On Fri, Jun 04, 2021 at 07:58:53PM +0000, Satya Tangirala wrote:
> This function returns the required alignment for the number of sectors in
> a bio. In particular, the number of sectors passed to bio_split() must be
> aligned to this value.
>
> Signed-off-by: Satya Tangirala <satyat@xxxxxxxxxx>
> ---
> block/blk.h | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/block/blk.h b/block/blk.h
> index 8b3591aee0a5..c8dcad7dde81 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -262,6 +262,20 @@ static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
> return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
> }
>
> +/*
> + * The required sector alignment for a bio. The number of sectors in any bio
> + * must be aligned to this value.
> + */
> +static inline unsigned int bio_required_sector_alignment(struct bio *bio)
> +{
> + unsigned int alignmask =
> + (bdev_logical_block_size(bio->bi_bdev) >> SECTOR_SHIFT) - 1;
> +
> + alignmask |= blk_crypto_bio_sectors_alignment(bio) - 1;
> +
> + return alignmask + 1;
> +}
Looks fine, but I think we could rework the comment to be a bit easier to
understand:
/*
* Return the number of sectors to which the size of the given bio (and any bios
* split from it) must be aligned.
*
* Normally this is just the disk's logical block size in sectors, but it may be
* greater if the bio has an encryption context.
*/
static inline unsigned int bio_required_sector_alignment(struct bio *bio)
{
unsigned int alignmask =
(bdev_logical_block_size(bio->bi_bdev) >> SECTOR_SHIFT) - 1;
alignmask |= blk_crypto_bio_sectors_alignment(bio) - 1;
return alignmask + 1;
}
