2 #include <linux/spinlock.h>
3 #include <linux/slab.h>
4 #include <linux/blkdev.h>
5 #include <linux/smp_lock.h>
6 #include <linux/hdreg.h>
7 #include <linux/virtio.h>
8 #include <linux/virtio_blk.h>
9 #include <linux/scatterlist.h>
13 static int major, index;
19 struct virtio_device *vdev;
22 /* The disk structure for the kernel. */
25 /* Request tracking. */
26 struct list_head reqs;
30 /* What host tells us, plus 2 for header & tailer. */
31 unsigned int sg_elems;
33 /* Scatterlist: can be too big for stack. */
34 struct scatterlist sg[/*sg_elems*/];
39 struct list_head list;
41 struct virtio_blk_outhdr out_hdr;
42 struct virtio_scsi_inhdr in_hdr;
46 static void blk_done(struct virtqueue *vq)
48 struct virtio_blk *vblk = vq->vdev->priv;
49 struct virtblk_req *vbr;
53 spin_lock_irqsave(&vblk->lock, flags);
54 while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
57 switch (vbr->status) {
61 case VIRTIO_BLK_S_UNSUPP:
69 switch (vbr->req->cmd_type) {
70 case REQ_TYPE_BLOCK_PC:
71 vbr->req->resid_len = vbr->in_hdr.residual;
72 vbr->req->sense_len = vbr->in_hdr.sense_len;
73 vbr->req->errors = vbr->in_hdr.errors;
75 case REQ_TYPE_SPECIAL:
76 vbr->req->errors = (error != 0);
82 __blk_end_request_all(vbr->req, error);
84 mempool_free(vbr, vblk->pool);
86 /* In case queue is stopped waiting for more buffers. */
87 blk_start_queue(vblk->disk->queue);
88 spin_unlock_irqrestore(&vblk->lock, flags);
91 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
94 unsigned long num, out = 0, in = 0;
95 struct virtblk_req *vbr;
97 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
99 /* When another request finishes we'll try again. */
104 if (req->cmd_flags & REQ_FLUSH) {
105 vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
106 vbr->out_hdr.sector = 0;
107 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
109 switch (req->cmd_type) {
111 vbr->out_hdr.type = 0;
112 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
113 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
115 case REQ_TYPE_BLOCK_PC:
116 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
117 vbr->out_hdr.sector = 0;
118 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
120 case REQ_TYPE_SPECIAL:
121 vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID;
122 vbr->out_hdr.sector = 0;
123 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
126 /* We don't put anything else in the queue. */
131 if (vbr->req->cmd_flags & REQ_HARDBARRIER)
132 vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
134 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
137 * If this is a packet command we need a couple of additional headers.
138 * Behind the normal outhdr we put a segment with the scsi command
139 * block, and before the normal inhdr we put the sense data and the
140 * inhdr with additional status information before the normal inhdr.
142 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC)
143 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
145 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
147 if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) {
148 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
149 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
150 sizeof(vbr->in_hdr));
153 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
154 sizeof(vbr->status));
157 if (rq_data_dir(vbr->req) == WRITE) {
158 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
161 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
166 if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
167 mempool_free(vbr, vblk->pool);
171 list_add_tail(&vbr->list, &vblk->reqs);
175 static void do_virtblk_request(struct request_queue *q)
177 struct virtio_blk *vblk = q->queuedata;
179 unsigned int issued = 0;
181 while ((req = blk_peek_request(q)) != NULL) {
182 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
184 /* If this request fails, stop queue and wait for something to
185 finish to restart it. */
186 if (!do_req(q, vblk, req)) {
190 blk_start_request(req);
195 virtqueue_kick(vblk->vq);
198 /* return id (s/n) string for *disk to *id_str
200 static int virtblk_get_id(struct gendisk *disk, char *id_str)
202 struct virtio_blk *vblk = disk->private_data;
206 bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES,
211 req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL);
217 req->cmd_type = REQ_TYPE_SPECIAL;
218 return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
221 static int virtblk_locked_ioctl(struct block_device *bdev, fmode_t mode,
222 unsigned cmd, unsigned long data)
224 struct gendisk *disk = bdev->bd_disk;
225 struct virtio_blk *vblk = disk->private_data;
227 if (cmd == 0x56424944) { /* 'VBID' */
228 void __user *usr_data = (void __user *)data;
229 char id_str[VIRTIO_BLK_ID_BYTES];
232 err = virtblk_get_id(disk, id_str);
233 if (!err && copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
238 * Only allow the generic SCSI ioctls if the host can support it.
240 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
243 return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
244 (void __user *)data);
247 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
248 unsigned int cmd, unsigned long param)
253 ret = virtblk_locked_ioctl(bdev, mode, cmd, param);
259 /* We provide getgeo only to please some old bootloader/partitioning tools */
260 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
262 struct virtio_blk *vblk = bd->bd_disk->private_data;
263 struct virtio_blk_geometry vgeo;
266 /* see if the host passed in geometry config */
267 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
268 offsetof(struct virtio_blk_config, geometry),
272 geo->heads = vgeo.heads;
273 geo->sectors = vgeo.sectors;
274 geo->cylinders = vgeo.cylinders;
276 /* some standard values, similar to sd */
278 geo->sectors = 1 << 5;
279 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
284 static const struct block_device_operations virtblk_fops = {
285 .ioctl = virtblk_ioctl,
286 .owner = THIS_MODULE,
287 .getgeo = virtblk_getgeo,
290 static int index_to_minor(int index)
292 return index << PART_BITS;
295 static int __devinit virtblk_probe(struct virtio_device *vdev)
297 struct virtio_blk *vblk;
298 struct request_queue *q;
301 u32 v, blk_size, sg_elems, opt_io_size;
303 u8 physical_block_exp, alignment_offset;
305 if (index_to_minor(index) >= 1 << MINORBITS)
308 /* We need to know how many segments before we allocate. */
309 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
310 offsetof(struct virtio_blk_config, seg_max),
313 /* We need at least one SG element, whatever they say. */
314 if (err || !sg_elems)
317 /* We need an extra sg elements at head and tail. */
319 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
320 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
326 INIT_LIST_HEAD(&vblk->reqs);
327 spin_lock_init(&vblk->lock);
329 vblk->sg_elems = sg_elems;
330 sg_init_table(vblk->sg, vblk->sg_elems);
332 /* We expect one virtqueue, for output. */
333 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
334 if (IS_ERR(vblk->vq)) {
335 err = PTR_ERR(vblk->vq);
339 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
345 /* FIXME: How many partitions? How long is a piece of string? */
346 vblk->disk = alloc_disk(1 << PART_BITS);
352 q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
361 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
362 } else if (index < (26 + 1) * 26) {
363 sprintf(vblk->disk->disk_name, "vd%c%c",
364 'a' + index / 26 - 1, 'a' + index % 26);
366 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
367 const unsigned int m2 = (index / 26 - 1) % 26;
368 const unsigned int m3 = index % 26;
369 sprintf(vblk->disk->disk_name, "vd%c%c%c",
370 'a' + m1, 'a' + m2, 'a' + m3);
373 vblk->disk->major = major;
374 vblk->disk->first_minor = index_to_minor(index);
375 vblk->disk->private_data = vblk;
376 vblk->disk->fops = &virtblk_fops;
377 vblk->disk->driverfs_dev = &vdev->dev;
380 /* If barriers are supported, tell block layer that queue is ordered */
381 if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
382 blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH);
383 else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
384 blk_queue_ordered(q, QUEUE_ORDERED_TAG);
386 /* If disk is read-only in the host, the guest should obey */
387 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
388 set_disk_ro(vblk->disk, 1);
390 /* Host must always specify the capacity. */
391 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
394 /* If capacity is too big, truncate with warning. */
395 if ((sector_t)cap != cap) {
396 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
397 (unsigned long long)cap);
400 set_capacity(vblk->disk, cap);
402 /* We can handle whatever the host told us to handle. */
403 blk_queue_max_segments(q, vblk->sg_elems-2);
405 /* No need to bounce any requests */
406 blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
408 /* No real sector limit. */
409 blk_queue_max_hw_sectors(q, -1U);
411 /* Host can optionally specify maximum segment size and number of
413 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
414 offsetof(struct virtio_blk_config, size_max),
417 blk_queue_max_segment_size(q, v);
419 blk_queue_max_segment_size(q, -1U);
421 /* Host can optionally specify the block size of the device */
422 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
423 offsetof(struct virtio_blk_config, blk_size),
426 blk_queue_logical_block_size(q, blk_size);
428 blk_size = queue_logical_block_size(q);
430 /* Use topology information if available */
431 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
432 offsetof(struct virtio_blk_config, physical_block_exp),
433 &physical_block_exp);
434 if (!err && physical_block_exp)
435 blk_queue_physical_block_size(q,
436 blk_size * (1 << physical_block_exp));
438 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
439 offsetof(struct virtio_blk_config, alignment_offset),
441 if (!err && alignment_offset)
442 blk_queue_alignment_offset(q, blk_size * alignment_offset);
444 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
445 offsetof(struct virtio_blk_config, min_io_size),
447 if (!err && min_io_size)
448 blk_queue_io_min(q, blk_size * min_io_size);
450 err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
451 offsetof(struct virtio_blk_config, opt_io_size),
453 if (!err && opt_io_size)
454 blk_queue_io_opt(q, blk_size * opt_io_size);
457 add_disk(vblk->disk);
461 put_disk(vblk->disk);
463 mempool_destroy(vblk->pool);
465 vdev->config->del_vqs(vdev);
472 static void __devexit virtblk_remove(struct virtio_device *vdev)
474 struct virtio_blk *vblk = vdev->priv;
476 /* Nothing should be pending. */
477 BUG_ON(!list_empty(&vblk->reqs));
479 /* Stop all the virtqueues. */
480 vdev->config->reset(vdev);
482 del_gendisk(vblk->disk);
483 blk_cleanup_queue(vblk->disk->queue);
484 put_disk(vblk->disk);
485 mempool_destroy(vblk->pool);
486 vdev->config->del_vqs(vdev);
490 static const struct virtio_device_id id_table[] = {
491 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
495 static unsigned int features[] = {
496 VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
497 VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
498 VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
502 * virtio_blk causes spurious section mismatch warning by
503 * simultaneously referring to a __devinit and a __devexit function.
504 * Use __refdata to avoid this warning.
506 static struct virtio_driver __refdata virtio_blk = {
507 .feature_table = features,
508 .feature_table_size = ARRAY_SIZE(features),
509 .driver.name = KBUILD_MODNAME,
510 .driver.owner = THIS_MODULE,
511 .id_table = id_table,
512 .probe = virtblk_probe,
513 .remove = __devexit_p(virtblk_remove),
516 static int __init init(void)
518 major = register_blkdev(0, "virtblk");
521 return register_virtio_driver(&virtio_blk);
524 static void __exit fini(void)
526 unregister_blkdev(major, "virtblk");
527 unregister_virtio_driver(&virtio_blk);
532 MODULE_DEVICE_TABLE(virtio, id_table);
533 MODULE_DESCRIPTION("Virtio block driver");
534 MODULE_LICENSE("GPL");