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>
14 static int major, index;
15 struct workqueue_struct *virtblk_wq;
21 struct virtio_device *vdev;
24 /* The disk structure for the kernel. */
27 /* Request tracking. */
28 struct list_head reqs;
32 /* Process context for config space updates */
33 struct work_struct config_work;
35 /* What host tells us, plus 2 for header & tailer. */
36 unsigned int sg_elems;
38 /* Scatterlist: can be too big for stack. */
39 struct scatterlist sg[/*sg_elems*/];
44 struct list_head list;
46 struct virtio_blk_outhdr out_hdr;
47 struct virtio_scsi_inhdr in_hdr;
51 static void blk_done(struct virtqueue *vq)
53 struct virtio_blk *vblk = vq->vdev->priv;
54 struct virtblk_req *vbr;
58 spin_lock_irqsave(&vblk->lock, flags);
59 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
62 switch (vbr->status) {
66 case VIRTIO_BLK_S_UNSUPP:
74 switch (vbr->req->cmd_type) {
75 case REQ_TYPE_BLOCK_PC:
76 vbr->req->resid_len = vbr->in_hdr.residual;
77 vbr->req->sense_len = vbr->in_hdr.sense_len;
78 vbr->req->errors = vbr->in_hdr.errors;
80 case REQ_TYPE_SPECIAL:
81 vbr->req->errors = (error != 0);
87 __blk_end_request_all(vbr->req, error);
89 mempool_free(vbr, vblk->pool);
91 /* In case queue is stopped waiting for more buffers. */
92 blk_start_queue(vblk->disk->queue);
93 spin_unlock_irqrestore(&vblk->lock, flags);
96 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
99 unsigned long num, out = 0, in = 0;
100 struct virtblk_req *vbr;
102 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
104 /* When another request finishes we'll try again. */
109 if (req->cmd_flags & REQ_FLUSH) {
110 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
111 vbr->out_hdr.sector = 0;
112 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
114 switch (req->cmd_type) {
116 vbr->out_hdr.type = 0;
117 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
118 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
120 case REQ_TYPE_BLOCK_PC:
121 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
122 vbr->out_hdr.sector = 0;
123 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
125 case REQ_TYPE_SPECIAL:
126 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
127 vbr->out_hdr.sector = 0;
128 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
131 /* We don't put anything else in the queue. */
136 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
139 * If this is a packet command we need a couple of additional headers.
140 * Behind the normal outhdr we put a segment with the scsi command
141 * block, and before the normal inhdr we put the sense data and the
142 * inhdr with additional status information before the normal inhdr.
144 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
145 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
147 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
149 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
150 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
151 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
152 sizeof(vbr->in_hdr));
155 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
156 sizeof(vbr->status));
159 if (rq_data_dir(vbr->req) == WRITE) {
160 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
163 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
168 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
169 mempool_free(vbr, vblk->pool);
173 list_add_tail(&vbr->list, &vblk->reqs);
177 static void do_virtblk_request(struct request_queue *q)
179 struct virtio_blk *vblk = q->queuedata;
181 unsigned int issued = 0;
183 while ((req = blk_peek_request(q)) != NULL) {
184 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
186 /* If this request fails, stop queue and wait for something to
187 finish to restart it. */
188 if (!do_req(q, vblk, req)) {
192 blk_start_request(req);
197 virtqueue_kick(vblk->vq);
200 /* return id (s/n) string for *disk to *id_str
202 static int virtblk_get_id(struct gendisk *disk, char *id_str)
204 struct virtio_blk *vblk = disk->private_data;
209 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
214 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
220 req->cmd_type = REQ_TYPE_SPECIAL;
221 err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
222 blk_put_request(req);
227 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
228 unsigned int cmd, unsigned long data)
230 struct gendisk *disk = bdev->bd_disk;
231 struct virtio_blk *vblk = disk->private_data;
234 * Only allow the generic SCSI ioctls if the host can support it.
236 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
239 return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
240 (void __user *)data);
243 /* We provide getgeo only to please some old bootloader/partitioning tools */
244 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
246 struct virtio_blk *vblk = bd->bd_disk->private_data;
247 struct virtio_blk_geometry vgeo;
250 /* see if the host passed in geometry config */
251 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
252 offsetof(struct virtio_blk_config, geometry),
256 geo->heads = vgeo.heads;
257 geo->sectors = vgeo.sectors;
258 geo->cylinders = vgeo.cylinders;
260 /* some standard values, similar to sd */
262 geo->sectors = 1 << 5;
263 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
268 static const struct block_device_operations virtblk_fops = {
269 .ioctl = virtblk_ioctl,
270 .owner = THIS_MODULE,
271 .getgeo = virtblk_getgeo,
274 static int index_to_minor(int index)
276 return index << PART_BITS;
279 static ssize_t virtblk_serial_show(struct device *dev,
280 struct device_attribute *attr, char *buf)
282 struct gendisk *disk = dev_to_disk(dev);
285 /* sysfs gives us a PAGE_SIZE buffer */
286 BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
288 buf[VIRTIO_BLK_ID_BYTES] = '\0';
289 err = virtblk_get_id(disk, buf);
293 if (err == -EIO) /* Unsupported? Make it empty. */
298 DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
300 static void virtblk_config_changed_work(struct work_struct *work)
302 struct virtio_blk *vblk =
303 container_of(work, struct virtio_blk, config_work);
304 struct virtio_device *vdev = vblk->vdev;
305 struct request_queue *q = vblk->disk->queue;
306 char cap_str_2[10], cap_str_10[10];
309 /* Host must always specify the capacity. */
310 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
311 &capacity, sizeof(capacity));
313 /* If capacity is too big, truncate with warning. */
314 if ((sector_t)capacity != capacity) {
315 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
316 (unsigned long long)capacity);
317 capacity = (sector_t)-1;
320 size = capacity * queue_logical_block_size(q);
321 string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
322 string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
324 dev_notice(&vdev->dev,
325 "new size: %llu %d-byte logical blocks (%s/%s)\n",
326 (unsigned long long)capacity,
327 queue_logical_block_size(q),
328 cap_str_10, cap_str_2);
330 set_capacity(vblk->disk, capacity);
333 static void virtblk_config_changed(struct virtio_device *vdev)
335 struct virtio_blk *vblk = vdev->priv;
337 queue_work(virtblk_wq, &vblk->config_work);
340 static int __devinit virtblk_probe(struct virtio_device *vdev)
342 struct virtio_blk *vblk;
343 struct request_queue *q;
346 u32 v, blk_size, sg_elems, opt_io_size;
348 u8 physical_block_exp, alignment_offset;
350 if (index_to_minor(index) >= 1 << MINORBITS)
353 /* We need to know how many segments before we allocate. */
354 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
355 offsetof(struct virtio_blk_config, seg_max),
358 /* We need at least one SG element, whatever they say. */
359 if (err || !sg_elems)
362 /* We need an extra sg elements at head and tail. */
364 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
365 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
371 INIT_LIST_HEAD(&vblk->reqs);
372 spin_lock_init(&vblk->lock);
374 vblk->sg_elems = sg_elems;
375 sg_init_table(vblk->sg, vblk->sg_elems);
376 INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
378 /* We expect one virtqueue, for output. */
379 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
380 if (IS_ERR(vblk->vq)) {
381 err = PTR_ERR(vblk->vq);
385 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
391 /* FIXME: How many partitions? How long is a piece of string? */
392 vblk->disk = alloc_disk(1 << PART_BITS);
398 q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
407 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
408 } else if (index < (26 + 1) * 26) {
409 sprintf(vblk->disk->disk_name, "vd%c%c",
410 'a' + index / 26 - 1, 'a' + index % 26);
412 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
413 const unsigned int m2 = (index / 26 - 1) % 26;
414 const unsigned int m3 = index % 26;
415 sprintf(vblk->disk->disk_name, "vd%c%c%c",
416 'a' + m1, 'a' + m2, 'a' + m3);
419 vblk->disk->major = major;
420 vblk->disk->first_minor = index_to_minor(index);
421 vblk->disk->private_data = vblk;
422 vblk->disk->fops = &virtblk_fops;
423 vblk->disk->driverfs_dev = &vdev->dev;
426 /* configure queue flush support */
427 if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
428 blk_queue_flush(q, REQ_FLUSH);
430 /* If disk is read-only in the host, the guest should obey */
431 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
432 set_disk_ro(vblk->disk, 1);
434 /* Host must always specify the capacity. */
435 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
438 /* If capacity is too big, truncate with warning. */
439 if ((sector_t)cap != cap) {
440 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
441 (unsigned long long)cap);
444 set_capacity(vblk->disk, cap);
446 /* We can handle whatever the host told us to handle. */
447 blk_queue_max_segments(q, vblk->sg_elems-2);
449 /* No need to bounce any requests */
450 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
452 /* No real sector limit. */
453 blk_queue_max_hw_sectors(q, -1U);
455 /* Host can optionally specify maximum segment size and number of
457 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
458 offsetof(struct virtio_blk_config, size_max),
461 blk_queue_max_segment_size(q, v);
463 blk_queue_max_segment_size(q, -1U);
465 /* Host can optionally specify the block size of the device */
466 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
467 offsetof(struct virtio_blk_config, blk_size),
470 blk_queue_logical_block_size(q, blk_size);
472 blk_size = queue_logical_block_size(q);
474 /* Use topology information if available */
475 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
476 offsetof(struct virtio_blk_config, physical_block_exp),
477 &physical_block_exp);
478 if (!err && physical_block_exp)
479 blk_queue_physical_block_size(q,
480 blk_size * (1 << physical_block_exp));
482 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
483 offsetof(struct virtio_blk_config, alignment_offset),
485 if (!err && alignment_offset)
486 blk_queue_alignment_offset(q, blk_size * alignment_offset);
488 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
489 offsetof(struct virtio_blk_config, min_io_size),
491 if (!err && min_io_size)
492 blk_queue_io_min(q, blk_size * min_io_size);
494 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
495 offsetof(struct virtio_blk_config, opt_io_size),
497 if (!err && opt_io_size)
498 blk_queue_io_opt(q, blk_size * opt_io_size);
501 add_disk(vblk->disk);
502 err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
509 del_gendisk(vblk->disk);
510 blk_cleanup_queue(vblk->disk->queue);
512 put_disk(vblk->disk);
514 mempool_destroy(vblk->pool);
516 vdev->config->del_vqs(vdev);
523 static void __devexit virtblk_remove(struct virtio_device *vdev)
525 struct virtio_blk *vblk = vdev->priv;
527 flush_work(&vblk->config_work);
529 /* Nothing should be pending. */
530 BUG_ON(!list_empty(&vblk->reqs));
532 /* Stop all the virtqueues. */
533 vdev->config->reset(vdev);
535 del_gendisk(vblk->disk);
536 blk_cleanup_queue(vblk->disk->queue);
537 put_disk(vblk->disk);
538 mempool_destroy(vblk->pool);
539 vdev->config->del_vqs(vdev);
543 static const struct virtio_device_id id_table[] = {
544 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
548 static unsigned int features[] = {
549 VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
550 VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
551 VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
555 * virtio_blk causes spurious section mismatch warning by
556 * simultaneously referring to a __devinit and a __devexit function.
557 * Use __refdata to avoid this warning.
559 static struct virtio_driver __refdata virtio_blk = {
560 .feature_table = features,
561 .feature_table_size = ARRAY_SIZE(features),
562 .driver.name = KBUILD_MODNAME,
563 .driver.owner = THIS_MODULE,
564 .id_table = id_table,
565 .probe = virtblk_probe,
566 .remove = __devexit_p(virtblk_remove),
567 .config_changed = virtblk_config_changed,
570 static int __init init(void)
574 virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
578 major = register_blkdev(0, "virtblk");
581 goto out_destroy_workqueue;
584 error = register_virtio_driver(&virtio_blk);
586 goto out_unregister_blkdev;
589 out_unregister_blkdev:
590 unregister_blkdev(major, "virtblk");
591 out_destroy_workqueue:
592 destroy_workqueue(virtblk_wq);
596 static void __exit fini(void)
598 unregister_blkdev(major, "virtblk");
599 unregister_virtio_driver(&virtio_blk);
600 destroy_workqueue(virtblk_wq);
605 MODULE_DEVICE_TABLE(virtio, id_table);
606 MODULE_DESCRIPTION("Virtio block driver");
607 MODULE_LICENSE("GPL");