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. [0] https://lore.kernel.org/linux-block/888f3b1d-7817-4007-b3b3-1a2ea04df...@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(-) -- 2.31.1
