1 files changed, 23 insertions, 201 deletions

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 02a916ba62..acdc28756d 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -102,7 +102,6 @@ struct deadline_data {
 	int prio_aging_expire;
 
 	spinlock_t lock;
-	spinlock_t zone_lock;
 };
 
 /* Maps an I/O priority class to a deadline scheduler priority. */
@@ -129,36 +128,7 @@ static u8 dd_rq_ioclass(struct request *rq)
 }
 
 /*
- * get the request before `rq' in sector-sorted order
- */
-static inline struct request *
-deadline_earlier_request(struct request *rq)
-{
-	struct rb_node *node = rb_prev(&rq->rb_node);
-
-	if (node)
-		return rb_entry_rq(node);
-
-	return NULL;
-}
-
-/*
- * 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;
-}
-
-/*
- * 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.
+ * Return the first request for which blk_rq_pos() >= @pos.
  */
 static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,
 				enum dd_data_dir data_dir, sector_t pos)
@@ -170,14 +140,6 @@ static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,
 		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) {
@@ -309,36 +271,6 @@ static inline bool deadline_check_fifo(struct dd_per_prio *per_prio,
 }
 
 /*
- * Check if rq has a sequential request preceding it.
- */
-static bool deadline_is_seq_write(struct deadline_data *dd, struct request *rq)
-{
-	struct request *prev = deadline_earlier_request(rq);
-
-	if (!prev)
-		return false;
-
-	return blk_rq_pos(prev) + blk_rq_sectors(prev) == blk_rq_pos(rq);
-}
-
-/*
- * Skip all write requests that are sequential from @rq, even if we cross
- * a zone boundary.
- */
-static struct request *deadline_skip_seq_writes(struct deadline_data *dd,
-						struct request *rq)
-{
-	sector_t pos = blk_rq_pos(rq);
-
-	do {
-		pos += blk_rq_sectors(rq);
-		rq = deadline_latter_request(rq);
-	} while (rq && blk_rq_pos(rq) == pos);
-
-	return rq;
-}
-
-/*
  * For the specified data direction, return the next request to
  * dispatch using arrival ordered lists.
  */
@@ -346,40 +278,10 @@ 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, *rb_rq, *next;
-	unsigned long flags;
-
 	if (list_empty(&per_prio->fifo_list[data_dir]))
 		return NULL;
 
-	rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
-	if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
-		return rq;
-
-	/*
-	 * Look for a write request that can be dispatched, that is one with
-	 * an unlocked target zone. For some HDDs, breaking a sequential
-	 * write stream can lead to lower throughput, so make sure to preserve
-	 * sequential write streams, even if that stream crosses into the next
-	 * zones and these zones are unlocked.
-	 */
-	spin_lock_irqsave(&dd->zone_lock, flags);
-	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)))
-			goto out;
-	}
-	rq = NULL;
-out:
-	spin_unlock_irqrestore(&dd->zone_lock, flags);
-
-	return rq;
+	return rq_entry_fifo(per_prio->fifo_list[data_dir].next);
 }
 
 /*
@@ -390,36 +292,8 @@ static struct request *
 deadline_next_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
 		      enum dd_data_dir data_dir)
 {
-	struct request *rq;
-	unsigned long flags;
-
-	rq = deadline_from_pos(per_prio, data_dir,
-			       per_prio->latest_pos[data_dir]);
-	if (!rq)
-		return NULL;
-
-	if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
-		return rq;
-
-	/*
-	 * Look for a write request that can be dispatched, that is one with
-	 * an unlocked target zone. For some HDDs, breaking a sequential
-	 * write stream can lead to lower throughput, so make sure to preserve
-	 * sequential write streams, even if that stream crosses into the next
-	 * zones and these zones are unlocked.
-	 */
-	spin_lock_irqsave(&dd->zone_lock, flags);
-	while (rq) {
-		if (blk_req_can_dispatch_to_zone(rq))
-			break;
-		if (blk_queue_nonrot(rq->q))
-			rq = deadline_latter_request(rq);
-		else
-			rq = deadline_skip_seq_writes(dd, rq);
-	}
-	spin_unlock_irqrestore(&dd->zone_lock, flags);
-
-	return rq;
+	return deadline_from_pos(per_prio, data_dir,
+				 per_prio->latest_pos[data_dir]);
 }
 
 /*
@@ -525,10 +399,6 @@ dispatch_find_request:
 		rq = next_rq;
 	}
 
-	/*
-	 * For a zoned block device, if we only have writes queued and none of
-	 * them can be dispatched, rq will be NULL.
-	 */
 	if (!rq)
 		return NULL;
 
@@ -549,10 +419,6 @@ done:
 	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.
-	 */
-	blk_req_zone_write_lock(rq);
 	rq->rq_flags |= RQF_STARTED;
 	return rq;
 }
@@ -622,6 +488,20 @@ unlock:
 }
 
 /*
+ * 'depth' is a number in the range 1..INT_MAX representing a number of
+ * requests. Scale it with a factor (1 << bt->sb.shift) / q->nr_requests since
+ * 1..(1 << bt->sb.shift) is the range expected by sbitmap_get_shallow().
+ * Values larger than q->nr_requests have the same effect as q->nr_requests.
+ */
+static int dd_to_word_depth(struct blk_mq_hw_ctx *hctx, unsigned int qdepth)
+{
+	struct sbitmap_queue *bt = &hctx->sched_tags->bitmap_tags;
+	const unsigned int nrr = hctx->queue->nr_requests;
+
+	return ((qdepth << bt->sb.shift) + nrr - 1) / nrr;
+}
+
+/*
  * Called by __blk_mq_alloc_request(). The shallow_depth value set by this
  * function is used by __blk_mq_get_tag().
  */
@@ -637,7 +517,7 @@ static void dd_limit_depth(blk_opf_t opf, struct blk_mq_alloc_data *data)
 	 * Throttle asynchronous requests and writes such that these requests
 	 * do not block the allocation of synchronous requests.
 	 */
-	data->shallow_depth = dd->async_depth;
+	data->shallow_depth = dd_to_word_depth(data->hctx, dd->async_depth);
 }
 
 /* Called by blk_mq_update_nr_requests(). */
@@ -647,9 +527,9 @@ static void dd_depth_updated(struct blk_mq_hw_ctx *hctx)
 	struct deadline_data *dd = q->elevator->elevator_data;
 	struct blk_mq_tags *tags = hctx->sched_tags;
 
-	dd->async_depth = max(1UL, 3 * q->nr_requests / 4);
+	dd->async_depth = q->nr_requests;
 
-	sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, dd->async_depth);
+	sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, 1);
 }
 
 /* Called by blk_mq_init_hctx() and blk_mq_init_sched(). */
@@ -722,7 +602,6 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
 	dd->fifo_batch = fifo_batch;
 	dd->prio_aging_expire = prio_aging_expire;
 	spin_lock_init(&dd->lock);
-	spin_lock_init(&dd->zone_lock);
 
 	/* We dispatch from request queue wide instead of hw queue */
 	blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q);
@@ -804,12 +683,6 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 
 	lockdep_assert_held(&dd->lock);
 
-	/*
-	 * This may be a requeue of a write request that has locked its
-	 * target zone. If it is the case, this releases the zone lock.
-	 */
-	blk_req_zone_write_unlock(rq);
-
 	prio = ioprio_class_to_prio[ioprio_class];
 	per_prio = &dd->per_prio[prio];
 	if (!rq->elv.priv[0]) {
@@ -841,18 +714,6 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		 */
 		rq->fifo_time = jiffies + dd->fifo_expire[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);
 	}
 }
@@ -887,33 +748,8 @@ static void dd_prepare_request(struct request *rq)
 	rq->elv.priv[0] = NULL;
 }
 
-static bool dd_has_write_work(struct blk_mq_hw_ctx *hctx)
-{
-	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
-	enum dd_prio p;
-
-	for (p = 0; p <= DD_PRIO_MAX; p++)
-		if (!list_empty_careful(&dd->per_prio[p].fifo_list[DD_WRITE]))
-			return true;
-
-	return false;
-}
-
 /*
  * Callback from inside blk_mq_free_request().
- *
- * For zoned block devices, write unlock the target zone of
- * completed write requests. Do this while holding the zone lock
- * spinlock so that the zone is never unlocked while deadline_fifo_request()
- * or deadline_next_request() are executing. This function is called for
- * all requests, whether or not these requests complete successfully.
- *
- * For a zoned block device, __dd_dispatch_request() may have stopped
- * dispatching requests if all the queued requests are write requests directed
- * at zones that are already locked due to on-going write requests. To ensure
- * write request dispatch progress in this case, mark the queue as needing a
- * restart to ensure that the queue is run again after completion of the
- * request and zones being unlocked.
  */
 static void dd_finish_request(struct request *rq)
 {
@@ -928,21 +764,8 @@ static void dd_finish_request(struct request *rq)
 	 * called dd_insert_requests(). Skip requests that bypassed I/O
 	 * scheduling. See also blk_mq_request_bypass_insert().
 	 */
-	if (!rq->elv.priv[0])
-		return;
-
-	atomic_inc(&per_prio->stats.completed);
-
-	if (blk_queue_is_zoned(q)) {
-		unsigned long flags;
-
-		spin_lock_irqsave(&dd->zone_lock, flags);
-		blk_req_zone_write_unlock(rq);
-		spin_unlock_irqrestore(&dd->zone_lock, flags);
-
-		if (dd_has_write_work(rq->mq_hctx))
-			blk_mq_sched_mark_restart_hctx(rq->mq_hctx);
-	}
+	if (rq->elv.priv[0])
+		atomic_inc(&per_prio->stats.completed);
 }
 
 static bool dd_has_work_for_prio(struct dd_per_prio *per_prio)
@@ -1266,7 +1089,6 @@ static struct elevator_type mq_deadline = {
 	.elevator_attrs = deadline_attrs,
 	.elevator_name = "mq-deadline",
 	.elevator_alias = "deadline",
-	.elevator_features = ELEVATOR_F_ZBD_SEQ_WRITE,
 	.elevator_owner = THIS_MODULE,
 };
 MODULE_ALIAS("mq-deadline-iosched");