On 04/12/2016 10:39 PM, Bart Van Assche wrote:
> Move the code for rounding down a sector into a new function.
> This patch does not change any functionality.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
> Cc: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
> ---
> block/blk-lib.c | 32 +++++++++++++++++++++++++-------
> 1 file changed, 25 insertions(+), 7 deletions(-)
>
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index 9ebf653..2f4c6b2 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -26,6 +26,26 @@ static void bio_batch_end_io(struct bio *bio)
> bio_put(bio);
> }
>
> +/*
> + * Return the largest number that is less than or equal to @s and for which
> + * the remainder of the division by @granularity is @alignment.
> + */
> +static sector_t blk_round_sect_down(sector_t s, u32 granularity, u32 alignment)
> +{
> + sector_t tmp = s, res = s;
> + u32 remainder;
> +
> + WARN_ON_ONCE(alignment >= granularity);
> +
> + remainder = sector_div(tmp, granularity);
> + if (remainder == alignment)
> + return res;
> + res -= remainder - alignment;
> + if (remainder < alignment)
> + res -= granularity;
> + return min(res, s);
> +}
> +
> /**
> * blkdev_issue_discard - queue a discard
> * @bdev: blockdev to issue discard for
> @@ -73,7 +93,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
> blk_start_plug(&plug);
> while (nr_sects) {
> unsigned int req_sects;
> - sector_t end_sect, tmp;
> + sector_t end_sect;
>
> bio = bio_alloc(gfp_mask, 1);
> if (!bio) {
> @@ -89,12 +109,10 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
> * misaligned, stop the discard at the previous aligned sector.
> */
> end_sect = sector + req_sects;
> - tmp = end_sect;
> - if (req_sects < nr_sects &&
> - sector_div(tmp, granularity) != alignment) {
> - end_sect = end_sect - alignment;
> - sector_div(end_sect, granularity);
> - end_sect = end_sect * granularity + alignment;
> + if (req_sects < nr_sects) {
> + end_sect = blk_round_sect_down(end_sect, granularity,
> + alignment);
> + WARN_ON_ONCE(end_sect < sector);
> req_sects = end_sect - sector;
> }
>
>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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