Re: [RFC] block: avoid the unnecessary blk_bio_discard_split()

[Sergei Shtylyov <sergei.shtylyov@gmail.com>]

Hello!

On 06.12.2020 9:15, Tom Yan wrote:

> It doesn't seem necessary to have the redundant layer of splitting.
> The request size will even be more consistent / aligned to the cap.
> 
> Signed-off-by: Tom Yan <tom.ty89@gmail.com>
> ---
>   block/blk-lib.c   | 5 ++++-
>   block/blk-merge.c | 2 +-
>   block/blk.h       | 8 ++++++--
>   3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index e90614fd8d6a..f606184a9050 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -85,9 +85,12 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
>   		 *   is split in device drive, the split ones are very probably
>   		 *   to be aligned to discard_granularity of the device's queue.
>   		 */
> -		if (granularity_aligned_lba == sector_mapped)
> +		if (granularity_aligned_lba == sector_mapped) {
>   			req_sects = min_t(sector_t, nr_sects,
>   					  bio_aligned_discard_max_sectors(q));
> +			if (!req_sects)
> +				return -EOPNOTSUPP;
> +		}
>   		else

    Needs to be } else { according to the CodingStyle doc...

>   			req_sects = min_t(sector_t, nr_sects,
>   					  granularity_aligned_lba - sector_mapped);
[...]

MBR, Sergei