From: Yu Kuai <yukuai3@huawei.com>

This method is used to check if blocks can be skipped before calling
into pers->sync_request(), llbitmap will use this method to skip
resync for unwritten/clean data blocks, and recovery/check/repair for
unwritten data blocks;

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Li Nan <linan122@huawei.com>
---
 drivers/md/md-bitmap.h | 1 +
 drivers/md/md.c        | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 8616ced49077..95453696c68e 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -89,6 +89,7 @@ struct bitmap_operations {
 	md_bitmap_fn *start_discard;
 	md_bitmap_fn *end_discard;
 
+	sector_t (*skip_sync_blocks)(struct mddev *mddev, sector_t offset);
 	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 6560bd89d0a2..7196e7f6b2a4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9460,6 +9460,12 @@ void md_do_sync(struct md_thread *thread)
 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 			break;
 
+		if (mddev->bitmap_ops && mddev->bitmap_ops->skip_sync_blocks) {
+			sectors = mddev->bitmap_ops->skip_sync_blocks(mddev, j);
+			if (sectors)
+				goto update;
+		}
+
 		sectors = mddev->pers->sync_request(mddev, j, max_sectors,
 						    &skipped);
 		if (sectors == 0) {
@@ -9475,6 +9481,7 @@ void md_do_sync(struct md_thread *thread)
 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 			break;
 
+update:
 		j += sectors;
 		if (j > max_sectors)
 			/* when skipping, extra large numbers can be returned. */
-- 
2.39.2