[PATCH RFC v4 0/8] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs

[PATCH RFC v4 0/8] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs

[Hannes Reinecke]

Hi all,

here now is an updated version of the v2 patchset from John Garry,
including the suggestions and reviews from the mailing list.
John, apologies for hijacking your work :-)

The main diffence is that I've changed the bitmaps to be allocated
separately in all cases, and just set the pointer to the shared bitmap
for the hostwide tags case.
I've also modified smartpqi and hpsa to take advantage of host_tags.

I did audit the iterators, and I _think_ they do the correct thing even
in the shared bitmap case. But then I might have overlooked things,
so feedback and reviews are welcome.

The one thing I'm not happy with is the debugfs interface; for shared
bitmaps all will be displaying essentially the same information, which
could be moved to a top-level directory. But that would change the
layout and I'm not sure if that buys us anything.

Differences to v3:
- Include reviews from Ming Lei

Differences to v2:
- Drop embedded tag bitmaps
- Do not share scheduling tags
- Add patches for hpsa and smartpqi

Differences to v1:
- Use a shared sbitmap, and not a separate shared tags (a big change!)
	- Drop request.shared_tag
- Add RB tags

Hannes Reinecke (4):
  blk-mq: Use a pointer for sbitmap
  scsi: Add template flag 'host_tagset'
  smartpqi: enable host tagset
  hpsa: switch to using blk-mq

John Garry (3):
  blk-mq: Remove some unused function arguments
  blk-mq: Facilitate a shared sbitmap per tagset
  scsi: hisi_sas: Switch v3 hw to MQ

Ming Lei (1):
  blk-mq: rename BLK_MQ_F_TAG_SHARED as BLK_MQ_F_TAG_QUEUE_SHARED

 block/bfq-iosched.c                    |   4 +-
 block/blk-mq-debugfs.c                 |  10 +--
 block/blk-mq-sched.c                   |   7 +-
 block/blk-mq-tag.c                     | 119 +++++++++++++++++++++++----------
 block/blk-mq-tag.h                     |  25 ++++---
 block/blk-mq.c                         | 102 ++++++++++++++++++----------
 block/blk-mq.h                         |  12 +++-
 block/kyber-iosched.c                  |   4 +-
 drivers/scsi/hisi_sas/hisi_sas.h       |   3 +-
 drivers/scsi/hisi_sas/hisi_sas_main.c  |  36 +++++-----
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c |  86 ++++++++++--------------
 drivers/scsi/hpsa.c                    |  44 ++----------
 drivers/scsi/hpsa.h                    |   1 -
 drivers/scsi/scsi_lib.c                |   2 +
 drivers/scsi/smartpqi/smartpqi_init.c  |  38 ++++++++---
 include/linux/blk-mq.h                 |   6 +-
 include/scsi/scsi_host.h               |   3 +
 17 files changed, 289 insertions(+), 213 deletions(-)

-- 
2.16.4

[PATCH 1/8] blk-mq: Remove some unused function arguments

[Hannes Reinecke]

From: John Garry <john.garry@huawei.com>

The struct blk_mq_hw_ctx * argument in blk_mq_put_tag(),
blk_mq_poll_nsecs(), and blk_mq_poll_hybrid_sleep() is unused, so remove
it.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Garry <john.garry@huawei.com>
---
 block/blk-mq-tag.c |  4 ++--
 block/blk-mq-tag.h |  4 ++--
 block/blk-mq.c     | 10 ++++------
 block/blk-mq.h     |  2 +-
 4 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 008388e82b5c..53b4a9414fbd 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -191,8 +191,8 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
 	return tag + tag_offset;
 }
 
-void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
-		    struct blk_mq_ctx *ctx, unsigned int tag)
+void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
+		    unsigned int tag)
 {
 	if (!blk_mq_tag_is_reserved(tags, tag)) {
 		const int real_tag = tag - tags->nr_reserved_tags;
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 61deab0b5a5a..66d04dea0bdb 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -26,8 +26,8 @@ extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int r
 extern void blk_mq_free_tags(struct blk_mq_tags *tags);
 
 extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
-extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
-			   struct blk_mq_ctx *ctx, unsigned int tag);
+extern void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
+				unsigned int tag);
 extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
 extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
 					struct blk_mq_tags **tags,
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6e3b15f70cd7..16aa20d23b67 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -499,9 +499,9 @@ static void __blk_mq_free_request(struct request *rq)
 	blk_pm_mark_last_busy(rq);
 	rq->mq_hctx = NULL;
 	if (rq->tag != -1)
-		blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
+		blk_mq_put_tag(hctx->tags, ctx, rq->tag);
 	if (sched_tag != -1)
-		blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag);
+		blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
 	blk_mq_sched_restart(hctx);
 	blk_queue_exit(q);
 }
@@ -3354,7 +3354,6 @@ static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
 }
 
 static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
-				       struct blk_mq_hw_ctx *hctx,
 				       struct request *rq)
 {
 	unsigned long ret = 0;
@@ -3387,7 +3386,6 @@ static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
 }
 
 static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
-				     struct blk_mq_hw_ctx *hctx,
 				     struct request *rq)
 {
 	struct hrtimer_sleeper hs;
@@ -3407,7 +3405,7 @@ static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
 	if (q->poll_nsec > 0)
 		nsecs = q->poll_nsec;
 	else
-		nsecs = blk_mq_poll_nsecs(q, hctx, rq);
+		nsecs = blk_mq_poll_nsecs(q, rq);
 
 	if (!nsecs)
 		return false;
@@ -3462,7 +3460,7 @@ static bool blk_mq_poll_hybrid(struct request_queue *q,
 			return false;
 	}
 
-	return blk_mq_poll_hybrid_sleep(q, hctx, rq);
+	return blk_mq_poll_hybrid_sleep(q, rq);
 }
 
 /**
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 32c62c64e6c2..78d38b5f2793 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -208,7 +208,7 @@ static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
 static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
 					   struct request *rq)
 {
-	blk_mq_put_tag(hctx, hctx->tags, rq->mq_ctx, rq->tag);
+	blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
 	rq->tag = -1;
 
 	if (rq->rq_flags & RQF_MQ_INFLIGHT) {
-- 
2.16.4

[PATCH 2/8] blk-mq: rename BLK_MQ_F_TAG_SHARED as BLK_MQ_F_TAG_QUEUE_SHARED

[Hannes Reinecke]

From: Ming Lei <ming.lei@redhat.com>

BLK_MQ_F_TAG_SHARED actually means that tags is shared among request
queues, all of which should belong to LUNs attached to same HBA.

So rename it to make the point explicitly.

Suggested-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
 block/blk-mq-debugfs.c |  2 +-
 block/blk-mq-tag.c     |  2 +-
 block/blk-mq-tag.h     |  4 ++--
 block/blk-mq.c         | 20 ++++++++++----------
 include/linux/blk-mq.h |  2 +-
 5 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index b3f2ba483992..33a40ae1d60f 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -236,7 +236,7 @@ static const char *const alloc_policy_name[] = {
 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 static const char *const hctx_flag_name[] = {
 	HCTX_FLAG_NAME(SHOULD_MERGE),
-	HCTX_FLAG_NAME(TAG_SHARED),
+	HCTX_FLAG_NAME(TAG_QUEUE_SHARED),
 	HCTX_FLAG_NAME(BLOCKING),
 	HCTX_FLAG_NAME(NO_SCHED),
 };
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 53b4a9414fbd..d7aa23c82dbf 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -73,7 +73,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
 {
 	unsigned int depth, users;
 
-	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
+	if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
 		return true;
 	if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
 		return true;
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 66d04dea0bdb..6c0f7c9ce9f6 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -55,7 +55,7 @@ extern void __blk_mq_tag_idle(struct blk_mq_hw_ctx *);
 
 static inline bool blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
 {
-	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
+	if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
 		return false;
 
 	return __blk_mq_tag_busy(hctx);
@@ -63,7 +63,7 @@ static inline bool blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
 
 static inline void blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
 {
-	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
+	if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
 		return;
 
 	__blk_mq_tag_idle(hctx);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 16aa20d23b67..6b39cf0efdcd 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -302,7 +302,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 		rq->tag = -1;
 		rq->internal_tag = tag;
 	} else {
-		if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) {
+		if (data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) {
 			rq_flags = RQF_MQ_INFLIGHT;
 			atomic_inc(&data->hctx->nr_active);
 		}
@@ -1118,7 +1118,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
 	wait_queue_entry_t *wait;
 	bool ret;
 
-	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED)) {
+	if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
 		blk_mq_sched_mark_restart_hctx(hctx);
 
 		/*
@@ -1249,7 +1249,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 				 * For non-shared tags, the RESTART check
 				 * will suffice.
 				 */
-				if (hctx->flags & BLK_MQ_F_TAG_SHARED)
+				if (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
 					no_tag = true;
 				break;
 			}
@@ -2358,7 +2358,7 @@ blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
 	spin_lock_init(&hctx->lock);
 	INIT_LIST_HEAD(&hctx->dispatch);
 	hctx->queue = q;
-	hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
+	hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
 
 	INIT_LIST_HEAD(&hctx->hctx_list);
 
@@ -2575,9 +2575,9 @@ static void queue_set_hctx_shared(struct request_queue *q, bool shared)
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (shared)
-			hctx->flags |= BLK_MQ_F_TAG_SHARED;
+			hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
 		else
-			hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
+			hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
 	}
 }
 
@@ -2603,7 +2603,7 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q)
 	list_del_rcu(&q->tag_set_list);
 	if (list_is_singular(&set->tag_list)) {
 		/* just transitioned to unshared */
-		set->flags &= ~BLK_MQ_F_TAG_SHARED;
+		set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
 		/* update existing queue */
 		blk_mq_update_tag_set_depth(set, false);
 	}
@@ -2620,12 +2620,12 @@ static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
 	 * Check to see if we're transitioning to shared (from 1 to 2 queues).
 	 */
 	if (!list_empty(&set->tag_list) &&
-	    !(set->flags & BLK_MQ_F_TAG_SHARED)) {
-		set->flags |= BLK_MQ_F_TAG_SHARED;
+	    !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
+		set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
 		/* update existing queue */
 		blk_mq_update_tag_set_depth(set, true);
 	}
-	if (set->flags & BLK_MQ_F_TAG_SHARED)
+	if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
 		queue_set_hctx_shared(q, true);
 	list_add_tail_rcu(&q->tag_set_list, &set->tag_list);
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0bf056de5cc3..147185394a25 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -225,7 +225,7 @@ struct blk_mq_ops {
 
 enum {
 	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
-	BLK_MQ_F_TAG_SHARED	= 1 << 1,
+	BLK_MQ_F_TAG_QUEUE_SHARED	= 1 << 1,
 	BLK_MQ_F_BLOCKING	= 1 << 5,
 	BLK_MQ_F_NO_SCHED	= 1 << 6,
 	BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
-- 
2.16.4

[PATCH 3/8] blk-mq: Use a pointer for sbitmap

[Hannes Reinecke]

Instead of allocating the tag bitmap in place we should be using a
pointer. This is in preparation for shared host-wide bitmaps.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 block/bfq-iosched.c    |  4 +--
 block/blk-mq-debugfs.c |  8 +++---
 block/blk-mq-tag.c     | 68 +++++++++++++++++++++++++++++++-------------------
 block/blk-mq-tag.h     |  4 +--
 block/blk-mq.c         |  5 ++--
 block/kyber-iosched.c  |  4 +--
 6 files changed, 54 insertions(+), 39 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0319d6339822..ca89d0c34994 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -6327,8 +6327,8 @@ static void bfq_depth_updated(struct blk_mq_hw_ctx *hctx)
 	struct blk_mq_tags *tags = hctx->sched_tags;
 	unsigned int min_shallow;
 
-	min_shallow = bfq_update_depths(bfqd, &tags->bitmap_tags);
-	sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, min_shallow);
+	min_shallow = bfq_update_depths(bfqd, tags->bitmap_tags);
+	sbitmap_queue_min_shallow_depth(tags->bitmap_tags, min_shallow);
 }
 
 static int bfq_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int index)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 33a40ae1d60f..fca87470e267 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -449,11 +449,11 @@ static void blk_mq_debugfs_tags_show(struct seq_file *m,
 		   atomic_read(&tags->active_queues));
 
 	seq_puts(m, "\nbitmap_tags:\n");
-	sbitmap_queue_show(&tags->bitmap_tags, m);
+	sbitmap_queue_show(tags->bitmap_tags, m);
 
 	if (tags->nr_reserved_tags) {
 		seq_puts(m, "\nbreserved_tags:\n");
-		sbitmap_queue_show(&tags->breserved_tags, m);
+		sbitmap_queue_show(tags->breserved_tags, m);
 	}
 }
 
@@ -484,7 +484,7 @@ static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 	if (res)
 		goto out;
 	if (hctx->tags)
-		sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
+		sbitmap_bitmap_show(&hctx->tags->bitmap_tags->sb, m);
 	mutex_unlock(&q->sysfs_lock);
 
 out:
@@ -518,7 +518,7 @@ static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 	if (res)
 		goto out;
 	if (hctx->sched_tags)
-		sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
+		sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags->sb, m);
 	mutex_unlock(&q->sysfs_lock);
 
 out:
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d7aa23c82dbf..332d71cd3976 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -20,7 +20,7 @@ bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
 	if (!tags)
 		return true;
 
-	return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
+	return sbitmap_any_bit_clear(&tags->bitmap_tags->sb);
 }
 
 /*
@@ -43,9 +43,9 @@ bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
  */
 void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
 {
-	sbitmap_queue_wake_all(&tags->bitmap_tags);
+	sbitmap_queue_wake_all(tags->bitmap_tags);
 	if (include_reserve)
-		sbitmap_queue_wake_all(&tags->breserved_tags);
+		sbitmap_queue_wake_all(tags->breserved_tags);
 }
 
 /*
@@ -121,10 +121,10 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
 			WARN_ON_ONCE(1);
 			return BLK_MQ_TAG_FAIL;
 		}
-		bt = &tags->breserved_tags;
+		bt = tags->breserved_tags;
 		tag_offset = 0;
 	} else {
-		bt = &tags->bitmap_tags;
+		bt = tags->bitmap_tags;
 		tag_offset = tags->nr_reserved_tags;
 	}
 
@@ -170,9 +170,9 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
 						data->ctx);
 		tags = blk_mq_tags_from_data(data);
 		if (data->flags & BLK_MQ_REQ_RESERVED)
-			bt = &tags->breserved_tags;
+			bt = tags->breserved_tags;
 		else
-			bt = &tags->bitmap_tags;
+			bt = tags->bitmap_tags;
 
 		/*
 		 * If destination hw queue is changed, fake wake up on
@@ -198,10 +198,10 @@ void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
 		const int real_tag = tag - tags->nr_reserved_tags;
 
 		BUG_ON(real_tag >= tags->nr_tags);
-		sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
+		sbitmap_queue_clear(tags->bitmap_tags, real_tag, ctx->cpu);
 	} else {
 		BUG_ON(tag >= tags->nr_reserved_tags);
-		sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
+		sbitmap_queue_clear(tags->breserved_tags, tag, ctx->cpu);
 	}
 }
 
@@ -329,8 +329,8 @@ static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
 		busy_tag_iter_fn *fn, void *priv)
 {
 	if (tags->nr_reserved_tags)
-		bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
-	bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
+		bt_tags_for_each(tags, tags->breserved_tags, fn, priv, true);
+	bt_tags_for_each(tags, tags->bitmap_tags, fn, priv, false);
 }
 
 /**
@@ -427,8 +427,8 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 			continue;
 
 		if (tags->nr_reserved_tags)
-			bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
-		bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
+			bt_for_each(hctx, tags->breserved_tags, fn, priv, true);
+		bt_for_each(hctx, tags->bitmap_tags, fn, priv, false);
 	}
 	blk_queue_exit(q);
 }
@@ -440,24 +440,34 @@ static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
 				       node);
 }
 
-static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
-						   int node, int alloc_policy)
+static int blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
+				   int node, int alloc_policy)
 {
 	unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
 	bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
 
-	if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node))
+	tags->bitmap_tags = kzalloc(sizeof(struct sbitmap_queue), GFP_KERNEL);
+	if (!tags->bitmap_tags)
+		return -ENOMEM;
+	if (bt_alloc(tags->bitmap_tags, depth, round_robin, node))
 		goto free_tags;
-	if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin,
-		     node))
+
+	tags->breserved_tags = kzalloc(sizeof(struct sbitmap_queue),
+				       GFP_KERNEL);
+	if (!tags->breserved_tags)
 		goto free_bitmap_tags;
+	if (bt_alloc(tags->breserved_tags, tags->nr_reserved_tags,
+		     round_robin, node))
+		goto free_reserved_tags;
 
-	return tags;
+	return 0;
+free_reserved_tags:
+	kfree(tags->breserved_tags);
 free_bitmap_tags:
-	sbitmap_queue_free(&tags->bitmap_tags);
+	sbitmap_queue_free(tags->bitmap_tags);
 free_tags:
-	kfree(tags);
-	return NULL;
+	kfree(tags->bitmap_tags);
+	return -ENOMEM;
 }
 
 struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
@@ -478,13 +488,19 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
 	tags->nr_tags = total_tags;
 	tags->nr_reserved_tags = reserved_tags;
 
-	return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
+	if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
+		kfree(tags);
+		tags = NULL;
+	}
+	return tags;
 }
 
 void blk_mq_free_tags(struct blk_mq_tags *tags)
 {
-	sbitmap_queue_free(&tags->bitmap_tags);
-	sbitmap_queue_free(&tags->breserved_tags);
+	sbitmap_queue_free(tags->bitmap_tags);
+	kfree(tags->bitmap_tags);
+	sbitmap_queue_free(tags->breserved_tags);
+	kfree(tags->breserved_tags);
 	kfree(tags);
 }
 
@@ -534,7 +550,7 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
 		 * Don't need (or can't) update reserved tags here, they
 		 * remain static and should never need resizing.
 		 */
-		sbitmap_queue_resize(&tags->bitmap_tags,
+		sbitmap_queue_resize(tags->bitmap_tags,
 				tdepth - tags->nr_reserved_tags);
 	}
 
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 6c0f7c9ce9f6..10b66fd4664a 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -13,8 +13,8 @@ struct blk_mq_tags {
 
 	atomic_t active_queues;
 
-	struct sbitmap_queue bitmap_tags;
-	struct sbitmap_queue breserved_tags;
+	struct sbitmap_queue *bitmap_tags;
+	struct sbitmap_queue *breserved_tags;
 
 	struct request **rqs;
 	struct request **static_rqs;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6b39cf0efdcd..f0c40fcbd8ae 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1095,7 +1095,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
 		struct sbitmap_queue *sbq;
 
 		list_del_init(&wait->entry);
-		sbq = &hctx->tags->bitmap_tags;
+		sbq = hctx->tags->bitmap_tags;
 		atomic_dec(&sbq->ws_active);
 	}
 	spin_unlock(&hctx->dispatch_wait_lock);
@@ -1113,7 +1113,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
 				 struct request *rq)
 {
-	struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags;
+	struct sbitmap_queue *sbq = hctx->tags->bitmap_tags;
 	struct wait_queue_head *wq;
 	wait_queue_entry_t *wait;
 	bool ret;
@@ -2081,7 +2081,6 @@ void blk_mq_free_rq_map(struct blk_mq_tags *tags)
 	tags->rqs = NULL;
 	kfree(tags->static_rqs);
 	tags->static_rqs = NULL;
-
 	blk_mq_free_tags(tags);
 }
 
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 34dcea0ef637..a7a537501d70 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -359,7 +359,7 @@ static unsigned int kyber_sched_tags_shift(struct request_queue *q)
 	 * All of the hardware queues have the same depth, so we can just grab
 	 * the shift of the first one.
 	 */
-	return q->queue_hw_ctx[0]->sched_tags->bitmap_tags.sb.shift;
+	return q->queue_hw_ctx[0]->sched_tags->bitmap_tags->sb.shift;
 }
 
 static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q)
@@ -502,7 +502,7 @@ static int kyber_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
 	khd->batching = 0;
 
 	hctx->sched_data = khd;
-	sbitmap_queue_min_shallow_depth(&hctx->sched_tags->bitmap_tags,
+	sbitmap_queue_min_shallow_depth(hctx->sched_tags->bitmap_tags,
 					kqd->async_depth);
 
 	return 0;
-- 
2.16.4

[PATCH 4/8] blk-mq: Facilitate a shared sbitmap per tagset

[Hannes Reinecke]

From: John Garry <john.garry@huawei.com>

Some SCSI HBAs (such as HPSA, megaraid, mpt3sas, hisi_sas_v3 ..) support
multiple reply queues with single hostwide tags.

In addition, these drivers want to use interrupt assignment in
pci_alloc_irq_vectors(PCI_IRQ_AFFINITY). However, as discussed in [0],
CPU hotplug may cause in-flight IO completion to not be serviced when an
interrupt is shutdown.

To solve that problem, Ming's patchset to drain hctx's should ensure no
IOs are missed in-flight [1].

However, to take advantage of that patchset, we need to map the HBA HW
queues to blk mq hctx's; to do that, we need to expose the HBA HW queues.

In making that transition, the per-SCSI command request tags are no
longer unique per Scsi host - they are just unique per hctx. As such, the
HBA LLDD would have to generate this tag internally, which has a certain
performance overhead.

However another problem is that blk mq assumes the host may accept
(Scsi_host.can_queue * #hw queue) commands. In [2], we removed the Scsi
host busy counter, which would stop the LLDD being sent more than
.can_queue commands; however, we should still ensure that the block layer
does not issue more than .can_queue commands to the Scsi host.

To solve this problem, introduce a shared sbitmap per blk_mq_tag_set,
which may be requested at init time.

New flag BLK_MQ_F_TAG_HCTX_SHARED should be set when requesting the
tagset to indicate whether the shared sbitmap should be used.

Even when BLK_MQ_F_TAG_HCTX_SHARED is set, we still allocate a full set of
tags and requests per hctx; the reason for this is that if we only allocate
tags and requests for a single hctx - like hctx0 - we may break block
drivers which expect a request be associated with a specific hctx, i.e.
not hctx0.

This is based on work originally from Ming Lei in [3] and from Bart's
suggestion in [4].

[0] https://lore.kernel.org/linux-block/alpine.DEB.2.21.1904051331270.1802@nanos.tec.linutronix.de/
[1] https://lore.kernel.org/linux-block/20191014015043.25029-1-ming.lei@redhat.com/
[2] https://lore.kernel.org/linux-scsi/20191025065855.6309-1-ming.lei@redhat.com/
[3] https://lore.kernel.org/linux-block/20190531022801.10003-1-ming.lei@redhat.com/
[4] https://lore.kernel.org/linux-block/ff77beff-5fd9-9f05-12b6-826922bace1f@huawei.com/T/#m3db0a602f095cbcbff27e9c884d6b4ae826144be

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-mq-sched.c   |  7 +++---
 block/blk-mq-tag.c     | 51 ++++++++++++++++++++++++++++++--------
 block/blk-mq-tag.h     | 13 +++++++---
 block/blk-mq.c         | 67 ++++++++++++++++++++++++++++++++++++++------------
 block/blk-mq.h         | 10 ++++++--
 include/linux/blk-mq.h |  4 +++
 6 files changed, 118 insertions(+), 34 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index ca22afd47b3d..df6dbbb9578e 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -452,7 +452,7 @@ static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
 {
 	if (hctx->sched_tags) {
 		blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
-		blk_mq_free_rq_map(hctx->sched_tags);
+		blk_mq_free_rq_map(hctx->sched_tags, false);
 		hctx->sched_tags = NULL;
 	}
 }
@@ -464,8 +464,9 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q,
 	struct blk_mq_tag_set *set = q->tag_set;
 	int ret;
 
+	/* Scheduler tags are never shared */
 	hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
-					       set->reserved_tags);
+					       set->reserved_tags, false);
 	if (!hctx->sched_tags)
 		return -ENOMEM;
 
@@ -484,7 +485,7 @@ static void blk_mq_sched_tags_teardown(struct request_queue *q)
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (hctx->sched_tags) {
-			blk_mq_free_rq_map(hctx->sched_tags);
+			blk_mq_free_rq_map(hctx->sched_tags, false);
 			hctx->sched_tags = NULL;
 		}
 	}
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 332d71cd3976..e646fe6b8c3d 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -228,7 +228,7 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
 	 * We can hit rq == NULL here, because the tagging functions
 	 * test and set the bit before assigning ->rqs[].
 	 */
-	if (rq && rq->q == hctx->queue)
+	if (rq && rq->q == hctx->queue && rq->mq_hctx == hctx)
 		return iter_data->fn(hctx, rq, iter_data->data, reserved);
 	return true;
 }
@@ -470,9 +470,38 @@ static int blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
 	return -ENOMEM;
 }
 
-struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
+bool blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *tag_set)
+{
+	unsigned int depth = tag_set->queue_depth -tag_set->reserved_tags;
+	int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(tag_set->flags);
+	bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
+	int node = tag_set->numa_node;
+
+	if (bt_alloc(&tag_set->shared_bitmap_tags, depth, round_robin, node))
+		return false;
+	if (bt_alloc(&tag_set->shared_breserved_tags, tag_set->reserved_tags,
+		     round_robin, node))
+		goto free_bitmap_tags;
+
+	return true;
+free_bitmap_tags:
+	sbitmap_queue_free(&tag_set->shared_bitmap_tags);
+	return false;
+}
+
+void blk_mq_exit_shared_sbitmap(struct blk_mq_tag_set *tag_set)
+{
+	if (blk_mq_is_sbitmap_shared(tag_set)) {
+		sbitmap_queue_free(&tag_set->shared_bitmap_tags);
+		sbitmap_queue_free(&tag_set->shared_breserved_tags);
+	}
+}
+
+struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set,
+				     unsigned int total_tags,
 				     unsigned int reserved_tags,
-				     int node, int alloc_policy)
+				     int node, int alloc_policy,
+				     bool shared_tags)
 {
 	struct blk_mq_tags *tags;
 
@@ -488,9 +517,11 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
 	tags->nr_tags = total_tags;
 	tags->nr_reserved_tags = reserved_tags;
 
-	if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
-		kfree(tags);
-		tags = NULL;
+	if (shared_tags) {
+		if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
+			kfree(tags);
+			tags = NULL;
+		}
 	}
 	return tags;
 }
@@ -506,7 +537,7 @@ void blk_mq_free_tags(struct blk_mq_tags *tags)
 
 int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
 			    struct blk_mq_tags **tagsptr, unsigned int tdepth,
-			    bool can_grow)
+			    bool can_grow, bool shared_tags)
 {
 	struct blk_mq_tags *tags = *tagsptr;
 
@@ -533,17 +564,17 @@ int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
 			return -EINVAL;
 
 		new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth,
-				tags->nr_reserved_tags);
+				tags->nr_reserved_tags, shared_tags);
 		if (!new)
 			return -ENOMEM;
 		ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
 		if (ret) {
-			blk_mq_free_rq_map(new);
+			blk_mq_free_rq_map(new, shared_tags);
 			return -ENOMEM;
 		}
 
 		blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
-		blk_mq_free_rq_map(*tagsptr);
+		blk_mq_free_rq_map(*tagsptr, shared_tags);
 		*tagsptr = new;
 	} else {
 		/*
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 10b66fd4664a..3b0ece3c594c 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -22,7 +22,13 @@ struct blk_mq_tags {
 };
 
 
-extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node, int alloc_policy);
+extern bool blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *tag_set);
+extern void blk_mq_exit_shared_sbitmap(struct blk_mq_tag_set *tag_set);
+extern struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *tag_set,
+					    unsigned int nr_tags,
+					    unsigned int reserved_tags,
+					    int node, int alloc_policy,
+					    bool shared_tags);
 extern void blk_mq_free_tags(struct blk_mq_tags *tags);
 
 extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
@@ -30,8 +36,9 @@ extern void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
 				unsigned int tag);
 extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
 extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
-					struct blk_mq_tags **tags,
-					unsigned int depth, bool can_grow);
+				   struct blk_mq_tags **tags,
+				   unsigned int depth, bool can_grow,
+				   bool shared_tags);
 extern void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);
 void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 		void *priv);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f0c40fcbd8ae..3c93a070d3bb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2075,19 +2075,21 @@ void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
 	}
 }
 
-void blk_mq_free_rq_map(struct blk_mq_tags *tags)
+void blk_mq_free_rq_map(struct blk_mq_tags *tags, bool shared)
 {
 	kfree(tags->rqs);
 	tags->rqs = NULL;
 	kfree(tags->static_rqs);
 	tags->static_rqs = NULL;
-	blk_mq_free_tags(tags);
+	if (!shared)
+		blk_mq_free_tags(tags);
 }
 
 struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 					unsigned int hctx_idx,
 					unsigned int nr_tags,
-					unsigned int reserved_tags)
+					unsigned int reserved_tags,
+					bool shared_tags)
 {
 	struct blk_mq_tags *tags;
 	int node;
@@ -2096,8 +2098,9 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 	if (node == NUMA_NO_NODE)
 		node = set->numa_node;
 
-	tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
-				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
+	tags = blk_mq_init_tags(set, nr_tags, reserved_tags, node,
+				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags),
+				shared_tags);
 	if (!tags)
 		return NULL;
 
@@ -2105,7 +2108,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 				 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
 				 node);
 	if (!tags->rqs) {
-		blk_mq_free_tags(tags);
+		if (!blk_mq_is_sbitmap_shared(set))
+			blk_mq_free_tags(tags);
 		return NULL;
 	}
 
@@ -2114,7 +2118,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 					node);
 	if (!tags->static_rqs) {
 		kfree(tags->rqs);
-		blk_mq_free_tags(tags);
+		if (!blk_mq_is_sbitmap_shared(set))
+			blk_mq_free_tags(tags);
 		return NULL;
 	}
 
@@ -2435,9 +2440,10 @@ static void blk_mq_init_cpu_queues(struct request_queue *q,
 static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx)
 {
 	int ret = 0;
+	bool shared = blk_mq_is_sbitmap_shared(set);
 
 	set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
-					set->queue_depth, set->reserved_tags);
+				set->queue_depth, set->reserved_tags, shared);
 	if (!set->tags[hctx_idx])
 		return false;
 
@@ -2446,7 +2452,7 @@ static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx)
 	if (!ret)
 		return true;
 
-	blk_mq_free_rq_map(set->tags[hctx_idx]);
+	blk_mq_free_rq_map(set->tags[hctx_idx], shared);
 	set->tags[hctx_idx] = NULL;
 	return false;
 }
@@ -2456,7 +2462,8 @@ static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
 {
 	if (set->tags && set->tags[hctx_idx]) {
 		blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx);
-		blk_mq_free_rq_map(set->tags[hctx_idx]);
+		blk_mq_free_rq_map(set->tags[hctx_idx],
+				   blk_mq_is_sbitmap_shared(set));
 		set->tags[hctx_idx] = NULL;
 	}
 }
@@ -2954,7 +2961,7 @@ static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
 
 out_unwind:
 	while (--i >= 0)
-		blk_mq_free_rq_map(set->tags[i]);
+		blk_mq_free_rq_map(set->tags[i], blk_mq_is_sbitmap_shared(set));
 
 	return -ENOMEM;
 }
@@ -3099,11 +3106,28 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 	if (ret)
 		goto out_free_mq_map;
 
+	if (blk_mq_is_sbitmap_shared(set)) {
+		if (!blk_mq_init_shared_sbitmap(set)) {
+			ret = -ENOMEM;
+			goto out_free_rq_map;
+		}
+
+		for (i = 0; i < set->nr_hw_queues; i++) {
+			struct blk_mq_tags *tags = set->tags[i];
+
+			tags->bitmap_tags = &set->shared_bitmap_tags;
+			tags->breserved_tags = &set->shared_breserved_tags;
+		}
+	}
+
 	mutex_init(&set->tag_list_lock);
 	INIT_LIST_HEAD(&set->tag_list);
 
 	return 0;
 
+out_free_rq_map:
+	for (i = 0; i < nr_hw_queues(set); i++)
+		blk_mq_free_map_and_requests(set, i);
 out_free_mq_map:
 	for (i = 0; i < set->nr_maps; i++) {
 		kfree(set->map[i].mq_map);
@@ -3121,7 +3145,7 @@ void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
 
 	for (i = 0; i < nr_hw_queues(set); i++)
 		blk_mq_free_map_and_requests(set, i);
-
+	blk_mq_exit_shared_sbitmap(set);
 	for (j = 0; j < set->nr_maps; j++) {
 		kfree(set->map[j].mq_map);
 		set->map[j].mq_map = NULL;
@@ -3137,6 +3161,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 	struct blk_mq_tag_set *set = q->tag_set;
 	struct blk_mq_hw_ctx *hctx;
 	int i, ret;
+	bool shared_tags = blk_mq_is_sbitmap_shared(set);
 
 	if (!set)
 		return -EINVAL;
@@ -3156,11 +3181,12 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 		 * queue depth. This is similar to what the old code would do.
 		 */
 		if (!hctx->sched_tags) {
-			ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
-							false);
+			ret = blk_mq_tag_update_depth(hctx, &hctx->tags,
+						      nr, false, shared_tags);
 		} else {
+			shared_tags = false;
 			ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
-							nr, true);
+						      nr, true, shared_tags);
 		}
 		if (ret)
 			break;
@@ -3168,8 +3194,17 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 			q->elevator->type->ops.depth_updated(hctx);
 	}
 
-	if (!ret)
+	if (!ret) {
+		if (shared_tags) {
+			sbitmap_queue_resize(&set->shared_bitmap_tags, nr);
+			sbitmap_queue_resize(&set->shared_breserved_tags, nr);
+		}
 		q->nr_requests = nr;
+	}
+	/*
+	 * if ret != 0, q->nr_requests would not be updated, yet the depth
+	 * for some hctx may have changed - is that right?
+	 */
 
 	blk_mq_unquiesce_queue(q);
 	blk_mq_unfreeze_queue(q);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 78d38b5f2793..2445d5b64e79 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -53,11 +53,12 @@ struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
  */
 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
 		     unsigned int hctx_idx);
-void blk_mq_free_rq_map(struct blk_mq_tags *tags);
+void blk_mq_free_rq_map(struct blk_mq_tags *tags, bool shared);
 struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 					unsigned int hctx_idx,
 					unsigned int nr_tags,
-					unsigned int reserved_tags);
+					unsigned int reserved_tags,
+					bool shared_tags);
 int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
 		     unsigned int hctx_idx, unsigned int depth);
 
@@ -166,6 +167,11 @@ struct blk_mq_alloc_data {
 	struct blk_mq_hw_ctx *hctx;
 };
 
+static inline bool blk_mq_is_sbitmap_shared(struct blk_mq_tag_set *tag_set)
+{
+	return !!(tag_set->flags & BLK_MQ_F_TAG_HCTX_SHARED);
+}
+
 static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
 {
 	if (data->flags & BLK_MQ_REQ_INTERNAL)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 147185394a25..3be5a70d9f6a 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -109,6 +109,9 @@ struct blk_mq_tag_set {
 	unsigned int		flags;		/* BLK_MQ_F_* */
 	void			*driver_data;
 
+	struct sbitmap_queue shared_bitmap_tags;
+	struct sbitmap_queue shared_breserved_tags;
+
 	struct blk_mq_tags	**tags;
 
 	struct mutex		tag_list_lock;
@@ -226,6 +229,7 @@ struct blk_mq_ops {
 enum {
 	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
 	BLK_MQ_F_TAG_QUEUE_SHARED	= 1 << 1,
+	BLK_MQ_F_TAG_HCTX_SHARED	= 1 << 2,
 	BLK_MQ_F_BLOCKING	= 1 << 5,
 	BLK_MQ_F_NO_SCHED	= 1 << 6,
 	BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
-- 
2.16.4

[PATCH 5/8] scsi: Add template flag 'host_tagset'

[Hannes Reinecke]

From: Hannes Reinecke <hare@suse.com>

Add a host template flag 'host_tagset' so hostwide tagset can be
shared on multiple reply queues after the SCSI device's reply queue
is converted to blk-mq hw queue.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
 drivers/scsi/scsi_lib.c  | 2 ++
 include/scsi/scsi_host.h | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2563b061f56b..d7ad7b99bc05 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1899,6 +1899,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
 	shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
 	shost->tag_set.flags |=
 		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
+	if (shost->hostt->host_tagset)
+		shost->tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED;
 	shost->tag_set.driver_data = shost;
 
 	return blk_mq_alloc_tag_set(&shost->tag_set);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index f577647bf5f2..4fd0af0883dd 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -429,6 +429,9 @@ struct scsi_host_template {
 	/* True if the low-level driver supports blk-mq only */
 	unsigned force_blk_mq:1;
 
+	/* True if the host uses host-wide tagspace */
+	unsigned host_tagset:1;
+
 	/*
 	 * Countdown for host blocking with no commands outstanding.
 	 */
-- 
2.16.4

[PATCH 6/8] scsi: hisi_sas: Switch v3 hw to MQ

[Hannes Reinecke]

From: John Garry <john.garry@huawei.com>

Now that the block layer provides a shared tag, we can switch the driver
to expose all HW queues.

Signed-off-by: John Garry <john.garry@huawei.com>
---
 drivers/scsi/hisi_sas/hisi_sas.h       |  3 +-
 drivers/scsi/hisi_sas/hisi_sas_main.c  | 36 +++++++-------
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 86 ++++++++++++++--------------------
 3 files changed, 56 insertions(+), 69 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 233c73e01246..0405602df2a4 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -8,6 +8,8 @@
 #define _HISI_SAS_H_
 
 #include <linux/acpi.h>
+#include <linux/blk-mq.h>
+#include <linux/blk-mq-pci.h>
 #include <linux/clk.h>
 #include <linux/debugfs.h>
 #include <linux/dmapool.h>
@@ -431,7 +433,6 @@ struct hisi_hba {
 	u32 intr_coal_count;	/* Interrupt count to coalesce */
 
 	int cq_nvecs;
-	unsigned int *reply_map;
 
 	/* bist */
 	enum sas_linkrate debugfs_bist_linkrate;
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 03588ec3c394..e185935c3399 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -421,6 +421,7 @@ static int hisi_sas_task_prep(struct sas_task *task,
 	struct device *dev = hisi_hba->dev;
 	int dlvry_queue_slot, dlvry_queue, rc, slot_idx;
 	int n_elem = 0, n_elem_dif = 0, n_elem_req = 0;
+	struct scsi_cmnd *scmd = NULL;
 	struct hisi_sas_dq *dq;
 	unsigned long flags;
 	int wr_q_index;
@@ -436,10 +437,23 @@ static int hisi_sas_task_prep(struct sas_task *task,
 		return -ECOMM;
 	}
 
-	if (hisi_hba->reply_map) {
-		int cpu = raw_smp_processor_id();
-		unsigned int dq_index = hisi_hba->reply_map[cpu];
+	if (task->uldd_task) {
+		struct ata_queued_cmd *qc;
 
+		if (dev_is_sata(device)) {
+			qc = task->uldd_task;
+			scmd = qc->scsicmd;
+		} else {
+			scmd = task->uldd_task;
+		}
+	}
+
+	if (scmd) {
+		unsigned int dq_index;
+		u32 blk_tag;
+
+		blk_tag = blk_mq_unique_tag(scmd->request);
+		dq_index = blk_mq_unique_tag_to_hwq(blk_tag);
 		*dq_pointer = dq = &hisi_hba->dq[dq_index];
 	} else {
 		*dq_pointer = dq = sas_dev->dq;
@@ -468,21 +482,9 @@ static int hisi_sas_task_prep(struct sas_task *task,
 
 	if (hisi_hba->hw->slot_index_alloc)
 		rc = hisi_hba->hw->slot_index_alloc(hisi_hba, device);
-	else {
-		struct scsi_cmnd *scsi_cmnd = NULL;
-
-		if (task->uldd_task) {
-			struct ata_queued_cmd *qc;
+	else
+		rc = hisi_sas_slot_index_alloc(hisi_hba, scmd);
 
-			if (dev_is_sata(device)) {
-				qc = task->uldd_task;
-				scsi_cmnd = qc->scsicmd;
-			} else {
-				scsi_cmnd = task->uldd_task;
-			}
-		}
-		rc  = hisi_sas_slot_index_alloc(hisi_hba, scsi_cmnd);
-	}
 	if (rc < 0)
 		goto err_out_dif_dma_unmap;
 
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index bf5d5f138437..e7b015d88968 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2353,66 +2353,35 @@ static irqreturn_t cq_interrupt_v3_hw(int irq_no, void *p)
 	return IRQ_HANDLED;
 }
 
-static void setup_reply_map_v3_hw(struct hisi_hba *hisi_hba, int nvecs)
+static int interrupt_preinit_v3_hw(struct hisi_hba *hisi_hba)
 {
-	const struct cpumask *mask;
-	int queue, cpu;
-
-	for (queue = 0; queue < nvecs; queue++) {
-		struct hisi_sas_cq *cq = &hisi_hba->cq[queue];
+	int vectors;
+	int max_msi = HISI_SAS_MSI_COUNT_V3_HW, min_msi;
+	struct Scsi_Host *shost = hisi_hba->shost;
+	struct irq_affinity desc = {
+		.pre_vectors = BASE_VECTORS_V3_HW,
+	};
+
+	min_msi = MIN_AFFINE_VECTORS_V3_HW;
+	vectors = pci_alloc_irq_vectors_affinity(hisi_hba->pci_dev,
+						 min_msi, max_msi,
+						 PCI_IRQ_MSI |
+						 PCI_IRQ_AFFINITY,
+						 &desc);
+	if (vectors < 0)
+		return -ENOENT;
 
-		mask = pci_irq_get_affinity(hisi_hba->pci_dev, queue +
-					    BASE_VECTORS_V3_HW);
-		if (!mask)
-			goto fallback;
-		cq->pci_irq_mask = mask;
-		for_each_cpu(cpu, mask)
-			hisi_hba->reply_map[cpu] = queue;
-	}
-	return;
+	hisi_hba->cq_nvecs = vectors - BASE_VECTORS_V3_HW;
+	shost->nr_hw_queues = hisi_hba->cq_nvecs;
 
-fallback:
-	for_each_possible_cpu(cpu)
-		hisi_hba->reply_map[cpu] = cpu % hisi_hba->queue_count;
-	/* Don't clean all CQ masks */
+	return 0;
 }
 
 static int interrupt_init_v3_hw(struct hisi_hba *hisi_hba)
 {
 	struct device *dev = hisi_hba->dev;
 	struct pci_dev *pdev = hisi_hba->pci_dev;
-	int vectors, rc, i;
-	int max_msi = HISI_SAS_MSI_COUNT_V3_HW, min_msi;
-
-	if (auto_affine_msi_experimental) {
-		struct irq_affinity desc = {
-			.pre_vectors = BASE_VECTORS_V3_HW,
-		};
-
-		min_msi = MIN_AFFINE_VECTORS_V3_HW;
-
-		hisi_hba->reply_map = devm_kcalloc(dev, nr_cpu_ids,
-						   sizeof(unsigned int),
-						   GFP_KERNEL);
-		if (!hisi_hba->reply_map)
-			return -ENOMEM;
-		vectors = pci_alloc_irq_vectors_affinity(hisi_hba->pci_dev,
-							 min_msi, max_msi,
-							 PCI_IRQ_MSI |
-							 PCI_IRQ_AFFINITY,
-							 &desc);
-		if (vectors < 0)
-			return -ENOENT;
-		setup_reply_map_v3_hw(hisi_hba, vectors - BASE_VECTORS_V3_HW);
-	} else {
-		min_msi = max_msi;
-		vectors = pci_alloc_irq_vectors(hisi_hba->pci_dev, min_msi,
-						max_msi, PCI_IRQ_MSI);
-		if (vectors < 0)
-			return vectors;
-	}
-
-	hisi_hba->cq_nvecs = vectors - BASE_VECTORS_V3_HW;
+	int rc, i;
 
 	rc = devm_request_irq(dev, pci_irq_vector(pdev, 1),
 			      int_phy_up_down_bcast_v3_hw, 0,
@@ -3057,6 +3026,15 @@ static int debugfs_set_bist_v3_hw(struct hisi_hba *hisi_hba, bool enable)
 	return 0;
 }
 
+static int hisi_sas_map_queues(struct Scsi_Host *shost)
+{
+	struct hisi_hba *hisi_hba = shost_priv(shost);
+	struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
+
+	return blk_mq_pci_map_queues(qmap, hisi_hba->pci_dev,
+					     BASE_VECTORS_V3_HW);
+}
+
 static struct scsi_host_template sht_v3_hw = {
 	.name			= DRV_NAME,
 	.module			= THIS_MODULE,
@@ -3065,6 +3043,7 @@ static struct scsi_host_template sht_v3_hw = {
 	.slave_configure	= hisi_sas_slave_configure,
 	.scan_finished		= hisi_sas_scan_finished,
 	.scan_start		= hisi_sas_scan_start,
+	.map_queues		= hisi_sas_map_queues,
 	.change_queue_depth	= sas_change_queue_depth,
 	.bios_param		= sas_bios_param,
 	.this_id		= -1,
@@ -3078,6 +3057,7 @@ static struct scsi_host_template sht_v3_hw = {
 	.shost_attrs		= host_attrs_v3_hw,
 	.tag_alloc_policy	= BLK_TAG_ALLOC_RR,
 	.host_reset             = hisi_sas_host_reset,
+	.host_tagset		= 1,
 };
 
 static const struct hisi_sas_hw hisi_sas_v3_hw = {
@@ -3249,6 +3229,10 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (hisi_sas_debugfs_enable)
 		hisi_sas_debugfs_init(hisi_hba);
 
+	rc = interrupt_preinit_v3_hw(hisi_hba);
+	if (rc)
+		goto err_out_ha;
+	dev_err(dev, "%d hw qeues\n", shost->nr_hw_queues);
 	rc = scsi_add_host(shost, dev);
 	if (rc)
 		goto err_out_ha;
-- 
2.16.4

[PATCH 7/8] smartpqi: enable host tagset

[Hannes Reinecke]

Enable host tagset for smartpqi; with this we can use the request
tag to look command from the pool avoiding the list iteration in
the hot path.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/smartpqi/smartpqi_init.c | 38 ++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index 7b7ef3acb504..c17b533c84ad 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -575,17 +575,29 @@ static inline void pqi_reinit_io_request(struct pqi_io_request *io_request)
 }
 
 static struct pqi_io_request *pqi_alloc_io_request(
-	struct pqi_ctrl_info *ctrl_info)
+	struct pqi_ctrl_info *ctrl_info, struct scsi_cmnd *scmd)
 {
 	struct pqi_io_request *io_request;
+	unsigned int limit = PQI_RESERVED_IO_SLOTS;
 	u16 i = ctrl_info->next_io_request_slot;	/* benignly racy */
 
-	while (1) {
+	if (scmd) {
+		u32 blk_tag = blk_mq_unique_tag(scmd->request);
+
+		i = blk_mq_unique_tag_to_tag(blk_tag) + limit;
 		io_request = &ctrl_info->io_request_pool[i];
-		if (atomic_inc_return(&io_request->refcount) == 1)
-			break;
-		atomic_dec(&io_request->refcount);
-		i = (i + 1) % ctrl_info->max_io_slots;
+		if (WARN_ON(atomic_inc_return(&io_request->refcount) > 1)) {
+			atomic_dec(&io_request->refcount);
+			return NULL;
+		}
+	} else {
+		while (1) {
+			io_request = &ctrl_info->io_request_pool[i];
+			if (atomic_inc_return(&io_request->refcount) == 1)
+				break;
+			atomic_dec(&io_request->refcount);
+			i = (i + 1) % limit;
+		}
 	}
 
 	/* benignly racy */
@@ -4075,7 +4087,7 @@ static int pqi_submit_raid_request_synchronous(struct pqi_ctrl_info *ctrl_info,
 
 	atomic_inc(&ctrl_info->sync_cmds_outstanding);
 
-	io_request = pqi_alloc_io_request(ctrl_info);
+	io_request = pqi_alloc_io_request(ctrl_info, NULL);
 
 	put_unaligned_le16(io_request->index,
 		&(((struct pqi_raid_path_request *)request)->request_id));
@@ -5032,7 +5044,9 @@ static inline int pqi_raid_submit_scsi_cmd(struct pqi_ctrl_info *ctrl_info,
 {
 	struct pqi_io_request *io_request;
 
-	io_request = pqi_alloc_io_request(ctrl_info);
+	io_request = pqi_alloc_io_request(ctrl_info, scmd);
+	if (!io_request)
+		return SCSI_MLQUEUE_HOST_BUSY;
 
 	return pqi_raid_submit_scsi_cmd_with_io_request(ctrl_info, io_request,
 		device, scmd, queue_group);
@@ -5230,7 +5244,10 @@ static int pqi_aio_submit_io(struct pqi_ctrl_info *ctrl_info,
 	struct pqi_io_request *io_request;
 	struct pqi_aio_path_request *request;
 
-	io_request = pqi_alloc_io_request(ctrl_info);
+	io_request = pqi_alloc_io_request(ctrl_info, scmd);
+	if (!io_request)
+		return SCSI_MLQUEUE_HOST_BUSY;
+
 	io_request->io_complete_callback = pqi_aio_io_complete;
 	io_request->scmd = scmd;
 	io_request->raid_bypass = raid_bypass;
@@ -5657,7 +5674,7 @@ static int pqi_lun_reset(struct pqi_ctrl_info *ctrl_info,
 	DECLARE_COMPLETION_ONSTACK(wait);
 	struct pqi_task_management_request *request;
 
-	io_request = pqi_alloc_io_request(ctrl_info);
+	io_request = pqi_alloc_io_request(ctrl_info, NULL);
 	io_request->io_complete_callback = pqi_lun_reset_complete;
 	io_request->context = &wait;
 
@@ -6504,6 +6521,7 @@ static struct scsi_host_template pqi_driver_template = {
 	.map_queues = pqi_map_queues,
 	.sdev_attrs = pqi_sdev_attrs,
 	.shost_attrs = pqi_shost_attrs,
+	.host_tagset = 1,
 };
 
 static int pqi_register_scsi(struct pqi_ctrl_info *ctrl_info)
-- 
2.16.4

[PATCH 8/8] hpsa: switch to using blk-mq

[Hannes Reinecke]

Enable host_tagset and switch to using blk-mq.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/hpsa.c | 44 +++++++-------------------------------------
 drivers/scsi/hpsa.h |  1 -
 2 files changed, 7 insertions(+), 38 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index ac39ed79ccaa..2b811c981b43 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -974,6 +974,7 @@ static struct scsi_host_template hpsa_driver_template = {
 	.shost_attrs = hpsa_shost_attrs,
 	.max_sectors = 2048,
 	.no_write_same = 1,
+	.host_tagset = 1,
 };
 
 static inline u32 next_command(struct ctlr_info *h, u8 q)
@@ -1138,12 +1139,14 @@ static void dial_up_lockup_detection_on_fw_flash_complete(struct ctlr_info *h,
 static void __enqueue_cmd_and_start_io(struct ctlr_info *h,
 	struct CommandList *c, int reply_queue)
 {
+	u32 blk_tag = blk_mq_unique_tag(c->scsi_cmd->request);
+
 	dial_down_lockup_detection_during_fw_flash(h, c);
 	atomic_inc(&h->commands_outstanding);
 	if (c->device)
 		atomic_inc(&c->device->commands_outstanding);
 
-	reply_queue = h->reply_map[raw_smp_processor_id()];
+	reply_queue = blk_mq_unique_tag_to_hwq(blk_tag);
 	switch (c->cmd_type) {
 	case CMD_IOACCEL1:
 		set_ioaccel1_performant_mode(h, c, reply_queue);
@@ -5628,8 +5631,6 @@ static int hpsa_scsi_queue_command(struct Scsi_Host *sh, struct scsi_cmnd *cmd)
 	/* Get the ptr to our adapter structure out of cmd->host. */
 	h = sdev_to_hba(cmd->device);
 
-	BUG_ON(cmd->request->tag < 0);
-
 	dev = cmd->device->hostdata;
 	if (!dev) {
 		cmd->result = DID_NO_CONNECT << 16;
@@ -5805,7 +5806,7 @@ static int hpsa_scsi_host_alloc(struct ctlr_info *h)
 	sh->hostdata[0] = (unsigned long) h;
 	sh->irq = pci_irq_vector(h->pdev, 0);
 	sh->unique_id = sh->irq;
-
+	sh->nr_hw_queues = h->msix_vectors > 0 ? h->msix_vectors : 1;
 	h->scsi_host = sh;
 	return 0;
 }
@@ -5831,7 +5832,8 @@ static int hpsa_scsi_add_host(struct ctlr_info *h)
  */
 static int hpsa_get_cmd_index(struct scsi_cmnd *scmd)
 {
-	int idx = scmd->request->tag;
+	u32 blk_tag = blk_mq_unique_tag(scmd->request);
+	int idx = blk_mq_unique_tag_to_tag(blk_tag);
 
 	if (idx < 0)
 		return idx;
@@ -7431,26 +7433,6 @@ static void hpsa_disable_interrupt_mode(struct ctlr_info *h)
 	h->msix_vectors = 0;
 }
 
-static void hpsa_setup_reply_map(struct ctlr_info *h)
-{
-	const struct cpumask *mask;
-	unsigned int queue, cpu;
-
-	for (queue = 0; queue < h->msix_vectors; queue++) {
-		mask = pci_irq_get_affinity(h->pdev, queue);
-		if (!mask)
-			goto fallback;
-
-		for_each_cpu(cpu, mask)
-			h->reply_map[cpu] = queue;
-	}
-	return;
-
-fallback:
-	for_each_possible_cpu(cpu)
-		h->reply_map[cpu] = 0;
-}
-
 /* If MSI/MSI-X is supported by the kernel we will try to enable it on
  * controllers that are capable. If not, we use legacy INTx mode.
  */
@@ -7847,9 +7829,6 @@ static int hpsa_pci_init(struct ctlr_info *h)
 	if (err)
 		goto clean1;
 
-	/* setup mapping between CPU and reply queue */
-	hpsa_setup_reply_map(h);
-
 	err = hpsa_pci_find_memory_BAR(h->pdev, &h->paddr);
 	if (err)
 		goto clean2;	/* intmode+region, pci */
@@ -8575,7 +8554,6 @@ static struct workqueue_struct *hpsa_create_controller_wq(struct ctlr_info *h,
 
 static void hpda_free_ctlr_info(struct ctlr_info *h)
 {
-	kfree(h->reply_map);
 	kfree(h);
 }
 
@@ -8584,14 +8562,6 @@ static struct ctlr_info *hpda_alloc_ctlr_info(void)
 	struct ctlr_info *h;
 
 	h = kzalloc(sizeof(*h), GFP_KERNEL);
-	if (!h)
-		return NULL;
-
-	h->reply_map = kcalloc(nr_cpu_ids, sizeof(*h->reply_map), GFP_KERNEL);
-	if (!h->reply_map) {
-		kfree(h);
-		return NULL;
-	}
 	return h;
 }
 
diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index f8c88fc7b80a..ea4a609e3eb7 100644
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -161,7 +161,6 @@ struct bmic_controller_parameters {
 #pragma pack()
 
 struct ctlr_info {
-	unsigned int *reply_map;
 	int	ctlr;
 	char	devname[8];
 	char    *product_name;
-- 
2.16.4

Re: [PATCH 4/8] blk-mq: Facilitate a shared sbitmap per tagset

[John Garry]

> +		blk_mq_free_tags(tags);
>   }
>   
>   struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   					unsigned int hctx_idx,
>   					unsigned int nr_tags,
> -					unsigned int reserved_tags)
> +					unsigned int reserved_tags,
> +					bool shared_tags)
>   {
>   	struct blk_mq_tags *tags;
>   	int node;
> @@ -2096,8 +2098,9 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   	if (node == NUMA_NO_NODE)
>   		node = set->numa_node;
>   
> -	tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
> -				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
> +	tags = blk_mq_init_tags(set, nr_tags, reserved_tags, node,
> +				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags),
> +				shared_tags);
>   	if (!tags)
>   		return NULL;
>   
> @@ -2105,7 +2108,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   				 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
>   				 node);
>   	if (!tags->rqs) {
> -		blk_mq_free_tags(tags);
> +		if (!blk_mq_is_sbitmap_shared(set))
> +			blk_mq_free_tags(tags);

Don't we still need to free the tags memory but not have the 
blk_mq_free_tags()->sbitmap_queue_free() calls in case of shared tags?

>   		return NULL;
>   	}
>   
> @@ -2114,7 +2118,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   					node);
>   	if (!tags->static_rqs) {
>   		kfree(tags->rqs);
> -		blk_mq_free_tags(tags);
> +		if (!blk_mq_is_sbitmap_shared(set))
> +			blk_mq_free_tags(tags);
>   		return NULL;
>   	}

Re: [PATCH 4/8] blk-mq: Facilitate a shared sbitmap per tagset

[Hannes Reinecke]

On 11/26/19 2:59 PM, John Garry wrote:
> 
>> +        blk_mq_free_tags(tags);
>>   }
>>     struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>>                       unsigned int hctx_idx,
>>                       unsigned int nr_tags,
>> -                    unsigned int reserved_tags)
>> +                    unsigned int reserved_tags,
>> +                    bool shared_tags)
>>   {
>>       struct blk_mq_tags *tags;
>>       int node;
>> @@ -2096,8 +2098,9 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct
>> blk_mq_tag_set *set,
>>       if (node == NUMA_NO_NODE)
>>           node = set->numa_node;
>>   -    tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
>> -                BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
>> +    tags = blk_mq_init_tags(set, nr_tags, reserved_tags, node,
>> +                BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags),
>> +                shared_tags);
>>       if (!tags)
>>           return NULL;
>>   @@ -2105,7 +2108,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct
>> blk_mq_tag_set *set,
>>                    GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
>>                    node);
>>       if (!tags->rqs) {
>> -        blk_mq_free_tags(tags);
>> +        if (!blk_mq_is_sbitmap_shared(set))
>> +            blk_mq_free_tags(tags);
> 
> Don't we still need to free the tags memory but not have the
> blk_mq_free_tags()->sbitmap_queue_free() calls in case of shared tags?
> 

Ah, indeed, you are right.
Oh, well, another round.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      Teamlead Storage & Networking
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer

Re: [PATCH 3/8] blk-mq: Use a pointer for sbitmap

[Christoph Hellwig]

On Tue, Nov 26, 2019 at 02:10:04PM +0100, Hannes Reinecke wrote:
> Instead of allocating the tag bitmap in place we should be using a
> pointer. This is in preparation for shared host-wide bitmaps.

We should is a rather vague statement that needs to be followed up by
an actual reason.

Re: [PATCH 8/8] hpsa: switch to using blk-mq

[Christoph Hellwig]

The subject is weird.  All SCSI drivers use blk-mq as there is no
other I/O path..

Re: [PATCH 4/8] blk-mq: Facilitate a shared sbitmap per tagset

[Bart Van Assche]

On 11/26/19 5:10 AM, Hannes Reinecke wrote:
> -struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
> +bool blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *tag_set)
> +{
> +	unsigned int depth = tag_set->queue_depth -tag_set->reserved_tags;

A nit: please follow the coding style for spaces around the subtraction 
sign.

> +struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set,
> +				     unsigned int total_tags,
>   				     unsigned int reserved_tags,
> -				     int node, int alloc_policy)
> +				     int node, int alloc_policy,
> +				     bool shared_tags)
>   {
>   	struct blk_mq_tags *tags;
>   
> @@ -488,9 +517,11 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
>   	tags->nr_tags = total_tags;
>   	tags->nr_reserved_tags = reserved_tags;
>   
> -	if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
> -		kfree(tags);
> -		tags = NULL;
> +	if (shared_tags) {
> +		if (blk_mq_init_bitmap_tags(tags, node, alloc_policy) < 0) {
> +			kfree(tags);
> +			tags = NULL;
> +		}
>   	}
>   	return tags;
>   }

The above looks weird to me: the existing code path is only called if 
shared tags are enabled? Shouldn't "if (shared_tags)" be changed into 
"if (!shared_tags)"?

> +static inline bool blk_mq_is_sbitmap_shared(struct blk_mq_tag_set *tag_set)
> +{
> +	return !!(tag_set->flags & BLK_MQ_F_TAG_HCTX_SHARED);
> +}

Another nit: since the return type of this function is 'bool', the 
double exclamation mark and the parentheses are superfluous.

Bart.

[PATCH 6/8] scsi: hisi_sas: Switch v3 hw to MQ

[Hannes Reinecke]

From: John Garry <john.garry@huawei.com>

Now that the block layer provides a shared tag, we can switch the driver
to expose all HW queues.

Signed-off-by: John Garry <john.garry@huawei.com>
---
 drivers/scsi/hisi_sas/hisi_sas.h       |  3 +-
 drivers/scsi/hisi_sas/hisi_sas_main.c  | 36 +++++++-------
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 86 ++++++++++++++--------------------
 3 files changed, 56 insertions(+), 69 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 233c73e01246..0405602df2a4 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -8,6 +8,8 @@
 #define _HISI_SAS_H_
 
 #include <linux/acpi.h>
+#include <linux/blk-mq.h>
+#include <linux/blk-mq-pci.h>
 #include <linux/clk.h>
 #include <linux/debugfs.h>
 #include <linux/dmapool.h>
@@ -431,7 +433,6 @@ struct hisi_hba {
 	u32 intr_coal_count;	/* Interrupt count to coalesce */
 
 	int cq_nvecs;
-	unsigned int *reply_map;
 
 	/* bist */
 	enum sas_linkrate debugfs_bist_linkrate;
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 03588ec3c394..e185935c3399 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -421,6 +421,7 @@ static int hisi_sas_task_prep(struct sas_task *task,
 	struct device *dev = hisi_hba->dev;
 	int dlvry_queue_slot, dlvry_queue, rc, slot_idx;
 	int n_elem = 0, n_elem_dif = 0, n_elem_req = 0;
+	struct scsi_cmnd *scmd = NULL;
 	struct hisi_sas_dq *dq;
 	unsigned long flags;
 	int wr_q_index;
@@ -436,10 +437,23 @@ static int hisi_sas_task_prep(struct sas_task *task,
 		return -ECOMM;
 	}
 
-	if (hisi_hba->reply_map) {
-		int cpu = raw_smp_processor_id();
-		unsigned int dq_index = hisi_hba->reply_map[cpu];
+	if (task->uldd_task) {
+		struct ata_queued_cmd *qc;
 
+		if (dev_is_sata(device)) {
+			qc = task->uldd_task;
+			scmd = qc->scsicmd;
+		} else {
+			scmd = task->uldd_task;
+		}
+	}
+
+	if (scmd) {
+		unsigned int dq_index;
+		u32 blk_tag;
+
+		blk_tag = blk_mq_unique_tag(scmd->request);
+		dq_index = blk_mq_unique_tag_to_hwq(blk_tag);
 		*dq_pointer = dq = &hisi_hba->dq[dq_index];
 	} else {
 		*dq_pointer = dq = sas_dev->dq;
@@ -468,21 +482,9 @@ static int hisi_sas_task_prep(struct sas_task *task,
 
 	if (hisi_hba->hw->slot_index_alloc)
 		rc = hisi_hba->hw->slot_index_alloc(hisi_hba, device);
-	else {
-		struct scsi_cmnd *scsi_cmnd = NULL;
-
-		if (task->uldd_task) {
-			struct ata_queued_cmd *qc;
+	else
+		rc = hisi_sas_slot_index_alloc(hisi_hba, scmd);
 
-			if (dev_is_sata(device)) {
-				qc = task->uldd_task;
-				scsi_cmnd = qc->scsicmd;
-			} else {
-				scsi_cmnd = task->uldd_task;
-			}
-		}
-		rc  = hisi_sas_slot_index_alloc(hisi_hba, scsi_cmnd);
-	}
 	if (rc < 0)
 		goto err_out_dif_dma_unmap;
 
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index bf5d5f138437..e7b015d88968 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2353,66 +2353,35 @@ static irqreturn_t cq_interrupt_v3_hw(int irq_no, void *p)
 	return IRQ_HANDLED;
 }
 
-static void setup_reply_map_v3_hw(struct hisi_hba *hisi_hba, int nvecs)
+static int interrupt_preinit_v3_hw(struct hisi_hba *hisi_hba)
 {
-	const struct cpumask *mask;
-	int queue, cpu;
-
-	for (queue = 0; queue < nvecs; queue++) {
-		struct hisi_sas_cq *cq = &hisi_hba->cq[queue];
+	int vectors;
+	int max_msi = HISI_SAS_MSI_COUNT_V3_HW, min_msi;
+	struct Scsi_Host *shost = hisi_hba->shost;
+	struct irq_affinity desc = {
+		.pre_vectors = BASE_VECTORS_V3_HW,
+	};
+
+	min_msi = MIN_AFFINE_VECTORS_V3_HW;
+	vectors = pci_alloc_irq_vectors_affinity(hisi_hba->pci_dev,
+						 min_msi, max_msi,
+						 PCI_IRQ_MSI |
+						 PCI_IRQ_AFFINITY,
+						 &desc);
+	if (vectors < 0)
+		return -ENOENT;
 
-		mask = pci_irq_get_affinity(hisi_hba->pci_dev, queue +
-					    BASE_VECTORS_V3_HW);
-		if (!mask)
-			goto fallback;
-		cq->pci_irq_mask = mask;
-		for_each_cpu(cpu, mask)
-			hisi_hba->reply_map[cpu] = queue;
-	}
-	return;
+	hisi_hba->cq_nvecs = vectors - BASE_VECTORS_V3_HW;
+	shost->nr_hw_queues = hisi_hba->cq_nvecs;
 
-fallback:
-	for_each_possible_cpu(cpu)
-		hisi_hba->reply_map[cpu] = cpu % hisi_hba->queue_count;
-	/* Don't clean all CQ masks */
+	return 0;
 }
 
 static int interrupt_init_v3_hw(struct hisi_hba *hisi_hba)
 {
 	struct device *dev = hisi_hba->dev;
 	struct pci_dev *pdev = hisi_hba->pci_dev;
-	int vectors, rc, i;
-	int max_msi = HISI_SAS_MSI_COUNT_V3_HW, min_msi;
-
-	if (auto_affine_msi_experimental) {
-		struct irq_affinity desc = {
-			.pre_vectors = BASE_VECTORS_V3_HW,
-		};
-
-		min_msi = MIN_AFFINE_VECTORS_V3_HW;
-
-		hisi_hba->reply_map = devm_kcalloc(dev, nr_cpu_ids,
-						   sizeof(unsigned int),
-						   GFP_KERNEL);
-		if (!hisi_hba->reply_map)
-			return -ENOMEM;
-		vectors = pci_alloc_irq_vectors_affinity(hisi_hba->pci_dev,
-							 min_msi, max_msi,
-							 PCI_IRQ_MSI |
-							 PCI_IRQ_AFFINITY,
-							 &desc);
-		if (vectors < 0)
-			return -ENOENT;
-		setup_reply_map_v3_hw(hisi_hba, vectors - BASE_VECTORS_V3_HW);
-	} else {
-		min_msi = max_msi;
-		vectors = pci_alloc_irq_vectors(hisi_hba->pci_dev, min_msi,
-						max_msi, PCI_IRQ_MSI);
-		if (vectors < 0)
-			return vectors;
-	}
-
-	hisi_hba->cq_nvecs = vectors - BASE_VECTORS_V3_HW;
+	int rc, i;
 
 	rc = devm_request_irq(dev, pci_irq_vector(pdev, 1),
 			      int_phy_up_down_bcast_v3_hw, 0,
@@ -3057,6 +3026,15 @@ static int debugfs_set_bist_v3_hw(struct hisi_hba *hisi_hba, bool enable)
 	return 0;
 }
 
+static int hisi_sas_map_queues(struct Scsi_Host *shost)
+{
+	struct hisi_hba *hisi_hba = shost_priv(shost);
+	struct blk_mq_queue_map *qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
+
+	return blk_mq_pci_map_queues(qmap, hisi_hba->pci_dev,
+					     BASE_VECTORS_V3_HW);
+}
+
 static struct scsi_host_template sht_v3_hw = {
 	.name			= DRV_NAME,
 	.module			= THIS_MODULE,
@@ -3065,6 +3043,7 @@ static struct scsi_host_template sht_v3_hw = {
 	.slave_configure	= hisi_sas_slave_configure,
 	.scan_finished		= hisi_sas_scan_finished,
 	.scan_start		= hisi_sas_scan_start,
+	.map_queues		= hisi_sas_map_queues,
 	.change_queue_depth	= sas_change_queue_depth,
 	.bios_param		= sas_bios_param,
 	.this_id		= -1,
@@ -3078,6 +3057,7 @@ static struct scsi_host_template sht_v3_hw = {
 	.shost_attrs		= host_attrs_v3_hw,
 	.tag_alloc_policy	= BLK_TAG_ALLOC_RR,
 	.host_reset             = hisi_sas_host_reset,
+	.host_tagset		= 1,
 };
 
 static const struct hisi_sas_hw hisi_sas_v3_hw = {
@@ -3249,6 +3229,10 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (hisi_sas_debugfs_enable)
 		hisi_sas_debugfs_init(hisi_hba);
 
+	rc = interrupt_preinit_v3_hw(hisi_hba);
+	if (rc)
+		goto err_out_ha;
+	dev_err(dev, "%d hw qeues\n", shost->nr_hw_queues);
 	rc = scsi_add_host(shost, dev);
 	if (rc)
 		goto err_out_ha;
-- 
2.16.4