2 #include <linux/spinlock.h>
3 #include <linux/slab.h>
4 #include <linux/blkdev.h>
5 #include <linux/hdreg.h>
6 #include <linux/virtio.h>
7 #include <linux/virtio_blk.h>
8 #include <linux/scatterlist.h>
9 #include <linux/string_helpers.h>
10 #include <scsi/scsi_cmnd.h>
11 #include <linux/idr.h>
16 static DEFINE_IDA(vd_index_ida);
18 struct workqueue_struct *virtblk_wq;
24 struct virtio_device *vdev;
27 /* The disk structure for the kernel. */
30 /* Request tracking. */
31 struct list_head reqs;
35 /* Process context for config space updates */
36 struct work_struct config_work;
38 /* What host tells us, plus 2 for header & tailer. */
39 unsigned int sg_elems;
41 /* Ida index - used to track minor number allocations. */
44 /* Scatterlist: can be too big for stack. */
45 struct scatterlist sg[/*sg_elems*/];
50 struct list_head list;
52 struct virtio_blk_outhdr out_hdr;
53 struct virtio_scsi_inhdr in_hdr;
57 static void blk_done(struct virtqueue *vq)
59 struct virtio_blk *vblk = vq->vdev->priv;
60 struct virtblk_req *vbr;
64 spin_lock_irqsave(&vblk->lock, flags);
65 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
68 switch (vbr->status) {
72 case VIRTIO_BLK_S_UNSUPP:
80 switch (vbr->req->cmd_type) {
81 case REQ_TYPE_BLOCK_PC:
82 vbr->req->resid_len = vbr->in_hdr.residual;
83 vbr->req->sense_len = vbr->in_hdr.sense_len;
84 vbr->req->errors = vbr->in_hdr.errors;
86 case REQ_TYPE_SPECIAL:
87 vbr->req->errors = (error != 0);
93 __blk_end_request_all(vbr->req, error);
95 mempool_free(vbr, vblk->pool);
97 /* In case queue is stopped waiting for more buffers. */
98 blk_start_queue(vblk->disk->queue);
99 spin_unlock_irqrestore(&vblk->lock, flags);
102 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
105 unsigned long num, out = 0, in = 0;
106 struct virtblk_req *vbr;
108 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
110 /* When another request finishes we'll try again. */
115 if (req->cmd_flags & REQ_FLUSH) {
116 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
117 vbr->out_hdr.sector = 0;
118 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
120 switch (req->cmd_type) {
122 vbr->out_hdr.type = 0;
123 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
124 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
126 case REQ_TYPE_BLOCK_PC:
127 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
128 vbr->out_hdr.sector = 0;
129 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
131 case REQ_TYPE_SPECIAL:
132 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
133 vbr->out_hdr.sector = 0;
134 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
137 /* We don't put anything else in the queue. */
142 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
145 * If this is a packet command we need a couple of additional headers.
146 * Behind the normal outhdr we put a segment with the scsi command
147 * block, and before the normal inhdr we put the sense data and the
148 * inhdr with additional status information before the normal inhdr.
150 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
151 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
153 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
155 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
156 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
157 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
158 sizeof(vbr->in_hdr));
161 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
162 sizeof(vbr->status));
165 if (rq_data_dir(vbr->req) == WRITE) {
166 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
169 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
174 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
175 mempool_free(vbr, vblk->pool);
179 list_add_tail(&vbr->list, &vblk->reqs);
183 static void do_virtblk_request(struct request_queue *q)
185 struct virtio_blk *vblk = q->queuedata;
187 unsigned int issued = 0;
189 while ((req = blk_peek_request(q)) != NULL) {
190 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
192 /* If this request fails, stop queue and wait for something to
193 finish to restart it. */
194 if (!do_req(q, vblk, req)) {
198 blk_start_request(req);
203 virtqueue_kick(vblk->vq);
206 /* return id (s/n) string for *disk to *id_str
208 static int virtblk_get_id(struct gendisk *disk, char *id_str)
210 struct virtio_blk *vblk = disk->private_data;
215 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
220 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
226 req->cmd_type = REQ_TYPE_SPECIAL;
227 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
228 blk_put_request(req);
233 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
234 unsigned int cmd, unsigned long data)
236 struct gendisk *disk = bdev->bd_disk;
237 struct virtio_blk *vblk = disk->private_data;
240 * Only allow the generic SCSI ioctls if the host can support it.
242 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
245 return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
246 (void __user *)data);
249 /* We provide getgeo only to please some old bootloader/partitioning tools */
250 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
252 struct virtio_blk *vblk = bd->bd_disk->private_data;
253 struct virtio_blk_geometry vgeo;
256 /* see if the host passed in geometry config */
257 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
258 offsetof(struct virtio_blk_config, geometry),
262 geo->heads = vgeo.heads;
263 geo->sectors = vgeo.sectors;
264 geo->cylinders = vgeo.cylinders;
266 /* some standard values, similar to sd */
268 geo->sectors = 1 << 5;
269 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
274 static const struct block_device_operations virtblk_fops = {
275 .ioctl = virtblk_ioctl,
276 .owner = THIS_MODULE,
277 .getgeo = virtblk_getgeo,
280 static int index_to_minor(int index)
282 return index << PART_BITS;
285 static int minor_to_index(int minor)
287 return minor >> PART_BITS;
290 static ssize_t virtblk_serial_show(struct device *dev,
291 struct device_attribute *attr, char *buf)
293 struct gendisk *disk = dev_to_disk(dev);
296 /* sysfs gives us a PAGE_SIZE buffer */
297 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
299 buf[VIRTIO_BLK_ID_BYTES] = '\0';
300 err = virtblk_get_id(disk, buf);
304 if (err == -EIO) /* Unsupported? Make it empty. */
309 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
311 static void virtblk_config_changed_work(struct work_struct *work)
313 struct virtio_blk *vblk =
314 container_of(work, struct virtio_blk, config_work);
315 struct virtio_device *vdev = vblk->vdev;
316 struct request_queue *q = vblk->disk->queue;
317 char cap_str_2[10], cap_str_10[10];
320 /* Host must always specify the capacity. */
321 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
322 &capacity, sizeof(capacity));
324 /* If capacity is too big, truncate with warning. */
325 if ((sector_t)capacity != capacity) {
326 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
327 (unsigned long long)capacity);
328 capacity = (sector_t)-1;
331 size = capacity * queue_logical_block_size(q);
332 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
333 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
335 dev_notice(&vdev->dev,
336 "new size: %llu %d-byte logical blocks (%s/%s)\n",
337 (unsigned long long)capacity,
338 queue_logical_block_size(q),
339 cap_str_10, cap_str_2);
341 set_capacity(vblk->disk, capacity);
344 static void virtblk_config_changed(struct virtio_device *vdev)
346 struct virtio_blk *vblk = vdev->priv;
348 queue_work(virtblk_wq, &vblk->config_work);
351 static int __devinit virtblk_probe(struct virtio_device *vdev)
353 struct virtio_blk *vblk;
354 struct request_queue *q;
357 u32 v, blk_size, sg_elems, opt_io_size;
359 u8 physical_block_exp, alignment_offset;
361 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
367 /* We need to know how many segments before we allocate. */
368 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
369 offsetof(struct virtio_blk_config, seg_max),
372 /* We need at least one SG element, whatever they say. */
373 if (err || !sg_elems)
376 /* We need an extra sg elements at head and tail. */
378 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
379 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
385 INIT_LIST_HEAD(&vblk->reqs);
386 spin_lock_init(&vblk->lock);
388 vblk->sg_elems = sg_elems;
389 sg_init_table(vblk->sg, vblk->sg_elems);
390 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
392 /* We expect one virtqueue, for output. */
393 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
394 if (IS_ERR(vblk->vq)) {
395 err = PTR_ERR(vblk->vq);
399 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
405 /* FIXME: How many partitions? How long is a piece of string? */
406 vblk->disk = alloc_disk(1 << PART_BITS);
412 q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
421 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
422 } else if (index < (26 + 1) * 26) {
423 sprintf(vblk->disk->disk_name, "vd%c%c",
424 'a' + index / 26 - 1, 'a' + index % 26);
426 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
427 const unsigned int m2 = (index / 26 - 1) % 26;
428 const unsigned int m3 = index % 26;
429 sprintf(vblk->disk->disk_name, "vd%c%c%c",
430 'a' + m1, 'a' + m2, 'a' + m3);
433 vblk->disk->major = major;
434 vblk->disk->first_minor = index_to_minor(index);
435 vblk->disk->private_data = vblk;
436 vblk->disk->fops = &virtblk_fops;
437 vblk->disk->driverfs_dev = &vdev->dev;
440 /* configure queue flush support */
441 if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
442 blk_queue_flush(q, REQ_FLUSH);
444 /* If disk is read-only in the host, the guest should obey */
445 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
446 set_disk_ro(vblk->disk, 1);
448 /* Host must always specify the capacity. */
449 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
452 /* If capacity is too big, truncate with warning. */
453 if ((sector_t)cap != cap) {
454 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
455 (unsigned long long)cap);
458 set_capacity(vblk->disk, cap);
460 /* We can handle whatever the host told us to handle. */
461 blk_queue_max_segments(q, vblk->sg_elems-2);
463 /* No need to bounce any requests */
464 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
466 /* No real sector limit. */
467 blk_queue_max_hw_sectors(q, -1U);
469 /* Host can optionally specify maximum segment size and number of
471 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
472 offsetof(struct virtio_blk_config, size_max),
475 blk_queue_max_segment_size(q, v);
477 blk_queue_max_segment_size(q, -1U);
479 /* Host can optionally specify the block size of the device */
480 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
481 offsetof(struct virtio_blk_config, blk_size),
484 blk_queue_logical_block_size(q, blk_size);
486 blk_size = queue_logical_block_size(q);
488 /* Use topology information if available */
489 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
490 offsetof(struct virtio_blk_config, physical_block_exp),
491 &physical_block_exp);
492 if (!err && physical_block_exp)
493 blk_queue_physical_block_size(q,
494 blk_size * (1 << physical_block_exp));
496 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
497 offsetof(struct virtio_blk_config, alignment_offset),
499 if (!err && alignment_offset)
500 blk_queue_alignment_offset(q, blk_size * alignment_offset);
502 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
503 offsetof(struct virtio_blk_config, min_io_size),
505 if (!err && min_io_size)
506 blk_queue_io_min(q, blk_size * min_io_size);
508 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
509 offsetof(struct virtio_blk_config, opt_io_size),
511 if (!err && opt_io_size)
512 blk_queue_io_opt(q, blk_size * opt_io_size);
515 add_disk(vblk->disk);
516 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
523 del_gendisk(vblk->disk);
524 blk_cleanup_queue(vblk->disk->queue);
526 put_disk(vblk->disk);
528 mempool_destroy(vblk->pool);
530 vdev->config->del_vqs(vdev);
534 ida_simple_remove(&vd_index_ida, index);
539 static void __devexit virtblk_remove(struct virtio_device *vdev)
541 struct virtio_blk *vblk = vdev->priv;
542 int index = vblk->index;
544 flush_work(&vblk->config_work);
546 /* Nothing should be pending. */
547 BUG_ON(!list_empty(&vblk->reqs));
549 /* Stop all the virtqueues. */
550 vdev->config->reset(vdev);
552 del_gendisk(vblk->disk);
553 blk_cleanup_queue(vblk->disk->queue);
554 put_disk(vblk->disk);
555 mempool_destroy(vblk->pool);
556 vdev->config->del_vqs(vdev);
558 ida_simple_remove(&vd_index_ida, index);
561 static const struct virtio_device_id id_table[] = {
562 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
566 static unsigned int features[] = {
567 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
568 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
569 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
573 * virtio_blk causes spurious section mismatch warning by
574 * simultaneously referring to a __devinit and a __devexit function.
575 * Use __refdata to avoid this warning.
577 static struct virtio_driver __refdata virtio_blk = {
578 .feature_table = features,
579 .feature_table_size = ARRAY_SIZE(features),
580 .driver.name = KBUILD_MODNAME,
581 .driver.owner = THIS_MODULE,
582 .id_table = id_table,
583 .probe = virtblk_probe,
584 .remove = __devexit_p(virtblk_remove),
585 .config_changed = virtblk_config_changed,
588 static int __init init(void)
592 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
596 major = register_blkdev(0, "virtblk");
599 goto out_destroy_workqueue;
602 error = register_virtio_driver(&virtio_blk);
604 goto out_unregister_blkdev;
607 out_unregister_blkdev:
608 unregister_blkdev(major, "virtblk");
609 out_destroy_workqueue:
610 destroy_workqueue(virtblk_wq);
614 static void __exit fini(void)
616 unregister_blkdev(major, "virtblk");
617 unregister_virtio_driver(&virtio_blk);
618 destroy_workqueue(virtblk_wq);
623 MODULE_DEVICE_TABLE(virtio, id_table);
624 MODULE_DESCRIPTION("Virtio block driver");
625 MODULE_LICENSE("GPL");