[deliverable/linux.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_ids.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) < 0) {
		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 -ENOTTY;

	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 __devinit 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 = virtio_find_single_vq(vdev, 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 need to bounce any requests */
	blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY);

	/* 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_vqs(vdev);
out_free_vblk:
	kfree(vblk);
out:
	return err;
}

static void __devexit 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_vqs(vdev);
	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
};

/*
 * virtio_blk causes spurious section mismatch warning by
 * simultaneously referring to a __devinit and a __devexit function.
 * Use __refdata to avoid this warning.
 */
static struct virtio_driver __refdata 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>
3ca4f5ca	6	#include <linux/virtio_ids.h>
e467cde2	7	#include <linux/virtio_blk.h>
3d1266c7 JA	8	#include <linux/scatterlist.h>
3d1266c7 JA	9
4f3bf19c	10	#define PART_BITS 4
e467cde2	11
d50ed907	12	static int major, index;
4f3bf19c	13
e467cde2 RR	14	struct virtio_blk
	15	{
	16	spinlock_t lock;
	17
	18	struct virtio_device *vdev;
	19	struct virtqueue *vq;
	20
	21	/* The disk structure for the kernel. */
	22	struct gendisk *disk;
	23
	24	/* Request tracking. */
	25	struct list_head reqs;
	26
	27	mempool_t *pool;
	28
0864b79a RR	29	/* What host tells us, plus 2 for header & tailer. */
	30	unsigned int sg_elems;
	31
e467cde2	32	/* Scatterlist: can be too big for stack. */
0864b79a	33	struct scatterlist sg[/sg_elems/];
e467cde2 RR	34	};
	35
	36	struct virtblk_req
	37	{
	38	struct list_head list;
	39	struct request *req;
	40	struct virtio_blk_outhdr out_hdr;
1cde26f9	41	struct virtio_scsi_inhdr in_hdr;
cb38fa23	42	u8 status;
e467cde2 RR	43	};
e467cde2 RR	44
18445c4d	45	static void blk_done(struct virtqueue *vq)
e467cde2 RR	46	{
	47	struct virtio_blk *vblk = vq->vdev->priv;
	48	struct virtblk_req *vbr;
	49	unsigned int len;
	50	unsigned long flags;
	51
	52	spin_lock_irqsave(&vblk->lock, flags);
	53	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
8316982a	54	int error;
1cde26f9	55
cb38fa23	56	switch (vbr->status) {
e467cde2	57	case VIRTIO_BLK_S_OK:
8316982a	58	error = 0;
e467cde2 RR	59	break;
e467cde2 RR	60	case VIRTIO_BLK_S_UNSUPP:
8316982a	61	error = -ENOTTY;
e467cde2 RR	62	break;
e467cde2 RR	63	default:
8316982a	64	error = -EIO;
e467cde2 RR	65	break;
	66	}
	67
1cde26f9 HR	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;
	72	}
	73
40cbbb78	74	__blk_end_request_all(vbr->req, error);
e467cde2 RR	75	list_del(&vbr->list);
	76	mempool_free(vbr, vblk->pool);
	77	}
	78	/* In case queue is stopped waiting for more buffers. */
	79	blk_start_queue(vblk->disk->queue);
	80	spin_unlock_irqrestore(&vblk->lock, flags);
e467cde2 RR	81	}
	82
	83	static bool do_req(struct request_queue q, struct virtio_blk vblk,
	84	struct request *req)
	85	{
1cde26f9	86	unsigned long num, out = 0, in = 0;
e467cde2 RR	87	struct virtblk_req *vbr;
	88
	89	vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
	90	if (!vbr)
	91	/* When another request finishes we'll try again. */
	92	return false;
	93
	94	vbr->req = req;
	95	if (blk_fs_request(vbr->req)) {
	96	vbr->out_hdr.type = 0;
83096ebf	97	vbr->out_hdr.sector = blk_rq_pos(vbr->req);
766ca442	98	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	99	} else if (blk_pc_request(vbr->req)) {
	100	vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
	101	vbr->out_hdr.sector = 0;
766ca442	102	vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
e467cde2 RR	103	} else {
	104	/* We don't put anything else in the queue. */
	105	BUG();
	106	}
	107
	108	if (blk_barrier_rq(vbr->req))
	109	vbr->out_hdr.type \|= VIRTIO_BLK_T_BARRIER;
	110
1cde26f9	111	sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
e467cde2	112
1cde26f9 HR	113	/*
	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.
	118	*/
	119	if (blk_pc_request(vbr->req))
	120	sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
	121
	122	num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
	123
	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));
	128	}
	129
	130	sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
	131	sizeof(vbr->status));
	132
	133	if (num) {
	134	if (rq_data_dir(vbr->req) == WRITE) {
	135	vbr->out_hdr.type \|= VIRTIO_BLK_T_OUT;
	136	out += num;
	137	} else {
	138	vbr->out_hdr.type \|= VIRTIO_BLK_T_IN;
	139	in += num;
	140	}
e467cde2 RR	141	}
e467cde2 RR	142
3c1b27d5	143	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
e467cde2 RR	144	mempool_free(vbr, vblk->pool);
	145	return false;
	146	}
	147
	148	list_add_tail(&vbr->list, &vblk->reqs);
	149	return true;
	150	}
	151
	152	static void do_virtblk_request(struct request_queue *q)
	153	{
6c3b46f7	154	struct virtio_blk *vblk = q->queuedata;
e467cde2 RR	155	struct request *req;
	156	unsigned int issued = 0;
	157
9934c8c0	158	while ((req = blk_peek_request(q)) != NULL) {
0864b79a	159	BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
e467cde2 RR	160
	161	/* If this request fails, stop queue and wait for something to
	162	finish to restart it. */
	163	if (!do_req(q, vblk, req)) {
	164	blk_stop_queue(q);
	165	break;
	166	}
9934c8c0	167	blk_start_request(req);
e467cde2 RR	168	issued++;
	169	}
	170
	171	if (issued)
	172	vblk->vq->vq_ops->kick(vblk->vq);
	173	}
	174
1d589bb1	175	/* return ATA identify data
	176	*/
	177	static int virtblk_identify(struct gendisk disk, void argp)
	178	{
	179	struct virtio_blk *vblk = disk->private_data;
	180	void *opaque;
	181	int err = -ENOMEM;
	182
	183	opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
	184	if (!opaque)
	185	goto out;
	186
	187	err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY,
	188	offsetof(struct virtio_blk_config, identify), opaque,
	189	VIRTIO_BLK_ID_BYTES);
	190
	191	if (err)
	192	goto out_kfree;
	193
	194	if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES))
	195	err = -EFAULT;
	196
	197	out_kfree:
	198	kfree(opaque);
	199	out:
	200	return err;
	201	}
	202
4e109852	203	static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
e467cde2 RR	204	unsigned cmd, unsigned long data)
e467cde2 RR	205	{
1cde26f9 HR	206	struct gendisk *disk = bdev->bd_disk;
1cde26f9 HR	207	struct virtio_blk *vblk = disk->private_data;
1d589bb1	208	void __user argp = (void __user )data;
	209
	210	if (cmd == HDIO_GET_IDENTITY)
	211	return virtblk_identify(disk, argp);
1cde26f9 HR	212
	213	/*
	214	* Only allow the generic SCSI ioctls if the host can support it.
	215	*/
	216	if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
d9ecdea7	217	return -ENOTTY;
1cde26f9	218
1d589bb1	219	return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, argp);
e467cde2 RR	220	}
e467cde2 RR	221
135da0b0 CB	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)
	224	{
48e4043d RH	225	struct virtio_blk *vblk = bd->bd_disk->private_data;
	226	struct virtio_blk_geometry vgeo;
	227	int err;
	228
	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),
	232	&vgeo);
	233
	234	if (!err) {
	235	geo->heads = vgeo.heads;
	236	geo->sectors = vgeo.sectors;
	237	geo->cylinders = vgeo.cylinders;
	238	} else {
	239	/* some standard values, similar to sd */
	240	geo->heads = 1 << 6;
	241	geo->sectors = 1 << 5;
	242	geo->cylinders = get_capacity(bd->bd_disk) >> 11;
	243	}
135da0b0 CB	244	return 0;
	245	}
	246
e467cde2	247	static struct block_device_operations virtblk_fops = {
4e109852	248	.locked_ioctl = virtblk_ioctl,
135da0b0 CB	249	.owner = THIS_MODULE,
135da0b0 CB	250	.getgeo = virtblk_getgeo,
e467cde2 RR	251	};
e467cde2 RR	252
d50ed907 CB	253	static int index_to_minor(int index)
	254	{
	255	return index << PART_BITS;
	256	}
	257
98e94444	258	static int __devinit virtblk_probe(struct virtio_device *vdev)
e467cde2 RR	259	{
e467cde2 RR	260	struct virtio_blk *vblk;
4f3bf19c	261	int err;
e467cde2 RR	262	u64 cap;
e467cde2 RR	263	u32 v;
0864b79a	264	u32 blk_size, sg_elems;
e467cde2	265
d50ed907	266	if (index_to_minor(index) >= 1 << MINORBITS)
4f3bf19c CB	267	return -ENOSPC;
4f3bf19c CB	268
0864b79a RR	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),
	272	&sg_elems);
	273	if (err)
	274	sg_elems = 1;
	275
	276	/* We need an extra sg elements at head and tail. */
	277	sg_elems += 2;
	278	vdev->priv = vblk = kmalloc(sizeof(*vblk) +
	279	sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
e467cde2 RR	280	if (!vblk) {
	281	err = -ENOMEM;
	282	goto out;
	283	}
	284
	285	INIT_LIST_HEAD(&vblk->reqs);
	286	spin_lock_init(&vblk->lock);
	287	vblk->vdev = vdev;
0864b79a RR	288	vblk->sg_elems = sg_elems;
0864b79a RR	289	sg_init_table(vblk->sg, vblk->sg_elems);
e467cde2 RR	290
e467cde2 RR	291	/* We expect one virtqueue, for output. */
d2a7ddda	292	vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
e467cde2 RR	293	if (IS_ERR(vblk->vq)) {
	294	err = PTR_ERR(vblk->vq);
	295	goto out_free_vblk;
	296	}
	297
	298	vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
	299	if (!vblk->pool) {
	300	err = -ENOMEM;
	301	goto out_free_vq;
	302	}
	303
e467cde2	304	/* FIXME: How many partitions? How long is a piece of string? */
4f3bf19c	305	vblk->disk = alloc_disk(1 << PART_BITS);
e467cde2 RR	306	if (!vblk->disk) {
e467cde2 RR	307	err = -ENOMEM;
4f3bf19c	308	goto out_mempool;
e467cde2 RR	309	}
	310
	311	vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
	312	if (!vblk->disk->queue) {
	313	err = -ENOMEM;
	314	goto out_put_disk;
	315	}
	316
6c3b46f7	317	vblk->disk->queue->queuedata = vblk;
7d116b62 FLVC	318	queue_flag_set_unlocked(QUEUE_FLAG_VIRT, vblk->disk->queue);
7d116b62 FLVC	319
d50ed907 CB	320	if (index < 26) {
	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);
	325	} else {
	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);
	331	}
	332
e467cde2	333	vblk->disk->major = major;
d50ed907	334	vblk->disk->first_minor = index_to_minor(index);
e467cde2 RR	335	vblk->disk->private_data = vblk;
e467cde2 RR	336	vblk->disk->fops = &virtblk_fops;
c4839346	337	vblk->disk->driverfs_dev = &vdev->dev;
d50ed907	338	index++;
4f3bf19c	339
e467cde2	340	/* If barriers are supported, tell block layer that queue is ordered */
c45a6816	341	if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
e467cde2 RR	342	blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
e467cde2 RR	343
3ef53609 CB	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);
	347
a586d4f6	348	/* Host must always specify the capacity. */
72e61eb4 RR	349	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
72e61eb4 RR	350	&cap, sizeof(cap));
e467cde2 RR	351
	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);
	356	cap = (sector_t)-1;
	357	}
	358	set_capacity(vblk->disk, cap);
	359
0864b79a RR	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);
	363
4eff3cae CH	364	/* No need to bounce any requests */
	365	blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY);
	366
4b7f7e20 RR	367	/* No real sector limit. */
	368	blk_queue_max_sectors(vblk->disk->queue, -1U);
	369
a586d4f6 RR	370	/* Host can optionally specify maximum segment size and number of
	371	* segments. */
	372	err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
	373	offsetof(struct virtio_blk_config, size_max),
	374	&v);
e467cde2 RR	375	if (!err)
e467cde2 RR	376	blk_queue_max_segment_size(vblk->disk->queue, v);
4b7f7e20	377	else
b194aee9	378	blk_queue_max_segment_size(vblk->disk->queue, -1U);
e467cde2	379
066f4d82 CB	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),
	383	&blk_size);
	384	if (!err)
e1defc4f	385	blk_queue_logical_block_size(vblk->disk->queue, blk_size);
066f4d82	386
e467cde2 RR	387	add_disk(vblk->disk);
	388	return 0;
	389
	390	out_put_disk:
	391	put_disk(vblk->disk);
e467cde2 RR	392	out_mempool:
	393	mempool_destroy(vblk->pool);
	394	out_free_vq:
d2a7ddda	395	vdev->config->del_vqs(vdev);
e467cde2 RR	396	out_free_vblk:
	397	kfree(vblk);
	398	out:
	399	return err;
	400	}
	401
98e94444	402	static void __devexit virtblk_remove(struct virtio_device *vdev)
e467cde2 RR	403	{
e467cde2 RR	404	struct virtio_blk *vblk = vdev->priv;
e467cde2	405
6e5aa7ef	406	/* Nothing should be pending. */
e467cde2	407	BUG_ON(!list_empty(&vblk->reqs));
6e5aa7ef RR	408
	409	/* Stop all the virtqueues. */
	410	vdev->config->reset(vdev);
	411
ac9d463a	412	del_gendisk(vblk->disk);
e467cde2 RR	413	blk_cleanup_queue(vblk->disk->queue);
e467cde2 RR	414	put_disk(vblk->disk);
e467cde2	415	mempool_destroy(vblk->pool);
d2a7ddda	416	vdev->config->del_vqs(vdev);
e467cde2 RR	417	kfree(vblk);
	418	}
	419
	420	static struct virtio_device_id id_table[] = {
	421	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
	422	{ 0 },
	423	};
	424
c45a6816 RR	425	static unsigned int features[] = {
c45a6816 RR	426	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
066f4d82	427	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
1d589bb1	428	VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY
c45a6816 RR	429	};
c45a6816 RR	430
4fbfff76 RM	431	/*
	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.
	435	*/
	436	static struct virtio_driver __refdata virtio_blk = {
c45a6816 RR	437	.feature_table = features,
c45a6816 RR	438	.feature_table_size = ARRAY_SIZE(features),
e467cde2 RR	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),
	444	};
	445
	446	static int __init init(void)
	447	{
4f3bf19c CB	448	major = register_blkdev(0, "virtblk");
	449	if (major < 0)
	450	return major;
e467cde2 RR	451	return register_virtio_driver(&virtio_blk);
	452	}
	453
	454	static void __exit fini(void)
	455	{
4f3bf19c	456	unregister_blkdev(major, "virtblk");
e467cde2 RR	457	unregister_virtio_driver(&virtio_blk);
	458	}
	459	module_init(init);
	460	module_exit(fini);
	461
	462	MODULE_DEVICE_TABLE(virtio, id_table);
	463	MODULE_DESCRIPTION("Virtio block driver");
	464	MODULE_LICENSE("GPL");