Current index allocation in virtio-blk is based on a monotonically increasing variable "index". It could cause some confusion about disk name in the case of hot-plugging disks. And it's impossible to find the lowest available index by just maintaining a simple index. So it's changed to use ida to allocate index via referring to the index allocation in scsi disk.
Signed-off-by: Mark Wu <[email protected]> --- drivers/block/virtio_blk.c | 37 ++++++++++++++++++++++++++++++++----- 1 files changed, 32 insertions(+), 5 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 079c088..ba734b3 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -8,10 +8,14 @@ #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_SPINLOCK(vd_index_lock); +static DEFINE_IDA(vd_index_ida); + struct workqueue_struct *virtblk_wq; struct virtio_blk @@ -23,6 +27,7 @@ struct virtio_blk /* The disk structure for the kernel. */ struct gendisk *disk; + u32 index; /* Request tracking. */ struct list_head reqs; @@ -343,12 +348,26 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) struct request_queue *q; int err; u64 cap; - u32 v, blk_size, sg_elems, opt_io_size; + u32 v, blk_size, sg_elems, opt_io_size, index; u16 min_io_size; u8 physical_block_exp, alignment_offset; - if (index_to_minor(index) >= 1 << MINORBITS) - return -ENOSPC; + do { + if (!ida_pre_get(&vd_index_ida, GFP_KERNEL)) + return err; + + spin_lock(&vd_index_lock); + err = ida_get_new(&vd_index_ida, &index); + spin_unlock(&vd_index_lock); + } while (err == -EAGAIN); + + if (err) + return err; + + if (index_to_minor(index) >= 1 << MINORBITS) { + err = -ENOSPC; + goto out_free_index; + } /* We need to know how many segments before we allocate. */ err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, @@ -421,7 +440,7 @@ 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 +535,10 @@ out_free_vq: vdev->config->del_vqs(vdev); out_free_vblk: kfree(vblk); +out_free_index: + spin_lock(&vd_index_lock); + ida_remove(&vd_index_ida, index); + spin_unlock(&vd_index_lock); out: return err; } @@ -529,6 +552,10 @@ static void __devexit virtblk_remove(struct virtio_device *vdev) /* Nothing should be pending. */ BUG_ON(!list_empty(&vblk->reqs)); + spin_lock(&vd_index_lock); + ida_remove(&vd_index_ida, vblk->index); + spin_unlock(&vd_index_lock); + /* Stop all the virtqueues. */ vdev->config->reset(vdev); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
