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;
24 struct virtio_device *vdev;
27 /* The disk structure for the kernel. */
32 /* Process context for config space updates */
33 struct work_struct config_work;
35 /* Lock for config space updates */
36 struct mutex config_lock;
38 /* enable config space updates */
41 /* What host tells us, plus 2 for header & tailer. */
42 unsigned int sg_elems;
44 /* Ida index - used to track minor number allocations. */
47 /* Scatterlist: can be too big for stack. */
48 struct scatterlist sg[/*sg_elems*/];
54 struct virtio_blk_outhdr out_hdr;
55 struct virtio_scsi_inhdr in_hdr;
59 static void blk_done(struct virtqueue *vq)
61 struct virtio_blk *vblk = vq->vdev->priv;
62 struct virtblk_req *vbr;
66 spin_lock_irqsave(vblk->disk->queue->queue_lock, flags);
67 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
70 switch (vbr->status) {
74 case VIRTIO_BLK_S_UNSUPP:
82 switch (vbr->req->cmd_type) {
83 case REQ_TYPE_BLOCK_PC:
84 vbr->req->resid_len = vbr->in_hdr.residual;
85 vbr->req->sense_len = vbr->in_hdr.sense_len;
86 vbr->req->errors = vbr->in_hdr.errors;
88 case REQ_TYPE_SPECIAL:
89 vbr->req->errors = (error != 0);
95 __blk_end_request_all(vbr->req, error);
96 mempool_free(vbr, vblk->pool);
98 /* In case queue is stopped waiting for more buffers. */
99 blk_start_queue(vblk->disk->queue);
100 spin_unlock_irqrestore(vblk->disk->queue->queue_lock, flags);
103 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
106 unsigned long num, out = 0, in = 0;
107 struct virtblk_req *vbr;
109 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
111 /* When another request finishes we'll try again. */
116 if (req->cmd_flags & REQ_FLUSH) {
117 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
118 vbr->out_hdr.sector = 0;
119 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
121 switch (req->cmd_type) {
123 vbr->out_hdr.type = 0;
124 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
125 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
127 case REQ_TYPE_BLOCK_PC:
128 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
129 vbr->out_hdr.sector = 0;
130 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
132 case REQ_TYPE_SPECIAL:
133 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
134 vbr->out_hdr.sector = 0;
135 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
138 /* We don't put anything else in the queue. */
143 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
146 * If this is a packet command we need a couple of additional headers.
147 * Behind the normal outhdr we put a segment with the scsi command
148 * block, and before the normal inhdr we put the sense data and the
149 * inhdr with additional status information before the normal inhdr.
151 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
152 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
154 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
156 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
157 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
158 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
159 sizeof(vbr->in_hdr));
162 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
163 sizeof(vbr->status));
166 if (rq_data_dir(vbr->req) == WRITE) {
167 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
170 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
175 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
176 mempool_free(vbr, vblk->pool);
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_blk_ioctl(bdev, 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 mutex_lock(&vblk->config_lock);
321 if (!vblk->config_enable)
324 /* Host must always specify the capacity. */
325 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
326 &capacity, sizeof(capacity));
328 /* If capacity is too big, truncate with warning. */
329 if ((sector_t)capacity != capacity) {
330 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
331 (unsigned long long)capacity);
332 capacity = (sector_t)-1;
335 size = capacity * queue_logical_block_size(q);
336 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
337 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
339 dev_notice(&vdev->dev,
340 "new size: %llu %d-byte logical blocks (%s/%s)\n",
341 (unsigned long long)capacity,
342 queue_logical_block_size(q),
343 cap_str_10, cap_str_2);
345 set_capacity(vblk->disk, capacity);
346 revalidate_disk(vblk->disk);
348 mutex_unlock(&vblk->config_lock);
351 static void virtblk_config_changed(struct virtio_device *vdev)
353 struct virtio_blk *vblk = vdev->priv;
355 queue_work(virtblk_wq, &vblk->config_work);
358 static int __devinit virtblk_probe(struct virtio_device *vdev)
360 struct virtio_blk *vblk;
361 struct request_queue *q;
364 u32 v, blk_size, sg_elems, opt_io_size;
366 u8 physical_block_exp, alignment_offset;
368 err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
374 /* We need to know how many segments before we allocate. */
375 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
376 offsetof(struct virtio_blk_config, seg_max),
379 /* We need at least one SG element, whatever they say. */
380 if (err || !sg_elems)
383 /* We need an extra sg elements at head and tail. */
385 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
386 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
393 vblk->sg_elems = sg_elems;
394 sg_init_table(vblk->sg, vblk->sg_elems);
395 mutex_init(&vblk->config_lock);
396 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
397 vblk->config_enable = true;
399 /* We expect one virtqueue, for output. */
400 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
401 if (IS_ERR(vblk->vq)) {
402 err = PTR_ERR(vblk->vq);
406 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
412 /* FIXME: How many partitions? How long is a piece of string? */
413 vblk->disk = alloc_disk(1 << PART_BITS);
419 q = vblk->disk->queue = blk_init_queue(do_virtblk_request, NULL);
428 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
429 } else if (index < (26 + 1) * 26) {
430 sprintf(vblk->disk->disk_name, "vd%c%c",
431 'a' + index / 26 - 1, 'a' + index % 26);
433 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
434 const unsigned int m2 = (index / 26 - 1) % 26;
435 const unsigned int m3 = index % 26;
436 sprintf(vblk->disk->disk_name, "vd%c%c%c",
437 'a' + m1, 'a' + m2, 'a' + m3);
440 vblk->disk->major = major;
441 vblk->disk->first_minor = index_to_minor(index);
442 vblk->disk->private_data = vblk;
443 vblk->disk->fops = &virtblk_fops;
444 vblk->disk->driverfs_dev = &vdev->dev;
447 /* configure queue flush support */
448 if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
449 blk_queue_flush(q, REQ_FLUSH);
451 /* If disk is read-only in the host, the guest should obey */
452 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
453 set_disk_ro(vblk->disk, 1);
455 /* Host must always specify the capacity. */
456 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
459 /* If capacity is too big, truncate with warning. */
460 if ((sector_t)cap != cap) {
461 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
462 (unsigned long long)cap);
465 set_capacity(vblk->disk, cap);
467 /* We can handle whatever the host told us to handle. */
468 blk_queue_max_segments(q, vblk->sg_elems-2);
470 /* No need to bounce any requests */
471 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
473 /* No real sector limit. */
474 blk_queue_max_hw_sectors(q, -1U);
476 /* Host can optionally specify maximum segment size and number of
478 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
479 offsetof(struct virtio_blk_config, size_max),
482 blk_queue_max_segment_size(q, v);
484 blk_queue_max_segment_size(q, -1U);
486 /* Host can optionally specify the block size of the device */
487 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
488 offsetof(struct virtio_blk_config, blk_size),
491 blk_queue_logical_block_size(q, blk_size);
493 blk_size = queue_logical_block_size(q);
495 /* Use topology information if available */
496 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
497 offsetof(struct virtio_blk_config, physical_block_exp),
498 &physical_block_exp);
499 if (!err && physical_block_exp)
500 blk_queue_physical_block_size(q,
501 blk_size * (1 << physical_block_exp));
503 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
504 offsetof(struct virtio_blk_config, alignment_offset),
506 if (!err && alignment_offset)
507 blk_queue_alignment_offset(q, blk_size * alignment_offset);
509 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
510 offsetof(struct virtio_blk_config, min_io_size),
512 if (!err && min_io_size)
513 blk_queue_io_min(q, blk_size * min_io_size);
515 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
516 offsetof(struct virtio_blk_config, opt_io_size),
518 if (!err && opt_io_size)
519 blk_queue_io_opt(q, blk_size * opt_io_size);
522 add_disk(vblk->disk);
523 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
530 del_gendisk(vblk->disk);
531 blk_cleanup_queue(vblk->disk->queue);
533 put_disk(vblk->disk);
535 mempool_destroy(vblk->pool);
537 vdev->config->del_vqs(vdev);
541 ida_simple_remove(&vd_index_ida, index);
546 static void __devexit virtblk_remove(struct virtio_device *vdev)
548 struct virtio_blk *vblk = vdev->priv;
549 int index = vblk->index;
552 /* Prevent config work handler from accessing the device. */
553 mutex_lock(&vblk->config_lock);
554 vblk->config_enable = false;
555 mutex_unlock(&vblk->config_lock);
557 del_gendisk(vblk->disk);
558 blk_cleanup_queue(vblk->disk->queue);
560 /* Stop all the virtqueues. */
561 vdev->config->reset(vdev);
563 flush_work(&vblk->config_work);
565 refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
566 put_disk(vblk->disk);
567 mempool_destroy(vblk->pool);
568 vdev->config->del_vqs(vdev);
571 /* Only free device id if we don't have any users */
573 ida_simple_remove(&vd_index_ida, index);
576 static const struct virtio_device_id id_table[] = {
577 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
581 static unsigned int features[] = {
582 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
583 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
584 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
588 * virtio_blk causes spurious section mismatch warning by
589 * simultaneously referring to a __devinit and a __devexit function.
590 * Use __refdata to avoid this warning.
592 static struct virtio_driver __refdata virtio_blk = {
593 .feature_table = features,
594 .feature_table_size = ARRAY_SIZE(features),
595 .driver.name = KBUILD_MODNAME,
596 .driver.owner = THIS_MODULE,
597 .id_table = id_table,
598 .probe = virtblk_probe,
599 .remove = __devexit_p(virtblk_remove),
600 .config_changed = virtblk_config_changed,
603 static int __init init(void)
607 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
611 major = register_blkdev(0, "virtblk");
614 goto out_destroy_workqueue;
617 error = register_virtio_driver(&virtio_blk);
619 goto out_unregister_blkdev;
622 out_unregister_blkdev:
623 unregister_blkdev(major, "virtblk");
624 out_destroy_workqueue:
625 destroy_workqueue(virtblk_wq);
629 static void __exit fini(void)
631 unregister_blkdev(major, "virtblk");
632 unregister_virtio_driver(&virtio_blk);
633 destroy_workqueue(virtblk_wq);
638 MODULE_DEVICE_TABLE(virtio, id_table);
639 MODULE_DESCRIPTION("Virtio block driver");
640 MODULE_LICENSE("GPL");