2 #include <linux/spinlock.h>
3 #include <linux/slab.h>
4 #include <linux/blkdev.h>
5 #include <linux/hdreg.h>
6 #include <linux/module.h>
7 #include <linux/mutex.h>
8 #include <linux/virtio.h>
9 #include <linux/virtio_blk.h>
10 #include <linux/scatterlist.h>
11 #include <linux/string_helpers.h>
12 #include <scsi/scsi_cmnd.h>
13 #include <linux/idr.h>
18 static DEFINE_IDA(vd_index_ida
);
20 struct workqueue_struct
*virtblk_wq
;
26 struct virtio_device
*vdev
;
29 /* The disk structure for the kernel. */
34 /* Process context for config space updates */
35 struct work_struct config_work
;
37 /* Lock for config space updates */
38 struct mutex config_lock
;
40 /* enable config space updates */
43 /* What host tells us, plus 2 for header & tailer. */
44 unsigned int sg_elems
;
46 /* Ida index - used to track minor number allocations. */
49 /* Scatterlist: can be too big for stack. */
50 struct scatterlist sg
[/*sg_elems*/];
56 struct virtio_blk_outhdr out_hdr
;
57 struct virtio_scsi_inhdr in_hdr
;
61 static void blk_done(struct virtqueue
*vq
)
63 struct virtio_blk
*vblk
= vq
->vdev
->priv
;
64 struct virtblk_req
*vbr
;
68 spin_lock_irqsave(&vblk
->lock
, flags
);
69 while ((vbr
= virtqueue_get_buf(vblk
->vq
, &len
)) != NULL
) {
72 switch (vbr
->status
) {
76 case VIRTIO_BLK_S_UNSUPP
:
84 switch (vbr
->req
->cmd_type
) {
85 case REQ_TYPE_BLOCK_PC
:
86 vbr
->req
->resid_len
= vbr
->in_hdr
.residual
;
87 vbr
->req
->sense_len
= vbr
->in_hdr
.sense_len
;
88 vbr
->req
->errors
= vbr
->in_hdr
.errors
;
90 case REQ_TYPE_SPECIAL
:
91 vbr
->req
->errors
= (error
!= 0);
97 __blk_end_request_all(vbr
->req
, error
);
98 mempool_free(vbr
, vblk
->pool
);
100 /* In case queue is stopped waiting for more buffers. */
101 blk_start_queue(vblk
->disk
->queue
);
102 spin_unlock_irqrestore(&vblk
->lock
, flags
);
105 static bool do_req(struct request_queue
*q
, struct virtio_blk
*vblk
,
108 unsigned long num
, out
= 0, in
= 0;
109 struct virtblk_req
*vbr
;
111 vbr
= mempool_alloc(vblk
->pool
, GFP_ATOMIC
);
113 /* When another request finishes we'll try again. */
118 if (req
->cmd_flags
& REQ_FLUSH
) {
119 vbr
->out_hdr
.type
= VIRTIO_BLK_T_FLUSH
;
120 vbr
->out_hdr
.sector
= 0;
121 vbr
->out_hdr
.ioprio
= req_get_ioprio(vbr
->req
);
123 switch (req
->cmd_type
) {
125 vbr
->out_hdr
.type
= 0;
126 vbr
->out_hdr
.sector
= blk_rq_pos(vbr
->req
);
127 vbr
->out_hdr
.ioprio
= req_get_ioprio(vbr
->req
);
129 case REQ_TYPE_BLOCK_PC
:
130 vbr
->out_hdr
.type
= VIRTIO_BLK_T_SCSI_CMD
;
131 vbr
->out_hdr
.sector
= 0;
132 vbr
->out_hdr
.ioprio
= req_get_ioprio(vbr
->req
);
134 case REQ_TYPE_SPECIAL
:
135 vbr
->out_hdr
.type
= VIRTIO_BLK_T_GET_ID
;
136 vbr
->out_hdr
.sector
= 0;
137 vbr
->out_hdr
.ioprio
= req_get_ioprio(vbr
->req
);
140 /* We don't put anything else in the queue. */
145 sg_set_buf(&vblk
->sg
[out
++], &vbr
->out_hdr
, sizeof(vbr
->out_hdr
));
148 * If this is a packet command we need a couple of additional headers.
149 * Behind the normal outhdr we put a segment with the scsi command
150 * block, and before the normal inhdr we put the sense data and the
151 * inhdr with additional status information before the normal inhdr.
153 if (vbr
->req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
154 sg_set_buf(&vblk
->sg
[out
++], vbr
->req
->cmd
, vbr
->req
->cmd_len
);
156 num
= blk_rq_map_sg(q
, vbr
->req
, vblk
->sg
+ out
);
158 if (vbr
->req
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
159 sg_set_buf(&vblk
->sg
[num
+ out
+ in
++], vbr
->req
->sense
, SCSI_SENSE_BUFFERSIZE
);
160 sg_set_buf(&vblk
->sg
[num
+ out
+ in
++], &vbr
->in_hdr
,
161 sizeof(vbr
->in_hdr
));
164 sg_set_buf(&vblk
->sg
[num
+ out
+ in
++], &vbr
->status
,
165 sizeof(vbr
->status
));
168 if (rq_data_dir(vbr
->req
) == WRITE
) {
169 vbr
->out_hdr
.type
|= VIRTIO_BLK_T_OUT
;
172 vbr
->out_hdr
.type
|= VIRTIO_BLK_T_IN
;
177 if (virtqueue_add_buf(vblk
->vq
, vblk
->sg
, out
, in
, vbr
, GFP_ATOMIC
)<0) {
178 mempool_free(vbr
, vblk
->pool
);
185 static void do_virtblk_request(struct request_queue
*q
)
187 struct virtio_blk
*vblk
= q
->queuedata
;
189 unsigned int issued
= 0;
191 while ((req
= blk_peek_request(q
)) != NULL
) {
192 BUG_ON(req
->nr_phys_segments
+ 2 > vblk
->sg_elems
);
194 /* If this request fails, stop queue and wait for something to
195 finish to restart it. */
196 if (!do_req(q
, vblk
, req
)) {
200 blk_start_request(req
);
205 virtqueue_kick(vblk
->vq
);
208 /* return id (s/n) string for *disk to *id_str
210 static int virtblk_get_id(struct gendisk
*disk
, char *id_str
)
212 struct virtio_blk
*vblk
= disk
->private_data
;
217 bio
= bio_map_kern(vblk
->disk
->queue
, id_str
, VIRTIO_BLK_ID_BYTES
,
222 req
= blk_make_request(vblk
->disk
->queue
, bio
, GFP_KERNEL
);
228 req
->cmd_type
= REQ_TYPE_SPECIAL
;
229 err
= blk_execute_rq(vblk
->disk
->queue
, vblk
->disk
, req
, false);
230 blk_put_request(req
);
235 static int virtblk_ioctl(struct block_device
*bdev
, fmode_t mode
,
236 unsigned int cmd
, unsigned long data
)
238 struct gendisk
*disk
= bdev
->bd_disk
;
239 struct virtio_blk
*vblk
= disk
->private_data
;
242 * Only allow the generic SCSI ioctls if the host can support it.
244 if (!virtio_has_feature(vblk
->vdev
, VIRTIO_BLK_F_SCSI
))
247 return scsi_cmd_blk_ioctl(bdev
, mode
, cmd
,
248 (void __user
*)data
);
251 /* We provide getgeo only to please some old bootloader/partitioning tools */
252 static int virtblk_getgeo(struct block_device
*bd
, struct hd_geometry
*geo
)
254 struct virtio_blk
*vblk
= bd
->bd_disk
->private_data
;
255 struct virtio_blk_geometry vgeo
;
258 /* see if the host passed in geometry config */
259 err
= virtio_config_val(vblk
->vdev
, VIRTIO_BLK_F_GEOMETRY
,
260 offsetof(struct virtio_blk_config
, geometry
),
264 geo
->heads
= vgeo
.heads
;
265 geo
->sectors
= vgeo
.sectors
;
266 geo
->cylinders
= vgeo
.cylinders
;
268 /* some standard values, similar to sd */
270 geo
->sectors
= 1 << 5;
271 geo
->cylinders
= get_capacity(bd
->bd_disk
) >> 11;
276 static const struct block_device_operations virtblk_fops
= {
277 .ioctl
= virtblk_ioctl
,
278 .owner
= THIS_MODULE
,
279 .getgeo
= virtblk_getgeo
,
282 static int index_to_minor(int index
)
284 return index
<< PART_BITS
;
287 static int minor_to_index(int minor
)
289 return minor
>> PART_BITS
;
292 static ssize_t
virtblk_serial_show(struct device
*dev
,
293 struct device_attribute
*attr
, char *buf
)
295 struct gendisk
*disk
= dev_to_disk(dev
);
298 /* sysfs gives us a PAGE_SIZE buffer */
299 BUILD_BUG_ON(PAGE_SIZE
< VIRTIO_BLK_ID_BYTES
);
301 buf
[VIRTIO_BLK_ID_BYTES
] = '\0';
302 err
= virtblk_get_id(disk
, buf
);
306 if (err
== -EIO
) /* Unsupported? Make it empty. */
311 DEVICE_ATTR(serial
, S_IRUGO
, virtblk_serial_show
, NULL
);
313 static void virtblk_config_changed_work(struct work_struct
*work
)
315 struct virtio_blk
*vblk
=
316 container_of(work
, struct virtio_blk
, config_work
);
317 struct virtio_device
*vdev
= vblk
->vdev
;
318 struct request_queue
*q
= vblk
->disk
->queue
;
319 char cap_str_2
[10], cap_str_10
[10];
322 mutex_lock(&vblk
->config_lock
);
323 if (!vblk
->config_enable
)
326 /* Host must always specify the capacity. */
327 vdev
->config
->get(vdev
, offsetof(struct virtio_blk_config
, capacity
),
328 &capacity
, sizeof(capacity
));
330 /* If capacity is too big, truncate with warning. */
331 if ((sector_t
)capacity
!= capacity
) {
332 dev_warn(&vdev
->dev
, "Capacity %llu too large: truncating\n",
333 (unsigned long long)capacity
);
334 capacity
= (sector_t
)-1;
337 size
= capacity
* queue_logical_block_size(q
);
338 string_get_size(size
, STRING_UNITS_2
, cap_str_2
, sizeof(cap_str_2
));
339 string_get_size(size
, STRING_UNITS_10
, cap_str_10
, sizeof(cap_str_10
));
341 dev_notice(&vdev
->dev
,
342 "new size: %llu %d-byte logical blocks (%s/%s)\n",
343 (unsigned long long)capacity
,
344 queue_logical_block_size(q
),
345 cap_str_10
, cap_str_2
);
347 set_capacity(vblk
->disk
, capacity
);
348 revalidate_disk(vblk
->disk
);
350 mutex_unlock(&vblk
->config_lock
);
353 static void virtblk_config_changed(struct virtio_device
*vdev
)
355 struct virtio_blk
*vblk
= vdev
->priv
;
357 queue_work(virtblk_wq
, &vblk
->config_work
);
360 static int init_vq(struct virtio_blk
*vblk
)
364 /* We expect one virtqueue, for output. */
365 vblk
->vq
= virtio_find_single_vq(vblk
->vdev
, blk_done
, "requests");
366 if (IS_ERR(vblk
->vq
))
367 err
= PTR_ERR(vblk
->vq
);
373 * Legacy naming scheme used for virtio devices. We are stuck with it for
374 * virtio blk but don't ever use it for any new driver.
376 static int virtblk_name_format(char *prefix
, int index
, char *buf
, int buflen
)
378 const int base
= 'z' - 'a' + 1;
379 char *begin
= buf
+ strlen(prefix
);
380 char *end
= buf
+ buflen
;
390 *--p
= 'a' + (index
% unit
);
391 index
= (index
/ unit
) - 1;
392 } while (index
>= 0);
394 memmove(begin
, p
, end
- p
);
395 memcpy(buf
, prefix
, strlen(prefix
));
400 static int __devinit
virtblk_probe(struct virtio_device
*vdev
)
402 struct virtio_blk
*vblk
;
403 struct request_queue
*q
;
406 u32 v
, blk_size
, sg_elems
, opt_io_size
;
408 u8 physical_block_exp
, alignment_offset
;
410 err
= ida_simple_get(&vd_index_ida
, 0, minor_to_index(1 << MINORBITS
),
416 /* We need to know how many segments before we allocate. */
417 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_SEG_MAX
,
418 offsetof(struct virtio_blk_config
, seg_max
),
421 /* We need at least one SG element, whatever they say. */
422 if (err
|| !sg_elems
)
425 /* We need an extra sg elements at head and tail. */
427 vdev
->priv
= vblk
= kmalloc(sizeof(*vblk
) +
428 sizeof(vblk
->sg
[0]) * sg_elems
, GFP_KERNEL
);
434 spin_lock_init(&vblk
->lock
);
436 vblk
->sg_elems
= sg_elems
;
437 sg_init_table(vblk
->sg
, vblk
->sg_elems
);
438 mutex_init(&vblk
->config_lock
);
439 INIT_WORK(&vblk
->config_work
, virtblk_config_changed_work
);
440 vblk
->config_enable
= true;
446 vblk
->pool
= mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req
));
452 /* FIXME: How many partitions? How long is a piece of string? */
453 vblk
->disk
= alloc_disk(1 << PART_BITS
);
459 q
= vblk
->disk
->queue
= blk_init_queue(do_virtblk_request
, &vblk
->lock
);
467 virtblk_name_format("vd", index
, vblk
->disk
->disk_name
, DISK_NAME_LEN
);
469 vblk
->disk
->major
= major
;
470 vblk
->disk
->first_minor
= index_to_minor(index
);
471 vblk
->disk
->private_data
= vblk
;
472 vblk
->disk
->fops
= &virtblk_fops
;
473 vblk
->disk
->driverfs_dev
= &vdev
->dev
;
476 /* configure queue flush support */
477 if (virtio_has_feature(vdev
, VIRTIO_BLK_F_FLUSH
))
478 blk_queue_flush(q
, REQ_FLUSH
);
480 /* If disk is read-only in the host, the guest should obey */
481 if (virtio_has_feature(vdev
, VIRTIO_BLK_F_RO
))
482 set_disk_ro(vblk
->disk
, 1);
484 /* Host must always specify the capacity. */
485 vdev
->config
->get(vdev
, offsetof(struct virtio_blk_config
, capacity
),
488 /* If capacity is too big, truncate with warning. */
489 if ((sector_t
)cap
!= cap
) {
490 dev_warn(&vdev
->dev
, "Capacity %llu too large: truncating\n",
491 (unsigned long long)cap
);
494 set_capacity(vblk
->disk
, cap
);
496 /* We can handle whatever the host told us to handle. */
497 blk_queue_max_segments(q
, vblk
->sg_elems
-2);
499 /* No need to bounce any requests */
500 blk_queue_bounce_limit(q
, BLK_BOUNCE_ANY
);
502 /* No real sector limit. */
503 blk_queue_max_hw_sectors(q
, -1U);
505 /* Host can optionally specify maximum segment size and number of
507 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_SIZE_MAX
,
508 offsetof(struct virtio_blk_config
, size_max
),
511 blk_queue_max_segment_size(q
, v
);
513 blk_queue_max_segment_size(q
, -1U);
515 /* Host can optionally specify the block size of the device */
516 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_BLK_SIZE
,
517 offsetof(struct virtio_blk_config
, blk_size
),
520 blk_queue_logical_block_size(q
, blk_size
);
522 blk_size
= queue_logical_block_size(q
);
524 /* Use topology information if available */
525 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_TOPOLOGY
,
526 offsetof(struct virtio_blk_config
, physical_block_exp
),
527 &physical_block_exp
);
528 if (!err
&& physical_block_exp
)
529 blk_queue_physical_block_size(q
,
530 blk_size
* (1 << physical_block_exp
));
532 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_TOPOLOGY
,
533 offsetof(struct virtio_blk_config
, alignment_offset
),
535 if (!err
&& alignment_offset
)
536 blk_queue_alignment_offset(q
, blk_size
* alignment_offset
);
538 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_TOPOLOGY
,
539 offsetof(struct virtio_blk_config
, min_io_size
),
541 if (!err
&& min_io_size
)
542 blk_queue_io_min(q
, blk_size
* min_io_size
);
544 err
= virtio_config_val(vdev
, VIRTIO_BLK_F_TOPOLOGY
,
545 offsetof(struct virtio_blk_config
, opt_io_size
),
547 if (!err
&& opt_io_size
)
548 blk_queue_io_opt(q
, blk_size
* opt_io_size
);
551 add_disk(vblk
->disk
);
552 err
= device_create_file(disk_to_dev(vblk
->disk
), &dev_attr_serial
);
559 del_gendisk(vblk
->disk
);
560 blk_cleanup_queue(vblk
->disk
->queue
);
562 put_disk(vblk
->disk
);
564 mempool_destroy(vblk
->pool
);
566 vdev
->config
->del_vqs(vdev
);
570 ida_simple_remove(&vd_index_ida
, index
);
575 static void __devexit
virtblk_remove(struct virtio_device
*vdev
)
577 struct virtio_blk
*vblk
= vdev
->priv
;
578 int index
= vblk
->index
;
579 struct virtblk_req
*vbr
;
582 /* Prevent config work handler from accessing the device. */
583 mutex_lock(&vblk
->config_lock
);
584 vblk
->config_enable
= false;
585 mutex_unlock(&vblk
->config_lock
);
587 /* Stop all the virtqueues. */
588 vdev
->config
->reset(vdev
);
590 flush_work(&vblk
->config_work
);
592 del_gendisk(vblk
->disk
);
594 /* Abort requests dispatched to driver. */
595 spin_lock_irqsave(&vblk
->lock
, flags
);
596 while ((vbr
= virtqueue_detach_unused_buf(vblk
->vq
))) {
597 __blk_end_request_all(vbr
->req
, -EIO
);
598 mempool_free(vbr
, vblk
->pool
);
600 spin_unlock_irqrestore(&vblk
->lock
, flags
);
602 blk_cleanup_queue(vblk
->disk
->queue
);
603 put_disk(vblk
->disk
);
604 mempool_destroy(vblk
->pool
);
605 vdev
->config
->del_vqs(vdev
);
607 ida_simple_remove(&vd_index_ida
, index
);
611 static int virtblk_freeze(struct virtio_device
*vdev
)
613 struct virtio_blk
*vblk
= vdev
->priv
;
615 /* Ensure we don't receive any more interrupts */
616 vdev
->config
->reset(vdev
);
618 /* Prevent config work handler from accessing the device. */
619 mutex_lock(&vblk
->config_lock
);
620 vblk
->config_enable
= false;
621 mutex_unlock(&vblk
->config_lock
);
623 flush_work(&vblk
->config_work
);
625 spin_lock_irq(vblk
->disk
->queue
->queue_lock
);
626 blk_stop_queue(vblk
->disk
->queue
);
627 spin_unlock_irq(vblk
->disk
->queue
->queue_lock
);
628 blk_sync_queue(vblk
->disk
->queue
);
630 vdev
->config
->del_vqs(vdev
);
634 static int virtblk_restore(struct virtio_device
*vdev
)
636 struct virtio_blk
*vblk
= vdev
->priv
;
639 vblk
->config_enable
= true;
640 ret
= init_vq(vdev
->priv
);
642 spin_lock_irq(vblk
->disk
->queue
->queue_lock
);
643 blk_start_queue(vblk
->disk
->queue
);
644 spin_unlock_irq(vblk
->disk
->queue
->queue_lock
);
650 static const struct virtio_device_id id_table
[] = {
651 { VIRTIO_ID_BLOCK
, VIRTIO_DEV_ANY_ID
},
655 static unsigned int features
[] = {
656 VIRTIO_BLK_F_SEG_MAX
, VIRTIO_BLK_F_SIZE_MAX
, VIRTIO_BLK_F_GEOMETRY
,
657 VIRTIO_BLK_F_RO
, VIRTIO_BLK_F_BLK_SIZE
, VIRTIO_BLK_F_SCSI
,
658 VIRTIO_BLK_F_FLUSH
, VIRTIO_BLK_F_TOPOLOGY
662 * virtio_blk causes spurious section mismatch warning by
663 * simultaneously referring to a __devinit and a __devexit function.
664 * Use __refdata to avoid this warning.
666 static struct virtio_driver __refdata virtio_blk
= {
667 .feature_table
= features
,
668 .feature_table_size
= ARRAY_SIZE(features
),
669 .driver
.name
= KBUILD_MODNAME
,
670 .driver
.owner
= THIS_MODULE
,
671 .id_table
= id_table
,
672 .probe
= virtblk_probe
,
673 .remove
= __devexit_p(virtblk_remove
),
674 .config_changed
= virtblk_config_changed
,
676 .freeze
= virtblk_freeze
,
677 .restore
= virtblk_restore
,
681 static int __init
init(void)
685 virtblk_wq
= alloc_workqueue("virtio-blk", 0, 0);
689 major
= register_blkdev(0, "virtblk");
692 goto out_destroy_workqueue
;
695 error
= register_virtio_driver(&virtio_blk
);
697 goto out_unregister_blkdev
;
700 out_unregister_blkdev
:
701 unregister_blkdev(major
, "virtblk");
702 out_destroy_workqueue
:
703 destroy_workqueue(virtblk_wq
);
707 static void __exit
fini(void)
709 unregister_blkdev(major
, "virtblk");
710 unregister_virtio_driver(&virtio_blk
);
711 destroy_workqueue(virtblk_wq
);
716 MODULE_DEVICE_TABLE(virtio
, id_table
);
717 MODULE_DESCRIPTION("Virtio block driver");
718 MODULE_LICENSE("GPL");