Messages in this thread | | | Date | Fri, 16 Nov 2018 14:58:03 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH V10 18/19] block: kill QUEUE_FLAG_NO_SG_MERGE |
| |
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. > > Cc: Dave Chinner <dchinner@redhat.com> > Cc: Kent Overstreet <kent.overstreet@gmail.com> > Cc: Mike Snitzer <snitzer@redhat.com> > Cc: dm-devel@redhat.com > Cc: Alexander Viro <viro@zeniv.linux.org.uk> > Cc: linux-fsdevel@vger.kernel.org > Cc: Shaohua Li <shli@kernel.org> > Cc: linux-raid@vger.kernel.org > Cc: linux-erofs@lists.ozlabs.org > Cc: David Sterba <dsterba@suse.com> > Cc: linux-btrfs@vger.kernel.org > Cc: Darrick J. Wong <darrick.wong@oracle.com> > Cc: linux-xfs@vger.kernel.org > Cc: Gao Xiang <gaoxiang25@huawei.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Theodore Ts'o <tytso@mit.edu> > Cc: linux-ext4@vger.kernel.org > Cc: Coly Li <colyli@suse.de> > Cc: linux-bcache@vger.kernel.org > Cc: Boaz Harrosh <ooo@electrozaur.com> > Cc: Bob Peterson <rpeterso@redhat.com> > Cc: cluster-devel@redhat.com > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > block/blk-merge.c | 31 ++++++------------------------- > block/blk-mq-debugfs.c | 1 - > block/blk-mq.c | 3 --- > drivers/md/dm-table.c | 13 ------------- > include/linux/blkdev.h | 1 - > 5 files changed, 6 insertions(+), 43 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 153a659fde74..06be298be332 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -351,8 +351,7 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) > EXPORT_SYMBOL(blk_queue_split); > > static unsigned int __blk_recalc_rq_segments(struct request_queue *q, > - struct bio *bio, > - bool no_sg_merge) > + struct bio *bio) > { > struct bio_vec bv, bvprv = { NULL }; > int cluster, prev = 0; > @@ -379,13 +378,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, > nr_phys_segs = 0; > for_each_bio(bio) { > bio_for_each_bvec(bv, bio, iter) { > - /* > - * If SG merging is disabled, each bio vector is > - * a segment > - */ > - if (no_sg_merge) > - goto new_segment; > - > if (prev && cluster) { > if (seg_size + bv.bv_len > > queue_max_segment_size(q)) > @@ -420,27 +412,16 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, > > void blk_recalc_rq_segments(struct request *rq) > { > - bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, > - &rq->q->queue_flags); > - > - rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, > - no_sg_merge); > + rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
Can we rename __blk_recalc_rq_segments to blk_recalc_rq_segments can kill the old blk_recalc_rq_segments now?
Otherwise looks fine:
Reviewed-by: Christoph Hellwig <hch@lst.de>
| |