md/raid0: set chunk_sectors limit

JIRA: https://issues.redhat.com/browse/RHEL-106845

commit 4b8beba
Author: John Garry <john.g.garry@oracle.com>
Date:   Fri Jul 11 10:52:55 2025 +0000

    md/raid0: set chunk_sectors limit

    Currently we use min io size as the chunk size when deciding on the
    atomic write size limits - see blk_stack_atomic_writes_head().

    The limit min_io size is not a reliable value to store the chunk size, as
    this may be mutated by the block stacking code. Such an example would be
    for the min io size less than the physical block size, and the min io size
    is raised to the physical block size - see blk_stack_limits().

    The block stacking limits will rely on chunk_sectors in future,
    so set this value (to the chunk size).

    Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
    Reviewed-by: Yu Kuai <yukuai3@huawei.com>
    Signed-off-by: John Garry <john.g.garry@oracle.com>
    Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
    Link: https://lore.kernel.org/r/20250711105258.3135198-4-john.g.garry@oracle.com
    Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Ming Lei <ming.lei@redhat.com>

Author: Ming Lei

drivers/md/raid0.c

@@ -384,6 +384,7 @@ static int raid0_set_limits(struct mddev *mddev)
 	lim.max_write_zeroes_sectors = mddev->chunk_sectors;
 	lim.io_min = mddev->chunk_sectors << 9;
 	lim.io_opt = lim.io_min * mddev->raid_disks;
+	lim.chunk_sectors = mddev->chunk_sectors;
 	lim.features |= BLK_FEAT_ATOMIC_WRITES;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err)