diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2011-10-30 21:29:59 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2011-11-02 11:41:02 +1030 |
| commit | 5087a50e66bd51b6e72c60bce4757a42b93f6b2c (patch) | |
| tree | b0a0f017fbeeef3b6be8604f6e40b54ce1053bac /drivers/block/virtio_blk.c | |
| parent | edfd52e6367270c90f3fd7cc302b375ffa89f91e (diff) | |
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: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/block/virtio_blk.c')
| -rw-r--r-- | 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 079c08808d8..e7a5750a93d 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -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 @@ 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[] = { |