[mirror_ubuntu-bionic-kernel.git] / drivers / block / virtio_blk.c

//#define DEBUG
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/virtio.h>
#include <linux/virtio_blk.h>
#include <linux/scatterlist.h>

#define PART_BITS 4

static int major, index;

struct virtio_blk
{
	spinlock_t lock;

	struct virtio_device *vdev;
	struct virtqueue *vq;

	/* The disk structure for the kernel. */
	struct gendisk *disk;

	/* Request tracking. */
	struct list_head reqs;

	mempool_t *pool;

	/* What host tells us, plus 2 for header & tailer. */
	unsigned int sg_elems;

	/* Scatterlist: can be too big for stack. */
	struct scatterlist sg[/*sg_elems*/];
};

struct virtblk_req
{
	struct list_head list;
	struct request *req;
	struct virtio_blk_outhdr out_hdr;
	u8 status;
};

static void blk_done(struct virtqueue *vq)
{
	struct virtio_blk *vblk = vq->vdev->priv;
	struct virtblk_req *vbr;
	unsigned int len;
	unsigned long flags;

	spin_lock_irqsave(&vblk->lock, flags);
	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
		int error;
		switch (vbr->status) {
		case VIRTIO_BLK_S_OK:
			error = 0;
			break;
		case VIRTIO_BLK_S_UNSUPP:
			error = -ENOTTY;
			break;
		default:
			error = -EIO;
			break;
		}

		__blk_end_request_all(vbr->req, error);
		list_del(&vbr->list);
		mempool_free(vbr, vblk->pool);
	}
	/* In case queue is stopped waiting for more buffers. */
	blk_start_queue(vblk->disk->queue);
	spin_unlock_irqrestore(&vblk->lock, flags);
}

static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
		   struct request *req)
{
	unsigned long num, out, in;
	struct virtblk_req *vbr;

	vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
	if (!vbr)
		/* When another request finishes we'll try again. */
		return false;

	vbr->req = req;
	if (blk_fs_request(vbr->req)) {
		vbr->out_hdr.type = 0;
		vbr->out_hdr.sector = blk_rq_pos(vbr->req);
		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
	} else if (blk_pc_request(vbr->req)) {
		vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
		vbr->out_hdr.sector = 0;
		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
	} else {
		/* We don't put anything else in the queue. */
		BUG();
	}

	if (blk_barrier_rq(vbr->req))
		vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;

	sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
	num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);
	sg_set_buf(&vblk->sg[num+1], &vbr->status, sizeof(vbr->status));

	if (rq_data_dir(vbr->req) == WRITE) {
		vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
		out = 1 + num;
		in = 1;
	} else {
		vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
		out = 1;
		in = 1 + num;
	}

	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
		mempool_free(vbr, vblk->pool);
		return false;
	}

	list_add_tail(&vbr->list, &vblk->reqs);
	return true;
}

static void do_virtblk_request(struct request_queue *q)
{
	struct virtio_blk *vblk = NULL;
	struct request *req;
	unsigned int issued = 0;

	while ((req = elv_next_request(q)) != NULL) {
		vblk = req->rq_disk->private_data;
		BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);

		/* If this request fails, stop queue and wait for something to
		   finish to restart it. */
		if (!do_req(q, vblk, req)) {
			blk_stop_queue(q);
			break;
		}
		blkdev_dequeue_request(req);
		issued++;
	}

	if (issued)
		vblk->vq->vq_ops->kick(vblk->vq);
}

static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
			 unsigned cmd, unsigned long data)
{
	return scsi_cmd_ioctl(bdev->bd_disk->queue,
			      bdev->bd_disk, mode, cmd,
			      (void __user *)data);
}

/* We provide getgeo only to please some old bootloader/partitioning tools */
static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
{
	struct virtio_blk *vblk = bd->bd_disk->private_data;
	struct virtio_blk_geometry vgeo;
	int err;

	/* see if the host passed in geometry config */
	err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
				offsetof(struct virtio_blk_config, geometry),
				&vgeo);

	if (!err) {
		geo->heads = vgeo.heads;
		geo->sectors = vgeo.sectors;
		geo->cylinders = vgeo.cylinders;
	} else {
		/* some standard values, similar to sd */
		geo->heads = 1 << 6;
		geo->sectors = 1 << 5;
		geo->cylinders = get_capacity(bd->bd_disk) >> 11;
	}
	return 0;
}

static struct block_device_operations virtblk_fops = {
	.locked_ioctl = virtblk_ioctl,
	.owner  = THIS_MODULE,
	.getgeo = virtblk_getgeo,
};

static int index_to_minor(int index)
{
	return index << PART_BITS;
}

static int virtblk_probe(struct virtio_device *vdev)
{
	struct virtio_blk *vblk;
	int err;
	u64 cap;
	u32 v;
	u32 blk_size, sg_elems;

	if (index_to_minor(index) >= 1 << MINORBITS)
		return -ENOSPC;

	/* We need to know how many segments before we allocate. */
	err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
				offsetof(struct virtio_blk_config, seg_max),
				&sg_elems);
	if (err)
		sg_elems = 1;

	/* We need an extra sg elements at head and tail. */
	sg_elems += 2;
	vdev->priv = vblk = kmalloc(sizeof(*vblk) +
				    sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
	if (!vblk) {
		err = -ENOMEM;
		goto out;
	}

	INIT_LIST_HEAD(&vblk->reqs);
	spin_lock_init(&vblk->lock);
	vblk->vdev = vdev;
	vblk->sg_elems = sg_elems;
	sg_init_table(vblk->sg, vblk->sg_elems);

	/* We expect one virtqueue, for output. */
	vblk->vq = vdev->config->find_vq(vdev, 0, blk_done);
	if (IS_ERR(vblk->vq)) {
		err = PTR_ERR(vblk->vq);
		goto out_free_vblk;
	}

	vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
	if (!vblk->pool) {
		err = -ENOMEM;
		goto out_free_vq;
	}

	/* FIXME: How many partitions?  How long is a piece of string? */
	vblk->disk = alloc_disk(1 << PART_BITS);
	if (!vblk->disk) {
		err = -ENOMEM;
		goto out_mempool;
	}

	vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
	if (!vblk->disk->queue) {
		err = -ENOMEM;
		goto out_put_disk;
	}

	queue_flag_set_unlocked(QUEUE_FLAG_VIRT, vblk->disk->queue);

	if (index < 26) {
		sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
	} else if (index < (26 + 1) * 26) {
		sprintf(vblk->disk->disk_name, "vd%c%c",
			'a' + index / 26 - 1, 'a' + index % 26);
	} else {
		const unsigned int m1 = (index / 26 - 1) / 26 - 1;
		const unsigned int m2 = (index / 26 - 1) % 26;
		const unsigned int m3 =  index % 26;
		sprintf(vblk->disk->disk_name, "vd%c%c%c",
			'a' + m1, 'a' + m2, 'a' + m3);
	}

	vblk->disk->major = major;
	vblk->disk->first_minor = index_to_minor(index);
	vblk->disk->private_data = vblk;
	vblk->disk->fops = &virtblk_fops;
	vblk->disk->driverfs_dev = &vdev->dev;
	index++;

	/* If barriers are supported, tell block layer that queue is ordered */
	if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
		blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);

	/* If disk is read-only in the host, the guest should obey */
	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
		set_disk_ro(vblk->disk, 1);

	/* Host must always specify the capacity. */
	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
			  &cap, sizeof(cap));

	/* If capacity is too big, truncate with warning. */
	if ((sector_t)cap != cap) {
		dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
			 (unsigned long long)cap);
		cap = (sector_t)-1;
	}
	set_capacity(vblk->disk, cap);

	/* We can handle whatever the host told us to handle. */
	blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2);
	blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2);

	/* No real sector limit. */
	blk_queue_max_sectors(vblk->disk->queue, -1U);

	/* Host can optionally specify maximum segment size and number of
	 * segments. */
	err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
				offsetof(struct virtio_blk_config, size_max),
				&v);
	if (!err)
		blk_queue_max_segment_size(vblk->disk->queue, v);
	else
		blk_queue_max_segment_size(vblk->disk->queue, -1U);

	/* Host can optionally specify the block size of the device */
	err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
				offsetof(struct virtio_blk_config, blk_size),
				&blk_size);
	if (!err)
		blk_queue_hardsect_size(vblk->disk->queue, blk_size);

	add_disk(vblk->disk);
	return 0;

out_put_disk:
	put_disk(vblk->disk);
out_mempool:
	mempool_destroy(vblk->pool);
out_free_vq:
	vdev->config->del_vq(vblk->vq);
out_free_vblk:
	kfree(vblk);
out:
	return err;
}

static void virtblk_remove(struct virtio_device *vdev)
{
	struct virtio_blk *vblk = vdev->priv;

	/* Nothing should be pending. */
	BUG_ON(!list_empty(&vblk->reqs));

	/* Stop all the virtqueues. */
	vdev->config->reset(vdev);

	del_gendisk(vblk->disk);
	blk_cleanup_queue(vblk->disk->queue);
	put_disk(vblk->disk);
	mempool_destroy(vblk->pool);
	vdev->config->del_vq(vblk->vq);
	kfree(vblk);
}

static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
	{ 0 },
};

static unsigned int features[] = {
	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
};

static struct virtio_driver virtio_blk = {
	.feature_table = features,
	.feature_table_size = ARRAY_SIZE(features),
	.driver.name =	KBUILD_MODNAME,
	.driver.owner =	THIS_MODULE,
	.id_table =	id_table,
	.probe =	virtblk_probe,
	.remove =	__devexit_p(virtblk_remove),
};

static int __init init(void)
{
	major = register_blkdev(0, "virtblk");
	if (major < 0)
		return major;
	return register_virtio_driver(&virtio_blk);
}

static void __exit fini(void)
{
	unregister_blkdev(major, "virtblk");
	unregister_virtio_driver(&virtio_blk);
}
module_init(init);
module_exit(fini);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio block driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
e467cde2 RR	1	//#define DEBUG
	2	#include <linux/spinlock.h>
	3	#include <linux/blkdev.h>
	4	#include <linux/hdreg.h>
	5	#include <linux/virtio.h>
	6	#include <linux/virtio_blk.h>
3d1266c7 JA	7	#include <linux/scatterlist.h>
3d1266c7 JA	8
4f3bf19c	9	#define PART_BITS 4
e467cde2	10
d50ed907	11	static int major, index;
4f3bf19c	12
e467cde2 RR	13	struct virtio_blk
	14	{
	15	spinlock_t lock;
	16
	17	struct virtio_device *vdev;
	18	struct virtqueue *vq;
	19
	20	/* The disk structure for the kernel. */
	21	struct gendisk *disk;
	22
	23	/* Request tracking. */
	24	struct list_head reqs;
	25
	26	mempool_t *pool;
	27
0864b79a RR	28	/* What host tells us, plus 2 for header & tailer. */
	29	unsigned int sg_elems;
	30
e467cde2	31	/* Scatterlist: can be too big for stack. */
0864b79a	32	struct scatterlist sg[/sg_elems/];
e467cde2 RR	33	};
	34
	35	struct virtblk_req
	36	{
	37	struct list_head list;
	38	struct request *req;
	39	struct virtio_blk_outhdr out_hdr;
cb38fa23	40	u8 status;
e467cde2 RR	41	};
e467cde2 RR	42
18445c4d	43	static void blk_done(struct virtqueue *vq)
e467cde2 RR	44	{
	45	struct virtio_blk *vblk = vq->vdev->priv;
	46	struct virtblk_req *vbr;
	47	unsigned int len;
	48	unsigned long flags;
	49
	50	spin_lock_irqsave(&vblk->lock, flags);
	51	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
8316982a	52	int error;
cb38fa23	53	switch (vbr->status) {
e467cde2	54	case VIRTIO_BLK_S_OK:
8316982a	55	error = 0;
e467cde2 RR	56	break;
e467cde2 RR	57	case VIRTIO_BLK_S_UNSUPP:
8316982a	58	error = -ENOTTY;
e467cde2 RR	59	break;
e467cde2 RR	60	default:
8316982a	61	error = -EIO;
e467cde2 RR	62	break;
	63	}
	64
40cbbb78	65	__blk_end_request_all(vbr->req, error);
e467cde2 RR	66	list_del(&vbr->list);
	67	mempool_free(vbr, vblk->pool);
	68	}
	69	/* In case queue is stopped waiting for more buffers. */
	70	blk_start_queue(vblk->disk->queue);
	71	spin_unlock_irqrestore(&vblk->lock, flags);
e467cde2 RR	72	}
	73
	74	static bool do_req(struct request_queue q, struct virtio_blk vblk,
	75	struct request *req)
	76	{
	77	unsigned long num, out, in;
	78	struct virtblk_req *vbr;
	79
	80	vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
	81	if (!vbr)
	82	/* When another request finishes we'll try again. */
	83	return false;
	84
	85	vbr->req = req;
	86	if (blk_fs_request(vbr->req)) {
	87	vbr->out_hdr.type = 0;
83096ebf	88	vbr->out_hdr.sector = blk_rq_pos(vbr->req);
766ca442	89	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	90	} else if (blk_pc_request(vbr->req)) {
	91	vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
	92	vbr->out_hdr.sector = 0;
766ca442	93	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	94	} else {
	95	/* We don't put anything else in the queue. */
	96	BUG();
	97	}
	98
	99	if (blk_barrier_rq(vbr->req))
	100	vbr->out_hdr.type \|= VIRTIO_BLK_T_BARRIER;
	101
e467cde2 RR	102	sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
e467cde2 RR	103	num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);
cb38fa23	104	sg_set_buf(&vblk->sg[num+1], &vbr->status, sizeof(vbr->status));
e467cde2 RR	105
	106	if (rq_data_dir(vbr->req) == WRITE) {
	107	vbr->out_hdr.type \|= VIRTIO_BLK_T_OUT;
	108	out = 1 + num;
	109	in = 1;
	110	} else {
	111	vbr->out_hdr.type \|= VIRTIO_BLK_T_IN;
	112	out = 1;
	113	in = 1 + num;
	114	}
	115
	116	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
	117	mempool_free(vbr, vblk->pool);
	118	return false;
	119	}
	120
	121	list_add_tail(&vbr->list, &vblk->reqs);
	122	return true;
	123	}
	124
	125	static void do_virtblk_request(struct request_queue *q)
	126	{
	127	struct virtio_blk *vblk = NULL;
	128	struct request *req;
	129	unsigned int issued = 0;
	130
	131	while ((req = elv_next_request(q)) != NULL) {
	132	vblk = req->rq_disk->private_data;
0864b79a	133	BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
e467cde2 RR	134
	135	/* If this request fails, stop queue and wait for something to
	136	finish to restart it. */
	137	if (!do_req(q, vblk, req)) {
	138	blk_stop_queue(q);
	139	break;
	140	}
	141	blkdev_dequeue_request(req);
	142	issued++;
	143	}
	144
	145	if (issued)
	146	vblk->vq->vq_ops->kick(vblk->vq);
	147	}
	148
4e109852	149	static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
e467cde2 RR	150	unsigned cmd, unsigned long data)
e467cde2 RR	151	{
4e109852 AV	152	return scsi_cmd_ioctl(bdev->bd_disk->queue,
4e109852 AV	153	bdev->bd_disk, mode, cmd,
e467cde2 RR	154	(void __user *)data);
	155	}
	156
135da0b0 CB	157	/* We provide getgeo only to please some old bootloader/partitioning tools */
	158	static int virtblk_getgeo(struct block_device bd, struct hd_geometry geo)
	159	{
48e4043d RH	160	struct virtio_blk *vblk = bd->bd_disk->private_data;
	161	struct virtio_blk_geometry vgeo;
	162	int err;
	163
	164	/* see if the host passed in geometry config */
	165	err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
	166	offsetof(struct virtio_blk_config, geometry),
	167	&vgeo);
	168
	169	if (!err) {
	170	geo->heads = vgeo.heads;
	171	geo->sectors = vgeo.sectors;
	172	geo->cylinders = vgeo.cylinders;
	173	} else {
	174	/* some standard values, similar to sd */
	175	geo->heads = 1 << 6;
	176	geo->sectors = 1 << 5;
	177	geo->cylinders = get_capacity(bd->bd_disk) >> 11;
	178	}
135da0b0 CB	179	return 0;
	180	}
	181
e467cde2	182	static struct block_device_operations virtblk_fops = {
4e109852	183	.locked_ioctl = virtblk_ioctl,
135da0b0 CB	184	.owner = THIS_MODULE,
135da0b0 CB	185	.getgeo = virtblk_getgeo,
e467cde2 RR	186	};
e467cde2 RR	187
d50ed907 CB	188	static int index_to_minor(int index)
	189	{
	190	return index << PART_BITS;
	191	}
	192
e467cde2 RR	193	static int virtblk_probe(struct virtio_device *vdev)
	194	{
	195	struct virtio_blk *vblk;
4f3bf19c	196	int err;
e467cde2 RR	197	u64 cap;
e467cde2 RR	198	u32 v;
0864b79a	199	u32 blk_size, sg_elems;
e467cde2	200
d50ed907	201	if (index_to_minor(index) >= 1 << MINORBITS)
4f3bf19c CB	202	return -ENOSPC;
4f3bf19c CB	203
0864b79a RR	204	/* We need to know how many segments before we allocate. */
	205	err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
	206	offsetof(struct virtio_blk_config, seg_max),
	207	&sg_elems);
	208	if (err)
	209	sg_elems = 1;
	210
	211	/* We need an extra sg elements at head and tail. */
	212	sg_elems += 2;
	213	vdev->priv = vblk = kmalloc(sizeof(*vblk) +
	214	sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
e467cde2 RR	215	if (!vblk) {
	216	err = -ENOMEM;
	217	goto out;
	218	}
	219
	220	INIT_LIST_HEAD(&vblk->reqs);
	221	spin_lock_init(&vblk->lock);
	222	vblk->vdev = vdev;
0864b79a RR	223	vblk->sg_elems = sg_elems;
0864b79a RR	224	sg_init_table(vblk->sg, vblk->sg_elems);
e467cde2 RR	225
e467cde2 RR	226	/* We expect one virtqueue, for output. */
a586d4f6	227	vblk->vq = vdev->config->find_vq(vdev, 0, blk_done);
e467cde2 RR	228	if (IS_ERR(vblk->vq)) {
	229	err = PTR_ERR(vblk->vq);
	230	goto out_free_vblk;
	231	}
	232
	233	vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
	234	if (!vblk->pool) {
	235	err = -ENOMEM;
	236	goto out_free_vq;
	237	}
	238
e467cde2	239	/* FIXME: How many partitions? How long is a piece of string? */
4f3bf19c	240	vblk->disk = alloc_disk(1 << PART_BITS);
e467cde2 RR	241	if (!vblk->disk) {
e467cde2 RR	242	err = -ENOMEM;
4f3bf19c	243	goto out_mempool;
e467cde2 RR	244	}
	245
	246	vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
	247	if (!vblk->disk->queue) {
	248	err = -ENOMEM;
	249	goto out_put_disk;
	250	}
	251
7d116b62 FLVC	252	queue_flag_set_unlocked(QUEUE_FLAG_VIRT, vblk->disk->queue);
7d116b62 FLVC	253
d50ed907 CB	254	if (index < 26) {
	255	sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
	256	} else if (index < (26 + 1) * 26) {
	257	sprintf(vblk->disk->disk_name, "vd%c%c",
	258	'a' + index / 26 - 1, 'a' + index % 26);
	259	} else {
	260	const unsigned int m1 = (index / 26 - 1) / 26 - 1;
	261	const unsigned int m2 = (index / 26 - 1) % 26;
	262	const unsigned int m3 = index % 26;
	263	sprintf(vblk->disk->disk_name, "vd%c%c%c",
	264	'a' + m1, 'a' + m2, 'a' + m3);
	265	}
	266
e467cde2	267	vblk->disk->major = major;
d50ed907	268	vblk->disk->first_minor = index_to_minor(index);
e467cde2 RR	269	vblk->disk->private_data = vblk;
e467cde2 RR	270	vblk->disk->fops = &virtblk_fops;
c4839346	271	vblk->disk->driverfs_dev = &vdev->dev;
d50ed907	272	index++;
4f3bf19c	273
e467cde2	274	/* If barriers are supported, tell block layer that queue is ordered */
c45a6816	275	if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
e467cde2 RR	276	blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
e467cde2 RR	277
3ef53609 CB	278	/* If disk is read-only in the host, the guest should obey */
	279	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
	280	set_disk_ro(vblk->disk, 1);
	281
a586d4f6	282	/* Host must always specify the capacity. */
72e61eb4 RR	283	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
72e61eb4 RR	284	&cap, sizeof(cap));
e467cde2 RR	285
	286	/* If capacity is too big, truncate with warning. */
	287	if ((sector_t)cap != cap) {
	288	dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
	289	(unsigned long long)cap);
	290	cap = (sector_t)-1;
	291	}
	292	set_capacity(vblk->disk, cap);
	293
0864b79a RR	294	/* We can handle whatever the host told us to handle. */
	295	blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2);
	296	blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2);
	297
4b7f7e20 RR	298	/* No real sector limit. */
	299	blk_queue_max_sectors(vblk->disk->queue, -1U);
	300
a586d4f6 RR	301	/* Host can optionally specify maximum segment size and number of
	302	* segments. */
	303	err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
	304	offsetof(struct virtio_blk_config, size_max),
	305	&v);
e467cde2 RR	306	if (!err)
e467cde2 RR	307	blk_queue_max_segment_size(vblk->disk->queue, v);
4b7f7e20	308	else
b194aee9	309	blk_queue_max_segment_size(vblk->disk->queue, -1U);
e467cde2	310
066f4d82 CB	311	/* Host can optionally specify the block size of the device */
	312	err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
	313	offsetof(struct virtio_blk_config, blk_size),
	314	&blk_size);
	315	if (!err)
	316	blk_queue_hardsect_size(vblk->disk->queue, blk_size);
	317
e467cde2 RR	318	add_disk(vblk->disk);
	319	return 0;
	320
	321	out_put_disk:
	322	put_disk(vblk->disk);
e467cde2 RR	323	out_mempool:
	324	mempool_destroy(vblk->pool);
	325	out_free_vq:
	326	vdev->config->del_vq(vblk->vq);
	327	out_free_vblk:
	328	kfree(vblk);
	329	out:
	330	return err;
	331	}
	332
	333	static void virtblk_remove(struct virtio_device *vdev)
	334	{
	335	struct virtio_blk *vblk = vdev->priv;
e467cde2	336
6e5aa7ef	337	/* Nothing should be pending. */
e467cde2	338	BUG_ON(!list_empty(&vblk->reqs));
6e5aa7ef RR	339
	340	/* Stop all the virtqueues. */
	341	vdev->config->reset(vdev);
	342
ac9d463a	343	del_gendisk(vblk->disk);
e467cde2 RR	344	blk_cleanup_queue(vblk->disk->queue);
e467cde2 RR	345	put_disk(vblk->disk);
e467cde2	346	mempool_destroy(vblk->pool);
74b2553f	347	vdev->config->del_vq(vblk->vq);
e467cde2 RR	348	kfree(vblk);
	349	}
	350
	351	static struct virtio_device_id id_table[] = {
	352	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
	353	{ 0 },
	354	};
	355
c45a6816 RR	356	static unsigned int features[] = {
c45a6816 RR	357	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
066f4d82	358	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
c45a6816 RR	359	};
c45a6816 RR	360
e467cde2	361	static struct virtio_driver virtio_blk = {
c45a6816 RR	362	.feature_table = features,
c45a6816 RR	363	.feature_table_size = ARRAY_SIZE(features),
e467cde2 RR	364	.driver.name = KBUILD_MODNAME,
	365	.driver.owner = THIS_MODULE,
	366	.id_table = id_table,
	367	.probe = virtblk_probe,
	368	.remove = __devexit_p(virtblk_remove),
	369	};
	370
	371	static int __init init(void)
	372	{
4f3bf19c CB	373	major = register_blkdev(0, "virtblk");
	374	if (major < 0)
	375	return major;
e467cde2 RR	376	return register_virtio_driver(&virtio_blk);
	377	}
	378
	379	static void __exit fini(void)
	380	{
4f3bf19c	381	unregister_blkdev(major, "virtblk");
e467cde2 RR	382	unregister_virtio_driver(&virtio_blk);
	383	}
	384	module_init(init);
	385	module_exit(fini);
	386
	387	MODULE_DEVICE_TABLE(virtio, id_table);
	388	MODULE_DESCRIPTION("Virtio block driver");
	389	MODULE_LICENSE("GPL");