Re: [PATCH V10 18/19] block: kill QUEUE_FLAG_NO_SG_MERGE

Omar Sandoval
2018-11-16T02:18:17Z

On Thu, Nov 15, 2018 at 04:53:05PM +0800, Ming Lei wrote:
> Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"),
> physical segment number is mainly figured out in blk_queue_split() for
> fast path, and the flag of BIO_SEG_VALID is set there too.
>
> Now only blk_recount_segments() and blk_recalc_rq_segments() use this
> flag.
>
> Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID
> is set in blk_queue_split().
>
> For another user of blk_recalc_rq_segments():
>
> - run in partial completion branch of blk_update_request, which is an unusual case
>
> - run in blk_cloned_rq_check_limits(), still not a big problem if the flag is killed
> since dm-rq is the only user.
>
> Multi-page bvec is enabled now, QUEUE_FLAG_NO_SG_MERGE doesn't make sense any more.

This commit message wasn't very clear. Is it the case that
QUEUE_FLAG_NO_SG_MERGE is no longer set by any drivers?