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-rw-r--r--block/blk-cgroup.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 8908298d6ad3..88b1fce90520 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -634,6 +634,14 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
q = bdev_get_queue(bdev);
+ /*
+ * blkcg_deactivate_policy() requires queue to be frozen, we can grab
+ * q_usage_counter to prevent concurrent with blkcg_deactivate_policy().
+ */
+ ret = blk_queue_enter(q, 0);
+ if (ret)
+ return ret;
+
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
@@ -703,6 +711,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
goto success;
}
success:
+ blk_queue_exit(q);
ctx->bdev = bdev;
ctx->blkg = blkg;
ctx->body = input;
@@ -715,6 +724,7 @@ fail_unlock:
rcu_read_unlock();
fail:
blkdev_put_no_open(bdev);
+ blk_queue_exit(q);
/*
* If queue was bypassing, we should retry. Do so after a
* short msleep(). It isn't strictly necessary but queue