block: add blk_start_queue_async()

We currently only have an inline/sync helper to restart a stopped
queue. If drivers need an async version, they have to roll their
own. Add a generic helper instead.

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-core.c b/block/blk-core.c
index c487b94c59e3052074f5e40c99680d0cb709b517..33e2f62d50622ea8b40153175d0f44d96df399a6 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -206,6 +206,22 @@ void blk_delay_queue(struct request_queue *q, unsigned long msecs)
 }
 EXPORT_SYMBOL(blk_delay_queue);
 
+/**
+ * blk_start_queue_async - asynchronously restart a previously stopped queue
+ * @q:    The &struct request_queue in question
+ *
+ * Description:
+ *   blk_start_queue_async() will clear the stop flag on the queue, and
+ *   ensure that the request_fn for the queue is run from an async
+ *   context.
+ **/
+void blk_start_queue_async(struct request_queue *q)
+{
+       queue_flag_clear(QUEUE_FLAG_STOPPED, q);
+       blk_run_queue_async(q);
+}
+EXPORT_SYMBOL(blk_start_queue_async);
+
 /**
  * blk_start_queue - restart a previously stopped queue
  * @q:    The &struct request_queue in question

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0169ba2e2e64b9c4bba07bf72b9c1194fe2db08a..c70e3588a48c723f4b7cd8536c0dabfc02871d5c 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -797,6 +797,7 @@ extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 extern int blk_queue_enter(struct request_queue *q, gfp_t gfp);
 extern void blk_queue_exit(struct request_queue *q);
 extern void blk_start_queue(struct request_queue *q);
+extern void blk_start_queue_async(struct request_queue *q);
 extern void blk_stop_queue(struct request_queue *q);
 extern void blk_sync_queue(struct request_queue *q);
 extern void __blk_stop_queue(struct request_queue *q);