[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;
	struct virtio_scsi_inhdr in_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;
		}

		if (blk_pc_request(vbr->req)) {
			vbr->req->resid_len = vbr->in_hdr.residual;
			vbr->req->sense_len = vbr->in_hdr.sense_len;
			vbr->req->errors = vbr->in_hdr.errors;
		}

		__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 = 0, in = 0;
	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[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));

	/*
	 * If this is a packet command we need a couple of additional headers.
	 * Behind the normal outhdr we put a segment with the scsi command
	 * block, and before the normal inhdr we put the sense data and the
	 * inhdr with additional status information before the normal inhdr.
	 */
	if (blk_pc_request(vbr->req))
		sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);

	num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);

	if (blk_pc_request(vbr->req)) {
		sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
		sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
			   sizeof(vbr->in_hdr));
	}

	sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
		   sizeof(vbr->status));

	if (num) {
		if (rq_data_dir(vbr->req) == WRITE) {
			vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
			out += num;
		} else {
			vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
			in += 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 = q->queuedata;
	struct request *req;
	unsigned int issued = 0;

	while ((req = blk_peek_request(q)) != NULL) {
		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;
		}
		blk_start_request(req);
		issued++;
	}

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

/* return ATA identify data
 */
static int virtblk_identify(struct gendisk *disk, void *argp)
{
	struct virtio_blk *vblk = disk->private_data;
	void *opaque;
	int err = -ENOMEM;

	opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
	if (!opaque)
		goto out;

	err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
		offsetof(struct virtio_blk_config, identify), opaque,
		VIRTIO_BLK_ID_BYTES);

	if (err)
		goto out_kfree;

	if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
		err = -EFAULT;

out_kfree:
	kfree(opaque);
out:
	return err;
}

static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
			 unsigned cmd, unsigned long data)
{
	struct gendisk *disk = bdev->bd_disk;
	struct virtio_blk *vblk = disk->private_data;
	void __user *argp = (void __user *)data;

	if (cmd == HDIO_GET_IDENTITY)
		return virtblk_identify(disk, argp);

	/*
	 * Only allow the generic SCSI ioctls if the host can support it.
	 */
	if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
		return -ENOIOCTLCMD;

	return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, argp);
}

/* 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, "requests");
	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;
	}

	vblk->disk->queue->queuedata = vblk;
	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_logical_block_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,
	VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY
};

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;
1cde26f9	40	struct virtio_scsi_inhdr in_hdr;
cb38fa23	41	u8 status;
e467cde2 RR	42	};
e467cde2 RR	43
18445c4d	44	static void blk_done(struct virtqueue *vq)
e467cde2 RR	45	{
	46	struct virtio_blk *vblk = vq->vdev->priv;
	47	struct virtblk_req *vbr;
	48	unsigned int len;
	49	unsigned long flags;
	50
	51	spin_lock_irqsave(&vblk->lock, flags);
	52	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
8316982a	53	int error;
1cde26f9	54
cb38fa23	55	switch (vbr->status) {
e467cde2	56	case VIRTIO_BLK_S_OK:
8316982a	57	error = 0;
e467cde2 RR	58	break;
e467cde2 RR	59	case VIRTIO_BLK_S_UNSUPP:
8316982a	60	error = -ENOTTY;
e467cde2 RR	61	break;
e467cde2 RR	62	default:
8316982a	63	error = -EIO;
e467cde2 RR	64	break;
	65	}
	66
1cde26f9 HR	67	if (blk_pc_request(vbr->req)) {
	68	vbr->req->resid_len = vbr->in_hdr.residual;
	69	vbr->req->sense_len = vbr->in_hdr.sense_len;
	70	vbr->req->errors = vbr->in_hdr.errors;
	71	}
	72
40cbbb78	73	__blk_end_request_all(vbr->req, error);
e467cde2 RR	74	list_del(&vbr->list);
	75	mempool_free(vbr, vblk->pool);
	76	}
	77	/* In case queue is stopped waiting for more buffers. */
	78	blk_start_queue(vblk->disk->queue);
	79	spin_unlock_irqrestore(&vblk->lock, flags);
e467cde2 RR	80	}
	81
	82	static bool do_req(struct request_queue q, struct virtio_blk vblk,
	83	struct request *req)
	84	{
1cde26f9	85	unsigned long num, out = 0, in = 0;
e467cde2 RR	86	struct virtblk_req *vbr;
	87
	88	vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
	89	if (!vbr)
	90	/* When another request finishes we'll try again. */
	91	return false;
	92
	93	vbr->req = req;
	94	if (blk_fs_request(vbr->req)) {
	95	vbr->out_hdr.type = 0;
83096ebf	96	vbr->out_hdr.sector = blk_rq_pos(vbr->req);
766ca442	97	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	98	} else if (blk_pc_request(vbr->req)) {
	99	vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
	100	vbr->out_hdr.sector = 0;
766ca442	101	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	102	} else {
	103	/* We don't put anything else in the queue. */
	104	BUG();
	105	}
	106
	107	if (blk_barrier_rq(vbr->req))
	108	vbr->out_hdr.type \|= VIRTIO_BLK_T_BARRIER;
	109
1cde26f9	110	sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
e467cde2	111
1cde26f9 HR	112	/*
	113	* If this is a packet command we need a couple of additional headers.
	114	* Behind the normal outhdr we put a segment with the scsi command
	115	* block, and before the normal inhdr we put the sense data and the
	116	* inhdr with additional status information before the normal inhdr.
	117	*/
	118	if (blk_pc_request(vbr->req))
	119	sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
	120
	121	num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
	122
	123	if (blk_pc_request(vbr->req)) {
	124	sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
	125	sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
	126	sizeof(vbr->in_hdr));
	127	}
	128
	129	sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
	130	sizeof(vbr->status));
	131
	132	if (num) {
	133	if (rq_data_dir(vbr->req) == WRITE) {
	134	vbr->out_hdr.type \|= VIRTIO_BLK_T_OUT;
	135	out += num;
	136	} else {
	137	vbr->out_hdr.type \|= VIRTIO_BLK_T_IN;
	138	in += num;
	139	}
e467cde2 RR	140	}
	141
	142	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
	143	mempool_free(vbr, vblk->pool);
	144	return false;
	145	}
	146
	147	list_add_tail(&vbr->list, &vblk->reqs);
	148	return true;
	149	}
	150
	151	static void do_virtblk_request(struct request_queue *q)
	152	{
6c3b46f7	153	struct virtio_blk *vblk = q->queuedata;
e467cde2 RR	154	struct request *req;
	155	unsigned int issued = 0;
	156
9934c8c0	157	while ((req = blk_peek_request(q)) != NULL) {
0864b79a	158	BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
e467cde2 RR	159
	160	/* If this request fails, stop queue and wait for something to
	161	finish to restart it. */
	162	if (!do_req(q, vblk, req)) {
	163	blk_stop_queue(q);
	164	break;
	165	}
9934c8c0	166	blk_start_request(req);
e467cde2 RR	167	issued++;
	168	}
	169
	170	if (issued)
	171	vblk->vq->vq_ops->kick(vblk->vq);
	172	}
	173
1d589bb1	174	/* return ATA identify data
	175	*/
	176	static int virtblk_identify(struct gendisk disk, void argp)
	177	{
	178	struct virtio_blk *vblk = disk->private_data;
	179	void *opaque;
	180	int err = -ENOMEM;
	181
	182	opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
	183	if (!opaque)
	184	goto out;
	185
	186	err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
	187	offsetof(struct virtio_blk_config, identify), opaque,
	188	VIRTIO_BLK_ID_BYTES);
	189
	190	if (err)
	191	goto out_kfree;
	192
	193	if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
	194	err = -EFAULT;
	195
	196	out_kfree:
	197	kfree(opaque);
	198	out:
	199	return err;
	200	}
	201
4e109852	202	static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
e467cde2 RR	203	unsigned cmd, unsigned long data)
e467cde2 RR	204	{
1cde26f9 HR	205	struct gendisk *disk = bdev->bd_disk;
1cde26f9 HR	206	struct virtio_blk *vblk = disk->private_data;
1d589bb1	207	void __user argp = (void __user )data;
	208
	209	if (cmd == HDIO_GET_IDENTITY)
	210	return virtblk_identify(disk, argp);
1cde26f9 HR	211
	212	/*
	213	* Only allow the generic SCSI ioctls if the host can support it.
	214	*/
	215	if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
	216	return -ENOIOCTLCMD;
	217
1d589bb1	218	return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, argp);
e467cde2 RR	219	}
e467cde2 RR	220
135da0b0 CB	221	/* We provide getgeo only to please some old bootloader/partitioning tools */
	222	static int virtblk_getgeo(struct block_device bd, struct hd_geometry geo)
	223	{
48e4043d RH	224	struct virtio_blk *vblk = bd->bd_disk->private_data;
	225	struct virtio_blk_geometry vgeo;
	226	int err;
	227
	228	/* see if the host passed in geometry config */
	229	err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
	230	offsetof(struct virtio_blk_config, geometry),
	231	&vgeo);
	232
	233	if (!err) {
	234	geo->heads = vgeo.heads;
	235	geo->sectors = vgeo.sectors;
	236	geo->cylinders = vgeo.cylinders;
	237	} else {
	238	/* some standard values, similar to sd */
	239	geo->heads = 1 << 6;
	240	geo->sectors = 1 << 5;
	241	geo->cylinders = get_capacity(bd->bd_disk) >> 11;
	242	}
135da0b0 CB	243	return 0;
	244	}
	245
e467cde2	246	static struct block_device_operations virtblk_fops = {
4e109852	247	.locked_ioctl = virtblk_ioctl,
135da0b0 CB	248	.owner = THIS_MODULE,
135da0b0 CB	249	.getgeo = virtblk_getgeo,
e467cde2 RR	250	};
e467cde2 RR	251
d50ed907 CB	252	static int index_to_minor(int index)
	253	{
	254	return index << PART_BITS;
	255	}
	256
e467cde2 RR	257	static int virtblk_probe(struct virtio_device *vdev)
	258	{
	259	struct virtio_blk *vblk;
4f3bf19c	260	int err;
e467cde2 RR	261	u64 cap;
e467cde2 RR	262	u32 v;
0864b79a	263	u32 blk_size, sg_elems;
e467cde2	264
d50ed907	265	if (index_to_minor(index) >= 1 << MINORBITS)
4f3bf19c CB	266	return -ENOSPC;
4f3bf19c CB	267
0864b79a RR	268	/* We need to know how many segments before we allocate. */
	269	err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
	270	offsetof(struct virtio_blk_config, seg_max),
	271	&sg_elems);
	272	if (err)
	273	sg_elems = 1;
	274
	275	/* We need an extra sg elements at head and tail. */
	276	sg_elems += 2;
	277	vdev->priv = vblk = kmalloc(sizeof(*vblk) +
	278	sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
e467cde2 RR	279	if (!vblk) {
	280	err = -ENOMEM;
	281	goto out;
	282	}
	283
	284	INIT_LIST_HEAD(&vblk->reqs);
	285	spin_lock_init(&vblk->lock);
	286	vblk->vdev = vdev;
0864b79a RR	287	vblk->sg_elems = sg_elems;
0864b79a RR	288	sg_init_table(vblk->sg, vblk->sg_elems);
e467cde2 RR	289
e467cde2 RR	290	/* We expect one virtqueue, for output. */
9499f5e7	291	vblk->vq = vdev->config->find_vq(vdev, 0, blk_done, "requests");
e467cde2 RR	292	if (IS_ERR(vblk->vq)) {
	293	err = PTR_ERR(vblk->vq);
	294	goto out_free_vblk;
	295	}
	296
	297	vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
	298	if (!vblk->pool) {
	299	err = -ENOMEM;
	300	goto out_free_vq;
	301	}
	302
e467cde2	303	/* FIXME: How many partitions? How long is a piece of string? */
4f3bf19c	304	vblk->disk = alloc_disk(1 << PART_BITS);
e467cde2 RR	305	if (!vblk->disk) {
e467cde2 RR	306	err = -ENOMEM;
4f3bf19c	307	goto out_mempool;
e467cde2 RR	308	}
	309
	310	vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
	311	if (!vblk->disk->queue) {
	312	err = -ENOMEM;
	313	goto out_put_disk;
	314	}
	315
6c3b46f7	316	vblk->disk->queue->queuedata = vblk;
7d116b62 FLVC	317	queue_flag_set_unlocked(QUEUE_FLAG_VIRT, vblk->disk->queue);
7d116b62 FLVC	318
d50ed907 CB	319	if (index < 26) {
	320	sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
	321	} else if (index < (26 + 1) * 26) {
	322	sprintf(vblk->disk->disk_name, "vd%c%c",
	323	'a' + index / 26 - 1, 'a' + index % 26);
	324	} else {
	325	const unsigned int m1 = (index / 26 - 1) / 26 - 1;
	326	const unsigned int m2 = (index / 26 - 1) % 26;
	327	const unsigned int m3 = index % 26;
	328	sprintf(vblk->disk->disk_name, "vd%c%c%c",
	329	'a' + m1, 'a' + m2, 'a' + m3);
	330	}
	331
e467cde2	332	vblk->disk->major = major;
d50ed907	333	vblk->disk->first_minor = index_to_minor(index);
e467cde2 RR	334	vblk->disk->private_data = vblk;
e467cde2 RR	335	vblk->disk->fops = &virtblk_fops;
c4839346	336	vblk->disk->driverfs_dev = &vdev->dev;
d50ed907	337	index++;
4f3bf19c	338
e467cde2	339	/* If barriers are supported, tell block layer that queue is ordered */
c45a6816	340	if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
e467cde2 RR	341	blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
e467cde2 RR	342
3ef53609 CB	343	/* If disk is read-only in the host, the guest should obey */
	344	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
	345	set_disk_ro(vblk->disk, 1);
	346
a586d4f6	347	/* Host must always specify the capacity. */
72e61eb4 RR	348	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
72e61eb4 RR	349	&cap, sizeof(cap));
e467cde2 RR	350
	351	/* If capacity is too big, truncate with warning. */
	352	if ((sector_t)cap != cap) {
	353	dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
	354	(unsigned long long)cap);
	355	cap = (sector_t)-1;
	356	}
	357	set_capacity(vblk->disk, cap);
	358
0864b79a RR	359	/* We can handle whatever the host told us to handle. */
	360	blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2);
	361	blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2);
	362
4b7f7e20 RR	363	/* No real sector limit. */
	364	blk_queue_max_sectors(vblk->disk->queue, -1U);
	365
a586d4f6 RR	366	/* Host can optionally specify maximum segment size and number of
	367	* segments. */
	368	err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
	369	offsetof(struct virtio_blk_config, size_max),
	370	&v);
e467cde2 RR	371	if (!err)
e467cde2 RR	372	blk_queue_max_segment_size(vblk->disk->queue, v);
4b7f7e20	373	else
b194aee9	374	blk_queue_max_segment_size(vblk->disk->queue, -1U);
e467cde2	375
066f4d82 CB	376	/* Host can optionally specify the block size of the device */
	377	err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
	378	offsetof(struct virtio_blk_config, blk_size),
	379	&blk_size);
	380	if (!err)
e1defc4f	381	blk_queue_logical_block_size(vblk->disk->queue, blk_size);
066f4d82	382
e467cde2 RR	383	add_disk(vblk->disk);
	384	return 0;
	385
	386	out_put_disk:
	387	put_disk(vblk->disk);
e467cde2 RR	388	out_mempool:
	389	mempool_destroy(vblk->pool);
	390	out_free_vq:
	391	vdev->config->del_vq(vblk->vq);
	392	out_free_vblk:
	393	kfree(vblk);
	394	out:
	395	return err;
	396	}
	397
	398	static void virtblk_remove(struct virtio_device *vdev)
	399	{
	400	struct virtio_blk *vblk = vdev->priv;
e467cde2	401
6e5aa7ef	402	/* Nothing should be pending. */
e467cde2	403	BUG_ON(!list_empty(&vblk->reqs));
6e5aa7ef RR	404
	405	/* Stop all the virtqueues. */
	406	vdev->config->reset(vdev);
	407
ac9d463a	408	del_gendisk(vblk->disk);
e467cde2 RR	409	blk_cleanup_queue(vblk->disk->queue);
e467cde2 RR	410	put_disk(vblk->disk);
e467cde2	411	mempool_destroy(vblk->pool);
74b2553f	412	vdev->config->del_vq(vblk->vq);
e467cde2 RR	413	kfree(vblk);
	414	}
	415
	416	static struct virtio_device_id id_table[] = {
	417	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
	418	{ 0 },
	419	};
	420
c45a6816 RR	421	static unsigned int features[] = {
c45a6816 RR	422	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
066f4d82	423	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1d589bb1	424	VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY
c45a6816 RR	425	};
c45a6816 RR	426
e467cde2	427	static struct virtio_driver virtio_blk = {
c45a6816 RR	428	.feature_table = features,
c45a6816 RR	429	.feature_table_size = ARRAY_SIZE(features),
e467cde2 RR	430	.driver.name = KBUILD_MODNAME,
	431	.driver.owner = THIS_MODULE,
	432	.id_table = id_table,
	433	.probe = virtblk_probe,
	434	.remove = __devexit_p(virtblk_remove),
	435	};
	436
	437	static int __init init(void)
	438	{
4f3bf19c CB	439	major = register_blkdev(0, "virtblk");
	440	if (major < 0)
	441	return major;
e467cde2 RR	442	return register_virtio_driver(&virtio_blk);
	443	}
	444
	445	static void __exit fini(void)
	446	{
4f3bf19c	447	unregister_blkdev(major, "virtblk");
e467cde2 RR	448	unregister_virtio_driver(&virtio_blk);
	449	}
	450	module_init(init);
	451	module_exit(fini);
	452
	453	MODULE_DEVICE_TABLE(virtio, id_table);
	454	MODULE_DESCRIPTION("Virtio block driver");
	455	MODULE_LICENSE("GPL");