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virtio-blk: use ida to allocate disk index

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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: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Michael S. Tsirkin 2011-10-31 08:05:36 +01:00 committed by Jens Axboe
parent c4853efec6
commit a0eda62552
1 changed files with 24 additions and 6 deletions
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30
drivers/block/virtio_blk.c
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@ -8,10 +8,13 @@
#include <linux/scatterlist.h>
#include <linux/string_helpers.h>
#include <scsi/scsi_cmnd.h>
#include <linux/idr.h>
#define PART_BITS 4
static int major, index;
static int major;
static DEFINE_IDA(vd_index_ida);
struct workqueue_struct *virtblk_wq;
struct virtio_blk
@ -35,6 +38,9 @@ struct virtio_blk
/* What host tells us, plus 2 for header & tailer. */
unsigned int sg_elems;
/* Ida index - used to track minor number allocations. */
int index;
/* Scatterlist: can be too big for stack. */
struct scatterlist sg[/*sg_elems*/];
};
@ -276,6 +282,11 @@ static int index_to_minor(int index)
return index << PART_BITS;
}
static int minor_to_index(int minor)
{
return minor >> PART_BITS;
}
static ssize_t virtblk_serial_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -341,14 +352,17 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
struct request_queue *q;
int err;
int err, index;
u64 cap;
u32 v, blk_size, sg_elems, opt_io_size;
u16 min_io_size;
u8 physical_block_exp, alignment_offset;
if (index_to_minor(index) >= 1 << MINORBITS)
return -ENOSPC;
err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
GFP_KERNEL);
if (err < 0)
goto out;
index = err;
/* We need to know how many segments before we allocate. */
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);
if (!vblk) {
err = -ENOMEM;
goto out;
goto out_free_index;
}
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->fops = &virtblk_fops;
vblk->disk->driverfs_dev = &vdev->dev;
index++;
vblk->index = index;
/* configure queue flush support */
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);
out_free_vblk:
kfree(vblk);
out_free_index:
ida_simple_remove(&vd_index_ida, index);
out:
return err;
}
@ -523,6 +539,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
static void __devexit virtblk_remove(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
int index = vblk->index;
flush_work(&vblk->config_work);
@ -538,6 +555,7 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
mempool_destroy(vblk->pool);
vdev->config->del_vqs(vdev);
kfree(vblk);
ida_simple_remove(&vd_index_ida, index);
}
static const struct virtio_device_id id_table[] = {