1 files changed, 24 insertions, 31 deletions

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 461a9af11efe..1d94a20374fc 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -166,7 +166,7 @@ static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
 		int diff = limit - inflight;
 
 		if (!inflight || diff >= rwb->wb_background / 2)
-			wake_up_all(&rqw->wait);
+			wake_up(&rqw->wait);
 	}
 }
 
@@ -474,30 +474,6 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw)
 	return limit;
 }
 
-static inline bool may_queue(struct rq_wb *rwb, struct rq_wait *rqw,
-			     wait_queue_entry_t *wait, unsigned long rw)
-{
-	/*
-	 * inc it here even if disabled, since we'll dec it at completion.
-	 * this only happens if the task was sleeping in __wbt_wait(),
-	 * and someone turned it off at the same time.
-	 */
-	if (!rwb_enabled(rwb)) {
-		atomic_inc(&rqw->inflight);
-		return true;
-	}
-
-	/*
-	 * If the waitqueue is already active and we are not the next
-	 * in line to be woken up, wait for our turn.
-	 */
-	if (waitqueue_active(&rqw->wait) &&
-	    rqw->wait.head.next != &wait->entry)
-		return false;
-
-	return rq_wait_inc_below(rqw, get_limit(rwb, rw));
-}
-
 /*
  * Block if we will exceed our limit, or if we are currently waiting for
  * the timer to kick off queuing again.
@@ -508,16 +484,32 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
 	__acquires(lock)
 {
 	struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
-	DEFINE_WAIT(wait);
+	DECLARE_WAITQUEUE(wait, current);
+
+	/*
+	* inc it here even if disabled, since we'll dec it at completion.
+	* this only happens if the task was sleeping in __wbt_wait(),
+	* and someone turned it off at the same time.
+	*/
+	if (!rwb_enabled(rwb)) {
+		atomic_inc(&rqw->inflight);
+		return;
+	}
 
-	if (may_queue(rwb, rqw, &wait, rw))
+	if (!waitqueue_active(&rqw->wait)
+		&& rq_wait_inc_below(rqw, get_limit(rwb, rw)))
 		return;
 
+	add_wait_queue_exclusive(&rqw->wait, &wait);
 	do {
-		prepare_to_wait_exclusive(&rqw->wait, &wait,
-						TASK_UNINTERRUPTIBLE);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+
+		if (!rwb_enabled(rwb)) {
+			atomic_inc(&rqw->inflight);
+			break;
+		}
 
-		if (may_queue(rwb, rqw, &wait, rw))
+		if (rq_wait_inc_below(rqw, get_limit(rwb, rw)))
 			break;
 
 		if (lock) {
@@ -528,7 +520,8 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
 			io_schedule();
 	} while (1);
 
-	finish_wait(&rqw->wait, &wait);
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(&rqw->wait, &wait);
 }
 
 static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)