4 * XenLinux virtual block device driver.
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
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:
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:
26 * The above copyright notice and this permission notice shall be included in
27 * all copies or substantial portions of the Software.
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
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 #include <linux/bitmap.h>
49 #include <xen/xenbus.h>
50 #include <xen/grant_table.h>
51 #include <xen/events.h>
53 #include <xen/platform_pci.h>
55 #include <xen/interface/grant_table.h>
56 #include <xen/interface/io/blkif.h>
57 #include <xen/interface/io/protocols.h>
59 #include <asm/xen/hypervisor.h>
62 BLKIF_STATE_DISCONNECTED
,
63 BLKIF_STATE_CONNECTED
,
64 BLKIF_STATE_SUSPENDED
,
68 struct blkif_request req
;
69 struct request
*request
;
70 unsigned long frame
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
73 static DEFINE_MUTEX(blkfront_mutex
);
74 static const struct block_device_operations xlvbd_block_fops
;
76 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
79 * We have one of these per vbd, whether ide, scsi or 'other'. They
80 * hang in private_data off the gendisk structure. We may end up
81 * putting all kinds of interesting stuff here :-)
87 struct xenbus_device
*xbdev
;
91 enum blkif_state connected
;
93 struct blkif_front_ring ring
;
94 struct scatterlist sg
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
95 unsigned int evtchn
, irq
;
96 struct request_queue
*rq
;
97 struct work_struct work
;
98 struct gnttab_free_callback callback
;
99 struct blk_shadow shadow
[BLK_RING_SIZE
];
100 unsigned long shadow_free
;
101 unsigned int feature_flush
;
102 unsigned int flush_op
;
103 unsigned int feature_discard
:1;
104 unsigned int feature_secdiscard
:1;
105 unsigned int discard_granularity
;
106 unsigned int discard_alignment
;
110 static unsigned int nr_minors
;
111 static unsigned long *minors
;
112 static DEFINE_SPINLOCK(minor_lock
);
114 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
115 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
116 #define GRANT_INVALID_REF 0
118 #define PARTS_PER_DISK 16
119 #define PARTS_PER_EXT_DISK 256
121 #define BLKIF_MAJOR(dev) ((dev)>>8)
122 #define BLKIF_MINOR(dev) ((dev) & 0xff)
125 #define EXTENDED (1<<EXT_SHIFT)
126 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
127 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
128 #define EMULATED_HD_DISK_MINOR_OFFSET (0)
129 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
130 #define EMULATED_SD_DISK_MINOR_OFFSET (0)
131 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
133 #define DEV_NAME "xvd" /* name in /dev */
135 static int get_id_from_freelist(struct blkfront_info
*info
)
137 unsigned long free
= info
->shadow_free
;
138 BUG_ON(free
>= BLK_RING_SIZE
);
139 info
->shadow_free
= info
->shadow
[free
].req
.u
.rw
.id
;
140 info
->shadow
[free
].req
.u
.rw
.id
= 0x0fffffee; /* debug */
144 static int add_id_to_freelist(struct blkfront_info
*info
,
147 if (info
->shadow
[id
].req
.u
.rw
.id
!= id
)
149 if (info
->shadow
[id
].request
== NULL
)
151 info
->shadow
[id
].req
.u
.rw
.id
= info
->shadow_free
;
152 info
->shadow
[id
].request
= NULL
;
153 info
->shadow_free
= id
;
157 static const char *op_name(int op
)
159 static const char *const names
[] = {
160 [BLKIF_OP_READ
] = "read",
161 [BLKIF_OP_WRITE
] = "write",
162 [BLKIF_OP_WRITE_BARRIER
] = "barrier",
163 [BLKIF_OP_FLUSH_DISKCACHE
] = "flush",
164 [BLKIF_OP_DISCARD
] = "discard" };
166 if (op
< 0 || op
>= ARRAY_SIZE(names
))
174 static int xlbd_reserve_minors(unsigned int minor
, unsigned int nr
)
176 unsigned int end
= minor
+ nr
;
179 if (end
> nr_minors
) {
180 unsigned long *bitmap
, *old
;
182 bitmap
= kcalloc(BITS_TO_LONGS(end
), sizeof(*bitmap
),
187 spin_lock(&minor_lock
);
188 if (end
> nr_minors
) {
190 memcpy(bitmap
, minors
,
191 BITS_TO_LONGS(nr_minors
) * sizeof(*bitmap
));
193 nr_minors
= BITS_TO_LONGS(end
) * BITS_PER_LONG
;
196 spin_unlock(&minor_lock
);
200 spin_lock(&minor_lock
);
201 if (find_next_bit(minors
, end
, minor
) >= end
) {
202 bitmap_set(minors
, minor
, nr
);
206 spin_unlock(&minor_lock
);
211 static void xlbd_release_minors(unsigned int minor
, unsigned int nr
)
213 unsigned int end
= minor
+ nr
;
215 BUG_ON(end
> nr_minors
);
216 spin_lock(&minor_lock
);
217 bitmap_clear(minors
, minor
, nr
);
218 spin_unlock(&minor_lock
);
221 static void blkif_restart_queue_callback(void *arg
)
223 struct blkfront_info
*info
= (struct blkfront_info
*)arg
;
224 schedule_work(&info
->work
);
227 static int blkif_getgeo(struct block_device
*bd
, struct hd_geometry
*hg
)
229 /* We don't have real geometry info, but let's at least return
230 values consistent with the size of the device */
231 sector_t nsect
= get_capacity(bd
->bd_disk
);
232 sector_t cylinders
= nsect
;
236 sector_div(cylinders
, hg
->heads
* hg
->sectors
);
237 hg
->cylinders
= cylinders
;
238 if ((sector_t
)(hg
->cylinders
+ 1) * hg
->heads
* hg
->sectors
< nsect
)
239 hg
->cylinders
= 0xffff;
243 static int blkif_ioctl(struct block_device
*bdev
, fmode_t mode
,
244 unsigned command
, unsigned long argument
)
246 struct blkfront_info
*info
= bdev
->bd_disk
->private_data
;
249 dev_dbg(&info
->xbdev
->dev
, "command: 0x%x, argument: 0x%lx\n",
250 command
, (long)argument
);
253 case CDROMMULTISESSION
:
254 dev_dbg(&info
->xbdev
->dev
, "FIXME: support multisession CDs later\n");
255 for (i
= 0; i
< sizeof(struct cdrom_multisession
); i
++)
256 if (put_user(0, (char __user
*)(argument
+ i
)))
260 case CDROM_GET_CAPABILITY
: {
261 struct gendisk
*gd
= info
->gd
;
262 if (gd
->flags
& GENHD_FL_CD
)
268 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
270 return -EINVAL
; /* same return as native Linux */
277 * Generate a Xen blkfront IO request from a blk layer request. Reads
278 * and writes are handled as expected.
280 * @req: a request struct
282 static int blkif_queue_request(struct request
*req
)
284 struct blkfront_info
*info
= req
->rq_disk
->private_data
;
285 unsigned long buffer_mfn
;
286 struct blkif_request
*ring_req
;
288 unsigned int fsect
, lsect
;
290 grant_ref_t gref_head
;
291 struct scatterlist
*sg
;
293 if (unlikely(info
->connected
!= BLKIF_STATE_CONNECTED
))
296 if (gnttab_alloc_grant_references(
297 BLKIF_MAX_SEGMENTS_PER_REQUEST
, &gref_head
) < 0) {
298 gnttab_request_free_callback(
300 blkif_restart_queue_callback
,
302 BLKIF_MAX_SEGMENTS_PER_REQUEST
);
306 /* Fill out a communications ring structure. */
307 ring_req
= RING_GET_REQUEST(&info
->ring
, info
->ring
.req_prod_pvt
);
308 id
= get_id_from_freelist(info
);
309 info
->shadow
[id
].request
= req
;
311 ring_req
->u
.rw
.id
= id
;
312 ring_req
->u
.rw
.sector_number
= (blkif_sector_t
)blk_rq_pos(req
);
313 ring_req
->u
.rw
.handle
= info
->handle
;
315 ring_req
->operation
= rq_data_dir(req
) ?
316 BLKIF_OP_WRITE
: BLKIF_OP_READ
;
318 if (req
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
)) {
320 * Ideally we can do an unordered flush-to-disk. In case the
321 * backend onlysupports barriers, use that. A barrier request
322 * a superset of FUA, so we can implement it the same
323 * way. (It's also a FLUSH+FUA, since it is
324 * guaranteed ordered WRT previous writes.)
326 ring_req
->operation
= info
->flush_op
;
329 if (unlikely(req
->cmd_flags
& (REQ_DISCARD
| REQ_SECURE
))) {
330 /* id, sector_number and handle are set above. */
331 ring_req
->operation
= BLKIF_OP_DISCARD
;
332 ring_req
->u
.discard
.nr_sectors
= blk_rq_sectors(req
);
333 if ((req
->cmd_flags
& REQ_SECURE
) && info
->feature_secdiscard
)
334 ring_req
->u
.discard
.flag
= BLKIF_DISCARD_SECURE
;
336 ring_req
->u
.discard
.flag
= 0;
338 ring_req
->u
.rw
.nr_segments
= blk_rq_map_sg(req
->q
, req
,
340 BUG_ON(ring_req
->u
.rw
.nr_segments
>
341 BLKIF_MAX_SEGMENTS_PER_REQUEST
);
343 for_each_sg(info
->sg
, sg
, ring_req
->u
.rw
.nr_segments
, i
) {
344 buffer_mfn
= pfn_to_mfn(page_to_pfn(sg_page(sg
)));
345 fsect
= sg
->offset
>> 9;
346 lsect
= fsect
+ (sg
->length
>> 9) - 1;
347 /* install a grant reference. */
348 ref
= gnttab_claim_grant_reference(&gref_head
);
349 BUG_ON(ref
== -ENOSPC
);
351 gnttab_grant_foreign_access_ref(
353 info
->xbdev
->otherend_id
,
357 info
->shadow
[id
].frame
[i
] = mfn_to_pfn(buffer_mfn
);
358 ring_req
->u
.rw
.seg
[i
] =
359 (struct blkif_request_segment
) {
362 .last_sect
= lsect
};
366 info
->ring
.req_prod_pvt
++;
368 /* Keep a private copy so we can reissue requests when recovering. */
369 info
->shadow
[id
].req
= *ring_req
;
371 gnttab_free_grant_references(gref_head
);
377 static inline void flush_requests(struct blkfront_info
*info
)
381 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info
->ring
, notify
);
384 notify_remote_via_irq(info
->irq
);
389 * read a block; request is in a request queue
391 static void do_blkif_request(struct request_queue
*rq
)
393 struct blkfront_info
*info
= NULL
;
397 pr_debug("Entered do_blkif_request\n");
401 while ((req
= blk_peek_request(rq
)) != NULL
) {
402 info
= req
->rq_disk
->private_data
;
404 if (RING_FULL(&info
->ring
))
407 blk_start_request(req
);
409 if ((req
->cmd_type
!= REQ_TYPE_FS
) ||
410 ((req
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
)) &&
412 __blk_end_request_all(req
, -EIO
);
416 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
417 "(%u/%u) buffer:%p [%s]\n",
418 req
, req
->cmd
, (unsigned long)blk_rq_pos(req
),
419 blk_rq_cur_sectors(req
), blk_rq_sectors(req
),
420 req
->buffer
, rq_data_dir(req
) ? "write" : "read");
422 if (blkif_queue_request(req
)) {
423 blk_requeue_request(rq
, req
);
425 /* Avoid pointless unplugs. */
434 flush_requests(info
);
437 static int xlvbd_init_blk_queue(struct gendisk
*gd
, u16 sector_size
)
439 struct request_queue
*rq
;
440 struct blkfront_info
*info
= gd
->private_data
;
442 rq
= blk_init_queue(do_blkif_request
, &info
->io_lock
);
446 queue_flag_set_unlocked(QUEUE_FLAG_VIRT
, rq
);
448 if (info
->feature_discard
) {
449 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
, rq
);
450 blk_queue_max_discard_sectors(rq
, get_capacity(gd
));
451 rq
->limits
.discard_granularity
= info
->discard_granularity
;
452 rq
->limits
.discard_alignment
= info
->discard_alignment
;
453 if (info
->feature_secdiscard
)
454 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD
, rq
);
457 /* Hard sector size and max sectors impersonate the equiv. hardware. */
458 blk_queue_logical_block_size(rq
, sector_size
);
459 blk_queue_max_hw_sectors(rq
, 512);
461 /* Each segment in a request is up to an aligned page in size. */
462 blk_queue_segment_boundary(rq
, PAGE_SIZE
- 1);
463 blk_queue_max_segment_size(rq
, PAGE_SIZE
);
465 /* Ensure a merged request will fit in a single I/O ring slot. */
466 blk_queue_max_segments(rq
, BLKIF_MAX_SEGMENTS_PER_REQUEST
);
468 /* Make sure buffer addresses are sector-aligned. */
469 blk_queue_dma_alignment(rq
, 511);
471 /* Make sure we don't use bounce buffers. */
472 blk_queue_bounce_limit(rq
, BLK_BOUNCE_ANY
);
480 static void xlvbd_flush(struct blkfront_info
*info
)
482 blk_queue_flush(info
->rq
, info
->feature_flush
);
483 printk(KERN_INFO
"blkfront: %s: %s: %s\n",
485 info
->flush_op
== BLKIF_OP_WRITE_BARRIER
?
486 "barrier" : (info
->flush_op
== BLKIF_OP_FLUSH_DISKCACHE
?
487 "flush diskcache" : "barrier or flush"),
488 info
->feature_flush
? "enabled" : "disabled");
491 static int xen_translate_vdev(int vdevice
, int *minor
, unsigned int *offset
)
494 major
= BLKIF_MAJOR(vdevice
);
495 *minor
= BLKIF_MINOR(vdevice
);
498 *offset
= (*minor
/ 64) + EMULATED_HD_DISK_NAME_OFFSET
;
499 *minor
= ((*minor
/ 64) * PARTS_PER_DISK
) +
500 EMULATED_HD_DISK_MINOR_OFFSET
;
503 *offset
= (*minor
/ 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET
;
504 *minor
= (((*minor
/ 64) + 2) * PARTS_PER_DISK
) +
505 EMULATED_HD_DISK_MINOR_OFFSET
;
507 case XEN_SCSI_DISK0_MAJOR
:
508 *offset
= (*minor
/ PARTS_PER_DISK
) + EMULATED_SD_DISK_NAME_OFFSET
;
509 *minor
= *minor
+ EMULATED_SD_DISK_MINOR_OFFSET
;
511 case XEN_SCSI_DISK1_MAJOR
:
512 case XEN_SCSI_DISK2_MAJOR
:
513 case XEN_SCSI_DISK3_MAJOR
:
514 case XEN_SCSI_DISK4_MAJOR
:
515 case XEN_SCSI_DISK5_MAJOR
:
516 case XEN_SCSI_DISK6_MAJOR
:
517 case XEN_SCSI_DISK7_MAJOR
:
518 *offset
= (*minor
/ PARTS_PER_DISK
) +
519 ((major
- XEN_SCSI_DISK1_MAJOR
+ 1) * 16) +
520 EMULATED_SD_DISK_NAME_OFFSET
;
522 ((major
- XEN_SCSI_DISK1_MAJOR
+ 1) * 16 * PARTS_PER_DISK
) +
523 EMULATED_SD_DISK_MINOR_OFFSET
;
525 case XEN_SCSI_DISK8_MAJOR
:
526 case XEN_SCSI_DISK9_MAJOR
:
527 case XEN_SCSI_DISK10_MAJOR
:
528 case XEN_SCSI_DISK11_MAJOR
:
529 case XEN_SCSI_DISK12_MAJOR
:
530 case XEN_SCSI_DISK13_MAJOR
:
531 case XEN_SCSI_DISK14_MAJOR
:
532 case XEN_SCSI_DISK15_MAJOR
:
533 *offset
= (*minor
/ PARTS_PER_DISK
) +
534 ((major
- XEN_SCSI_DISK8_MAJOR
+ 8) * 16) +
535 EMULATED_SD_DISK_NAME_OFFSET
;
537 ((major
- XEN_SCSI_DISK8_MAJOR
+ 8) * 16 * PARTS_PER_DISK
) +
538 EMULATED_SD_DISK_MINOR_OFFSET
;
541 *offset
= *minor
/ PARTS_PER_DISK
;
544 printk(KERN_WARNING
"blkfront: your disk configuration is "
545 "incorrect, please use an xvd device instead\n");
551 static char *encode_disk_name(char *ptr
, unsigned int n
)
554 ptr
= encode_disk_name(ptr
, n
/ 26 - 1);
559 static int xlvbd_alloc_gendisk(blkif_sector_t capacity
,
560 struct blkfront_info
*info
,
561 u16 vdisk_info
, u16 sector_size
)
571 BUG_ON(info
->gd
!= NULL
);
572 BUG_ON(info
->rq
!= NULL
);
574 if ((info
->vdevice
>>EXT_SHIFT
) > 1) {
575 /* this is above the extended range; something is wrong */
576 printk(KERN_WARNING
"blkfront: vdevice 0x%x is above the extended range; ignoring\n", info
->vdevice
);
580 if (!VDEV_IS_EXTENDED(info
->vdevice
)) {
581 err
= xen_translate_vdev(info
->vdevice
, &minor
, &offset
);
584 nr_parts
= PARTS_PER_DISK
;
586 minor
= BLKIF_MINOR_EXT(info
->vdevice
);
587 nr_parts
= PARTS_PER_EXT_DISK
;
588 offset
= minor
/ nr_parts
;
589 if (xen_hvm_domain() && offset
< EMULATED_HD_DISK_NAME_OFFSET
+ 4)
590 printk(KERN_WARNING
"blkfront: vdevice 0x%x might conflict with "
591 "emulated IDE disks,\n\t choose an xvd device name"
592 "from xvde on\n", info
->vdevice
);
594 if (minor
>> MINORBITS
) {
595 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
596 info
->vdevice
, minor
);
600 if ((minor
% nr_parts
) == 0)
601 nr_minors
= nr_parts
;
603 err
= xlbd_reserve_minors(minor
, nr_minors
);
608 gd
= alloc_disk(nr_minors
);
612 strcpy(gd
->disk_name
, DEV_NAME
);
613 ptr
= encode_disk_name(gd
->disk_name
+ sizeof(DEV_NAME
) - 1, offset
);
614 BUG_ON(ptr
>= gd
->disk_name
+ DISK_NAME_LEN
);
618 snprintf(ptr
, gd
->disk_name
+ DISK_NAME_LEN
- ptr
,
619 "%d", minor
& (nr_parts
- 1));
621 gd
->major
= XENVBD_MAJOR
;
622 gd
->first_minor
= minor
;
623 gd
->fops
= &xlvbd_block_fops
;
624 gd
->private_data
= info
;
625 gd
->driverfs_dev
= &(info
->xbdev
->dev
);
626 set_capacity(gd
, capacity
);
628 if (xlvbd_init_blk_queue(gd
, sector_size
)) {
633 info
->rq
= gd
->queue
;
638 if (vdisk_info
& VDISK_READONLY
)
641 if (vdisk_info
& VDISK_REMOVABLE
)
642 gd
->flags
|= GENHD_FL_REMOVABLE
;
644 if (vdisk_info
& VDISK_CDROM
)
645 gd
->flags
|= GENHD_FL_CD
;
650 xlbd_release_minors(minor
, nr_minors
);
655 static void xlvbd_release_gendisk(struct blkfront_info
*info
)
657 unsigned int minor
, nr_minors
;
660 if (info
->rq
== NULL
)
663 spin_lock_irqsave(&info
->io_lock
, flags
);
665 /* No more blkif_request(). */
666 blk_stop_queue(info
->rq
);
668 /* No more gnttab callback work. */
669 gnttab_cancel_free_callback(&info
->callback
);
670 spin_unlock_irqrestore(&info
->io_lock
, flags
);
672 /* Flush gnttab callback work. Must be done with no locks held. */
673 flush_work_sync(&info
->work
);
675 del_gendisk(info
->gd
);
677 minor
= info
->gd
->first_minor
;
678 nr_minors
= info
->gd
->minors
;
679 xlbd_release_minors(minor
, nr_minors
);
681 blk_cleanup_queue(info
->rq
);
688 static void kick_pending_request_queues(struct blkfront_info
*info
)
690 if (!RING_FULL(&info
->ring
)) {
691 /* Re-enable calldowns. */
692 blk_start_queue(info
->rq
);
693 /* Kick things off immediately. */
694 do_blkif_request(info
->rq
);
698 static void blkif_restart_queue(struct work_struct
*work
)
700 struct blkfront_info
*info
= container_of(work
, struct blkfront_info
, work
);
702 spin_lock_irq(&info
->io_lock
);
703 if (info
->connected
== BLKIF_STATE_CONNECTED
)
704 kick_pending_request_queues(info
);
705 spin_unlock_irq(&info
->io_lock
);
708 static void blkif_free(struct blkfront_info
*info
, int suspend
)
710 /* Prevent new requests being issued until we fix things up. */
711 spin_lock_irq(&info
->io_lock
);
712 info
->connected
= suspend
?
713 BLKIF_STATE_SUSPENDED
: BLKIF_STATE_DISCONNECTED
;
714 /* No more blkif_request(). */
716 blk_stop_queue(info
->rq
);
717 /* No more gnttab callback work. */
718 gnttab_cancel_free_callback(&info
->callback
);
719 spin_unlock_irq(&info
->io_lock
);
721 /* Flush gnttab callback work. Must be done with no locks held. */
722 flush_work_sync(&info
->work
);
724 /* Free resources associated with old device channel. */
725 if (info
->ring_ref
!= GRANT_INVALID_REF
) {
726 gnttab_end_foreign_access(info
->ring_ref
, 0,
727 (unsigned long)info
->ring
.sring
);
728 info
->ring_ref
= GRANT_INVALID_REF
;
729 info
->ring
.sring
= NULL
;
732 unbind_from_irqhandler(info
->irq
, info
);
733 info
->evtchn
= info
->irq
= 0;
737 static void blkif_completion(struct blk_shadow
*s
)
740 /* Do not let BLKIF_OP_DISCARD as nr_segment is in the same place
742 for (i
= 0; i
< s
->req
.u
.rw
.nr_segments
; i
++)
743 gnttab_end_foreign_access(s
->req
.u
.rw
.seg
[i
].gref
, 0, 0UL);
746 static irqreturn_t
blkif_interrupt(int irq
, void *dev_id
)
749 struct blkif_response
*bret
;
752 struct blkfront_info
*info
= (struct blkfront_info
*)dev_id
;
755 spin_lock_irqsave(&info
->io_lock
, flags
);
757 if (unlikely(info
->connected
!= BLKIF_STATE_CONNECTED
)) {
758 spin_unlock_irqrestore(&info
->io_lock
, flags
);
763 rp
= info
->ring
.sring
->rsp_prod
;
764 rmb(); /* Ensure we see queued responses up to 'rp'. */
766 for (i
= info
->ring
.rsp_cons
; i
!= rp
; i
++) {
769 bret
= RING_GET_RESPONSE(&info
->ring
, i
);
772 * The backend has messed up and given us an id that we would
773 * never have given to it (we stamp it up to BLK_RING_SIZE -
774 * look in get_id_from_freelist.
776 if (id
>= BLK_RING_SIZE
) {
777 WARN(1, "%s: response to %s has incorrect id (%ld)\n",
778 info
->gd
->disk_name
, op_name(bret
->operation
), id
);
779 /* We can't safely get the 'struct request' as
780 * the id is busted. */
783 req
= info
->shadow
[id
].request
;
785 if (bret
->operation
!= BLKIF_OP_DISCARD
)
786 blkif_completion(&info
->shadow
[id
]);
788 if (add_id_to_freelist(info
, id
)) {
789 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
790 info
->gd
->disk_name
, op_name(bret
->operation
), id
);
794 error
= (bret
->status
== BLKIF_RSP_OKAY
) ? 0 : -EIO
;
795 switch (bret
->operation
) {
796 case BLKIF_OP_DISCARD
:
797 if (unlikely(bret
->status
== BLKIF_RSP_EOPNOTSUPP
)) {
798 struct request_queue
*rq
= info
->rq
;
799 printk(KERN_WARNING
"blkfront: %s: %s op failed\n",
800 info
->gd
->disk_name
, op_name(bret
->operation
));
802 info
->feature_discard
= 0;
803 info
->feature_secdiscard
= 0;
804 queue_flag_clear(QUEUE_FLAG_DISCARD
, rq
);
805 queue_flag_clear(QUEUE_FLAG_SECDISCARD
, rq
);
807 __blk_end_request_all(req
, error
);
809 case BLKIF_OP_FLUSH_DISKCACHE
:
810 case BLKIF_OP_WRITE_BARRIER
:
811 if (unlikely(bret
->status
== BLKIF_RSP_EOPNOTSUPP
)) {
812 printk(KERN_WARNING
"blkfront: %s: %s op failed\n",
813 info
->gd
->disk_name
, op_name(bret
->operation
));
816 if (unlikely(bret
->status
== BLKIF_RSP_ERROR
&&
817 info
->shadow
[id
].req
.u
.rw
.nr_segments
== 0)) {
818 printk(KERN_WARNING
"blkfront: %s: empty %s op failed\n",
819 info
->gd
->disk_name
, op_name(bret
->operation
));
822 if (unlikely(error
)) {
823 if (error
== -EOPNOTSUPP
)
825 info
->feature_flush
= 0;
832 if (unlikely(bret
->status
!= BLKIF_RSP_OKAY
))
833 dev_dbg(&info
->xbdev
->dev
, "Bad return from blkdev data "
834 "request: %x\n", bret
->status
);
836 __blk_end_request_all(req
, error
);
843 info
->ring
.rsp_cons
= i
;
845 if (i
!= info
->ring
.req_prod_pvt
) {
847 RING_FINAL_CHECK_FOR_RESPONSES(&info
->ring
, more_to_do
);
851 info
->ring
.sring
->rsp_event
= i
+ 1;
853 kick_pending_request_queues(info
);
855 spin_unlock_irqrestore(&info
->io_lock
, flags
);
861 static int setup_blkring(struct xenbus_device
*dev
,
862 struct blkfront_info
*info
)
864 struct blkif_sring
*sring
;
867 info
->ring_ref
= GRANT_INVALID_REF
;
869 sring
= (struct blkif_sring
*)__get_free_page(GFP_NOIO
| __GFP_HIGH
);
871 xenbus_dev_fatal(dev
, -ENOMEM
, "allocating shared ring");
874 SHARED_RING_INIT(sring
);
875 FRONT_RING_INIT(&info
->ring
, sring
, PAGE_SIZE
);
877 sg_init_table(info
->sg
, BLKIF_MAX_SEGMENTS_PER_REQUEST
);
879 err
= xenbus_grant_ring(dev
, virt_to_mfn(info
->ring
.sring
));
881 free_page((unsigned long)sring
);
882 info
->ring
.sring
= NULL
;
885 info
->ring_ref
= err
;
887 err
= xenbus_alloc_evtchn(dev
, &info
->evtchn
);
891 err
= bind_evtchn_to_irqhandler(info
->evtchn
, blkif_interrupt
, 0,
894 xenbus_dev_fatal(dev
, err
,
895 "bind_evtchn_to_irqhandler failed");
907 /* Common code used when first setting up, and when resuming. */
908 static int talk_to_blkback(struct xenbus_device
*dev
,
909 struct blkfront_info
*info
)
911 const char *message
= NULL
;
912 struct xenbus_transaction xbt
;
915 /* Create shared ring, alloc event channel. */
916 err
= setup_blkring(dev
, info
);
921 err
= xenbus_transaction_start(&xbt
);
923 xenbus_dev_fatal(dev
, err
, "starting transaction");
924 goto destroy_blkring
;
927 err
= xenbus_printf(xbt
, dev
->nodename
,
928 "ring-ref", "%u", info
->ring_ref
);
930 message
= "writing ring-ref";
931 goto abort_transaction
;
933 err
= xenbus_printf(xbt
, dev
->nodename
,
934 "event-channel", "%u", info
->evtchn
);
936 message
= "writing event-channel";
937 goto abort_transaction
;
939 err
= xenbus_printf(xbt
, dev
->nodename
, "protocol", "%s",
940 XEN_IO_PROTO_ABI_NATIVE
);
942 message
= "writing protocol";
943 goto abort_transaction
;
946 err
= xenbus_transaction_end(xbt
, 0);
950 xenbus_dev_fatal(dev
, err
, "completing transaction");
951 goto destroy_blkring
;
954 xenbus_switch_state(dev
, XenbusStateInitialised
);
959 xenbus_transaction_end(xbt
, 1);
961 xenbus_dev_fatal(dev
, err
, "%s", message
);
969 * Entry point to this code when a new device is created. Allocate the basic
970 * structures and the ring buffer for communication with the backend, and
971 * inform the backend of the appropriate details for those. Switch to
974 static int blkfront_probe(struct xenbus_device
*dev
,
975 const struct xenbus_device_id
*id
)
978 struct blkfront_info
*info
;
980 /* FIXME: Use dynamic device id if this is not set. */
981 err
= xenbus_scanf(XBT_NIL
, dev
->nodename
,
982 "virtual-device", "%i", &vdevice
);
984 /* go looking in the extended area instead */
985 err
= xenbus_scanf(XBT_NIL
, dev
->nodename
, "virtual-device-ext",
988 xenbus_dev_fatal(dev
, err
, "reading virtual-device");
993 if (xen_hvm_domain()) {
996 /* no unplug has been done: do not hook devices != xen vbds */
997 if (xen_platform_pci_unplug
& XEN_UNPLUG_UNNECESSARY
) {
1000 if (!VDEV_IS_EXTENDED(vdevice
))
1001 major
= BLKIF_MAJOR(vdevice
);
1003 major
= XENVBD_MAJOR
;
1005 if (major
!= XENVBD_MAJOR
) {
1007 "%s: HVM does not support vbd %d as xen block device\n",
1008 __FUNCTION__
, vdevice
);
1012 /* do not create a PV cdrom device if we are an HVM guest */
1013 type
= xenbus_read(XBT_NIL
, dev
->nodename
, "device-type", &len
);
1016 if (strncmp(type
, "cdrom", 5) == 0) {
1022 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
1024 xenbus_dev_fatal(dev
, -ENOMEM
, "allocating info structure");
1028 mutex_init(&info
->mutex
);
1029 spin_lock_init(&info
->io_lock
);
1031 info
->vdevice
= vdevice
;
1032 info
->connected
= BLKIF_STATE_DISCONNECTED
;
1033 INIT_WORK(&info
->work
, blkif_restart_queue
);
1035 for (i
= 0; i
< BLK_RING_SIZE
; i
++)
1036 info
->shadow
[i
].req
.u
.rw
.id
= i
+1;
1037 info
->shadow
[BLK_RING_SIZE
-1].req
.u
.rw
.id
= 0x0fffffff;
1039 /* Front end dir is a number, which is used as the id. */
1040 info
->handle
= simple_strtoul(strrchr(dev
->nodename
, '/')+1, NULL
, 0);
1041 dev_set_drvdata(&dev
->dev
, info
);
1043 err
= talk_to_blkback(dev
, info
);
1046 dev_set_drvdata(&dev
->dev
, NULL
);
1054 static int blkif_recover(struct blkfront_info
*info
)
1057 struct blkif_request
*req
;
1058 struct blk_shadow
*copy
;
1061 /* Stage 1: Make a safe copy of the shadow state. */
1062 copy
= kmalloc(sizeof(info
->shadow
),
1063 GFP_NOIO
| __GFP_REPEAT
| __GFP_HIGH
);
1066 memcpy(copy
, info
->shadow
, sizeof(info
->shadow
));
1068 /* Stage 2: Set up free list. */
1069 memset(&info
->shadow
, 0, sizeof(info
->shadow
));
1070 for (i
= 0; i
< BLK_RING_SIZE
; i
++)
1071 info
->shadow
[i
].req
.u
.rw
.id
= i
+1;
1072 info
->shadow_free
= info
->ring
.req_prod_pvt
;
1073 info
->shadow
[BLK_RING_SIZE
-1].req
.u
.rw
.id
= 0x0fffffff;
1075 /* Stage 3: Find pending requests and requeue them. */
1076 for (i
= 0; i
< BLK_RING_SIZE
; i
++) {
1078 if (!copy
[i
].request
)
1081 /* Grab a request slot and copy shadow state into it. */
1082 req
= RING_GET_REQUEST(&info
->ring
, info
->ring
.req_prod_pvt
);
1085 /* We get a new request id, and must reset the shadow state. */
1086 req
->u
.rw
.id
= get_id_from_freelist(info
);
1087 memcpy(&info
->shadow
[req
->u
.rw
.id
], ©
[i
], sizeof(copy
[i
]));
1089 if (req
->operation
!= BLKIF_OP_DISCARD
) {
1090 /* Rewrite any grant references invalidated by susp/resume. */
1091 for (j
= 0; j
< req
->u
.rw
.nr_segments
; j
++)
1092 gnttab_grant_foreign_access_ref(
1093 req
->u
.rw
.seg
[j
].gref
,
1094 info
->xbdev
->otherend_id
,
1095 pfn_to_mfn(info
->shadow
[req
->u
.rw
.id
].frame
[j
]),
1096 rq_data_dir(info
->shadow
[req
->u
.rw
.id
].request
));
1098 info
->shadow
[req
->u
.rw
.id
].req
= *req
;
1100 info
->ring
.req_prod_pvt
++;
1105 xenbus_switch_state(info
->xbdev
, XenbusStateConnected
);
1107 spin_lock_irq(&info
->io_lock
);
1109 /* Now safe for us to use the shared ring */
1110 info
->connected
= BLKIF_STATE_CONNECTED
;
1112 /* Send off requeued requests */
1113 flush_requests(info
);
1115 /* Kick any other new requests queued since we resumed */
1116 kick_pending_request_queues(info
);
1118 spin_unlock_irq(&info
->io_lock
);
1124 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1125 * driver restart. We tear down our blkif structure and recreate it, but
1126 * leave the device-layer structures intact so that this is transparent to the
1127 * rest of the kernel.
1129 static int blkfront_resume(struct xenbus_device
*dev
)
1131 struct blkfront_info
*info
= dev_get_drvdata(&dev
->dev
);
1134 dev_dbg(&dev
->dev
, "blkfront_resume: %s\n", dev
->nodename
);
1136 blkif_free(info
, info
->connected
== BLKIF_STATE_CONNECTED
);
1138 err
= talk_to_blkback(dev
, info
);
1139 if (info
->connected
== BLKIF_STATE_SUSPENDED
&& !err
)
1140 err
= blkif_recover(info
);
1146 blkfront_closing(struct blkfront_info
*info
)
1148 struct xenbus_device
*xbdev
= info
->xbdev
;
1149 struct block_device
*bdev
= NULL
;
1151 mutex_lock(&info
->mutex
);
1153 if (xbdev
->state
== XenbusStateClosing
) {
1154 mutex_unlock(&info
->mutex
);
1159 bdev
= bdget_disk(info
->gd
, 0);
1161 mutex_unlock(&info
->mutex
);
1164 xenbus_frontend_closed(xbdev
);
1168 mutex_lock(&bdev
->bd_mutex
);
1170 if (bdev
->bd_openers
) {
1171 xenbus_dev_error(xbdev
, -EBUSY
,
1172 "Device in use; refusing to close");
1173 xenbus_switch_state(xbdev
, XenbusStateClosing
);
1175 xlvbd_release_gendisk(info
);
1176 xenbus_frontend_closed(xbdev
);
1179 mutex_unlock(&bdev
->bd_mutex
);
1183 static void blkfront_setup_discard(struct blkfront_info
*info
)
1187 unsigned int discard_granularity
;
1188 unsigned int discard_alignment
;
1189 unsigned int discard_secure
;
1191 type
= xenbus_read(XBT_NIL
, info
->xbdev
->otherend
, "type", NULL
);
1195 info
->feature_secdiscard
= 0;
1196 if (strncmp(type
, "phy", 3) == 0) {
1197 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1198 "discard-granularity", "%u", &discard_granularity
,
1199 "discard-alignment", "%u", &discard_alignment
,
1202 info
->feature_discard
= 1;
1203 info
->discard_granularity
= discard_granularity
;
1204 info
->discard_alignment
= discard_alignment
;
1206 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1207 "discard-secure", "%d", &discard_secure
,
1210 info
->feature_secdiscard
= discard_secure
;
1212 } else if (strncmp(type
, "file", 4) == 0)
1213 info
->feature_discard
= 1;
1219 * Invoked when the backend is finally 'ready' (and has told produced
1220 * the details about the physical device - #sectors, size, etc).
1222 static void blkfront_connect(struct blkfront_info
*info
)
1224 unsigned long long sectors
;
1225 unsigned long sector_size
;
1228 int barrier
, flush
, discard
;
1230 switch (info
->connected
) {
1231 case BLKIF_STATE_CONNECTED
:
1233 * Potentially, the back-end may be signalling
1234 * a capacity change; update the capacity.
1236 err
= xenbus_scanf(XBT_NIL
, info
->xbdev
->otherend
,
1237 "sectors", "%Lu", §ors
);
1238 if (XENBUS_EXIST_ERR(err
))
1240 printk(KERN_INFO
"Setting capacity to %Lu\n",
1242 set_capacity(info
->gd
, sectors
);
1243 revalidate_disk(info
->gd
);
1246 case BLKIF_STATE_SUSPENDED
:
1253 dev_dbg(&info
->xbdev
->dev
, "%s:%s.\n",
1254 __func__
, info
->xbdev
->otherend
);
1256 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1257 "sectors", "%llu", §ors
,
1258 "info", "%u", &binfo
,
1259 "sector-size", "%lu", §or_size
,
1262 xenbus_dev_fatal(info
->xbdev
, err
,
1263 "reading backend fields at %s",
1264 info
->xbdev
->otherend
);
1268 info
->feature_flush
= 0;
1271 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1272 "feature-barrier", "%d", &barrier
,
1276 * If there's no "feature-barrier" defined, then it means
1277 * we're dealing with a very old backend which writes
1278 * synchronously; nothing to do.
1280 * If there are barriers, then we use flush.
1282 if (!err
&& barrier
) {
1283 info
->feature_flush
= REQ_FLUSH
| REQ_FUA
;
1284 info
->flush_op
= BLKIF_OP_WRITE_BARRIER
;
1287 * And if there is "feature-flush-cache" use that above
1290 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1291 "feature-flush-cache", "%d", &flush
,
1294 if (!err
&& flush
) {
1295 info
->feature_flush
= REQ_FLUSH
;
1296 info
->flush_op
= BLKIF_OP_FLUSH_DISKCACHE
;
1299 err
= xenbus_gather(XBT_NIL
, info
->xbdev
->otherend
,
1300 "feature-discard", "%d", &discard
,
1303 if (!err
&& discard
)
1304 blkfront_setup_discard(info
);
1306 err
= xlvbd_alloc_gendisk(sectors
, info
, binfo
, sector_size
);
1308 xenbus_dev_fatal(info
->xbdev
, err
, "xlvbd_add at %s",
1309 info
->xbdev
->otherend
);
1313 xenbus_switch_state(info
->xbdev
, XenbusStateConnected
);
1315 /* Kick pending requests. */
1316 spin_lock_irq(&info
->io_lock
);
1317 info
->connected
= BLKIF_STATE_CONNECTED
;
1318 kick_pending_request_queues(info
);
1319 spin_unlock_irq(&info
->io_lock
);
1327 * Callback received when the backend's state changes.
1329 static void blkback_changed(struct xenbus_device
*dev
,
1330 enum xenbus_state backend_state
)
1332 struct blkfront_info
*info
= dev_get_drvdata(&dev
->dev
);
1334 dev_dbg(&dev
->dev
, "blkfront:blkback_changed to state %d.\n", backend_state
);
1336 switch (backend_state
) {
1337 case XenbusStateInitialising
:
1338 case XenbusStateInitWait
:
1339 case XenbusStateInitialised
:
1340 case XenbusStateReconfiguring
:
1341 case XenbusStateReconfigured
:
1342 case XenbusStateUnknown
:
1343 case XenbusStateClosed
:
1346 case XenbusStateConnected
:
1347 blkfront_connect(info
);
1350 case XenbusStateClosing
:
1351 blkfront_closing(info
);
1356 static int blkfront_remove(struct xenbus_device
*xbdev
)
1358 struct blkfront_info
*info
= dev_get_drvdata(&xbdev
->dev
);
1359 struct block_device
*bdev
= NULL
;
1360 struct gendisk
*disk
;
1362 dev_dbg(&xbdev
->dev
, "%s removed", xbdev
->nodename
);
1364 blkif_free(info
, 0);
1366 mutex_lock(&info
->mutex
);
1370 bdev
= bdget_disk(disk
, 0);
1373 mutex_unlock(&info
->mutex
);
1381 * The xbdev was removed before we reached the Closed
1382 * state. See if it's safe to remove the disk. If the bdev
1383 * isn't closed yet, we let release take care of it.
1386 mutex_lock(&bdev
->bd_mutex
);
1387 info
= disk
->private_data
;
1389 dev_warn(disk_to_dev(disk
),
1390 "%s was hot-unplugged, %d stale handles\n",
1391 xbdev
->nodename
, bdev
->bd_openers
);
1393 if (info
&& !bdev
->bd_openers
) {
1394 xlvbd_release_gendisk(info
);
1395 disk
->private_data
= NULL
;
1399 mutex_unlock(&bdev
->bd_mutex
);
1405 static int blkfront_is_ready(struct xenbus_device
*dev
)
1407 struct blkfront_info
*info
= dev_get_drvdata(&dev
->dev
);
1409 return info
->is_ready
&& info
->xbdev
;
1412 static int blkif_open(struct block_device
*bdev
, fmode_t mode
)
1414 struct gendisk
*disk
= bdev
->bd_disk
;
1415 struct blkfront_info
*info
;
1418 mutex_lock(&blkfront_mutex
);
1420 info
= disk
->private_data
;
1427 mutex_lock(&info
->mutex
);
1430 /* xbdev is closed */
1433 mutex_unlock(&info
->mutex
);
1436 mutex_unlock(&blkfront_mutex
);
1440 static int blkif_release(struct gendisk
*disk
, fmode_t mode
)
1442 struct blkfront_info
*info
= disk
->private_data
;
1443 struct block_device
*bdev
;
1444 struct xenbus_device
*xbdev
;
1446 mutex_lock(&blkfront_mutex
);
1448 bdev
= bdget_disk(disk
, 0);
1450 if (bdev
->bd_openers
)
1454 * Check if we have been instructed to close. We will have
1455 * deferred this request, because the bdev was still open.
1458 mutex_lock(&info
->mutex
);
1459 xbdev
= info
->xbdev
;
1461 if (xbdev
&& xbdev
->state
== XenbusStateClosing
) {
1462 /* pending switch to state closed */
1463 dev_info(disk_to_dev(bdev
->bd_disk
), "releasing disk\n");
1464 xlvbd_release_gendisk(info
);
1465 xenbus_frontend_closed(info
->xbdev
);
1468 mutex_unlock(&info
->mutex
);
1471 /* sudden device removal */
1472 dev_info(disk_to_dev(bdev
->bd_disk
), "releasing disk\n");
1473 xlvbd_release_gendisk(info
);
1474 disk
->private_data
= NULL
;
1480 mutex_unlock(&blkfront_mutex
);
1484 static const struct block_device_operations xlvbd_block_fops
=
1486 .owner
= THIS_MODULE
,
1488 .release
= blkif_release
,
1489 .getgeo
= blkif_getgeo
,
1490 .ioctl
= blkif_ioctl
,
1494 static const struct xenbus_device_id blkfront_ids
[] = {
1499 static DEFINE_XENBUS_DRIVER(blkfront
, ,
1500 .probe
= blkfront_probe
,
1501 .remove
= blkfront_remove
,
1502 .resume
= blkfront_resume
,
1503 .otherend_changed
= blkback_changed
,
1504 .is_ready
= blkfront_is_ready
,
1507 static int __init
xlblk_init(void)
1514 if (xen_hvm_domain() && !xen_platform_pci_unplug
)
1517 if (register_blkdev(XENVBD_MAJOR
, DEV_NAME
)) {
1518 printk(KERN_WARNING
"xen_blk: can't get major %d with name %s\n",
1519 XENVBD_MAJOR
, DEV_NAME
);
1523 ret
= xenbus_register_frontend(&blkfront_driver
);
1525 unregister_blkdev(XENVBD_MAJOR
, DEV_NAME
);
1531 module_init(xlblk_init
);
1534 static void __exit
xlblk_exit(void)
1536 xenbus_unregister_driver(&blkfront_driver
);
1537 unregister_blkdev(XENVBD_MAJOR
, DEV_NAME
);
1540 module_exit(xlblk_exit
);
1542 MODULE_DESCRIPTION("Xen virtual block device frontend");
1543 MODULE_LICENSE("GPL");
1544 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR
);
1545 MODULE_ALIAS("xen:vbd");
1546 MODULE_ALIAS("xenblk");