blk-cgroup: Fix potential deadlock in blk-cgroup

[net-next-2.6.git] / block / blk-cgroup.c

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1fa2654db0a62c1c3f07b92fb8b33eff473d1b41..e7dbbaf5fb3ee58698b1692508b991da8d38accd 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -147,16 +147,16 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
                return -EINVAL;
 
        blkcg = cgroup_to_blkio_cgroup(cgroup);
+       spin_lock(&blkio_list_lock);
        spin_lock_irq(&blkcg->lock);
        blkcg->weight = (unsigned int)val;
        hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
-               spin_lock(&blkio_list_lock);
                list_for_each_entry(blkiop, &blkio_list, list)
                        blkiop->ops.blkio_update_group_weight_fn(blkg,
                                        blkcg->weight);
-               spin_unlock(&blkio_list_lock);
        }
        spin_unlock_irq(&blkcg->lock);
+       spin_unlock(&blkio_list_lock);
        return 0;
 }