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Commit 5087a50e authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Rusty Russell
Browse files

virtio-blk: use ida to allocate disk index 



Based on a patch by Mark Wu <dwu@redhat.com>

Current index allocation in virtio-blk is based on a monotonically
increasing variable "index". This means we'll run out of numbers
after a while.  It also could cause confusion about the disk
name in the case of hot-plugging disks.
Change virtio-blk to use ida to allocate index, instead.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent edfd52e6

drivers/block/virtio_blk.c

+24 −6
Original line number Original line Diff line number Diff line
@@ -8,10 +8,13 @@ 
#include <linux/scatterlist.h>

#include <linux/scatterlist.h>

#include <linux/string_helpers.h>

#include <linux/string_helpers.h>

#include <scsi/scsi_cmnd.h>

#include <scsi/scsi_cmnd.h>

#include <linux/idr.h>





#define PART_BITS 4

#define PART_BITS 4





static int major, index;

static int major;

static DEFINE_IDA(vd_index_ida);



struct workqueue_struct *virtblk_wq;

struct workqueue_struct *virtblk_wq;





struct virtio_blk

struct virtio_blk
@@ -35,6 +38,9 @@ struct virtio_blk 
	/* What host tells us, plus 2 for header & tailer. */

	/* What host tells us, plus 2 for header & tailer. */

	unsigned int sg_elems;

	unsigned int sg_elems;





	/* Ida index - used to track minor number allocations. */

	int index;



	/* Scatterlist: can be too big for stack. */

	/* Scatterlist: can be too big for stack. */

	struct scatterlist sg[/*sg_elems*/];

	struct scatterlist sg[/*sg_elems*/];

};

};
@@ -276,6 +282,11 @@ static int index_to_minor(int index) 
	return index << PART_BITS;

	return index << PART_BITS;

}

}





static int minor_to_index(int minor)

{

	return minor >> PART_BITS;

}



static ssize_t virtblk_serial_show(struct device *dev,

static ssize_t virtblk_serial_show(struct device *dev,

				struct device_attribute *attr, char *buf)

				struct device_attribute *attr, char *buf)

{

{
@@ -341,14 +352,17 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
{

{

	struct virtio_blk *vblk;

	struct virtio_blk *vblk;

	struct request_queue *q;

	struct request_queue *q;

	int err;

	int err, index;

	u64 cap;

	u64 cap;

	u32 v, blk_size, sg_elems, opt_io_size;

	u32 v, blk_size, sg_elems, opt_io_size;

	u16 min_io_size;

	u16 min_io_size;

	u8 physical_block_exp, alignment_offset;

	u8 physical_block_exp, alignment_offset;





	if (index_to_minor(index) >= 1 << MINORBITS)

	err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),

		return -ENOSPC;

			     GFP_KERNEL);

	if (err < 0)

		goto out;

	index = err;





	/* We need to know how many segments before we allocate. */

	/* We need to know how many segments before we allocate. */

	err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,

	err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
@@ -365,7 +379,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
				    sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);

				    sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);

	if (!vblk) {

	if (!vblk) {

		err = -ENOMEM;

		err = -ENOMEM;

		goto out;

		goto out_free_index;

	}

	}





	INIT_LIST_HEAD(&vblk->reqs);

	INIT_LIST_HEAD(&vblk->reqs);
@@ -421,7 +435,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
	vblk->disk->private_data = vblk;

	vblk->disk->private_data = vblk;

	vblk->disk->fops = &virtblk_fops;

	vblk->disk->fops = &virtblk_fops;

	vblk->disk->driverfs_dev = &vdev->dev;

	vblk->disk->driverfs_dev = &vdev->dev;

	index++;

	vblk->index = index;





	/* configure queue flush support */

	/* configure queue flush support */

	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))

	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
@@ -516,6 +530,8 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
	vdev->config->del_vqs(vdev);

	vdev->config->del_vqs(vdev);

out_free_vblk:

out_free_vblk:

	kfree(vblk);

	kfree(vblk);

out_free_index:

	ida_simple_remove(&vd_index_ida, index);

out:

out:

	return err;

	return err;

}

}
@@ -523,6 +539,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
static void __devexit virtblk_remove(struct virtio_device *vdev)

static void __devexit virtblk_remove(struct virtio_device *vdev)

{

{

	struct virtio_blk *vblk = vdev->priv;

	struct virtio_blk *vblk = vdev->priv;

	int index = vblk->index;





	flush_work(&vblk->config_work);

	flush_work(&vblk->config_work);
@@ -538,6 +555,7 @@ static void __devexit virtblk_remove(struct virtio_device *vdev) 
	mempool_destroy(vblk->pool);

	mempool_destroy(vblk->pool);

	vdev->config->del_vqs(vdev);

	vdev->config->del_vqs(vdev);

	kfree(vblk);

	kfree(vblk);

	ida_simple_remove(&vd_index_ida, index);

}

}





static const struct virtio_device_id id_table[] = {

static const struct virtio_device_id id_table[] = {