[PATCH RFC 01/16] block: Add atomic write operations to request_queue limits

[Mike Snitzer]

On Wed, May 3, 2023 at 2:40 PM John Garry <john.g.garry at oracle.com> wrote:
>
> From: Himanshu Madhani <himanshu.madhani at oracle.com>
>
> Add the following limits:
> - atomic_write_boundary
> - atomic_write_max_bytes
> - atomic_write_unit_max
> - atomic_write_unit_min
>
> Signed-off-by: Himanshu Madhani <himanshu.madhani at oracle.com>
> Signed-off-by: John Garry <john.g.garry at oracle.com>
> ---
>  Documentation/ABI/stable/sysfs-block | 42 +++++++++++++++++++++
>  block/blk-settings.c                 | 56 ++++++++++++++++++++++++++++
>  block/blk-sysfs.c                    | 33 ++++++++++++++++
>  include/linux/blkdev.h               | 23 ++++++++++++
>  4 files changed, 154 insertions(+)
>

...

> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 896b4654ab00..e21731715a12 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -59,6 +59,9 @@ void blk_set_default_limits(struct queue_limits *lim)
>         lim->zoned = BLK_ZONED_NONE;
>         lim->zone_write_granularity = 0;
>         lim->dma_alignment = 511;
> +       lim->atomic_write_unit_min = lim->atomic_write_unit_max = 1;
> +       lim->atomic_write_max_bytes = 512;
> +       lim->atomic_write_boundary = 0;
>  }

Not seeing required changes to blk_set_stacking_limits() nor blk_stack_limits().

Sorry to remind you of DM and MD limits stacking requirements. ;)

Mike