On Wed, Jun 09, 2021 at 08:45:56AM +0800, Ming Lei wrote:
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index bcdff1879c34..65210e9a8efa 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -724,10 +724,10 @@ static inline bool blk_discard_mergable(struct request *req)
> static enum elv_merge blk_try_req_merge(struct request *req,
> struct request *next)
> {
> - if (blk_discard_mergable(req))
> - return ELEVATOR_DISCARD_MERGE;
> - else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next))
> + if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next))
> return ELEVATOR_BACK_MERGE;
Oh well, this breaks my previous suggestions.
> + struct req_discard_range r;
> +
> + rq_for_each_discard_range(r, req) {
... and I can't say I like this rather complex iterator.
What is the problem of just fixing the raid code to not submit stupidly
small discard requests instead?
