Based on a patch by Mark Wu
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
---
Changes from Mark's versions:
use the new ida_simple_get
error handling cleanup
fix user after free
Works fine for me.
Jens, could you merge this for 3.2?
That is, unless Rusty complains shortly ...
drivers/block/virtio_blk.c | 30 --
1 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 079c088..e7a5750 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -8,10 +8,13 @@
#include
#include
#include
+#include
#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 @@ out_free_vq:
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 @@ out:
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[] = {
--
1.7.5.53.gc233e
--
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