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>
14 #include <linux/blk-mq.h>
15 #include <linux/numa.h>
20 static DEFINE_IDA(vd_index_ida);
22 static struct workqueue_struct *virtblk_wq;
26 struct virtio_device *vdev;
30 /* The disk structure for the kernel. */
33 /* Block layer tags. */
34 struct blk_mq_tag_set tag_set;
36 /* Process context for config space updates */
37 struct work_struct config_work;
39 /* Lock for config space updates */
40 struct mutex config_lock;
42 /* enable config space updates */
45 /* What host tells us, plus 2 for header & tailer. */
46 unsigned int sg_elems;
48 /* Ida index - used to track minor number allocations. */
55 struct virtio_blk_outhdr out_hdr;
56 struct virtio_scsi_inhdr in_hdr;
58 struct scatterlist sg[];
61 static inline int virtblk_result(struct virtblk_req *vbr)
63 switch (vbr->status) {
66 case VIRTIO_BLK_S_UNSUPP:
73 static int __virtblk_add_req(struct virtqueue *vq,
74 struct virtblk_req *vbr,
75 struct scatterlist *data_sg,
78 struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
79 unsigned int num_out = 0, num_in = 0;
80 int type = vbr->out_hdr.type & ~VIRTIO_BLK_T_OUT;
82 sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
83 sgs[num_out++] = &hdr;
86 * If this is a packet command we need a couple of additional headers.
87 * Behind the normal outhdr we put a segment with the scsi command
88 * block, and before the normal inhdr we put the sense data and the
89 * inhdr with additional status information.
91 if (type == VIRTIO_BLK_T_SCSI_CMD) {
92 sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
93 sgs[num_out++] = &cmd;
97 if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT)
98 sgs[num_out++] = data_sg;
100 sgs[num_out + num_in++] = data_sg;
103 if (type == VIRTIO_BLK_T_SCSI_CMD) {
104 sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
105 sgs[num_out + num_in++] = &sense;
106 sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr));
107 sgs[num_out + num_in++] = &inhdr;
110 sg_init_one(&status, &vbr->status, sizeof(vbr->status));
111 sgs[num_out + num_in++] = &status;
113 return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
116 static inline void virtblk_request_done(struct request *req)
118 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
119 int error = virtblk_result(vbr);
121 if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
122 req->resid_len = vbr->in_hdr.residual;
123 req->sense_len = vbr->in_hdr.sense_len;
124 req->errors = vbr->in_hdr.errors;
125 } else if (req->cmd_type == REQ_TYPE_SPECIAL) {
126 req->errors = (error != 0);
129 blk_mq_end_io(req, error);
132 static void virtblk_done(struct virtqueue *vq)
134 struct virtio_blk *vblk = vq->vdev->priv;
135 bool req_done = false;
136 struct virtblk_req *vbr;
140 spin_lock_irqsave(&vblk->vq_lock, flags);
142 virtqueue_disable_cb(vq);
143 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
144 blk_mq_complete_request(vbr->req);
147 if (unlikely(virtqueue_is_broken(vq)))
149 } while (!virtqueue_enable_cb(vq));
151 /* In case queue is stopped waiting for more buffers. */
153 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
154 spin_unlock_irqrestore(&vblk->vq_lock, flags);
157 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
159 struct virtio_blk *vblk = hctx->queue->queuedata;
160 struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
163 const bool last = (req->cmd_flags & REQ_END) != 0;
167 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
170 if (req->cmd_flags & REQ_FLUSH) {
171 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
172 vbr->out_hdr.sector = 0;
173 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
175 switch (req->cmd_type) {
177 vbr->out_hdr.type = 0;
178 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
179 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
181 case REQ_TYPE_BLOCK_PC:
182 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
183 vbr->out_hdr.sector = 0;
184 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
186 case REQ_TYPE_SPECIAL:
187 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
188 vbr->out_hdr.sector = 0;
189 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
192 /* We don't put anything else in the queue. */
197 num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
199 if (rq_data_dir(vbr->req) == WRITE)
200 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
202 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
205 spin_lock_irqsave(&vblk->vq_lock, flags);
206 err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num);
208 virtqueue_kick(vblk->vq);
209 blk_mq_stop_hw_queue(hctx);
210 spin_unlock_irqrestore(&vblk->vq_lock, flags);
211 /* Out of mem doesn't actually happen, since we fall back
212 * to direct descriptors */
213 if (err == -ENOMEM || err == -ENOSPC)
214 return BLK_MQ_RQ_QUEUE_BUSY;
215 return BLK_MQ_RQ_QUEUE_ERROR;
218 if (last && virtqueue_kick_prepare(vblk->vq))
220 spin_unlock_irqrestore(&vblk->vq_lock, flags);
223 virtqueue_notify(vblk->vq);
224 return BLK_MQ_RQ_QUEUE_OK;
227 /* return id (s/n) string for *disk to *id_str
229 static int virtblk_get_id(struct gendisk *disk, char *id_str)
231 struct virtio_blk *vblk = disk->private_data;
236 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
241 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
247 req->cmd_type = REQ_TYPE_SPECIAL;
248 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
249 blk_put_request(req);
254 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
255 unsigned int cmd, unsigned long data)
257 struct gendisk *disk = bdev->bd_disk;
258 struct virtio_blk *vblk = disk->private_data;
261 * Only allow the generic SCSI ioctls if the host can support it.
263 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
266 return scsi_cmd_blk_ioctl(bdev, mode, cmd,
267 (void __user *)data);
270 /* We provide getgeo only to please some old bootloader/partitioning tools */
271 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
273 struct virtio_blk *vblk = bd->bd_disk->private_data;
275 /* see if the host passed in geometry config */
276 if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
277 virtio_cread(vblk->vdev, struct virtio_blk_config,
278 geometry.cylinders, &geo->cylinders);
279 virtio_cread(vblk->vdev, struct virtio_blk_config,
280 geometry.heads, &geo->heads);
281 virtio_cread(vblk->vdev, struct virtio_blk_config,
282 geometry.sectors, &geo->sectors);
284 /* some standard values, similar to sd */
286 geo->sectors = 1 << 5;
287 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
292 static const struct block_device_operations virtblk_fops = {
293 .ioctl = virtblk_ioctl,
294 .owner = THIS_MODULE,
295 .getgeo = virtblk_getgeo,
298 static int index_to_minor(int index)
300 return index << PART_BITS;
303 static int minor_to_index(int minor)
305 return minor >> PART_BITS;
308 static ssize_t virtblk_serial_show(struct device *dev,
309 struct device_attribute *attr, char *buf)
311 struct gendisk *disk = dev_to_disk(dev);
314 /* sysfs gives us a PAGE_SIZE buffer */
315 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
317 buf[VIRTIO_BLK_ID_BYTES] = '\0';
318 err = virtblk_get_id(disk, buf);
322 if (err == -EIO) /* Unsupported? Make it empty. */
327 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
329 static void virtblk_config_changed_work(struct work_struct *work)
331 struct virtio_blk *vblk =
332 container_of(work, struct virtio_blk, config_work);
333 struct virtio_device *vdev = vblk->vdev;
334 struct request_queue *q = vblk->disk->queue;
335 char cap_str_2[10], cap_str_10[10];
336 char *envp[] = { "RESIZE=1", NULL };
339 mutex_lock(&vblk->config_lock);
340 if (!vblk->config_enable)
343 /* Host must always specify the capacity. */
344 virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
346 /* If capacity is too big, truncate with warning. */
347 if ((sector_t)capacity != capacity) {
348 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
349 (unsigned long long)capacity);
350 capacity = (sector_t)-1;
353 size = capacity * queue_logical_block_size(q);
354 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
355 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
357 dev_notice(&vdev->dev,
358 "new size: %llu %d-byte logical blocks (%s/%s)\n",
359 (unsigned long long)capacity,
360 queue_logical_block_size(q),
361 cap_str_10, cap_str_2);
363 set_capacity(vblk->disk, capacity);
364 revalidate_disk(vblk->disk);
365 kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
367 mutex_unlock(&vblk->config_lock);
370 static void virtblk_config_changed(struct virtio_device *vdev)
372 struct virtio_blk *vblk = vdev->priv;
374 queue_work(virtblk_wq, &vblk->config_work);
377 static int init_vq(struct virtio_blk *vblk)
381 /* We expect one virtqueue, for output. */
382 vblk->vq = virtio_find_single_vq(vblk->vdev, virtblk_done, "requests");
383 if (IS_ERR(vblk->vq))
384 err = PTR_ERR(vblk->vq);
390 * Legacy naming scheme used for virtio devices. We are stuck with it for
391 * virtio blk but don't ever use it for any new driver.
393 static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
395 const int base = 'z' - 'a' + 1;
396 char *begin = buf + strlen(prefix);
397 char *end = buf + buflen;
407 *--p = 'a' + (index % unit);
408 index = (index / unit) - 1;
409 } while (index >= 0);
411 memmove(begin, p, end - p);
412 memcpy(buf, prefix, strlen(prefix));
417 static int virtblk_get_cache_mode(struct virtio_device *vdev)
422 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
423 struct virtio_blk_config, wce,
426 writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
431 static void virtblk_update_cache_mode(struct virtio_device *vdev)
433 u8 writeback = virtblk_get_cache_mode(vdev);
434 struct virtio_blk *vblk = vdev->priv;
437 blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
439 blk_queue_flush(vblk->disk->queue, 0);
441 revalidate_disk(vblk->disk);
444 static const char *const virtblk_cache_types[] = {
445 "write through", "write back"
449 virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
450 const char *buf, size_t count)
452 struct gendisk *disk = dev_to_disk(dev);
453 struct virtio_blk *vblk = disk->private_data;
454 struct virtio_device *vdev = vblk->vdev;
457 BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
458 for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
459 if (sysfs_streq(buf, virtblk_cache_types[i]))
465 virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
466 virtblk_update_cache_mode(vdev);
471 virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
474 struct gendisk *disk = dev_to_disk(dev);
475 struct virtio_blk *vblk = disk->private_data;
476 u8 writeback = virtblk_get_cache_mode(vblk->vdev);
478 BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
479 return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
482 static const struct device_attribute dev_attr_cache_type_ro =
483 __ATTR(cache_type, S_IRUGO,
484 virtblk_cache_type_show, NULL);
485 static const struct device_attribute dev_attr_cache_type_rw =
486 __ATTR(cache_type, S_IRUGO|S_IWUSR,
487 virtblk_cache_type_show, virtblk_cache_type_store);
489 static int virtblk_init_request(void *data, struct request *rq,
490 unsigned int hctx_idx, unsigned int request_idx,
491 unsigned int numa_node)
493 struct virtio_blk *vblk = data;
494 struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
496 sg_init_table(vbr->sg, vblk->sg_elems);
500 static struct blk_mq_ops virtio_mq_ops = {
501 .queue_rq = virtio_queue_rq,
502 .map_queue = blk_mq_map_queue,
503 .complete = virtblk_request_done,
504 .init_request = virtblk_init_request,
507 static unsigned int virtblk_queue_depth;
508 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
510 static int virtblk_probe(struct virtio_device *vdev)
512 struct virtio_blk *vblk;
513 struct request_queue *q;
517 u32 v, blk_size, sg_elems, opt_io_size;
519 u8 physical_block_exp, alignment_offset;
521 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
527 /* We need to know how many segments before we allocate. */
528 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
529 struct virtio_blk_config, seg_max,
532 /* We need at least one SG element, whatever they say. */
533 if (err || !sg_elems)
536 /* We need an extra sg elements at head and tail. */
538 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
545 vblk->sg_elems = sg_elems;
546 mutex_init(&vblk->config_lock);
548 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
549 vblk->config_enable = true;
554 spin_lock_init(&vblk->vq_lock);
556 /* FIXME: How many partitions? How long is a piece of string? */
557 vblk->disk = alloc_disk(1 << PART_BITS);
563 /* Default queue sizing is to fill the ring. */
564 if (!virtblk_queue_depth) {
565 virtblk_queue_depth = vblk->vq->num_free;
566 /* ... but without indirect descs, we use 2 descs per req */
567 if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
568 virtblk_queue_depth /= 2;
571 memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
572 vblk->tag_set.ops = &virtio_mq_ops;
573 vblk->tag_set.nr_hw_queues = 1;
574 vblk->tag_set.queue_depth = virtblk_queue_depth;
575 vblk->tag_set.numa_node = NUMA_NO_NODE;
576 vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
577 vblk->tag_set.cmd_size =
578 sizeof(struct virtblk_req) +
579 sizeof(struct scatterlist) * sg_elems;
580 vblk->tag_set.driver_data = vblk;
582 err = blk_mq_alloc_tag_set(&vblk->tag_set);
586 q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
594 virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
596 vblk->disk->major = major;
597 vblk->disk->first_minor = index_to_minor(index);
598 vblk->disk->private_data = vblk;
599 vblk->disk->fops = &virtblk_fops;
600 vblk->disk->driverfs_dev = &vdev->dev;
603 /* configure queue flush support */
604 virtblk_update_cache_mode(vdev);
606 /* If disk is read-only in the host, the guest should obey */
607 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
608 set_disk_ro(vblk->disk, 1);
610 /* Host must always specify the capacity. */
611 virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
613 /* If capacity is too big, truncate with warning. */
614 if ((sector_t)cap != cap) {
615 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
616 (unsigned long long)cap);
619 set_capacity(vblk->disk, cap);
621 /* We can handle whatever the host told us to handle. */
622 blk_queue_max_segments(q, vblk->sg_elems-2);
624 /* No need to bounce any requests */
625 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
627 /* No real sector limit. */
628 blk_queue_max_hw_sectors(q, -1U);
630 /* Host can optionally specify maximum segment size and number of
632 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
633 struct virtio_blk_config, size_max, &v);
635 blk_queue_max_segment_size(q, v);
637 blk_queue_max_segment_size(q, -1U);
639 /* Host can optionally specify the block size of the device */
640 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
641 struct virtio_blk_config, blk_size,
644 blk_queue_logical_block_size(q, blk_size);
646 blk_size = queue_logical_block_size(q);
648 /* Use topology information if available */
649 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
650 struct virtio_blk_config, physical_block_exp,
651 &physical_block_exp);
652 if (!err && physical_block_exp)
653 blk_queue_physical_block_size(q,
654 blk_size * (1 << physical_block_exp));
656 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
657 struct virtio_blk_config, alignment_offset,
659 if (!err && alignment_offset)
660 blk_queue_alignment_offset(q, blk_size * alignment_offset);
662 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
663 struct virtio_blk_config, min_io_size,
665 if (!err && min_io_size)
666 blk_queue_io_min(q, blk_size * min_io_size);
668 err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
669 struct virtio_blk_config, opt_io_size,
671 if (!err && opt_io_size)
672 blk_queue_io_opt(q, blk_size * opt_io_size);
674 add_disk(vblk->disk);
675 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
679 if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
680 err = device_create_file(disk_to_dev(vblk->disk),
681 &dev_attr_cache_type_rw);
683 err = device_create_file(disk_to_dev(vblk->disk),
684 &dev_attr_cache_type_ro);
690 del_gendisk(vblk->disk);
691 blk_cleanup_queue(vblk->disk->queue);
693 blk_mq_free_tag_set(&vblk->tag_set);
695 put_disk(vblk->disk);
697 vdev->config->del_vqs(vdev);
701 ida_simple_remove(&vd_index_ida, index);
706 static void virtblk_remove(struct virtio_device *vdev)
708 struct virtio_blk *vblk = vdev->priv;
709 int index = vblk->index;
712 /* Prevent config work handler from accessing the device. */
713 mutex_lock(&vblk->config_lock);
714 vblk->config_enable = false;
715 mutex_unlock(&vblk->config_lock);
717 del_gendisk(vblk->disk);
718 blk_cleanup_queue(vblk->disk->queue);
720 blk_mq_free_tag_set(&vblk->tag_set);
722 /* Stop all the virtqueues. */
723 vdev->config->reset(vdev);
725 flush_work(&vblk->config_work);
727 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
728 put_disk(vblk->disk);
729 vdev->config->del_vqs(vdev);
732 /* Only free device id if we don't have any users */
734 ida_simple_remove(&vd_index_ida, index);
737 #ifdef CONFIG_PM_SLEEP
738 static int virtblk_freeze(struct virtio_device *vdev)
740 struct virtio_blk *vblk = vdev->priv;
742 /* Ensure we don't receive any more interrupts */
743 vdev->config->reset(vdev);
745 /* Prevent config work handler from accessing the device. */
746 mutex_lock(&vblk->config_lock);
747 vblk->config_enable = false;
748 mutex_unlock(&vblk->config_lock);
750 flush_work(&vblk->config_work);
752 blk_mq_stop_hw_queues(vblk->disk->queue);
754 vdev->config->del_vqs(vdev);
758 static int virtblk_restore(struct virtio_device *vdev)
760 struct virtio_blk *vblk = vdev->priv;
763 vblk->config_enable = true;
764 ret = init_vq(vdev->priv);
766 blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
772 static const struct virtio_device_id id_table[] = {
773 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
777 static unsigned int features[] = {
778 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
779 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
780 VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE
783 static struct virtio_driver virtio_blk = {
784 .feature_table = features,
785 .feature_table_size = ARRAY_SIZE(features),
786 .driver.name = KBUILD_MODNAME,
787 .driver.owner = THIS_MODULE,
788 .id_table = id_table,
789 .probe = virtblk_probe,
790 .remove = virtblk_remove,
791 .config_changed = virtblk_config_changed,
792 #ifdef CONFIG_PM_SLEEP
793 .freeze = virtblk_freeze,
794 .restore = virtblk_restore,
798 static int __init init(void)
802 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
806 major = register_blkdev(0, "virtblk");
809 goto out_destroy_workqueue;
812 error = register_virtio_driver(&virtio_blk);
814 goto out_unregister_blkdev;
817 out_unregister_blkdev:
818 unregister_blkdev(major, "virtblk");
819 out_destroy_workqueue:
820 destroy_workqueue(virtblk_wq);
824 static void __exit fini(void)
826 unregister_blkdev(major, "virtblk");
827 unregister_virtio_driver(&virtio_blk);
828 destroy_workqueue(virtblk_wq);
833 MODULE_DEVICE_TABLE(virtio, id_table);
834 MODULE_DESCRIPTION("Virtio block driver");
835 MODULE_LICENSE("GPL");