Re: [PATCH 2/3] block: cap atomic write size by PI buffer size constraints

[John Garry <john.garry@linux.dev>]

On 9/7/26 08:40, Christoph Hellwig wrote:
> As Sashiko points out, 

Do you have a reference for that? I'm just curious, as we don't support 
atomics for integrity writes. Well, for SCSI we don't... we impose this 
restriction via sd_config_atomic(), I need to check for the same in NVMe...

> limiting the I/O size by the size of the available
> PI buffer can cause inconsistencies for atomic writes.  This also limit
> atomic_write_max_sectors in blk_validate_integrity_limits.
> 
> Fixes: ec7f31b2a2d3 ("block: make bio auto-integrity deadlock safe")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-settings.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 8274631290db..e469baa1f08b 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -206,6 +206,12 @@ static int blk_validate_integrity_limits(struct queue_limits *lim)
>   	lim->max_sectors = min(lim->max_sectors,
>   		max_integrity_io_size(lim) >> SECTOR_SHIFT);
>   
> +	if (lim->features & BLK_FEAT_ATOMIC_WRITES) {
> +		lim->atomic_write_max_sectors =
> +			min(lim->atomic_write_max_sectors,
> +				max_integrity_io_size(lim) >> SECTOR_SHIFT);
> +	}
> +
>   	return 0;
>   }
>