4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bart Van Assche <bart.vanass...@wdc.com>
commit 6bad9b210a228d2fe0e0efe26d9b115348529cee upstream.
This new function will be used in a later patch to verify whether a
queue has been dissociated from the cgroup controller before being
released.
Signed-off-by: Bart Van Assche <bart.vanass...@wdc.com>
Cc: Tejun Heo <t...@kernel.org>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Ming Lei <ming....@redhat.com>
Cc: Omar Sandoval <osan...@fb.com>
Cc: Johannes Thumshirn <jthumsh...@suse.de>
Cc: Alexandru Moise <00moses.alexande...@gmail.com>
Cc: Joseph Qi <joseph...@linux.alibaba.com>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
include/linux/blk-cgroup.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -296,6 +296,23 @@ static inline struct blkcg_gq *blkg_look
}
/**
+ * 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) { }
