Merge branch 'for-4.11/next' into for-next

6 files changed, 52 insertions, 28 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 4b3b11a51a79..d161d4ab7052 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1598,7 +1598,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 {
 	struct blk_plug *plug;
 	int el_ret, where = ELEVATOR_INSERT_SORT;
-	struct request *req;
+	struct request *req, *free;
 	unsigned int request_count = 0;
 	unsigned int wb_acct;
 
@@ -1639,15 +1639,21 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	if (el_ret == ELEVATOR_BACK_MERGE) {
 		if (bio_attempt_back_merge(q, req, bio)) {
 			elv_bio_merged(q, req, bio);
-			if (!attempt_back_merge(q, req))
+			free = attempt_back_merge(q, req);
+			if (!free)
 				elv_merged_request(q, req, el_ret);
+			else
+				__blk_put_request(q, free);
 			goto out_unlock;
 		}
 	} else if (el_ret == ELEVATOR_FRONT_MERGE) {
 		if (bio_attempt_front_merge(q, req, bio)) {
 			elv_bio_merged(q, req, bio);
-			if (!attempt_front_merge(q, req))
+			free = attempt_front_merge(q, req);
+			if (!free)
 				elv_merged_request(q, req, el_ret);
+			else
+				__blk_put_request(q, free);
 			goto out_unlock;
 		}
 	}
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 6aa43dec5af4..a373416dbc9a 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -659,31 +659,32 @@ static void blk_account_io_merge(struct request *req)
 }
 
 /*
- * Has to be called with the request spinlock acquired
+ * For non-mq, this has to be called with the request spinlock acquired.
+ * For mq with scheduling, the appropriate queue wide lock should be held.
  */
-static int attempt_merge(struct request_queue *q, struct request *req,
-			  struct request *next)
+static struct request *attempt_merge(struct request_queue *q,
+				     struct request *req, struct request *next)
 {
 	if (!rq_mergeable(req) || !rq_mergeable(next))
-		return 0;
+		return NULL;
 
 	if (req_op(req) != req_op(next))
-		return 0;
+		return NULL;
 
 	/*
 	 * not contiguous
 	 */
 	if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next))
-		return 0;
+		return NULL;
 
 	if (rq_data_dir(req) != rq_data_dir(next)
 	    || req->rq_disk != next->rq_disk
 	    || req_no_special_merge(next))
-		return 0;
+		return NULL;
 
 	if (req_op(req) == REQ_OP_WRITE_SAME &&
 	    !blk_write_same_mergeable(req->bio, next->bio))
-		return 0;
+		return NULL;
 
 	/*
 	 * If we are allowed to merge, then append bio list
@@ -692,7 +693,7 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 	 * counts here.
 	 */
 	if (!ll_merge_requests_fn(q, req, next))
-		return 0;
+		return NULL;
 
 	/*
 	 * If failfast settings disagree or any of the two is already
@@ -732,42 +733,51 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 	if (blk_rq_cpu_valid(next))
 		req->cpu = next->cpu;
 
-	/* owner-ship of bio passed from next to req */
+	/*
+	 * ownership of bio passed from next to req, return 'next' for
+	 * the caller to free
+	 */
 	next->bio = NULL;
-	__blk_put_request(q, next);
-	return 1;
+	return next;
 }
 
-int attempt_back_merge(struct request_queue *q, struct request *rq)
+struct request *attempt_back_merge(struct request_queue *q, struct request *rq)
 {
 	struct request *next = elv_latter_request(q, rq);
 
 	if (next)
 		return attempt_merge(q, rq, next);
 
-	return 0;
+	return NULL;
 }
 
-int attempt_front_merge(struct request_queue *q, struct request *rq)
+struct request *attempt_front_merge(struct request_queue *q, struct request *rq)
 {
 	struct request *prev = elv_former_request(q, rq);
 
 	if (prev)
 		return attempt_merge(q, prev, rq);
 
-	return 0;
+	return NULL;
 }
 
 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 			  struct request *next)
 {
 	struct elevator_queue *e = q->elevator;
+	struct request *free;
 
 	if (!e->uses_mq && e->type->ops.sq.elevator_allow_rq_merge_fn)
 		if (!e->type->ops.sq.elevator_allow_rq_merge_fn(q, rq, next))
 			return 0;
 
-	return attempt_merge(q, rq, next);
+	free = attempt_merge(q, rq, next);
+	if (free) {
+		__blk_put_request(q, free);
+		return 1;
+	}
+
+	return 0;
 }
 
 bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 3ec52f494094..ee455e7cf9d8 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -234,7 +234,8 @@ void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
 }
 EXPORT_SYMBOL_GPL(blk_mq_sched_move_to_dispatch);
 
-bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio)
+bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
+			    struct request **merged_request)
 {
 	struct request *rq;
 	int ret;
@@ -244,7 +245,8 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio)
 		if (!blk_mq_sched_allow_merge(q, rq, bio))
 			return false;
 		if (bio_attempt_back_merge(q, rq, bio)) {
-			if (!attempt_back_merge(q, rq))
+			*merged_request = attempt_back_merge(q, rq);
+			if (!*merged_request)
 				elv_merged_request(q, rq, ret);
 			return true;
 		}
@@ -252,7 +254,8 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio)
 		if (!blk_mq_sched_allow_merge(q, rq, bio))
 			return false;
 		if (bio_attempt_front_merge(q, rq, bio)) {
-			if (!attempt_front_merge(q, rq))
+			*merged_request = attempt_front_merge(q, rq);
+			if (!*merged_request)
 				elv_merged_request(q, rq, ret);
 			return true;
 		}
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index add5f090a8cd..5954859c8670 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -15,7 +15,8 @@ struct request *blk_mq_sched_get_request(struct request_queue *q, struct bio *bi
 void blk_mq_sched_put_request(struct request *rq);
 
 void blk_mq_sched_request_inserted(struct request *rq);
-bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio);
+bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
+				struct request **merged_request);
 bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio);
 bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq);
 void blk_mq_sched_restart_queues(struct blk_mq_hw_ctx *hctx);
diff --git a/block/blk.h b/block/blk.h
index 6aa53a4aad88..4972b98d47e1 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -208,8 +208,8 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req,
 		     struct bio *bio);
 int ll_front_merge_fn(struct request_queue *q, struct request *req, 
 		      struct bio *bio);
-int attempt_back_merge(struct request_queue *q, struct request *rq);
-int attempt_front_merge(struct request_queue *q, struct request *rq);
+struct request *attempt_back_merge(struct request_queue *q, struct request *rq);
+struct request *attempt_front_merge(struct request_queue *q, struct request *rq);
 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 				struct request *next);
 void blk_recalc_rq_segments(struct request *rq);
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 8f91f21e8663..d68d9c273a66 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -371,12 +371,16 @@ static bool dd_bio_merge(struct blk_mq_hw_ctx *hctx, struct bio *bio)
 {
 	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
-	int ret;
+	struct request *free = NULL;
+	bool ret;
 
 	spin_lock(&dd->lock);
-	ret = blk_mq_sched_try_merge(q, bio);
+	ret = blk_mq_sched_try_merge(q, bio, &free);
 	spin_unlock(&dd->lock);
 
+	if (free)
+		blk_mq_free_request(free);
+
 	return ret;
 }