[PATCH v2 12/14] md/raid1: clean up sync IO size calculation in raid1_sync_request

From: Li Nan <[email protected]>

Use 'nr_sectors' directly for sync IO size calculation. Prepare folio
allocation failure fallback.

No functional changes.

Signed-off-by: Li Nan <[email protected]>
---
 drivers/md/raid1.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index b5239b5cb4e9..2253e65c5f03 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2979,32 +2979,27 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 		max_sector = mddev->resync_max; /* Don't do IO beyond here */
 	if (max_sector > sector_nr + good_sectors)
 		max_sector = sector_nr + good_sectors;
-	nr_sectors = 0;
 	do {
-		int len = RESYNC_BLOCK_SIZE;
-
-		if (sector_nr + (len>>9) > max_sector)
-			len = (max_sector - sector_nr) << 9;
-		if (len == 0)
+		nr_sectors = max_sector - sector_nr;
+		if (nr_sectors == 0)
 			break;
 		if (!md_bitmap_start_sync(mddev, sector_nr,
 					  &sync_blocks, still_degraded) &&
 		    !conf->fullsync &&
 		    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
 			break;
-		if ((len >> 9) > sync_blocks)
-			len = sync_blocks<<9;
+		if (nr_sectors > sync_blocks)
+			nr_sectors = sync_blocks;
 
 		for (i = 0 ; i < conf->raid_disks * 2; i++) {
 			bio = r1_bio->bios[i];
 			if (bio->bi_end_io) {
 				struct resync_folio *rf = get_resync_folio(bio);
 
-				bio_add_folio_nofail(bio, rf->folio, len, 0);
+				bio_add_folio_nofail(bio, rf->folio, nr_sectors << 9, 0);
 			}
 		}
-		nr_sectors += len>>9;
-		sector_nr += len>>9;
+		sector_nr += nr_sectors;
 	} while (0);
 
 	r1_bio->sectors = nr_sectors;
-- 
2.39.2