1 files changed, 7 insertions, 0 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 4ef78d35cbd2..179ddfaebc5c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -16,6 +16,7 @@
 #include "blk-cgroup.h"
 
 extern void cfq_unlink_blkio_group(void *, struct blkio_group *);
+extern void cfq_update_blkio_group_weight(struct blkio_group *, unsigned int);
 
 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
 
@@ -116,12 +117,18 @@ static int
 blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
 {
         struct blkio_cgroup *blkcg;
+        struct blkio_group *blkg;
+        struct hlist_node *n;
 
         if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
                 return -EINVAL;
 
         blkcg = cgroup_to_blkio_cgroup(cgroup);
+        spin_lock_irq(&blkcg->lock);
         blkcg->weight = (unsigned int)val;
+        hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
+                cfq_update_blkio_group_weight(blkg, blkcg->weight);
+        spin_unlock_irq(&blkcg->lock);
         return 0;
 }