block: change the tag sync vs async restriction logic

Make them fully share the tag space, but disallow async requests using
the last any two slots.

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

1 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 564445be7a6d..a967dd775dbd 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -404,7 +404,7 @@ struct request_queue
 	struct list_head	tag_busy_list;
 
 	unsigned int		nr_sorted;
-	unsigned int		in_flight;
+	unsigned int		in_flight[2];
 
 	unsigned int		rq_timeout;
 	struct timer_list	timeout;
@@ -511,6 +511,11 @@ static inline void queue_flag_clear_unlocked(unsigned int flag,
 	__clear_bit(flag, &q->queue_flags);
 }
 
+static inline int queue_in_flight(struct request_queue *q)
+{
+	return q->in_flight[0] + q->in_flight[1];
+}
+
 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 {
 	WARN_ON_ONCE(!queue_is_locked(q));