1 files changed, 84 insertions, 41 deletions

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 5839a027e0f0..6aa5daf7ae32 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -74,8 +74,8 @@ struct dd_per_prio {
 	struct list_head dispatch;
 	struct rb_root sort_list[DD_DIR_COUNT];
 	struct list_head fifo_list[DD_DIR_COUNT];
-	/* Next request in FIFO order. Read, write or both are NULL. */
-	struct request *next_rq[DD_DIR_COUNT];
+	/* Position of the most recently dispatched request. */
+	sector_t latest_pos[DD_DIR_COUNT];
 	struct io_stats_per_prio stats;
 };
 
@@ -156,6 +156,40 @@ deadline_latter_request(struct request *rq)
 	return NULL;
 }
 
+/*
+ * Return the first request for which blk_rq_pos() >= @pos. For zoned devices,
+ * return the first request after the start of the zone containing @pos.
+ */
+static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,
+				enum dd_data_dir data_dir, sector_t pos)
+{
+	struct rb_node *node = per_prio->sort_list[data_dir].rb_node;
+	struct request *rq, *res = NULL;
+
+	if (!node)
+		return NULL;
+
+	rq = rb_entry_rq(node);
+	/*
+	 * A zoned write may have been requeued with a starting position that
+	 * is below that of the most recently dispatched request. Hence, for
+	 * zoned writes, start searching from the start of a zone.
+	 */
+	if (blk_rq_is_seq_zoned_write(rq))
+		pos -= round_down(pos, rq->q->limits.chunk_sectors);
+
+	while (node) {
+		rq = rb_entry_rq(node);
+		if (blk_rq_pos(rq) >= pos) {
+			res = rq;
+			node = node->rb_left;
+		} else {
+			node = node->rb_right;
+		}
+	}
+	return res;
+}
+
 static void
 deadline_add_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
 {
@@ -167,11 +201,6 @@ deadline_add_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
 static inline void
 deadline_del_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
 {
-	const enum dd_data_dir data_dir = rq_data_dir(rq);
-
-	if (per_prio->next_rq[data_dir] == rq)
-		per_prio->next_rq[data_dir] = deadline_latter_request(rq);
-
 	elv_rb_del(deadline_rb_root(per_prio, rq), rq);
 }
 
@@ -251,10 +280,6 @@ static void
 deadline_move_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
 		      struct request *rq)
 {
-	const enum dd_data_dir data_dir = rq_data_dir(rq);
-
-	per_prio->next_rq[data_dir] = deadline_latter_request(rq);
-
 	/*
 	 * take it off the sort and fifo list
 	 */
@@ -272,21 +297,15 @@ static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
 }
 
 /*
- * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
- * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
+ * deadline_check_fifo returns true if and only if there are expired requests
+ * in the FIFO list. Requires !list_empty(&dd->fifo_list[data_dir]).
  */
-static inline int deadline_check_fifo(struct dd_per_prio *per_prio,
-				      enum dd_data_dir data_dir)
+static inline bool deadline_check_fifo(struct dd_per_prio *per_prio,
+				       enum dd_data_dir data_dir)
 {
 	struct request *rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
 
-	/*
-	 * rq is expired!
-	 */
-	if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
-		return 1;
-
-	return 0;
+	return time_is_before_eq_jiffies((unsigned long)rq->fifo_time);
 }
 
 /*
@@ -310,14 +329,11 @@ static struct request *deadline_skip_seq_writes(struct deadline_data *dd,
 						struct request *rq)
 {
 	sector_t pos = blk_rq_pos(rq);
-	sector_t skipped_sectors = 0;
 
-	while (rq) {
-		if (blk_rq_pos(rq) != pos + skipped_sectors)
-			break;
-		skipped_sectors += blk_rq_sectors(rq);
+	do {
+		pos += blk_rq_sectors(rq);
 		rq = deadline_latter_request(rq);
-	}
+	} while (rq && blk_rq_pos(rq) == pos);
 
 	return rq;
 }
@@ -330,7 +346,7 @@ static struct request *
 deadline_fifo_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
 		      enum dd_data_dir data_dir)
 {
-	struct request *rq;
+	struct request *rq, *rb_rq, *next;
 	unsigned long flags;
 
 	if (list_empty(&per_prio->fifo_list[data_dir]))
@@ -348,7 +364,12 @@ deadline_fifo_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
 	 * zones and these zones are unlocked.
 	 */
 	spin_lock_irqsave(&dd->zone_lock, flags);
-	list_for_each_entry(rq, &per_prio->fifo_list[DD_WRITE], queuelist) {
+	list_for_each_entry_safe(rq, next, &per_prio->fifo_list[DD_WRITE],
+				 queuelist) {
+		/* Check whether a prior request exists for the same zone. */
+		rb_rq = deadline_from_pos(per_prio, data_dir, blk_rq_pos(rq));
+		if (rb_rq && blk_rq_pos(rb_rq) < blk_rq_pos(rq))
+			rq = rb_rq;
 		if (blk_req_can_dispatch_to_zone(rq) &&
 		    (blk_queue_nonrot(rq->q) ||
 		     !deadline_is_seq_write(dd, rq)))
@@ -372,7 +393,8 @@ deadline_next_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
 	struct request *rq;
 	unsigned long flags;
 
-	rq = per_prio->next_rq[data_dir];
+	rq = deadline_from_pos(per_prio, data_dir,
+			       per_prio->latest_pos[data_dir]);
 	if (!rq)
 		return NULL;
 
@@ -435,6 +457,7 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
 		if (started_after(dd, rq, latest_start))
 			return NULL;
 		list_del_init(&rq->queuelist);
+		data_dir = rq_data_dir(rq);
 		goto done;
 	}
 
@@ -442,9 +465,11 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
 	 * batches are currently reads XOR writes
 	 */
 	rq = deadline_next_request(dd, per_prio, dd->last_dir);
-	if (rq && dd->batching < dd->fifo_batch)
-		/* we have a next request are still entitled to batch */
+	if (rq && dd->batching < dd->fifo_batch) {
+		/* we have a next request and are still entitled to batch */
+		data_dir = rq_data_dir(rq);
 		goto dispatch_request;
+	}
 
 	/*
 	 * at this point we are not running a batch. select the appropriate
@@ -522,6 +547,7 @@ dispatch_request:
 done:
 	ioprio_class = dd_rq_ioclass(rq);
 	prio = ioprio_class_to_prio[ioprio_class];
+	dd->per_prio[prio].latest_pos[data_dir] = blk_rq_pos(rq);
 	dd->per_prio[prio].stats.dispatched++;
 	/*
 	 * If the request needs its target zone locked, do it.
@@ -766,7 +792,7 @@ static bool dd_bio_merge(struct request_queue *q, struct bio *bio,
  * add rq to rbtree and fifo
  */
 static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
-			      blk_insert_t flags)
+			      blk_insert_t flags, struct list_head *free)
 {
 	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
@@ -775,7 +801,6 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 	u8 ioprio_class = IOPRIO_PRIO_CLASS(ioprio);
 	struct dd_per_prio *per_prio;
 	enum dd_prio prio;
-	LIST_HEAD(free);
 
 	lockdep_assert_held(&dd->lock);
 
@@ -792,10 +817,8 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		rq->elv.priv[0] = (void *)(uintptr_t)1;
 	}
 
-	if (blk_mq_sched_try_insert_merge(q, rq, &free)) {
-		blk_mq_free_requests(&free);
+	if (blk_mq_sched_try_insert_merge(q, rq, free))
 		return;
-	}
 
 	trace_block_rq_insert(rq);
 
@@ -803,6 +826,8 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		list_add(&rq->queuelist, &per_prio->dispatch);
 		rq->fifo_time = jiffies;
 	} else {
+		struct list_head *insert_before;
+
 		deadline_add_rq_rb(per_prio, rq);
 
 		if (rq_mergeable(rq)) {
@@ -815,7 +840,20 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		 * set expire time and add to fifo list
 		 */
 		rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
-		list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
+		insert_before = &per_prio->fifo_list[data_dir];
+#ifdef CONFIG_BLK_DEV_ZONED
+		/*
+		 * Insert zoned writes such that requests are sorted by
+		 * position per zone.
+		 */
+		if (blk_rq_is_seq_zoned_write(rq)) {
+			struct request *rq2 = deadline_latter_request(rq);
+
+			if (rq2 && blk_rq_zone_no(rq2) == blk_rq_zone_no(rq))
+				insert_before = &rq2->queuelist;
+		}
+#endif
+		list_add_tail(&rq->queuelist, insert_before);
 	}
 }
 
@@ -828,6 +866,7 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 {
 	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
+	LIST_HEAD(free);
 
 	spin_lock(&dd->lock);
 	while (!list_empty(list)) {
@@ -835,9 +874,11 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 
 		rq = list_first_entry(list, struct request, queuelist);
 		list_del_init(&rq->queuelist);
-		dd_insert_request(hctx, rq, flags);
+		dd_insert_request(hctx, rq, flags, &free);
 	}
 	spin_unlock(&dd->lock);
+
+	blk_mq_free_requests(&free);
 }
 
 /* Callback from inside blk_mq_rq_ctx_init(). */
@@ -1035,8 +1076,10 @@ static int deadline_##name##_next_rq_show(void *data,			\
 	struct request_queue *q = data;					\
 	struct deadline_data *dd = q->elevator->elevator_data;		\
 	struct dd_per_prio *per_prio = &dd->per_prio[prio];		\
-	struct request *rq = per_prio->next_rq[data_dir];		\
+	struct request *rq;						\
 									\
+	rq = deadline_from_pos(per_prio, data_dir,			\
+			       per_prio->latest_pos[data_dir]);		\
 	if (rq)								\
 		__blk_mq_debugfs_rq_show(m, rq);			\
 	return 0;							\