blkcg: add blkcg_{init|drain|exit}_queue()

Currently block core calls directly into blk-throttle for init, drain
and exit.  This patch adds blkcg_{init|drain|exit}_queue() which wraps
the blk-throttle functions.  This is to give more control and
visiblity to blkcg core layer for proper layering.  Further patches
will add logic common to blkcg policies to the functions.

While at it, collapse blk_throtl_release() into blk_throtl_exit().
There's no reason to keep them separate.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 3 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 5a1b8cc03003..c3434c6395b9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -34,6 +34,7 @@
 #include <trace/events/block.h>
 
 #include "blk.h"
+#include "blk-cgroup.h"
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
@@ -280,7 +281,7 @@ EXPORT_SYMBOL(blk_stop_queue);
  *
  *     This function does not cancel any asynchronous activity arising
  *     out of elevator or throttling code. That would require elevaotor_exit()
- *     and blk_throtl_exit() to be called with queue lock initialized.
+ *     and blkcg_exit_queue() to be called with queue lock initialized.
  *
  */
 void blk_sync_queue(struct request_queue *q)
@@ -372,7 +373,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
                 if (q->elevator)
                         elv_drain_elevator(q);
 
-                blk_throtl_drain(q);
+                blkcg_drain_queue(q);
 
                 /*
                  * This function might be called on a queue which failed
@@ -562,7 +563,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
          */
         q->queue_lock = &q->__queue_lock;
 
-        if (blk_throtl_init(q))
+        if (blkcg_init_queue(q))
                 goto fail_id;
 
         return q;