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xen: only check xen_platform_pci_unplug if hvm
[deliverable/linux.git] / drivers / block / xen-blkfront.c
1 /*
2 * blkfront.c
3 *
4 * XenLinux virtual block device driver.
5 *
6 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
7 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
8 * Copyright (c) 2004, Christian Limpach
9 * Copyright (c) 2004, Andrew Warfield
10 * Copyright (c) 2005, Christopher Clark
11 * Copyright (c) 2005, XenSource Ltd
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License version 2
15 * as published by the Free Software Foundation; or, when distributed
16 * separately from the Linux kernel or incorporated into other
17 * software packages, subject to the following license:
18 *
19 * Permission is hereby granted, free of charge, to any person obtaining a copy
20 * of this source file (the "Software"), to deal in the Software without
21 * restriction, including without limitation the rights to use, copy, modify,
22 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
23 * and to permit persons to whom the Software is furnished to do so, subject to
24 * the following conditions:
25 *
26 * The above copyright notice and this permission notice shall be included in
27 * all copies or substantial portions of the Software.
28 *
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
30 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
31 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
32 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
33 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
34 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
35 * IN THE SOFTWARE.
36 */
37
38 #include <linux/interrupt.h>
39 #include <linux/blkdev.h>
40 #include <linux/hdreg.h>
41 #include <linux/cdrom.h>
42 #include <linux/module.h>
43 #include <linux/slab.h>
44 #include <linux/mutex.h>
45 #include <linux/scatterlist.h>
46
47 #include <xen/xen.h>
48 #include <xen/xenbus.h>
49 #include <xen/grant_table.h>
50 #include <xen/events.h>
51 #include <xen/page.h>
52 #include <xen/platform_pci.h>
53
54 #include <xen/interface/grant_table.h>
55 #include <xen/interface/io/blkif.h>
56 #include <xen/interface/io/protocols.h>
57
58 #include <asm/xen/hypervisor.h>
59
60 enum blkif_state {
61 BLKIF_STATE_DISCONNECTED,
62 BLKIF_STATE_CONNECTED,
63 BLKIF_STATE_SUSPENDED,
64 };
65
66 struct blk_shadow {
67 struct blkif_request req;
68 struct request *request;
69 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
70 };
71
72 static DEFINE_MUTEX(blkfront_mutex);
73 static const struct block_device_operations xlvbd_block_fops;
74
75 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
76
77 /*
78 * We have one of these per vbd, whether ide, scsi or 'other'. They
79 * hang in private_data off the gendisk structure. We may end up
80 * putting all kinds of interesting stuff here :-)
81 */
82 struct blkfront_info
83 {
84 struct mutex mutex;
85 struct xenbus_device *xbdev;
86 struct gendisk *gd;
87 int vdevice;
88 blkif_vdev_t handle;
89 enum blkif_state connected;
90 int ring_ref;
91 struct blkif_front_ring ring;
92 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
93 unsigned int evtchn, irq;
94 struct request_queue *rq;
95 struct work_struct work;
96 struct gnttab_free_callback callback;
97 struct blk_shadow shadow[BLK_RING_SIZE];
98 unsigned long shadow_free;
99 unsigned int feature_flush;
100 unsigned int flush_op;
101 unsigned int feature_discard;
102 unsigned int discard_granularity;
103 unsigned int discard_alignment;
104 int is_ready;
105 };
106
107 static DEFINE_SPINLOCK(blkif_io_lock);
108
109 static unsigned int nr_minors;
110 static unsigned long *minors;
111 static DEFINE_SPINLOCK(minor_lock);
112
113 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
114 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
115 #define GRANT_INVALID_REF 0
116
117 #define PARTS_PER_DISK 16
118 #define PARTS_PER_EXT_DISK 256
119
120 #define BLKIF_MAJOR(dev) ((dev)>>8)
121 #define BLKIF_MINOR(dev) ((dev) & 0xff)
122
123 #define EXT_SHIFT 28
124 #define EXTENDED (1<<EXT_SHIFT)
125 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
126 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
127 #define EMULATED_HD_DISK_MINOR_OFFSET (0)
128 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
129 #define EMULATED_SD_DISK_MINOR_OFFSET (0)
130 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
131
132 #define DEV_NAME "xvd" /* name in /dev */
133
134 static int get_id_from_freelist(struct blkfront_info *info)
135 {
136 unsigned long free = info->shadow_free;
137 BUG_ON(free >= BLK_RING_SIZE);
138 info->shadow_free = info->shadow[free].req.id;
139 info->shadow[free].req.id = 0x0fffffee; /* debug */
140 return free;
141 }
142
143 static void add_id_to_freelist(struct blkfront_info *info,
144 unsigned long id)
145 {
146 info->shadow[id].req.id = info->shadow_free;
147 info->shadow[id].request = NULL;
148 info->shadow_free = id;
149 }
150
151 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
152 {
153 unsigned int end = minor + nr;
154 int rc;
155
156 if (end > nr_minors) {
157 unsigned long *bitmap, *old;
158
159 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
160 GFP_KERNEL);
161 if (bitmap == NULL)
162 return -ENOMEM;
163
164 spin_lock(&minor_lock);
165 if (end > nr_minors) {
166 old = minors;
167 memcpy(bitmap, minors,
168 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
169 minors = bitmap;
170 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
171 } else
172 old = bitmap;
173 spin_unlock(&minor_lock);
174 kfree(old);
175 }
176
177 spin_lock(&minor_lock);
178 if (find_next_bit(minors, end, minor) >= end) {
179 for (; minor < end; ++minor)
180 __set_bit(minor, minors);
181 rc = 0;
182 } else
183 rc = -EBUSY;
184 spin_unlock(&minor_lock);
185
186 return rc;
187 }
188
189 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
190 {
191 unsigned int end = minor + nr;
192
193 BUG_ON(end > nr_minors);
194 spin_lock(&minor_lock);
195 for (; minor < end; ++minor)
196 __clear_bit(minor, minors);
197 spin_unlock(&minor_lock);
198 }
199
200 static void blkif_restart_queue_callback(void *arg)
201 {
202 struct blkfront_info *info = (struct blkfront_info *)arg;
203 schedule_work(&info->work);
204 }
205
206 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
207 {
208 /* We don't have real geometry info, but let's at least return
209 values consistent with the size of the device */
210 sector_t nsect = get_capacity(bd->bd_disk);
211 sector_t cylinders = nsect;
212
213 hg->heads = 0xff;
214 hg->sectors = 0x3f;
215 sector_div(cylinders, hg->heads * hg->sectors);
216 hg->cylinders = cylinders;
217 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
218 hg->cylinders = 0xffff;
219 return 0;
220 }
221
222 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
223 unsigned command, unsigned long argument)
224 {
225 struct blkfront_info *info = bdev->bd_disk->private_data;
226 int i;
227
228 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
229 command, (long)argument);
230
231 switch (command) {
232 case CDROMMULTISESSION:
233 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
234 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
235 if (put_user(0, (char __user *)(argument + i)))
236 return -EFAULT;
237 return 0;
238
239 case CDROM_GET_CAPABILITY: {
240 struct gendisk *gd = info->gd;
241 if (gd->flags & GENHD_FL_CD)
242 return 0;
243 return -EINVAL;
244 }
245
246 default:
247 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
248 command);*/
249 return -EINVAL; /* same return as native Linux */
250 }
251
252 return 0;
253 }
254
255 /*
256 * Generate a Xen blkfront IO request from a blk layer request. Reads
257 * and writes are handled as expected.
258 *
259 * @req: a request struct
260 */
261 static int blkif_queue_request(struct request *req)
262 {
263 struct blkfront_info *info = req->rq_disk->private_data;
264 unsigned long buffer_mfn;
265 struct blkif_request *ring_req;
266 unsigned long id;
267 unsigned int fsect, lsect;
268 int i, ref;
269 grant_ref_t gref_head;
270 struct scatterlist *sg;
271
272 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
273 return 1;
274
275 if (gnttab_alloc_grant_references(
276 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
277 gnttab_request_free_callback(
278 &info->callback,
279 blkif_restart_queue_callback,
280 info,
281 BLKIF_MAX_SEGMENTS_PER_REQUEST);
282 return 1;
283 }
284
285 /* Fill out a communications ring structure. */
286 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
287 id = get_id_from_freelist(info);
288 info->shadow[id].request = req;
289
290 ring_req->id = id;
291 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
292 ring_req->handle = info->handle;
293
294 ring_req->operation = rq_data_dir(req) ?
295 BLKIF_OP_WRITE : BLKIF_OP_READ;
296
297 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
298 /*
299 * Ideally we can do an unordered flush-to-disk. In case the
300 * backend onlysupports barriers, use that. A barrier request
301 * a superset of FUA, so we can implement it the same
302 * way. (It's also a FLUSH+FUA, since it is
303 * guaranteed ordered WRT previous writes.)
304 */
305 ring_req->operation = info->flush_op;
306 }
307
308 if (unlikely(req->cmd_flags & REQ_DISCARD)) {
309 /* id, sector_number and handle are set above. */
310 ring_req->operation = BLKIF_OP_DISCARD;
311 ring_req->nr_segments = 0;
312 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
313 } else {
314 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
315 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
316
317 for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
318 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
319 fsect = sg->offset >> 9;
320 lsect = fsect + (sg->length >> 9) - 1;
321 /* install a grant reference. */
322 ref = gnttab_claim_grant_reference(&gref_head);
323 BUG_ON(ref == -ENOSPC);
324
325 gnttab_grant_foreign_access_ref(
326 ref,
327 info->xbdev->otherend_id,
328 buffer_mfn,
329 rq_data_dir(req));
330
331 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
332 ring_req->u.rw.seg[i] =
333 (struct blkif_request_segment) {
334 .gref = ref,
335 .first_sect = fsect,
336 .last_sect = lsect };
337 }
338 }
339
340 info->ring.req_prod_pvt++;
341
342 /* Keep a private copy so we can reissue requests when recovering. */
343 info->shadow[id].req = *ring_req;
344
345 gnttab_free_grant_references(gref_head);
346
347 return 0;
348 }
349
350
351 static inline void flush_requests(struct blkfront_info *info)
352 {
353 int notify;
354
355 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
356
357 if (notify)
358 notify_remote_via_irq(info->irq);
359 }
360
361 /*
362 * do_blkif_request
363 * read a block; request is in a request queue
364 */
365 static void do_blkif_request(struct request_queue *rq)
366 {
367 struct blkfront_info *info = NULL;
368 struct request *req;
369 int queued;
370
371 pr_debug("Entered do_blkif_request\n");
372
373 queued = 0;
374
375 while ((req = blk_peek_request(rq)) != NULL) {
376 info = req->rq_disk->private_data;
377
378 if (RING_FULL(&info->ring))
379 goto wait;
380
381 blk_start_request(req);
382
383 if ((req->cmd_type != REQ_TYPE_FS) ||
384 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
385 !info->flush_op)) {
386 __blk_end_request_all(req, -EIO);
387 continue;
388 }
389
390 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
391 "(%u/%u) buffer:%p [%s]\n",
392 req, req->cmd, (unsigned long)blk_rq_pos(req),
393 blk_rq_cur_sectors(req), blk_rq_sectors(req),
394 req->buffer, rq_data_dir(req) ? "write" : "read");
395
396 if (blkif_queue_request(req)) {
397 blk_requeue_request(rq, req);
398 wait:
399 /* Avoid pointless unplugs. */
400 blk_stop_queue(rq);
401 break;
402 }
403
404 queued++;
405 }
406
407 if (queued != 0)
408 flush_requests(info);
409 }
410
411 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
412 {
413 struct request_queue *rq;
414 struct blkfront_info *info = gd->private_data;
415
416 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
417 if (rq == NULL)
418 return -1;
419
420 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
421
422 if (info->feature_discard) {
423 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
424 blk_queue_max_discard_sectors(rq, get_capacity(gd));
425 rq->limits.discard_granularity = info->discard_granularity;
426 rq->limits.discard_alignment = info->discard_alignment;
427 }
428
429 /* Hard sector size and max sectors impersonate the equiv. hardware. */
430 blk_queue_logical_block_size(rq, sector_size);
431 blk_queue_max_hw_sectors(rq, 512);
432
433 /* Each segment in a request is up to an aligned page in size. */
434 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
435 blk_queue_max_segment_size(rq, PAGE_SIZE);
436
437 /* Ensure a merged request will fit in a single I/O ring slot. */
438 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
439
440 /* Make sure buffer addresses are sector-aligned. */
441 blk_queue_dma_alignment(rq, 511);
442
443 /* Make sure we don't use bounce buffers. */
444 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
445
446 gd->queue = rq;
447
448 return 0;
449 }
450
451
452 static void xlvbd_flush(struct blkfront_info *info)
453 {
454 blk_queue_flush(info->rq, info->feature_flush);
455 printk(KERN_INFO "blkfront: %s: %s: %s\n",
456 info->gd->disk_name,
457 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
458 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ?
459 "flush diskcache" : "barrier or flush"),
460 info->feature_flush ? "enabled" : "disabled");
461 }
462
463 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
464 {
465 int major;
466 major = BLKIF_MAJOR(vdevice);
467 *minor = BLKIF_MINOR(vdevice);
468 switch (major) {
469 case XEN_IDE0_MAJOR:
470 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
471 *minor = ((*minor / 64) * PARTS_PER_DISK) +
472 EMULATED_HD_DISK_MINOR_OFFSET;
473 break;
474 case XEN_IDE1_MAJOR:
475 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
476 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
477 EMULATED_HD_DISK_MINOR_OFFSET;
478 break;
479 case XEN_SCSI_DISK0_MAJOR:
480 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
481 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
482 break;
483 case XEN_SCSI_DISK1_MAJOR:
484 case XEN_SCSI_DISK2_MAJOR:
485 case XEN_SCSI_DISK3_MAJOR:
486 case XEN_SCSI_DISK4_MAJOR:
487 case XEN_SCSI_DISK5_MAJOR:
488 case XEN_SCSI_DISK6_MAJOR:
489 case XEN_SCSI_DISK7_MAJOR:
490 *offset = (*minor / PARTS_PER_DISK) +
491 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
492 EMULATED_SD_DISK_NAME_OFFSET;
493 *minor = *minor +
494 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
495 EMULATED_SD_DISK_MINOR_OFFSET;
496 break;
497 case XEN_SCSI_DISK8_MAJOR:
498 case XEN_SCSI_DISK9_MAJOR:
499 case XEN_SCSI_DISK10_MAJOR:
500 case XEN_SCSI_DISK11_MAJOR:
501 case XEN_SCSI_DISK12_MAJOR:
502 case XEN_SCSI_DISK13_MAJOR:
503 case XEN_SCSI_DISK14_MAJOR:
504 case XEN_SCSI_DISK15_MAJOR:
505 *offset = (*minor / PARTS_PER_DISK) +
506 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
507 EMULATED_SD_DISK_NAME_OFFSET;
508 *minor = *minor +
509 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
510 EMULATED_SD_DISK_MINOR_OFFSET;
511 break;
512 case XENVBD_MAJOR:
513 *offset = *minor / PARTS_PER_DISK;
514 break;
515 default:
516 printk(KERN_WARNING "blkfront: your disk configuration is "
517 "incorrect, please use an xvd device instead\n");
518 return -ENODEV;
519 }
520 return 0;
521 }
522
523 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
524 struct blkfront_info *info,
525 u16 vdisk_info, u16 sector_size)
526 {
527 struct gendisk *gd;
528 int nr_minors = 1;
529 int err;
530 unsigned int offset;
531 int minor;
532 int nr_parts;
533
534 BUG_ON(info->gd != NULL);
535 BUG_ON(info->rq != NULL);
536
537 if ((info->vdevice>>EXT_SHIFT) > 1) {
538 /* this is above the extended range; something is wrong */
539 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
540 return -ENODEV;
541 }
542
543 if (!VDEV_IS_EXTENDED(info->vdevice)) {
544 err = xen_translate_vdev(info->vdevice, &minor, &offset);
545 if (err)
546 return err;
547 nr_parts = PARTS_PER_DISK;
548 } else {
549 minor = BLKIF_MINOR_EXT(info->vdevice);
550 nr_parts = PARTS_PER_EXT_DISK;
551 offset = minor / nr_parts;
552 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
553 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
554 "emulated IDE disks,\n\t choose an xvd device name"
555 "from xvde on\n", info->vdevice);
556 }
557 err = -ENODEV;
558
559 if ((minor % nr_parts) == 0)
560 nr_minors = nr_parts;
561
562 err = xlbd_reserve_minors(minor, nr_minors);
563 if (err)
564 goto out;
565 err = -ENODEV;
566
567 gd = alloc_disk(nr_minors);
568 if (gd == NULL)
569 goto release;
570
571 if (nr_minors > 1) {
572 if (offset < 26)
573 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
574 else
575 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
576 'a' + ((offset / 26)-1), 'a' + (offset % 26));
577 } else {
578 if (offset < 26)
579 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
580 'a' + offset,
581 minor & (nr_parts - 1));
582 else
583 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
584 'a' + ((offset / 26) - 1),
585 'a' + (offset % 26),
586 minor & (nr_parts - 1));
587 }
588
589 gd->major = XENVBD_MAJOR;
590 gd->first_minor = minor;
591 gd->fops = &xlvbd_block_fops;
592 gd->private_data = info;
593 gd->driverfs_dev = &(info->xbdev->dev);
594 set_capacity(gd, capacity);
595
596 if (xlvbd_init_blk_queue(gd, sector_size)) {
597 del_gendisk(gd);
598 goto release;
599 }
600
601 info->rq = gd->queue;
602 info->gd = gd;
603
604 xlvbd_flush(info);
605
606 if (vdisk_info & VDISK_READONLY)
607 set_disk_ro(gd, 1);
608
609 if (vdisk_info & VDISK_REMOVABLE)
610 gd->flags |= GENHD_FL_REMOVABLE;
611
612 if (vdisk_info & VDISK_CDROM)
613 gd->flags |= GENHD_FL_CD;
614
615 return 0;
616
617 release:
618 xlbd_release_minors(minor, nr_minors);
619 out:
620 return err;
621 }
622
623 static void xlvbd_release_gendisk(struct blkfront_info *info)
624 {
625 unsigned int minor, nr_minors;
626 unsigned long flags;
627
628 if (info->rq == NULL)
629 return;
630
631 spin_lock_irqsave(&blkif_io_lock, flags);
632
633 /* No more blkif_request(). */
634 blk_stop_queue(info->rq);
635
636 /* No more gnttab callback work. */
637 gnttab_cancel_free_callback(&info->callback);
638 spin_unlock_irqrestore(&blkif_io_lock, flags);
639
640 /* Flush gnttab callback work. Must be done with no locks held. */
641 flush_work_sync(&info->work);
642
643 del_gendisk(info->gd);
644
645 minor = info->gd->first_minor;
646 nr_minors = info->gd->minors;
647 xlbd_release_minors(minor, nr_minors);
648
649 blk_cleanup_queue(info->rq);
650 info->rq = NULL;
651
652 put_disk(info->gd);
653 info->gd = NULL;
654 }
655
656 static void kick_pending_request_queues(struct blkfront_info *info)
657 {
658 if (!RING_FULL(&info->ring)) {
659 /* Re-enable calldowns. */
660 blk_start_queue(info->rq);
661 /* Kick things off immediately. */
662 do_blkif_request(info->rq);
663 }
664 }
665
666 static void blkif_restart_queue(struct work_struct *work)
667 {
668 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
669
670 spin_lock_irq(&blkif_io_lock);
671 if (info->connected == BLKIF_STATE_CONNECTED)
672 kick_pending_request_queues(info);
673 spin_unlock_irq(&blkif_io_lock);
674 }
675
676 static void blkif_free(struct blkfront_info *info, int suspend)
677 {
678 /* Prevent new requests being issued until we fix things up. */
679 spin_lock_irq(&blkif_io_lock);
680 info->connected = suspend ?
681 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
682 /* No more blkif_request(). */
683 if (info->rq)
684 blk_stop_queue(info->rq);
685 /* No more gnttab callback work. */
686 gnttab_cancel_free_callback(&info->callback);
687 spin_unlock_irq(&blkif_io_lock);
688
689 /* Flush gnttab callback work. Must be done with no locks held. */
690 flush_work_sync(&info->work);
691
692 /* Free resources associated with old device channel. */
693 if (info->ring_ref != GRANT_INVALID_REF) {
694 gnttab_end_foreign_access(info->ring_ref, 0,
695 (unsigned long)info->ring.sring);
696 info->ring_ref = GRANT_INVALID_REF;
697 info->ring.sring = NULL;
698 }
699 if (info->irq)
700 unbind_from_irqhandler(info->irq, info);
701 info->evtchn = info->irq = 0;
702
703 }
704
705 static void blkif_completion(struct blk_shadow *s)
706 {
707 int i;
708 for (i = 0; i < s->req.nr_segments; i++)
709 gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);
710 }
711
712 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
713 {
714 struct request *req;
715 struct blkif_response *bret;
716 RING_IDX i, rp;
717 unsigned long flags;
718 struct blkfront_info *info = (struct blkfront_info *)dev_id;
719 int error;
720
721 spin_lock_irqsave(&blkif_io_lock, flags);
722
723 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
724 spin_unlock_irqrestore(&blkif_io_lock, flags);
725 return IRQ_HANDLED;
726 }
727
728 again:
729 rp = info->ring.sring->rsp_prod;
730 rmb(); /* Ensure we see queued responses up to 'rp'. */
731
732 for (i = info->ring.rsp_cons; i != rp; i++) {
733 unsigned long id;
734
735 bret = RING_GET_RESPONSE(&info->ring, i);
736 id = bret->id;
737 req = info->shadow[id].request;
738
739 blkif_completion(&info->shadow[id]);
740
741 add_id_to_freelist(info, id);
742
743 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
744 switch (bret->operation) {
745 case BLKIF_OP_DISCARD:
746 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
747 struct request_queue *rq = info->rq;
748 printk(KERN_WARNING "blkfront: %s: discard op failed\n",
749 info->gd->disk_name);
750 error = -EOPNOTSUPP;
751 info->feature_discard = 0;
752 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
753 }
754 __blk_end_request_all(req, error);
755 break;
756 case BLKIF_OP_FLUSH_DISKCACHE:
757 case BLKIF_OP_WRITE_BARRIER:
758 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
759 printk(KERN_WARNING "blkfront: %s: write %s op failed\n",
760 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
761 "barrier" : "flush disk cache",
762 info->gd->disk_name);
763 error = -EOPNOTSUPP;
764 }
765 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
766 info->shadow[id].req.nr_segments == 0)) {
767 printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n",
768 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
769 "barrier" : "flush disk cache",
770 info->gd->disk_name);
771 error = -EOPNOTSUPP;
772 }
773 if (unlikely(error)) {
774 if (error == -EOPNOTSUPP)
775 error = 0;
776 info->feature_flush = 0;
777 info->flush_op = 0;
778 xlvbd_flush(info);
779 }
780 /* fall through */
781 case BLKIF_OP_READ:
782 case BLKIF_OP_WRITE:
783 if (unlikely(bret->status != BLKIF_RSP_OKAY))
784 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
785 "request: %x\n", bret->status);
786
787 __blk_end_request_all(req, error);
788 break;
789 default:
790 BUG();
791 }
792 }
793
794 info->ring.rsp_cons = i;
795
796 if (i != info->ring.req_prod_pvt) {
797 int more_to_do;
798 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
799 if (more_to_do)
800 goto again;
801 } else
802 info->ring.sring->rsp_event = i + 1;
803
804 kick_pending_request_queues(info);
805
806 spin_unlock_irqrestore(&blkif_io_lock, flags);
807
808 return IRQ_HANDLED;
809 }
810
811
812 static int setup_blkring(struct xenbus_device *dev,
813 struct blkfront_info *info)
814 {
815 struct blkif_sring *sring;
816 int err;
817
818 info->ring_ref = GRANT_INVALID_REF;
819
820 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
821 if (!sring) {
822 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
823 return -ENOMEM;
824 }
825 SHARED_RING_INIT(sring);
826 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
827
828 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
829
830 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
831 if (err < 0) {
832 free_page((unsigned long)sring);
833 info->ring.sring = NULL;
834 goto fail;
835 }
836 info->ring_ref = err;
837
838 err = xenbus_alloc_evtchn(dev, &info->evtchn);
839 if (err)
840 goto fail;
841
842 err = bind_evtchn_to_irqhandler(info->evtchn,
843 blkif_interrupt,
844 IRQF_SAMPLE_RANDOM, "blkif", info);
845 if (err <= 0) {
846 xenbus_dev_fatal(dev, err,
847 "bind_evtchn_to_irqhandler failed");
848 goto fail;
849 }
850 info->irq = err;
851
852 return 0;
853 fail:
854 blkif_free(info, 0);
855 return err;
856 }
857
858
859 /* Common code used when first setting up, and when resuming. */
860 static int talk_to_blkback(struct xenbus_device *dev,
861 struct blkfront_info *info)
862 {
863 const char *message = NULL;
864 struct xenbus_transaction xbt;
865 int err;
866
867 /* Create shared ring, alloc event channel. */
868 err = setup_blkring(dev, info);
869 if (err)
870 goto out;
871
872 again:
873 err = xenbus_transaction_start(&xbt);
874 if (err) {
875 xenbus_dev_fatal(dev, err, "starting transaction");
876 goto destroy_blkring;
877 }
878
879 err = xenbus_printf(xbt, dev->nodename,
880 "ring-ref", "%u", info->ring_ref);
881 if (err) {
882 message = "writing ring-ref";
883 goto abort_transaction;
884 }
885 err = xenbus_printf(xbt, dev->nodename,
886 "event-channel", "%u", info->evtchn);
887 if (err) {
888 message = "writing event-channel";
889 goto abort_transaction;
890 }
891 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
892 XEN_IO_PROTO_ABI_NATIVE);
893 if (err) {
894 message = "writing protocol";
895 goto abort_transaction;
896 }
897
898 err = xenbus_transaction_end(xbt, 0);
899 if (err) {
900 if (err == -EAGAIN)
901 goto again;
902 xenbus_dev_fatal(dev, err, "completing transaction");
903 goto destroy_blkring;
904 }
905
906 xenbus_switch_state(dev, XenbusStateInitialised);
907
908 return 0;
909
910 abort_transaction:
911 xenbus_transaction_end(xbt, 1);
912 if (message)
913 xenbus_dev_fatal(dev, err, "%s", message);
914 destroy_blkring:
915 blkif_free(info, 0);
916 out:
917 return err;
918 }
919
920 /**
921 * Entry point to this code when a new device is created. Allocate the basic
922 * structures and the ring buffer for communication with the backend, and
923 * inform the backend of the appropriate details for those. Switch to
924 * Initialised state.
925 */
926 static int blkfront_probe(struct xenbus_device *dev,
927 const struct xenbus_device_id *id)
928 {
929 int err, vdevice, i;
930 struct blkfront_info *info;
931
932 /* FIXME: Use dynamic device id if this is not set. */
933 err = xenbus_scanf(XBT_NIL, dev->nodename,
934 "virtual-device", "%i", &vdevice);
935 if (err != 1) {
936 /* go looking in the extended area instead */
937 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
938 "%i", &vdevice);
939 if (err != 1) {
940 xenbus_dev_fatal(dev, err, "reading virtual-device");
941 return err;
942 }
943 }
944
945 if (xen_hvm_domain()) {
946 char *type;
947 int len;
948 /* no unplug has been done: do not hook devices != xen vbds */
949 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
950 int major;
951
952 if (!VDEV_IS_EXTENDED(vdevice))
953 major = BLKIF_MAJOR(vdevice);
954 else
955 major = XENVBD_MAJOR;
956
957 if (major != XENVBD_MAJOR) {
958 printk(KERN_INFO
959 "%s: HVM does not support vbd %d as xen block device\n",
960 __FUNCTION__, vdevice);
961 return -ENODEV;
962 }
963 }
964 /* do not create a PV cdrom device if we are an HVM guest */
965 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
966 if (IS_ERR(type))
967 return -ENODEV;
968 if (strncmp(type, "cdrom", 5) == 0) {
969 kfree(type);
970 return -ENODEV;
971 }
972 kfree(type);
973 }
974 info = kzalloc(sizeof(*info), GFP_KERNEL);
975 if (!info) {
976 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
977 return -ENOMEM;
978 }
979
980 mutex_init(&info->mutex);
981 info->xbdev = dev;
982 info->vdevice = vdevice;
983 info->connected = BLKIF_STATE_DISCONNECTED;
984 INIT_WORK(&info->work, blkif_restart_queue);
985
986 for (i = 0; i < BLK_RING_SIZE; i++)
987 info->shadow[i].req.id = i+1;
988 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
989
990 /* Front end dir is a number, which is used as the id. */
991 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
992 dev_set_drvdata(&dev->dev, info);
993
994 err = talk_to_blkback(dev, info);
995 if (err) {
996 kfree(info);
997 dev_set_drvdata(&dev->dev, NULL);
998 return err;
999 }
1000
1001 return 0;
1002 }
1003
1004
1005 static int blkif_recover(struct blkfront_info *info)
1006 {
1007 int i;
1008 struct blkif_request *req;
1009 struct blk_shadow *copy;
1010 int j;
1011
1012 /* Stage 1: Make a safe copy of the shadow state. */
1013 copy = kmalloc(sizeof(info->shadow),
1014 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
1015 if (!copy)
1016 return -ENOMEM;
1017 memcpy(copy, info->shadow, sizeof(info->shadow));
1018
1019 /* Stage 2: Set up free list. */
1020 memset(&info->shadow, 0, sizeof(info->shadow));
1021 for (i = 0; i < BLK_RING_SIZE; i++)
1022 info->shadow[i].req.id = i+1;
1023 info->shadow_free = info->ring.req_prod_pvt;
1024 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
1025
1026 /* Stage 3: Find pending requests and requeue them. */
1027 for (i = 0; i < BLK_RING_SIZE; i++) {
1028 /* Not in use? */
1029 if (!copy[i].request)
1030 continue;
1031
1032 /* Grab a request slot and copy shadow state into it. */
1033 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
1034 *req = copy[i].req;
1035
1036 /* We get a new request id, and must reset the shadow state. */
1037 req->id = get_id_from_freelist(info);
1038 memcpy(&info->shadow[req->id], &copy[i], sizeof(copy[i]));
1039
1040 /* Rewrite any grant references invalidated by susp/resume. */
1041 for (j = 0; j < req->nr_segments; j++)
1042 gnttab_grant_foreign_access_ref(
1043 req->u.rw.seg[j].gref,
1044 info->xbdev->otherend_id,
1045 pfn_to_mfn(info->shadow[req->id].frame[j]),
1046 rq_data_dir(info->shadow[req->id].request));
1047 info->shadow[req->id].req = *req;
1048
1049 info->ring.req_prod_pvt++;
1050 }
1051
1052 kfree(copy);
1053
1054 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1055
1056 spin_lock_irq(&blkif_io_lock);
1057
1058 /* Now safe for us to use the shared ring */
1059 info->connected = BLKIF_STATE_CONNECTED;
1060
1061 /* Send off requeued requests */
1062 flush_requests(info);
1063
1064 /* Kick any other new requests queued since we resumed */
1065 kick_pending_request_queues(info);
1066
1067 spin_unlock_irq(&blkif_io_lock);
1068
1069 return 0;
1070 }
1071
1072 /**
1073 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1074 * driver restart. We tear down our blkif structure and recreate it, but
1075 * leave the device-layer structures intact so that this is transparent to the
1076 * rest of the kernel.
1077 */
1078 static int blkfront_resume(struct xenbus_device *dev)
1079 {
1080 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1081 int err;
1082
1083 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
1084
1085 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
1086
1087 err = talk_to_blkback(dev, info);
1088 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
1089 err = blkif_recover(info);
1090
1091 return err;
1092 }
1093
1094 static void
1095 blkfront_closing(struct blkfront_info *info)
1096 {
1097 struct xenbus_device *xbdev = info->xbdev;
1098 struct block_device *bdev = NULL;
1099
1100 mutex_lock(&info->mutex);
1101
1102 if (xbdev->state == XenbusStateClosing) {
1103 mutex_unlock(&info->mutex);
1104 return;
1105 }
1106
1107 if (info->gd)
1108 bdev = bdget_disk(info->gd, 0);
1109
1110 mutex_unlock(&info->mutex);
1111
1112 if (!bdev) {
1113 xenbus_frontend_closed(xbdev);
1114 return;
1115 }
1116
1117 mutex_lock(&bdev->bd_mutex);
1118
1119 if (bdev->bd_openers) {
1120 xenbus_dev_error(xbdev, -EBUSY,
1121 "Device in use; refusing to close");
1122 xenbus_switch_state(xbdev, XenbusStateClosing);
1123 } else {
1124 xlvbd_release_gendisk(info);
1125 xenbus_frontend_closed(xbdev);
1126 }
1127
1128 mutex_unlock(&bdev->bd_mutex);
1129 bdput(bdev);
1130 }
1131
1132 static void blkfront_setup_discard(struct blkfront_info *info)
1133 {
1134 int err;
1135 char *type;
1136 unsigned int discard_granularity;
1137 unsigned int discard_alignment;
1138
1139 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
1140 if (IS_ERR(type))
1141 return;
1142
1143 if (strncmp(type, "phy", 3) == 0) {
1144 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1145 "discard-granularity", "%u", &discard_granularity,
1146 "discard-alignment", "%u", &discard_alignment,
1147 NULL);
1148 if (!err) {
1149 info->feature_discard = 1;
1150 info->discard_granularity = discard_granularity;
1151 info->discard_alignment = discard_alignment;
1152 }
1153 } else if (strncmp(type, "file", 4) == 0)
1154 info->feature_discard = 1;
1155
1156 kfree(type);
1157 }
1158
1159 /*
1160 * Invoked when the backend is finally 'ready' (and has told produced
1161 * the details about the physical device - #sectors, size, etc).
1162 */
1163 static void blkfront_connect(struct blkfront_info *info)
1164 {
1165 unsigned long long sectors;
1166 unsigned long sector_size;
1167 unsigned int binfo;
1168 int err;
1169 int barrier, flush, discard;
1170
1171 switch (info->connected) {
1172 case BLKIF_STATE_CONNECTED:
1173 /*
1174 * Potentially, the back-end may be signalling
1175 * a capacity change; update the capacity.
1176 */
1177 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1178 "sectors", "%Lu", &sectors);
1179 if (XENBUS_EXIST_ERR(err))
1180 return;
1181 printk(KERN_INFO "Setting capacity to %Lu\n",
1182 sectors);
1183 set_capacity(info->gd, sectors);
1184 revalidate_disk(info->gd);
1185
1186 /* fall through */
1187 case BLKIF_STATE_SUSPENDED:
1188 return;
1189
1190 default:
1191 break;
1192 }
1193
1194 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1195 __func__, info->xbdev->otherend);
1196
1197 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1198 "sectors", "%llu", &sectors,
1199 "info", "%u", &binfo,
1200 "sector-size", "%lu", &sector_size,
1201 NULL);
1202 if (err) {
1203 xenbus_dev_fatal(info->xbdev, err,
1204 "reading backend fields at %s",
1205 info->xbdev->otherend);
1206 return;
1207 }
1208
1209 info->feature_flush = 0;
1210 info->flush_op = 0;
1211
1212 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1213 "feature-barrier", "%d", &barrier,
1214 NULL);
1215
1216 /*
1217 * If there's no "feature-barrier" defined, then it means
1218 * we're dealing with a very old backend which writes
1219 * synchronously; nothing to do.
1220 *
1221 * If there are barriers, then we use flush.
1222 */
1223 if (!err && barrier) {
1224 info->feature_flush = REQ_FLUSH | REQ_FUA;
1225 info->flush_op = BLKIF_OP_WRITE_BARRIER;
1226 }
1227 /*
1228 * And if there is "feature-flush-cache" use that above
1229 * barriers.
1230 */
1231 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1232 "feature-flush-cache", "%d", &flush,
1233 NULL);
1234
1235 if (!err && flush) {
1236 info->feature_flush = REQ_FLUSH;
1237 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
1238 }
1239
1240 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1241 "feature-discard", "%d", &discard,
1242 NULL);
1243
1244 if (!err && discard)
1245 blkfront_setup_discard(info);
1246
1247 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1248 if (err) {
1249 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1250 info->xbdev->otherend);
1251 return;
1252 }
1253
1254 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1255
1256 /* Kick pending requests. */
1257 spin_lock_irq(&blkif_io_lock);
1258 info->connected = BLKIF_STATE_CONNECTED;
1259 kick_pending_request_queues(info);
1260 spin_unlock_irq(&blkif_io_lock);
1261
1262 add_disk(info->gd);
1263
1264 info->is_ready = 1;
1265 }
1266
1267 /**
1268 * Callback received when the backend's state changes.
1269 */
1270 static void blkback_changed(struct xenbus_device *dev,
1271 enum xenbus_state backend_state)
1272 {
1273 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1274
1275 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1276
1277 switch (backend_state) {
1278 case XenbusStateInitialising:
1279 case XenbusStateInitWait:
1280 case XenbusStateInitialised:
1281 case XenbusStateReconfiguring:
1282 case XenbusStateReconfigured:
1283 case XenbusStateUnknown:
1284 case XenbusStateClosed:
1285 break;
1286
1287 case XenbusStateConnected:
1288 blkfront_connect(info);
1289 break;
1290
1291 case XenbusStateClosing:
1292 blkfront_closing(info);
1293 break;
1294 }
1295 }
1296
1297 static int blkfront_remove(struct xenbus_device *xbdev)
1298 {
1299 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1300 struct block_device *bdev = NULL;
1301 struct gendisk *disk;
1302
1303 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1304
1305 blkif_free(info, 0);
1306
1307 mutex_lock(&info->mutex);
1308
1309 disk = info->gd;
1310 if (disk)
1311 bdev = bdget_disk(disk, 0);
1312
1313 info->xbdev = NULL;
1314 mutex_unlock(&info->mutex);
1315
1316 if (!bdev) {
1317 kfree(info);
1318 return 0;
1319 }
1320
1321 /*
1322 * The xbdev was removed before we reached the Closed
1323 * state. See if it's safe to remove the disk. If the bdev
1324 * isn't closed yet, we let release take care of it.
1325 */
1326
1327 mutex_lock(&bdev->bd_mutex);
1328 info = disk->private_data;
1329
1330 dev_warn(disk_to_dev(disk),
1331 "%s was hot-unplugged, %d stale handles\n",
1332 xbdev->nodename, bdev->bd_openers);
1333
1334 if (info && !bdev->bd_openers) {
1335 xlvbd_release_gendisk(info);
1336 disk->private_data = NULL;
1337 kfree(info);
1338 }
1339
1340 mutex_unlock(&bdev->bd_mutex);
1341 bdput(bdev);
1342
1343 return 0;
1344 }
1345
1346 static int blkfront_is_ready(struct xenbus_device *dev)
1347 {
1348 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1349
1350 return info->is_ready && info->xbdev;
1351 }
1352
1353 static int blkif_open(struct block_device *bdev, fmode_t mode)
1354 {
1355 struct gendisk *disk = bdev->bd_disk;
1356 struct blkfront_info *info;
1357 int err = 0;
1358
1359 mutex_lock(&blkfront_mutex);
1360
1361 info = disk->private_data;
1362 if (!info) {
1363 /* xbdev gone */
1364 err = -ERESTARTSYS;
1365 goto out;
1366 }
1367
1368 mutex_lock(&info->mutex);
1369
1370 if (!info->gd)
1371 /* xbdev is closed */
1372 err = -ERESTARTSYS;
1373
1374 mutex_unlock(&info->mutex);
1375
1376 out:
1377 mutex_unlock(&blkfront_mutex);
1378 return err;
1379 }
1380
1381 static int blkif_release(struct gendisk *disk, fmode_t mode)
1382 {
1383 struct blkfront_info *info = disk->private_data;
1384 struct block_device *bdev;
1385 struct xenbus_device *xbdev;
1386
1387 mutex_lock(&blkfront_mutex);
1388
1389 bdev = bdget_disk(disk, 0);
1390 bdput(bdev);
1391
1392 if (bdev->bd_openers)
1393 goto out;
1394
1395 /*
1396 * Check if we have been instructed to close. We will have
1397 * deferred this request, because the bdev was still open.
1398 */
1399
1400 mutex_lock(&info->mutex);
1401 xbdev = info->xbdev;
1402
1403 if (xbdev && xbdev->state == XenbusStateClosing) {
1404 /* pending switch to state closed */
1405 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1406 xlvbd_release_gendisk(info);
1407 xenbus_frontend_closed(info->xbdev);
1408 }
1409
1410 mutex_unlock(&info->mutex);
1411
1412 if (!xbdev) {
1413 /* sudden device removal */
1414 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1415 xlvbd_release_gendisk(info);
1416 disk->private_data = NULL;
1417 kfree(info);
1418 }
1419
1420 out:
1421 mutex_unlock(&blkfront_mutex);
1422 return 0;
1423 }
1424
1425 static const struct block_device_operations xlvbd_block_fops =
1426 {
1427 .owner = THIS_MODULE,
1428 .open = blkif_open,
1429 .release = blkif_release,
1430 .getgeo = blkif_getgeo,
1431 .ioctl = blkif_ioctl,
1432 };
1433
1434
1435 static const struct xenbus_device_id blkfront_ids[] = {
1436 { "vbd" },
1437 { "" }
1438 };
1439
1440 static DEFINE_XENBUS_DRIVER(blkfront, ,
1441 .probe = blkfront_probe,
1442 .remove = blkfront_remove,
1443 .resume = blkfront_resume,
1444 .otherend_changed = blkback_changed,
1445 .is_ready = blkfront_is_ready,
1446 );
1447
1448 static int __init xlblk_init(void)
1449 {
1450 int ret;
1451
1452 if (!xen_domain())
1453 return -ENODEV;
1454
1455 if (xen_hvm_domain() && !xen_platform_pci_unplug)
1456 return -ENODEV;
1457
1458 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1459 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1460 XENVBD_MAJOR, DEV_NAME);
1461 return -ENODEV;
1462 }
1463
1464 ret = xenbus_register_frontend(&blkfront_driver);
1465 if (ret) {
1466 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
1467 return ret;
1468 }
1469
1470 return 0;
1471 }
1472 module_init(xlblk_init);
1473
1474
1475 static void __exit xlblk_exit(void)
1476 {
1477 return xenbus_unregister_driver(&blkfront_driver);
1478 }
1479 module_exit(xlblk_exit);
1480
1481 MODULE_DESCRIPTION("Xen virtual block device frontend");
1482 MODULE_LICENSE("GPL");
1483 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1484 MODULE_ALIAS("xen:vbd");
1485 MODULE_ALIAS("xenblk");
Linux kernel - Deliverables
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