1 files changed, 74 insertions, 127 deletions

diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index acdc28756d9d..3e3719093aec 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -71,7 +71,6 @@ struct io_stats_per_prio {
  * present on both sort_list[] and fifo_list[].
  */
 struct dd_per_prio {
-	struct list_head dispatch;
 	struct rb_root sort_list[DD_DIR_COUNT];
 	struct list_head fifo_list[DD_DIR_COUNT];
 	/* Position of the most recently dispatched request. */
@@ -84,6 +83,7 @@ struct deadline_data {
 	 * run time data
 	 */
 
+	struct list_head dispatch;
 	struct dd_per_prio per_prio[DD_PRIO_COUNT];
 
 	/* Data direction of latest dispatched request. */
@@ -136,10 +136,6 @@ static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,
 	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);
 	while (node) {
 		rq = rb_entry_rq(node);
 		if (blk_rq_pos(rq) >= pos) {
@@ -310,6 +306,19 @@ static bool started_after(struct deadline_data *dd, struct request *rq,
 	return time_after(start_time, latest_start);
 }
 
+static struct request *dd_start_request(struct deadline_data *dd,
+					enum dd_data_dir data_dir,
+					struct request *rq)
+{
+	u8 ioprio_class = dd_rq_ioclass(rq);
+	enum dd_prio 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++;
+	rq->rq_flags |= RQF_STARTED;
+	return rq;
+}
+
 /*
  * deadline_dispatch_requests selects the best request according to
  * read/write expire, fifo_batch, etc and with a start time <= @latest_start.
@@ -320,21 +329,9 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
 {
 	struct request *rq, *next_rq;
 	enum dd_data_dir data_dir;
-	enum dd_prio prio;
-	u8 ioprio_class;
 
 	lockdep_assert_held(&dd->lock);
 
-	if (!list_empty(&per_prio->dispatch)) {
-		rq = list_first_entry(&per_prio->dispatch, struct request,
-				      queuelist);
-		if (started_after(dd, rq, latest_start))
-			return NULL;
-		list_del_init(&rq->queuelist);
-		data_dir = rq_data_dir(rq);
-		goto done;
-	}
-
 	/*
 	 * batches are currently reads XOR writes
 	 */
@@ -414,13 +411,7 @@ dispatch_request:
 	 */
 	dd->batching++;
 	deadline_move_request(dd, per_prio, rq);
-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++;
-	rq->rq_flags |= RQF_STARTED;
-	return rq;
+	return dd_start_request(dd, data_dir, rq);
 }
 
 /*
@@ -467,6 +458,14 @@ static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
 	enum dd_prio prio;
 
 	spin_lock(&dd->lock);
+
+	if (!list_empty(&dd->dispatch)) {
+		rq = list_first_entry(&dd->dispatch, struct request, queuelist);
+		list_del_init(&rq->queuelist);
+		dd_start_request(dd, rq_data_dir(rq), rq);
+		goto unlock;
+	}
+
 	rq = dd_dispatch_prio_aged_requests(dd, now);
 	if (rq)
 		goto unlock;
@@ -488,20 +487,6 @@ 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().
  */
@@ -517,26 +502,16 @@ 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_to_word_depth(data->hctx, dd->async_depth);
+	data->shallow_depth = dd->async_depth;
 }
 
 /* Called by blk_mq_update_nr_requests(). */
-static void dd_depth_updated(struct blk_mq_hw_ctx *hctx)
+static void dd_depth_updated(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
 	struct deadline_data *dd = q->elevator->elevator_data;
-	struct blk_mq_tags *tags = hctx->sched_tags;
 
 	dd->async_depth = q->nr_requests;
-
-	sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, 1);
-}
-
-/* Called by blk_mq_init_hctx() and blk_mq_init_sched(). */
-static int dd_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
-{
-	dd_depth_updated(hctx);
-	return 0;
+	blk_mq_set_min_shallow_depth(q, 1);
 }
 
 static void dd_exit_sched(struct elevator_queue *e)
@@ -568,27 +543,21 @@ static void dd_exit_sched(struct elevator_queue *e)
 /*
  * initialize elevator private data (deadline_data).
  */
-static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
+static int dd_init_sched(struct request_queue *q, struct elevator_queue *eq)
 {
 	struct deadline_data *dd;
-	struct elevator_queue *eq;
 	enum dd_prio prio;
-	int ret = -ENOMEM;
-
-	eq = elevator_alloc(q, e);
-	if (!eq)
-		return ret;
 
 	dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
 	if (!dd)
-		goto put_eq;
+		return -ENOMEM;
 
 	eq->elevator_data = dd;
 
+	INIT_LIST_HEAD(&dd->dispatch);
 	for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
 		struct dd_per_prio *per_prio = &dd->per_prio[prio];
 
-		INIT_LIST_HEAD(&per_prio->dispatch);
 		INIT_LIST_HEAD(&per_prio->fifo_list[DD_READ]);
 		INIT_LIST_HEAD(&per_prio->fifo_list[DD_WRITE]);
 		per_prio->sort_list[DD_READ] = RB_ROOT;
@@ -607,11 +576,8 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
 	blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q);
 
 	q->elevator = eq;
+	dd_depth_updated(q);
 	return 0;
-
-put_eq:
-	kobject_put(&eq->kobj);
-	return ret;
 }
 
 /*
@@ -685,10 +651,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 
 	prio = ioprio_class_to_prio[ioprio_class];
 	per_prio = &dd->per_prio[prio];
-	if (!rq->elv.priv[0]) {
+	if (!rq->elv.priv[0])
 		per_prio->stats.inserted++;
-		rq->elv.priv[0] = (void *)(uintptr_t)1;
-	}
+	rq->elv.priv[0] = per_prio;
 
 	if (blk_mq_sched_try_insert_merge(q, rq, free))
 		return;
@@ -696,11 +661,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 	trace_block_rq_insert(rq);
 
 	if (flags & BLK_MQ_INSERT_AT_HEAD) {
-		list_add(&rq->queuelist, &per_prio->dispatch);
+		list_add(&rq->queuelist, &dd->dispatch);
 		rq->fifo_time = jiffies;
 	} else {
-		struct list_head *insert_before;
-
 		deadline_add_rq_rb(per_prio, rq);
 
 		if (rq_mergeable(rq)) {
@@ -713,13 +676,12 @@ 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];
-		insert_before = &per_prio->fifo_list[data_dir];
-		list_add_tail(&rq->queuelist, insert_before);
+		list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
 	}
 }
 
 /*
- * Called from blk_mq_insert_request() or blk_mq_dispatch_plug_list().
+ * Called from blk_mq_insert_request() or blk_mq_dispatch_list().
  */
 static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 			       struct list_head *list,
@@ -753,25 +715,20 @@ static void dd_prepare_request(struct request *rq)
  */
 static void dd_finish_request(struct request *rq)
 {
-	struct request_queue *q = rq->q;
-	struct deadline_data *dd = q->elevator->elevator_data;
-	const u8 ioprio_class = dd_rq_ioclass(rq);
-	const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
-	struct dd_per_prio *per_prio = &dd->per_prio[prio];
+	struct dd_per_prio *per_prio = rq->elv.priv[0];
 
 	/*
 	 * The block layer core may call dd_finish_request() without having
 	 * called dd_insert_requests(). Skip requests that bypassed I/O
 	 * scheduling. See also blk_mq_request_bypass_insert().
 	 */
-	if (rq->elv.priv[0])
+	if (per_prio)
 		atomic_inc(&per_prio->stats.completed);
 }
 
 static bool dd_has_work_for_prio(struct dd_per_prio *per_prio)
 {
-	return !list_empty_careful(&per_prio->dispatch) ||
-		!list_empty_careful(&per_prio->fifo_list[DD_READ]) ||
+	return !list_empty_careful(&per_prio->fifo_list[DD_READ]) ||
 		!list_empty_careful(&per_prio->fifo_list[DD_WRITE]);
 }
 
@@ -780,6 +737,9 @@ static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
 	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
 	enum dd_prio prio;
 
+	if (!list_empty_careful(&dd->dispatch))
+		return true;
+
 	for (prio = 0; prio <= DD_PRIO_MAX; prio++)
 		if (dd_has_work_for_prio(&dd->per_prio[prio]))
 			return true;
@@ -842,7 +802,7 @@ STORE_INT(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX);
 #define DD_ATTR(name) \
 	__ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)
 
-static struct elv_fs_entry deadline_attrs[] = {
+static const struct elv_fs_entry deadline_attrs[] = {
 	DD_ATTR(read_expire),
 	DD_ATTR(write_expire),
 	DD_ATTR(writes_starved),
@@ -988,49 +948,39 @@ static int dd_owned_by_driver_show(void *data, struct seq_file *m)
 	return 0;
 }
 
-#define DEADLINE_DISPATCH_ATTR(prio)					\
-static void *deadline_dispatch##prio##_start(struct seq_file *m,	\
-					     loff_t *pos)		\
-	__acquires(&dd->lock)						\
-{									\
-	struct request_queue *q = m->private;				\
-	struct deadline_data *dd = q->elevator->elevator_data;		\
-	struct dd_per_prio *per_prio = &dd->per_prio[prio];		\
-									\
-	spin_lock(&dd->lock);						\
-	return seq_list_start(&per_prio->dispatch, *pos);		\
-}									\
-									\
-static void *deadline_dispatch##prio##_next(struct seq_file *m,		\
-					    void *v, loff_t *pos)	\
-{									\
-	struct request_queue *q = m->private;				\
-	struct deadline_data *dd = q->elevator->elevator_data;		\
-	struct dd_per_prio *per_prio = &dd->per_prio[prio];		\
-									\
-	return seq_list_next(v, &per_prio->dispatch, pos);		\
-}									\
-									\
-static void deadline_dispatch##prio##_stop(struct seq_file *m, void *v)	\
-	__releases(&dd->lock)						\
-{									\
-	struct request_queue *q = m->private;				\
-	struct deadline_data *dd = q->elevator->elevator_data;		\
-									\
-	spin_unlock(&dd->lock);						\
-}									\
-									\
-static const struct seq_operations deadline_dispatch##prio##_seq_ops = { \
-	.start	= deadline_dispatch##prio##_start,			\
-	.next	= deadline_dispatch##prio##_next,			\
-	.stop	= deadline_dispatch##prio##_stop,			\
-	.show	= blk_mq_debugfs_rq_show,				\
+static void *deadline_dispatch_start(struct seq_file *m, loff_t *pos)
+	__acquires(&dd->lock)
+{
+	struct request_queue *q = m->private;
+	struct deadline_data *dd = q->elevator->elevator_data;
+
+	spin_lock(&dd->lock);
+	return seq_list_start(&dd->dispatch, *pos);
+}
+
+static void *deadline_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct request_queue *q = m->private;
+	struct deadline_data *dd = q->elevator->elevator_data;
+
+	return seq_list_next(v, &dd->dispatch, pos);
 }
 
-DEADLINE_DISPATCH_ATTR(0);
-DEADLINE_DISPATCH_ATTR(1);
-DEADLINE_DISPATCH_ATTR(2);
-#undef DEADLINE_DISPATCH_ATTR
+static void deadline_dispatch_stop(struct seq_file *m, void *v)
+	__releases(&dd->lock)
+{
+	struct request_queue *q = m->private;
+	struct deadline_data *dd = q->elevator->elevator_data;
+
+	spin_unlock(&dd->lock);
+}
+
+static const struct seq_operations deadline_dispatch_seq_ops = {
+	.start	= deadline_dispatch_start,
+	.next	= deadline_dispatch_next,
+	.stop	= deadline_dispatch_stop,
+	.show	= blk_mq_debugfs_rq_show,
+};
 
 #define DEADLINE_QUEUE_DDIR_ATTRS(name)					\
 	{#name "_fifo_list", 0400,					\
@@ -1053,9 +1003,7 @@ static const struct blk_mq_debugfs_attr deadline_queue_debugfs_attrs[] = {
 	{"batching", 0400, deadline_batching_show},
 	{"starved", 0400, deadline_starved_show},
 	{"async_depth", 0400, dd_async_depth_show},
-	{"dispatch0", 0400, .seq_ops = &deadline_dispatch0_seq_ops},
-	{"dispatch1", 0400, .seq_ops = &deadline_dispatch1_seq_ops},
-	{"dispatch2", 0400, .seq_ops = &deadline_dispatch2_seq_ops},
+	{"dispatch", 0400, .seq_ops = &deadline_dispatch_seq_ops},
 	{"owned_by_driver", 0400, dd_owned_by_driver_show},
 	{"queued", 0400, dd_queued_show},
 	{},
@@ -1080,7 +1028,6 @@ static struct elevator_type mq_deadline = {
 		.has_work		= dd_has_work,
 		.init_sched		= dd_init_sched,
 		.exit_sched		= dd_exit_sched,
-		.init_hctx		= dd_init_hctx,
 	},
 
 #ifdef CONFIG_BLK_DEBUG_FS