[PATCH 14/15] md/raid10: clean up sync IO size calculation in raid10_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/raid10.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c3ef2ea38b08..f3e10e20ebb1 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3618,28 +3618,24 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 		}
 	}
 
-	nr_sectors = 0;
 	if (sector_nr + max_sync < max_sector)
 		max_sector = sector_nr + max_sync;
 	do {
-		int len = RESYNC_BLOCK_SIZE;
+		nr_sectors = max_sector - sector_nr;
 
-		if (sector_nr + (len>>9) > max_sector)
-			len = (max_sector - sector_nr) << 9;
-		if (len == 0)
+		if (nr_sectors == 0)
 			break;
 		for (bio= biolist ; bio ; bio=bio->bi_next) {
 			struct resync_folio *rf = get_resync_folio(bio);
 
-			if (WARN_ON(!bio_add_folio(bio, rf->folio, len, 0))) {
+			if (WARN_ON(!bio_add_folio(bio, rf->folio, nr_sectors << 9, 0))) {
 				bio->bi_status = BLK_STS_RESOURCE;
 				bio_endio(bio);
 				*skipped = 1;
-				return len;
+				return nr_sectors << 9;
 			}
 		}
-		nr_sectors += len>>9;
-		sector_nr += len>>9;
+		sector_nr += nr_sectors;;
 	} while (0);
 	r10_bio->sectors = nr_sectors;
 
-- 
2.39.2