[PATCH v19 04/11] blk-zoned: Add an argument to blk_zone_plug_bio()

[Bart Van Assche <bvanassche@xxxxxxx>]

Zoned writes may be submitted from multiple CPUs as long as these are
serialized per zone. Prepare for preserving the order of pipelined zoned
writes per zone by adding the 'from_cpu` argument to blk_zone_plug_bio().
This argument will be used to preserve the write order per zone by
submitting all zoned writes per zone from the same CPU as long as any
zoned writes are pending for that zone.

Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Damien Le Moal <dlemoal@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 block/blk-mq.c         | 7 +++----
 block/blk-zoned.c      | 4 +++-
 drivers/md/dm.c        | 5 ++---
 include/linux/blkdev.h | 5 +++--
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7935f6adda71..34304b6ac29e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3195,10 +3195,9 @@ void blk_mq_submit_bio(struct bio *bio)
 	if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
 		goto queue_exit;
 
-	if (bio_needs_zone_write_plugging(bio)) {
-		if (blk_zone_plug_bio(bio, nr_segs))
-			goto queue_exit;
-	}
+	if (bio_needs_zone_write_plugging(bio) &&
+	    blk_zone_plug_bio(bio, nr_segs, &from_cpu))
+		goto queue_exit;
 
 new_request:
 	if (rq && (from_cpu == -1 || from_cpu == rq->mq_ctx->cpu)) {
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index efe71b1a1da1..91a59bf54547 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1104,6 +1104,8 @@ static void blk_zone_wplug_handle_native_zone_append(struct bio *bio)
  * blk_zone_plug_bio - Handle a zone write BIO with zone write plugging
  * @bio: The BIO being submitted
  * @nr_segs: The number of physical segments of @bio
+ * @from_cpu: [out] CPU of the software queue to which the bio should be
+ *	queued
  *
  * Handle write, write zeroes and zone append operations requiring emulation
  * using zone write plugging.
@@ -1112,7 +1114,7 @@ static void blk_zone_wplug_handle_native_zone_append(struct bio *bio)
  * write plug. Otherwise, return false to let the submission path process
  * @bio normally.
  */
-bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs)
+bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs, int *from_cpu)
 {
 	struct block_device *bdev = bio->bi_bdev;
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ca889328fdfe..76c5eada7d03 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1814,9 +1814,8 @@ static inline bool dm_zone_bio_needs_split(struct mapped_device *md,
 
 static inline bool dm_zone_plug_bio(struct mapped_device *md, struct bio *bio)
 {
-	if (!bio_needs_zone_write_plugging(bio))
-		return false;
-	return blk_zone_plug_bio(bio, 0);
+	return bio_needs_zone_write_plugging(bio) &&
+		blk_zone_plug_bio(bio, 0, NULL);
 }
 
 static blk_status_t __send_zone_reset_all_emulated(struct clone_info *ci,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index aa1990d94130..46fe8d97b31f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -891,7 +891,7 @@ static inline bool bio_needs_zone_write_plugging(struct bio *bio)
 	}
 }
 
-bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs);
+bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs, int *from_cpu);
 
 /**
  * disk_zone_capacity - returns the zone capacity of zone containing @sector
@@ -926,7 +926,8 @@ static inline bool bio_needs_zone_write_plugging(struct bio *bio)
 	return false;
 }
 
-static inline bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs)
+static inline bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs,
+				     int *from_cpu)
 {
 	return false;
 }