Deadline iosched: Factor out finding latter reques

Factor finding the next request in sector-sorted order into
a function deadline_latter_request.
Signed-off-by: NAaron Carroll <aaronc@gelato.unsw.edu.au>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

block/deadline-iosched.c

@@ -55,6 +55,20 @@ static void deadline_move_request(struct deadline_data *, struct request *);
 
 #define RQ_RB_ROOT(dd, rq)	(&(dd)->sort_list[rq_data_dir((rq))])
 
+/*
+ * get the request after `rq' in sector-sorted order
+ */
+static inline struct request *
+deadline_latter_request(struct request *rq)
+{
+	struct rb_node *node = rb_next(&rq->rb_node);
+
+	if (node)
+		return rb_entry_rq(node);
+
+	return NULL;
+}
+
 static void
 deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
 {
@@ -74,13 +88,8 @@ deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
 {
 	const int data_dir = rq_data_dir(rq);
 
-	if (dd->next_rq[data_dir] == rq) {
-		struct rb_node *rbnext = rb_next(&rq->rb_node);
-
-		dd->next_rq[data_dir] = NULL;
-		if (rbnext)
-			dd->next_rq[data_dir] = rb_entry_rq(rbnext);
-	}
+	if (dd->next_rq[data_dir] == rq)
+		dd->next_rq[data_dir] = deadline_latter_request(rq);
 
 	elv_rb_del(RQ_RB_ROOT(dd, rq), rq);
 }
@@ -198,14 +207,11 @@ static void
 deadline_move_request(struct deadline_data *dd, struct request *rq)
 {
 	const int data_dir = rq_data_dir(rq);
-	struct rb_node *rbnext = rb_next(&rq->rb_node);
 
 	dd->next_rq[READ] = NULL;
 	dd->next_rq[WRITE] = NULL;
+	dd->next_rq[data_dir] = deadline_latter_request(rq);
 
-	if (rbnext)
-		dd->next_rq[data_dir] = rb_entry_rq(rbnext);
-	
 	dd->last_sector = rq->sector + rq->nr_sectors;
 
 	/*