blk-mq: provide a helper to check if a queue is busy
Returns true if the queue currently has requests pending,
false if not.
DM can use this to replace the atomic_inc/dec they do per device
to see if a device is busy.
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index ff497df..929e8ab 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -250,6 +250,8 @@
void blk_mq_free_request(struct request *rq);
bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
+bool blk_mq_queue_busy(struct request_queue *q);
+
enum {
/* return when out of requests */
BLK_MQ_REQ_NOWAIT = (__force blk_mq_req_flags_t)(1 << 0),