,
330 (atomic_read(&vp_pinned) < chan->p9_max_pages));
331 if (err == -ERESTARTSYS)
332 return err;
333 }
334 n = iov_iter_get_pages_alloc(data, pages, count, offs);
335 if (n < 0)
336 return n;
337 *need_drop = 1;
338 nr_pages = DIV_ROUND_UP(n + *offs, PAGE_SIZE);
339 atomic_add(nr_pages, &vp_pinned);
340 return n;
341 } else {
342
343 int index;
344 size_t len;
345 void *p;
346
347
348 while (1) {
349 len = iov_iter_single_seg_count(data);
350 if (likely(len)) {
351 p = data->kvec->iov_base + data->iov_offset;
352 break;
353 }
354 iov_iter_advance(data, 0);
355 }
356 if (len > count)
357 len = count;
358
359 nr_pages = DIV_ROUND_UP((unsigned long)p + len, PAGE_SIZE) -
360 (unsigned long)p / PAGE_SIZE;
361
362 *pages = kmalloc_array(nr_pages, sizeof(struct page *),
363 GFP_NOFS);
364 if (!*pages)
365 return -ENOMEM;
366
367 *need_drop = 0;
368 p -= (*offs = offset_in_page(p));
369 for (index = 0; index < nr_pages; index++) {
370 if (is_vmalloc_addr(p))
371 (*pages)[index] = vmalloc_to_page(p);
372 else
373 (*pages)[index] = kmap_to_page(p);
374 p += PAGE_SIZE;
375 }
376 return len;
377 }
378}
379
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389
390
391static int
392p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
393 struct iov_iter *uidata, struct iov_iter *uodata,
394 int inlen, int outlen, int in_hdr_len)
395{
396 int in, out, err, out_sgs, in_sgs;
397 unsigned long flags;
398 int in_nr_pages = 0, out_nr_pages = 0;
399 struct page **in_pages = NULL, **out_pages = NULL;
400 struct virtio_chan *chan = client->trans;
401 struct scatterlist *sgs[4];
402 size_t offs;
403 int need_drop = 0;
404 int kicked = 0;
405
406 p9_debug(P9_DEBUG_TRANS, "virtio request\n");
407
408 if (uodata) {
409 __le32 sz;
410 int n = p9_get_mapped_pages(chan, &out_pages, uodata,
411 outlen, &offs, &need_drop);
412 if (n < 0) {
413 err = n;
414 goto err_out;
415 }
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
423
424
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 err = n;
433 goto err_out;
434 }
435 in_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
436 if (n != inlen) {
437 __le32 v = cpu_to_le32(n);
438 memcpy(&req->tc.sdata[req->tc.size - 4], &v, 4);
439 inlen = n;
440 }
441 }
442 req->status = REQ_STATUS_SENT;
443req_retry_pinned:
444 spin_lock_irqsave(&chan->lock, flags);
445
446 out_sgs = in_sgs = 0;
447
448
449 out = pack_sg_list(chan->sg, 0,
450 VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);
451
452 if (out)
453 sgs[out_sgs++] = chan->sg;
454
455 if (out_pages) {
456 sgs[out_sgs++] = chan->sg + out;
457 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
458 out_pages, out_nr_pages, offs, outlen);
459 }
460
461
462
463
464
465
466
467
468 in = pack_sg_list(chan->sg, out,
469 VIRTQUEUE_NUM, req->rc.sdata, in_hdr_len);
470 if (in)
471 sgs[out_sgs + in_sgs++] = chan->sg + out;
472
473 if (in_pages) {
474 sgs[out_sgs + in_sgs++] = chan->sg + out + in;
475 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
476 in_pages, in_nr_pages, offs, inlen);
477 }
478
479 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
480 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,
481 GFP_ATOMIC);
482 if (err < 0) {
483 if (err == -ENOSPC) {
484 chan->ring_bufs_avail = 0;
485 spin_unlock_irqrestore(&chan->lock, flags);
486 err = wait_event_killable(*chan->vc_wq,
487 chan->ring_bufs_avail);
488 if (err == -ERESTARTSYS)
489 goto err_out;
490
491 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n");
492 goto req_retry_pinned;
493 } else {
494 spin_unlock_irqrestore(&chan->lock, flags);
495 p9_debug(P9_DEBUG_TRANS,
496 "virtio rpc add_sgs returned failure\n");
497 err = -EIO;
498 goto err_out;
499 }
500 }
501 virtqueue_kick(chan->vq);
502 spin_unlock_irqrestore(&chan->lock, flags);
503 kicked = 1;
504 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
505 err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
506
507
508
509err_out:
510 if (need_drop) {
511 if (in_pages) {
512 p9_release_pages(in_pages, in_nr_pages);
513 atomic_sub(in_nr_pages, &vp_pinned);
514 }
515 if (out_pages) {
516 p9_release_pages(out_pages, out_nr_pages);
517 atomic_sub(out_nr_pages, &vp_pinned);
518 }
519
520 wake_up(&vp_wq);
521 }
522 kvfree(in_pages);
523 kvfree(out_pages);
524 if (!kicked) {
525
526 p9_req_put(req);
527 }
528 return err;
529}
530
531static ssize_t p9_mount_tag_show(struct device *dev,
532 struct device_attribute *attr, char *buf)
533{
534 struct virtio_chan *chan;
535 struct virtio_device *vdev;
536 int tag_len;
537
538 vdev = dev_to_virtio(dev);
539 chan = vdev->priv;
540 tag_len = strlen(chan->tag);
541
542 memcpy(buf, chan->tag, tag_len + 1);
543
544 return tag_len + 1;
545}
546
547static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
548
549
550
551
552
553
554
555
556
557static int p9_virtio_probe(struct virtio_device *vdev)
558{
559 __u16 tag_len;
560 char *tag;
561 int err;
562 struct virtio_chan *chan;
563
564 if (!vdev->config->get) {
565 dev_err(&vdev->dev, "%s failure: config access disabled\n",
566 __func__);
567 return -EINVAL;
568 }
569
570 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
571 if (!chan) {
572 pr_err("Failed to allocate virtio 9P channel\n");
573 err = -ENOMEM;
574 goto fail;
575 }
576
577 chan->vdev = vdev;
578
579
580 chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
581 if (IS_ERR(chan->vq)) {
582 err = PTR_ERR(chan->vq);
583 goto out_free_chan;
584 }
585 chan->vq->vdev->priv = chan;
586 spin_lock_init(&chan->lock);
587
588 sg_init_table(chan->sg, VIRTQUEUE_NUM);
589
590 chan->inuse = false;
591 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
592 virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len);
593 } else {
594 err = -EINVAL;
595 goto out_free_vq;
596 }
597 tag = kzalloc(tag_len + 1, GFP_KERNEL);
598 if (!tag) {
599 err = -ENOMEM;
600 goto out_free_vq;
601 }
602
603 virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag),
604 tag, tag_len);
605 chan->tag = tag;
606 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
607 if (err) {
608 goto out_free_tag;
609 }
610 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
611 if (!chan->vc_wq) {
612 err = -ENOMEM;
613 goto out_remove_file;
614 }
615 init_waitqueue_head(chan->vc_wq);
616 chan->ring_bufs_avail = 1;
617
618 chan->p9_max_pages = nr_free_buffer_pages()/4;
619
620 virtio_device_ready(vdev);
621
622 mutex_lock(&virtio_9p_lock);
623 list_add_tail(&chan->chan_list, &virtio_chan_list);
624 mutex_unlock(&virtio_9p_lock);
625
626
627 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
628
629 return 0;
630
631out_remove_file:
632 sysfs_remove_file(&vdev->dev.kobj, &dev_attr_mount_tag.attr);
633out_free_tag:
634 kfree(tag);
635out_free_vq:
636 vdev->config->del_vqs(vdev);
637out_free_chan:
638 kfree(chan);
639fail:
640 return err;
641}
642
643
644
645
646
647
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650
651
652
653
654
655
656
657
658static int
659p9_virtio_create(struct p9_client *client, const char *devname, char *args)
660{
661 struct virtio_chan *chan;
662 int ret = -ENOENT;
663 int found = 0;
664
665 if (devname == NULL)
666 return -EINVAL;
667
668 mutex_lock(&virtio_9p_lock);
669 list_for_each_entry(chan, &virtio_chan_list, chan_list) {
670 if (!strcmp(devname, chan->tag)) {
671 if (!chan->inuse) {
672 chan->inuse = true;
673 found = 1;
674 break;
675 }
676 ret = -EBUSY;
677 }
678 }
679 mutex_unlock(&virtio_9p_lock);
680
681 if (!found) {
682 pr_err("no channels available for device %s\n", devname);
683 return ret;
684 }
685
686 client->trans = (void *)chan;
687 client->status = Connected;
688 chan->client = client;
689
690 return 0;
691}
692
693
694
695
696
697
698
699static void p9_virtio_remove(struct virtio_device *vdev)
700{
701 struct virtio_chan *chan = vdev->priv;
702 unsigned long warning_time;
703
704 mutex_lock(&virtio_9p_lock);
705
706
707 list_del(&chan->chan_list);
708 warning_time = jiffies;
709
710
711 while (chan->inuse) {
712 mutex_unlock(&virtio_9p_lock);
713 msleep(250);
714 if (time_after(jiffies, warning_time + 10 * HZ)) {
715 dev_emerg(&vdev->dev,
716 "p9_virtio_remove: waiting for device in use.\n");
717 warning_time = jiffies;
718 }
719 mutex_lock(&virtio_9p_lock);
720 }
721
722 mutex_unlock(&virtio_9p_lock);
723
724 virtio_reset_device(vdev);
725 vdev->config->del_vqs(vdev);
726
727 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
728 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);
729 kfree(chan->tag);
730 kfree(chan->vc_wq);
731 kfree(chan);
732
733}
734
735static struct virtio_device_id id_table[] = {
736 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
737 { 0 },
738};
739
740static unsigned int features[] = {
741 VIRTIO_9P_MOUNT_TAG,
742};
743
744
745static struct virtio_driver p9_virtio_drv = {
746 .feature_table = features,
747 .feature_table_size = ARRAY_SIZE(features),
748 .driver.name = KBUILD_MODNAME,
749 .driver.owner = THIS_MODULE,
750 .id_table = id_table,
751 .probe = p9_virtio_probe,
752 .remove = p9_virtio_remove,
753};
754
755static struct p9_trans_module p9_virtio_trans = {
756 .name = "virtio",
757 .create = p9_virtio_create,
758 .close = p9_virtio_close,
759 .request = p9_virtio_request,
760 .zc_request = p9_virtio_zc_request,
761 .cancel = p9_virtio_cancel,
762 .cancelled = p9_virtio_cancelled,
763
764
765
766
767
768
769 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
770 .def = 1,
771 .owner = THIS_MODULE,
772};
773
774
775static int __init p9_virtio_init(void)
776{
777 int rc;
778
779 INIT_LIST_HEAD(&virtio_chan_list);
780
781 v9fs_register_trans(&p9_virtio_trans);
782 rc = register_virtio_driver(&p9_virtio_drv);
783 if (rc)
784 v9fs_unregister_trans(&p9_virtio_trans);
785
786 return rc;
787}
788
789static void __exit p9_virtio_cleanup(void)
790{
791 unregister_virtio_driver(&p9_virtio_drv);
792 v9fs_unregister_trans(&p9_virtio_trans);
793}
794
795module_init(p9_virtio_init);
796module_exit(p9_virtio_cleanup);
797MODULE_ALIAS_9P("virtio");
798
799MODULE_DEVICE_TABLE(virtio, id_table);
800MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
801MODULE_DESCRIPTION("Virtio 9p Transport");
802MODULE_LICENSE("GPL");
803