[PATCH RFC v2 02/14] md/md-bitmap: pass discard information to bitmap_{start, end}write

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

It's not used for now, and prepare to handle discard for llbitmap in
following patches.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/md-bitmap.c |  4 ++--
 drivers/md/md-bitmap.h |  4 ++--
 drivers/md/md.c        | 10 ++++++++--
 drivers/md/md.h        |  1 +
 4 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 733fbb886f67..0cef5c199d32 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1667,7 +1667,7 @@ __acquires(bitmap->lock)
 }
 
 static int bitmap_startwrite(struct mddev *mddev, sector_t offset,
-			     unsigned long sectors)
+			     unsigned long sectors, bool is_discard)
 {
 	struct bitmap *bitmap = mddev->bitmap;
 
@@ -1722,7 +1722,7 @@ static int bitmap_startwrite(struct mddev *mddev, sector_t offset,
 }
 
 static void bitmap_endwrite(struct mddev *mddev, sector_t offset,
-			    unsigned long sectors)
+			    unsigned long sectors, bool is_discard)
 {
 	struct bitmap *bitmap = mddev->bitmap;
 
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index d3d50629af91..504d33d4980b 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -91,9 +91,9 @@ struct bitmap_operations {
 	void (*wait_behind_writes)(struct mddev *mddev);
 
 	int (*startwrite)(struct mddev *mddev, sector_t offset,
-			  unsigned long sectors);
+			  unsigned long sectors, bool is_discard);
 	void (*endwrite)(struct mddev *mddev, sector_t offset,
-			 unsigned long sectors);
+			 unsigned long sectors, bool is_discard);
 	bool (*start_sync)(struct mddev *mddev, sector_t offset,
 			   sector_t *blocks, bool degraded);
 	void (*end_sync)(struct mddev *mddev, sector_t offset, sector_t *blocks);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4a9aa6879e98..c06c41e39609 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8805,13 +8805,15 @@ static void md_bitmap_start(struct mddev *mddev,
 					   &md_io_clone->sectors);
 
 	mddev->bitmap_ops->startwrite(mddev, md_io_clone->offset,
-				      md_io_clone->sectors);
+				      md_io_clone->sectors,
+				      md_io_clone->is_discard);
 }
 
 static void md_bitmap_end(struct mddev *mddev, struct md_io_clone *md_io_clone)
 {
 	mddev->bitmap_ops->endwrite(mddev, md_io_clone->offset,
-				    md_io_clone->sectors);
+				    md_io_clone->sectors,
+				    md_io_clone->is_discard);
 }
 
 static void md_end_clone_io(struct bio *bio)
@@ -8850,6 +8852,10 @@ static void md_clone_bio(struct mddev *mddev, struct bio **bio)
 	if (bio_data_dir(*bio) == WRITE && md_bitmap_enabled(mddev)) {
 		md_io_clone->offset = (*bio)->bi_iter.bi_sector;
 		md_io_clone->sectors = bio_sectors(*bio);
+		if (unlikely(bio_op(*bio) == REQ_OP_DISCARD))
+			md_io_clone->is_discard = true;
+		else
+			md_io_clone->is_discard = false;
 		md_bitmap_start(mddev, md_io_clone);
 	}
 
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 254bbab6f443..ad18ef9b5061 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -858,6 +858,7 @@ struct md_io_clone {
 	unsigned long	start_time;
 	sector_t	offset;
 	unsigned long	sectors;
+	bool		is_discard;
 	struct bio	bio_clone;
 };
 
-- 
2.39.2