md: init queue_limits->max_hw_wzeroes_unmap_sectors parameter

The parameter max_hw_wzeroes_unmap_sectors in queue_limits should be
equal to max_write_zeroes_sectors if it is set to a non-zero value.
However, the stacked md drivers call md_init_stacking_limits() to
initialize this parameter to UINT_MAX but only adjust
max_write_zeroes_sectors when setting limits. Therefore, this
discrepancy triggers a value check failure in blk_validate_limits().

 $ modprobe scsi_debug num_parts=2 dev_size_mb=8 lbprz=1 lbpws=1
 $ mdadm --create /dev/md0 --level=0 --raid-device=2 /dev/sda1 /dev/sda2
   mdadm: Defaulting to version 1.2 metadata
   mdadm: RUN_ARRAY failed: Invalid argument

Fix this failure by explicitly setting max_hw_wzeroes_unmap_sectors to
max_write_zeroes_sectors. Since the linear and raid0 drivers support
write zeroes, so they can support unmap write zeroes operation if all of
the backend devices support it. However, the raid1/10/5 drivers don't
support write zeroes, so we have to set it to zero.

Fixes: 0c40d7c ("block: introduce max_{hw|user}_wzeroes_unmap_sectors to queue limits")
Reported-by: John Garry <john.g.garry@oracle.com>
Closes: https://lore.kernel.org/linux-block/803a2183-a0bb-4b7a-92f1-afc5097630d2@oracle.com/
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Tested-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Li Nan <linan122@huawei.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/linux-raid/20250910111107.3247530-2-yi.zhang@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Author: zhangyi089

drivers/md/md-linear.c

@@ -73,6 +73,7 @@ static int linear_set_limits(struct mddev *mddev)
 	md_init_stacking_limits(&lim);
 	lim.max_hw_sectors = mddev->chunk_sectors;
 	lim.max_write_zeroes_sectors = mddev->chunk_sectors;
+	lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors;
 	lim.io_min = mddev->chunk_sectors << 9;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err)

drivers/md/raid0.c

@@ -382,6 +382,7 @@ static int raid0_set_limits(struct mddev *mddev)
 	md_init_stacking_limits(&lim);
 	lim.max_hw_sectors = mddev->chunk_sectors;
 	lim.max_write_zeroes_sectors = mddev->chunk_sectors;
+	lim.max_hw_wzeroes_unmap_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;

drivers/md/raid1.c

@@ -3211,6 +3211,7 @@ static int raid1_set_limits(struct mddev *mddev)
 
 	md_init_stacking_limits(&lim);
 	lim.max_write_zeroes_sectors = 0;
+	lim.max_hw_wzeroes_unmap_sectors = 0;
 	lim.features |= BLK_FEAT_ATOMIC_WRITES;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err)

drivers/md/raid10.c

@@ -4008,6 +4008,7 @@ static int raid10_set_queue_limits(struct mddev *mddev)
 
 	md_init_stacking_limits(&lim);
 	lim.max_write_zeroes_sectors = 0;
+	lim.max_hw_wzeroes_unmap_sectors = 0;
 	lim.io_min = mddev->chunk_sectors << 9;
 	lim.chunk_sectors = mddev->chunk_sectors;
 	lim.io_opt = lim.io_min * raid10_nr_stripes(conf);

drivers/md/raid5.c

@@ -7732,6 +7732,7 @@ static int raid5_set_limits(struct mddev *mddev)
 	lim.features |= BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE;
 	lim.discard_granularity = stripe;
 	lim.max_write_zeroes_sectors = 0;
+	lim.max_hw_wzeroes_unmap_sectors = 0;
 	mddev_stack_rdev_limits(mddev, &lim, 0);
 	rdev_for_each(rdev, mddev)
 		queue_limits_stack_bdev(&lim, rdev->bdev, rdev->new_data_offset,