[PATCH 01/23] md: add a new parameter 'offset' to md_super_write()

[Yu Kuai <yukuai1@huaweicloud.com>]

From: Yu Kuai <yukuai3@huawei.com>

The parameter is always set to 0 for now, following patches will use
this helper to write llbitmap to underlying disks, allow writing
dirty sectors instead of the whole page.

Also rename md_super_write to md_write_metadata since there is nothing
super-block specific.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/md-bitmap.c |  3 ++-
 drivers/md/md.c        | 28 ++++++++++++++--------------
 drivers/md/md.h        |  5 +++--
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 431a3ab2e449..168eea6595b3 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -470,7 +470,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
 			return -EINVAL;
 	}
 
-	md_super_write(mddev, rdev, sboff + ps, (int)min(size, bitmap_limit), page);
+	md_write_metadata(mddev, rdev, sboff + ps, (int)min(size, bitmap_limit),
+			  page, 0);
 	return 0;
 }
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 32b997dfe6f4..18e03f651f6b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1021,8 +1021,9 @@ static void super_written(struct bio *bio)
 		wake_up(&mddev->sb_wait);
 }
 
-void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
-		   sector_t sector, int size, struct page *page)
+void md_write_metadata(struct mddev *mddev, struct md_rdev *rdev,
+		       sector_t sector, int size, struct page *page,
+		       unsigned int offset)
 {
 	/* write first size bytes of page to sector of rdev
 	 * Increment mddev->pending_writes before returning
@@ -1047,7 +1048,7 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 	atomic_inc(&rdev->nr_pending);
 
 	bio->bi_iter.bi_sector = sector;
-	__bio_add_page(bio, page, size, 0);
+	__bio_add_page(bio, page, size, offset);
 	bio->bi_private = rdev;
 	bio->bi_end_io = super_written;
 
@@ -1657,8 +1658,8 @@ super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
 	if ((u64)num_sectors >= (2ULL << 32) && rdev->mddev->level >= 1)
 		num_sectors = (sector_t)(2ULL << 32) - 2;
 	do {
-		md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
-		       rdev->sb_page);
+		md_write_metadata(rdev->mddev, rdev, rdev->sb_start,
+				  rdev->sb_size, rdev->sb_page, 0);
 	} while (md_super_wait(rdev->mddev) < 0);
 	return num_sectors;
 }
@@ -2306,8 +2307,8 @@ super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
 	sb->super_offset = cpu_to_le64(rdev->sb_start);
 	sb->sb_csum = calc_sb_1_csum(sb);
 	do {
-		md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
-			       rdev->sb_page);
+		md_write_metadata(rdev->mddev, rdev, rdev->sb_start,
+				  rdev->sb_size, rdev->sb_page, 0);
 	} while (md_super_wait(rdev->mddev) < 0);
 	return num_sectors;
 
@@ -2816,18 +2817,17 @@ void md_update_sb(struct mddev *mddev, int force_change)
 			continue; /* no noise on spare devices */
 
 		if (!test_bit(Faulty, &rdev->flags)) {
-			md_super_write(mddev,rdev,
-				       rdev->sb_start, rdev->sb_size,
-				       rdev->sb_page);
+			md_write_metadata(mddev, rdev, rdev->sb_start,
+					  rdev->sb_size, rdev->sb_page, 0);
 			pr_debug("md: (write) %pg's sb offset: %llu\n",
 				 rdev->bdev,
 				 (unsigned long long)rdev->sb_start);
 			rdev->sb_events = mddev->events;
 			if (rdev->badblocks.size) {
-				md_super_write(mddev, rdev,
-					       rdev->badblocks.sector,
-					       rdev->badblocks.size << 9,
-					       rdev->bb_page);
+				md_write_metadata(mddev, rdev,
+						  rdev->badblocks.sector,
+						  rdev->badblocks.size << 9,
+						  rdev->bb_page, 0);
 				rdev->badblocks.size = 0;
 			}
 
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 6eb5dfdf2f55..5ba4a9093a92 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -886,8 +886,9 @@ void md_account_bio(struct mddev *mddev, struct bio **bio);
 void md_free_cloned_bio(struct bio *bio);
 
 extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
-extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
-			   sector_t sector, int size, struct page *page);
+extern void md_write_metadata(struct mddev *mddev, struct md_rdev *rdev,
+			      sector_t sector, int size, struct page *page,
+			      unsigned int offset);
 extern int md_super_wait(struct mddev *mddev);
 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 		struct page *page, blk_opf_t opf, bool metadata_op);
-- 
2.39.2