2 #include <linux/spinlock.h>
3 #include <linux/blkdev.h>
4 #include <linux/hdreg.h>
5 #include <linux/virtio.h>
6 #include <linux/virtio_ids.h>
7 #include <linux/virtio_blk.h>
8 #include <linux/scatterlist.h>
12 static int major, index;
18 struct virtio_device *vdev;
21 /* The disk structure for the kernel. */
24 /* Request tracking. */
25 struct list_head reqs;
29 /* What host tells us, plus 2 for header & tailer. */
30 unsigned int sg_elems;
32 /* Scatterlist: can be too big for stack. */
33 struct scatterlist sg[/*sg_elems*/];
38 struct list_head list;
40 struct virtio_blk_outhdr out_hdr;
41 struct virtio_scsi_inhdr in_hdr;
45 static void blk_done(struct virtqueue *vq)
47 struct virtio_blk *vblk = vq->vdev->priv;
48 struct virtblk_req *vbr;
52 spin_lock_irqsave(&vblk->lock, flags);
53 while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
56 switch (vbr->status) {
60 case VIRTIO_BLK_S_UNSUPP:
68 if (blk_pc_request(vbr->req)) {
69 vbr->req->resid_len = vbr->in_hdr.residual;
70 vbr->req->sense_len = vbr->in_hdr.sense_len;
71 vbr->req->errors = vbr->in_hdr.errors;
74 __blk_end_request_all(vbr->req, error);
76 mempool_free(vbr, vblk->pool);
78 /* In case queue is stopped waiting for more buffers. */
79 blk_start_queue(vblk->disk->queue);
80 spin_unlock_irqrestore(&vblk->lock, flags);
83 static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
86 unsigned long num, out = 0, in = 0;
87 struct virtblk_req *vbr;
89 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
91 /* When another request finishes we'll try again. */
95 if (blk_fs_request(vbr->req)) {
96 vbr->out_hdr.type = 0;
97 vbr->out_hdr.sector = blk_rq_pos(vbr->req);
98 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
99 } else if (blk_pc_request(vbr->req)) {
100 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
101 vbr->out_hdr.sector = 0;
102 vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
104 /* We don't put anything else in the queue. */
108 if (blk_barrier_rq(vbr->req))
109 vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
111 sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
114 * If this is a packet command we need a couple of additional headers.
115 * Behind the normal outhdr we put a segment with the scsi command
116 * block, and before the normal inhdr we put the sense data and the
117 * inhdr with additional status information before the normal inhdr.
119 if (blk_pc_request(vbr->req))
120 sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
122 num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
124 if (blk_pc_request(vbr->req)) {
125 sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
126 sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
127 sizeof(vbr->in_hdr));
130 sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
131 sizeof(vbr->status));
134 if (rq_data_dir(vbr->req) == WRITE) {
135 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
138 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
143 if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
144 mempool_free(vbr, vblk->pool);
148 list_add_tail(&vbr->list, &vblk->reqs);
152 static void do_virtblk_request(struct request_queue *q)
154 struct virtio_blk *vblk = q->queuedata;
156 unsigned int issued = 0;
158 while ((req = blk_peek_request(q)) != NULL) {
159 BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
161 /* If this request fails, stop queue and wait for something to
162 finish to restart it. */
163 if (!do_req(q, vblk, req)) {
167 blk_start_request(req);
172 vblk->vq->vq_ops->kick(vblk->vq);
175 /* return ATA identify data
177 static int virtblk_identify(struct gendisk *disk, void *argp)
179 struct virtio_blk *vblk = disk->private_data;
183 opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
187 err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
188 offsetof(struct virtio_blk_config, identify), opaque,
189 VIRTIO_BLK_ID_BYTES);
194 if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
203 static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
204 unsigned cmd, unsigned long data)
206 struct gendisk *disk = bdev->bd_disk;
207 struct virtio_blk *vblk = disk->private_data;
208 void __user *argp = (void __user *)data;
210 if (cmd == HDIO_GET_IDENTITY)
211 return virtblk_identify(disk, argp);
214 * Only allow the generic SCSI ioctls if the host can support it.
216 if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
219 return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, argp);
222 /* We provide getgeo only to please some old bootloader/partitioning tools */
223 static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
225 struct virtio_blk *vblk = bd->bd_disk->private_data;
226 struct virtio_blk_geometry vgeo;
229 /* see if the host passed in geometry config */
230 err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
231 offsetof(struct virtio_blk_config, geometry),
235 geo->heads = vgeo.heads;
236 geo->sectors = vgeo.sectors;
237 geo->cylinders = vgeo.cylinders;
239 /* some standard values, similar to sd */
241 geo->sectors = 1 << 5;
242 geo->cylinders = get_capacity(bd->bd_disk) >> 11;
247 static struct block_device_operations virtblk_fops = {
248 .locked_ioctl = virtblk_ioctl,
249 .owner = THIS_MODULE,
250 .getgeo = virtblk_getgeo,
253 static int index_to_minor(int index)
255 return index << PART_BITS;
258 static int __devinit virtblk_probe(struct virtio_device *vdev)
260 struct virtio_blk *vblk;
264 u32 blk_size, sg_elems;
266 if (index_to_minor(index) >= 1 << MINORBITS)
269 /* We need to know how many segments before we allocate. */
270 err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
271 offsetof(struct virtio_blk_config, seg_max),
276 /* We need an extra sg elements at head and tail. */
278 vdev->priv = vblk = kmalloc(sizeof(*vblk) +
279 sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
285 INIT_LIST_HEAD(&vblk->reqs);
286 spin_lock_init(&vblk->lock);
288 vblk->sg_elems = sg_elems;
289 sg_init_table(vblk->sg, vblk->sg_elems);
291 /* We expect one virtqueue, for output. */
292 vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
293 if (IS_ERR(vblk->vq)) {
294 err = PTR_ERR(vblk->vq);
298 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
304 /* FIXME: How many partitions? How long is a piece of string? */
305 vblk->disk = alloc_disk(1 << PART_BITS);
311 vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
312 if (!vblk->disk->queue) {
317 vblk->disk->queue->queuedata = vblk;
318 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, vblk->disk->queue);
321 sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
322 } else if (index < (26 + 1) * 26) {
323 sprintf(vblk->disk->disk_name, "vd%c%c",
324 'a' + index / 26 - 1, 'a' + index % 26);
326 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
327 const unsigned int m2 = (index / 26 - 1) % 26;
328 const unsigned int m3 = index % 26;
329 sprintf(vblk->disk->disk_name, "vd%c%c%c",
330 'a' + m1, 'a' + m2, 'a' + m3);
333 vblk->disk->major = major;
334 vblk->disk->first_minor = index_to_minor(index);
335 vblk->disk->private_data = vblk;
336 vblk->disk->fops = &virtblk_fops;
337 vblk->disk->driverfs_dev = &vdev->dev;
340 /* If barriers are supported, tell block layer that queue is ordered */
341 if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
342 blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
344 /* If disk is read-only in the host, the guest should obey */
345 if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
346 set_disk_ro(vblk->disk, 1);
348 /* Host must always specify the capacity. */
349 vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
352 /* If capacity is too big, truncate with warning. */
353 if ((sector_t)cap != cap) {
354 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
355 (unsigned long long)cap);
358 set_capacity(vblk->disk, cap);
360 /* We can handle whatever the host told us to handle. */
361 blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2);
362 blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2);
364 /* No need to bounce any requests */
365 blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY);
367 /* No real sector limit. */
368 blk_queue_max_sectors(vblk->disk->queue, -1U);
370 /* Host can optionally specify maximum segment size and number of
372 err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
373 offsetof(struct virtio_blk_config, size_max),
376 blk_queue_max_segment_size(vblk->disk->queue, v);
378 blk_queue_max_segment_size(vblk->disk->queue, -1U);
380 /* Host can optionally specify the block size of the device */
381 err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
382 offsetof(struct virtio_blk_config, blk_size),
385 blk_queue_logical_block_size(vblk->disk->queue, blk_size);
387 add_disk(vblk->disk);
391 put_disk(vblk->disk);
393 mempool_destroy(vblk->pool);
395 vdev->config->del_vqs(vdev);
402 static void __devexit virtblk_remove(struct virtio_device *vdev)
404 struct virtio_blk *vblk = vdev->priv;
406 /* Nothing should be pending. */
407 BUG_ON(!list_empty(&vblk->reqs));
409 /* Stop all the virtqueues. */
410 vdev->config->reset(vdev);
412 del_gendisk(vblk->disk);
413 blk_cleanup_queue(vblk->disk->queue);
414 put_disk(vblk->disk);
415 mempool_destroy(vblk->pool);
416 vdev->config->del_vqs(vdev);
420 static struct virtio_device_id id_table[] = {
421 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
425 static unsigned int features[] = {
426 VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
427 VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
428 VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY
432 * virtio_blk causes spurious section mismatch warning by
433 * simultaneously referring to a __devinit and a __devexit function.
434 * Use __refdata to avoid this warning.
436 static struct virtio_driver __refdata virtio_blk = {
437 .feature_table = features,
438 .feature_table_size = ARRAY_SIZE(features),
439 .driver.name = KBUILD_MODNAME,
440 .driver.owner = THIS_MODULE,
441 .id_table = id_table,
442 .probe = virtblk_probe,
443 .remove = __devexit_p(virtblk_remove),
446 static int __init init(void)
448 major = register_blkdev(0, "virtblk");
451 return register_virtio_driver(&virtio_blk);
454 static void __exit fini(void)
456 unregister_blkdev(major, "virtblk");
457 unregister_virtio_driver(&virtio_blk);
462 MODULE_DEVICE_TABLE(virtio, id_table);
463 MODULE_DESCRIPTION("Virtio block driver");
464 MODULE_LICENSE("GPL");