md/raid0: Atomic write support

JIRA: https://issues.redhat.com/browse/RHEL-73514

commit fa6fec8
Author: John Garry <john.g.garry@oracle.com>
Date:   Mon Nov 18 10:50:16 2024 +0000

    md/raid0: Atomic write support

    Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes. All other
    stacked device request queue limits should automatically be set properly.
    With regards to atomic write max bytes limit, this will be set at
    hw_max_sectors and this is limited by the stripe width, which we want.

    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/20241118105018.1870052-4-john.g.garry@oracle.com
    Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Nigel Croxon <ncroxon@redhat.com>

Author: ncroxon

drivers/md/raid0.c

@@ -389,6 +389,7 @@ 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.features |= BLK_FEAT_ATOMIC_WRITES_STACKED;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err) {
 		queue_limits_cancel_update(mddev->gendisk->queue);