Re: [PATCHv4 3/9] block: export dma_alignment attribute

Eric Biggers
2022-05-26T07:31:01Z

On Wed, May 25, 2022 at 06:06:07PM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
>
> User space may want to know how to align their buffers to avoid
> bouncing. Export the queue attribute.
>
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
> Documentation/ABI/stable/sysfs-block | 9 +++++++++
> block/blk-sysfs.c | 7 +++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
> index e8797cd09aff..08f6d00df138 100644
> --- a/Documentation/ABI/stable/sysfs-block
> +++ b/Documentation/ABI/stable/sysfs-block
> @@ -142,6 +142,15 @@ Description:
> Default value of this file is '1'(on).
>
>
> +What: /sys/block/<disk>/queue/dma_alignment
> +Date: May 2022
> +Contact: linux-block@vger.kernel.org
> +Description:
> + Reports the alignment that user space addresses must have to be
> + used for raw block device access with O_DIRECT and other driver
> + specific passthrough mechanisms.
> +

Please keep this file in alphabetical order.

- Eric