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. */
32 /* Request tracking. */
33 struct list_head reqs;
37 /* Process context for config space updates */
38 struct work_struct config_work;
40 /* Lock for config space updates */
41 struct mutex config_lock;
43 /* enable config space updates */
46 /* What host tells us, plus 2 for header & tailer. */
47 unsigned int sg_elems;
49 /* Ida index - used to track minor number allocations. */
52 /* Scatterlist: can be too big for stack. */
53 struct scatterlist sg[/*sg_elems*/];
58 struct list_head list;
60 struct virtio_blk_outhdr out_hdr;
61 struct virtio_scsi_inhdr in_hdr;
65 static void blk_done(struct virtqueue *vq)
67 struct virtio_blk *vblk = vq->vdev->priv;
68 struct virtblk_req *vbr;
72 spin_lock_irqsave(&vblk->lock, flags);
73 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
76 switch (vbr->status) {
80 case VIRTIO_BLK_S_UNSUPP:
88 switch (vbr->req->cmd_type) {
89 case REQ_TYPE_BLOCK_PC:
90 vbr->req->resid_len = vbr->in_hdr.residual;
91 vbr->req->sense_len = vbr->in_hdr.sense_len;
92 vbr->req->errors = vbr->in_hdr.errors;
94 case REQ_TYPE_SPECIAL:
95 vbr->req->errors = (error != 0);
101 __blk_end_request_all(vbr->req, error);
102 list_del(&vbr->list);
103 mempool_free(vbr, vblk->pool);
105 /* In case queue is stopped waiting for more buffers. */
106 blk_start_queue(vblk->disk->queue);
107 spin_unlock_irqrestore(&vblk->lock, flags);
110 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
113 unsigned long num, out = 0, in = 0;
114 struct virtblk_req *vbr;
116 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
118 /* When another request finishes we'll try again. */
123 if (req->cmd_flags & REQ_FLUSH) {
124 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
125 vbr->out_hdr.sector = 0;
126 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
128 switch (req->cmd_type) {
130 vbr->out_hdr.type = 0;
131 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
132 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
134 case REQ_TYPE_BLOCK_PC:
135 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
136 vbr->out_hdr.sector = 0;
137 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
139 case REQ_TYPE_SPECIAL:
140 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
141 vbr->out_hdr.sector = 0;
142 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
145 /* We don't put anything else in the queue. */
150 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
153 * If this is a packet command we need a couple of additional headers.
154 * Behind the normal outhdr we put a segment with the scsi command
155 * block, and before the normal inhdr we put the sense data and the
156 * inhdr with additional status information before the normal inhdr.
158 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
159 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
161 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
163 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
164 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
165 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
166 sizeof(vbr->in_hdr));
169 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
170 sizeof(vbr->status));
173 if (rq_data_dir(vbr->req) == WRITE) {
174 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
177 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
182 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr, GFP_ATOMIC)<0) {
183 mempool_free(vbr, vblk->pool);
187 list_add_tail(&vbr->list, &vblk->reqs);
191 static void do_virtblk_request(struct request_queue *q)
193 struct virtio_blk *vblk = q->queuedata;
195 unsigned int issued = 0;
197 while ((req = blk_peek_request(q)) != NULL) {
198 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
200 /* If this request fails, stop queue and wait for something to
201 finish to restart it. */
202 if (!do_req(q, vblk, req)) {
206 blk_start_request(req);
211 virtqueue_kick(vblk->vq);
214 /* return id (s/n) string for *disk to *id_str
216 static int virtblk_get_id(struct gendisk *disk, char *id_str)
218 struct virtio_blk *vblk = disk->private_data;
223 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
228 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
234 req->cmd_type = REQ_TYPE_SPECIAL;
235 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
236 blk_put_request(req);
241 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
242 unsigned int cmd, unsigned long data)
244 struct gendisk *disk = bdev->bd_disk;
245 struct virtio_blk *vblk = disk->private_data;
248 * Only allow the generic SCSI ioctls if the host can support it.
250 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
253 return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
254 (void __user *)data);
257 /* We provide getgeo only to please some old bootloader/partitioning tools */
258 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
260 struct virtio_blk *vblk = bd->bd_disk->private_data;
261 struct virtio_blk_geometry vgeo;
264 /* see if the host passed in geometry config */
265 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
266 offsetof(struct virtio_blk_config, geometry),
270 geo->heads = vgeo.heads;
271 geo->sectors = vgeo.sectors;
272 geo->cylinders = vgeo.cylinders;
274 /* some standard values, similar to sd */
276 geo->sectors = 1 << 5;
277 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
282 static const struct block_device_operations virtblk_fops = {
283 .ioctl = virtblk_ioctl,
284 .owner = THIS_MODULE,
285 .getgeo = virtblk_getgeo,
288 static int index_to_minor(int index)
290 return index << PART_BITS;
293 static int minor_to_index(int minor)
295 return minor >> PART_BITS;
298 static ssize_t virtblk_serial_show(struct device *dev,
299 struct device_attribute *attr, char *buf)
301 struct gendisk *disk = dev_to_disk(dev);
304 /* sysfs gives us a PAGE_SIZE buffer */
305 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
307 buf[VIRTIO_BLK_ID_BYTES] = '\0';
308 err = virtblk_get_id(disk, buf);
312 if (err == -EIO) /* Unsupported? Make it empty. */
317 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
319 static void virtblk_config_changed_work(struct work_struct *work)
321 struct virtio_blk *vblk =
322 container_of(work, struct virtio_blk, config_work);
323 struct virtio_device *vdev = vblk->vdev;
324 struct request_queue *q = vblk->disk->queue;
325 char cap_str_2[10], cap_str_10[10];
328 mutex_lock(&vblk->config_lock);
329 if (!vblk->config_enable)
332 /* Host must always specify the capacity. */
333 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
334 &capacity, sizeof(capacity));
336 /* If capacity is too big, truncate with warning. */
337 if ((sector_t)capacity != capacity) {
338 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
339 (unsigned long long)capacity);
340 capacity = (sector_t)-1;
343 size = capacity * queue_logical_block_size(q);
344 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
345 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
347 dev_notice(&vdev->dev,
348 "new size: %llu %d-byte logical blocks (%s/%s)\n",
349 (unsigned long long)capacity,
350 queue_logical_block_size(q),
351 cap_str_10, cap_str_2);
353 set_capacity(vblk->disk, capacity);
355 mutex_unlock(&vblk->config_lock);
358 static void virtblk_config_changed(struct virtio_device *vdev)
360 struct virtio_blk *vblk = vdev->priv;
362 queue_work(virtblk_wq, &vblk->config_work);
365 static int __devinit virtblk_probe(struct virtio_device *vdev)
367 struct virtio_blk *vblk;
368 struct request_queue *q;
371 u32 v, blk_size, sg_elems, opt_io_size;
373 u8 physical_block_exp, alignment_offset;
375 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
381 /* We need to know how many segments before we allocate. */
382 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
383 offsetof(struct virtio_blk_config, seg_max),
386 /* We need at least one SG element, whatever they say. */
387 if (err || !sg_elems)
390 /* We need an extra sg elements at head and tail. */
392 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
393 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
399 INIT_LIST_HEAD(&vblk->reqs);
400 spin_lock_init(&vblk->lock);
402 vblk->sg_elems = sg_elems;
403 sg_init_table(vblk->sg, vblk->sg_elems);
404 mutex_init(&vblk->config_lock);
405 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
406 vblk->config_enable = true;
408 /* We expect one virtqueue, for output. */
409 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
410 if (IS_ERR(vblk->vq)) {
411 err = PTR_ERR(vblk->vq);
415 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
421 /* FIXME: How many partitions? How long is a piece of string? */
422 vblk->disk = alloc_disk(1 << PART_BITS);
428 q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
437 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
438 } else if (index < (26 + 1) * 26) {
439 sprintf(vblk->disk->disk_name, "vd%c%c",
440 'a' + index / 26 - 1, 'a' + index % 26);
442 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
443 const unsigned int m2 = (index / 26 - 1) % 26;
444 const unsigned int m3 = index % 26;
445 sprintf(vblk->disk->disk_name, "vd%c%c%c",
446 'a' + m1, 'a' + m2, 'a' + m3);
449 vblk->disk->major = major;
450 vblk->disk->first_minor = index_to_minor(index);
451 vblk->disk->private_data = vblk;
452 vblk->disk->fops = &virtblk_fops;
453 vblk->disk->driverfs_dev = &vdev->dev;
456 /* configure queue flush support */
457 if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
458 blk_queue_flush(q, REQ_FLUSH);
460 /* If disk is read-only in the host, the guest should obey */
461 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
462 set_disk_ro(vblk->disk, 1);
464 /* Host must always specify the capacity. */
465 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
468 /* If capacity is too big, truncate with warning. */
469 if ((sector_t)cap != cap) {
470 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
471 (unsigned long long)cap);
474 set_capacity(vblk->disk, cap);
476 /* We can handle whatever the host told us to handle. */
477 blk_queue_max_segments(q, vblk->sg_elems-2);
479 /* No need to bounce any requests */
480 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
482 /* No real sector limit. */
483 blk_queue_max_hw_sectors(q, -1U);
485 /* Host can optionally specify maximum segment size and number of
487 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
488 offsetof(struct virtio_blk_config, size_max),
491 blk_queue_max_segment_size(q, v);
493 blk_queue_max_segment_size(q, -1U);
495 /* Host can optionally specify the block size of the device */
496 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
497 offsetof(struct virtio_blk_config, blk_size),
500 blk_queue_logical_block_size(q, blk_size);
502 blk_size = queue_logical_block_size(q);
504 /* Use topology information if available */
505 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
506 offsetof(struct virtio_blk_config, physical_block_exp),
507 &physical_block_exp);
508 if (!err && physical_block_exp)
509 blk_queue_physical_block_size(q,
510 blk_size * (1 << physical_block_exp));
512 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
513 offsetof(struct virtio_blk_config, alignment_offset),
515 if (!err && alignment_offset)
516 blk_queue_alignment_offset(q, blk_size * alignment_offset);
518 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
519 offsetof(struct virtio_blk_config, min_io_size),
521 if (!err && min_io_size)
522 blk_queue_io_min(q, blk_size * min_io_size);
524 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
525 offsetof(struct virtio_blk_config, opt_io_size),
527 if (!err && opt_io_size)
528 blk_queue_io_opt(q, blk_size * opt_io_size);
531 add_disk(vblk->disk);
532 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
539 del_gendisk(vblk->disk);
540 blk_cleanup_queue(vblk->disk->queue);
542 put_disk(vblk->disk);
544 mempool_destroy(vblk->pool);
546 vdev->config->del_vqs(vdev);
550 ida_simple_remove(&vd_index_ida, index);
555 static void __devexit virtblk_remove(struct virtio_device *vdev)
557 struct virtio_blk *vblk = vdev->priv;
558 int index = vblk->index;
560 /* Prevent config work handler from accessing the device. */
561 mutex_lock(&vblk->config_lock);
562 vblk->config_enable = false;
563 mutex_unlock(&vblk->config_lock);
565 /* Nothing should be pending. */
566 BUG_ON(!list_empty(&vblk->reqs));
568 /* Stop all the virtqueues. */
569 vdev->config->reset(vdev);
571 flush_work(&vblk->config_work);
573 del_gendisk(vblk->disk);
574 blk_cleanup_queue(vblk->disk->queue);
575 put_disk(vblk->disk);
576 mempool_destroy(vblk->pool);
577 vdev->config->del_vqs(vdev);
579 ida_simple_remove(&vd_index_ida, index);
582 static const struct virtio_device_id id_table[] = {
583 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
587 static unsigned int features[] = {
588 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
589 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
590 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
594 * virtio_blk causes spurious section mismatch warning by
595 * simultaneously referring to a __devinit and a __devexit function.
596 * Use __refdata to avoid this warning.
598 static struct virtio_driver __refdata virtio_blk = {
599 .feature_table = features,
600 .feature_table_size = ARRAY_SIZE(features),
601 .driver.name = KBUILD_MODNAME,
602 .driver.owner = THIS_MODULE,
603 .id_table = id_table,
604 .probe = virtblk_probe,
605 .remove = __devexit_p(virtblk_remove),
606 .config_changed = virtblk_config_changed,
609 static int __init init(void)
613 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
617 major = register_blkdev(0, "virtblk");
620 goto out_destroy_workqueue;
623 error = register_virtio_driver(&virtio_blk);
625 goto out_unregister_blkdev;
628 out_unregister_blkdev:
629 unregister_blkdev(major, "virtblk");
630 out_destroy_workqueue:
631 destroy_workqueue(virtblk_wq);
635 static void __exit fini(void)
637 unregister_blkdev(major, "virtblk");
638 unregister_virtio_driver(&virtio_blk);
639 destroy_workqueue(virtblk_wq);
644 MODULE_DEVICE_TABLE(virtio, id_table);
645 MODULE_DESCRIPTION("Virtio block driver");
646 MODULE_LICENSE("GPL");