Re: [dm-devel] [PATCH 05/11] dm-zoned: don't set the discard_alignment queue limit

Damien Le Moal
2022-04-18T08:00:27Z

On 4/18/22 13:53, Christoph Hellwig wrote:
> The discard_alignment queue limit is named a bit misleading means the
> offset into the block device at which the discard granularity starts.
> Setting it to the discard granularity as done by dm-zoned is mostly
> harmless but also useless.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/md/dm-zoned-target.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
> index cac295cc8840e..0ec5d8b9b1a4e 100644
> --- a/drivers/md/dm-zoned-target.c
> +++ b/drivers/md/dm-zoned-target.c
> @@ -1001,7 +1001,7 @@ static void dmz_io_hints(struct dm_target *ti, struct queue_limits *limits)
> blk_limits_io_min(limits, DMZ_BLOCK_SIZE);
> blk_limits_io_opt(limits, DMZ_BLOCK_SIZE);
>
> - limits->discard_alignment = DMZ_BLOCK_SIZE;
> + limits->discard_alignment = 0;
> limits->discard_granularity = DMZ_BLOCK_SIZE;
> limits->max_discard_sectors = chunk_sectors;
> limits->max_hw_discard_sectors = chunk_sectors
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

--
Damien Le Moal
Western Digital Research