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Diffstat (limited to 'include/linux/blk-cgroup.h')
-rw-r--r--include/linux/blk-cgroup.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 6c666fd7de3c..0fce47d5acb1 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -296,6 +296,23 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
}
/**
+ * blkg_lookup - look up blkg for the specified request queue
+ * @q: request_queue of interest
+ *
+ * Lookup blkg for @q at the root level. See also blkg_lookup().
+ */
+static inline struct blkcg_gq *blkg_root_lookup(struct request_queue *q)
+{
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+ blkg = blkg_lookup(&blkcg_root, q);
+ rcu_read_unlock();
+
+ return blkg;
+}
+
+/**
* blkg_to_pdata - get policy private data
* @blkg: blkg of interest
* @pol: policy of interest
@@ -737,6 +754,7 @@ struct blkcg_policy {
#ifdef CONFIG_BLOCK
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
+static inline struct blkcg_gq *blkg_root_lookup(struct request_queue *q) { return NULL; }
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_exit_queue(struct request_queue *q) { }