+++ b/drivers/md/raid1.c
@@ -2129,7 +2129,7 @@ static void process_checks(struct r1bio *r1_bio)
int vcnt;
/* Fix variable parts of all bios */
- vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
+ vcnt = (r1_bio->sectors + PAGE_SECTORS - 1) >> (PAGE_SHIFT - 9);