Re: [PATCH v2 0/5] block/md/dm: set chunk_sectors from stacked dev stripe size

[John Garry <john.g.garry@oracle.com>]

On 18/06/2025 09:37, John Garry wrote:
> This value in io_min is used to configure any atomic write limit for the
> stacked device. The idea is that the atomic write unit max is a
> power-of-2 factor of the stripe size, and the stripe size is available
> in io_min.
> 
> Using io_min causes issues, as:
> a. it may be mutated
> b. the check for io_min being set for determining if we are dealing with
> a striped device is hard to get right, as reported in [0].
> 
> This series now sets chunk_sectors limit to share stripe size.

Any more comments here? It would be good to have the md/raid0 and 
md/raid10 changes checked by the md maintainers.

Thanks

> 
> [0] https://lore.kernel.org/linux-block/888f3b1d-7817-4007-b3b3-1a2ea04df771@linux.ibm.com/T/#mecca17129f72811137d3c2f1e477634e77f06781
> 
> Based on v6.16-rc2
> 
> Differences to RFC:
> - sanitize chunk_sectors for atomic write limits
> - set chunk_sectors in stripe_io_hints()
> 
> John Garry (5):
>    block: sanitize chunk_sectors for atomic write limits
>    md/raid0: set chunk_sectors limit
>    md/raid10: set chunk_sectors limit
>    dm-stripe: limit chunk_sectors to the stripe size
>    block: use chunk_sectors when evaluating stacked atomic write limits
> 
>   block/blk-settings.c   | 60 ++++++++++++++++++++++++++----------------
>   drivers/md/dm-stripe.c |  1 +
>   drivers/md/raid0.c     |  1 +
>   drivers/md/raid10.c    |  1 +
>   4 files changed, 40 insertions(+), 23 deletions(-)
>