From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 527C3C04AAF for ; Tue, 21 May 2019 08:06:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 118C12173C for ; Tue, 21 May 2019 08:06:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726201AbfEUIGO (ORCPT ); Tue, 21 May 2019 04:06:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34334 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726138AbfEUIGO (ORCPT ); Tue, 21 May 2019 04:06:14 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 84CCE30842A8; Tue, 21 May 2019 08:06:13 +0000 (UTC) Received: from ming.t460p (ovpn-8-24.pek2.redhat.com [10.72.8.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 65C5F5D9C8; Tue, 21 May 2019 08:06:08 +0000 (UTC) Date: Tue, 21 May 2019 16:06:04 +0800 From: Ming Lei To: Christoph Hellwig Cc: axboe@fb.com, linux-block@vger.kernel.org, Hannes Reinecke Subject: Re: [PATCH 4/4] block: remove the bi_seg_{front,back}_size fields in struct bio Message-ID: <20190521080603.GC27095@ming.t460p> References: <20190521070143.22631-1-hch@lst.de> <20190521070143.22631-5-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190521070143.22631-5-hch@lst.de> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Tue, 21 May 2019 08:06:13 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, May 21, 2019 at 09:01:43AM +0200, Christoph Hellwig wrote: > At this point these fields aren't used for anything, so we can remove > them. > > Signed-off-by: Christoph Hellwig > Reviewed-by: Hannes Reinecke > --- > block/blk-merge.c | 94 +++++---------------------------------- > include/linux/blk_types.h | 7 --- > 2 files changed, 12 insertions(+), 89 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index eee2c02c50ce..17713d7d98d5 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -162,8 +162,7 @@ static unsigned get_max_segment_size(struct request_queue *q, > * variables. > */ > static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv, > - unsigned *nsegs, unsigned *last_seg_size, > - unsigned *front_seg_size, unsigned *sectors, unsigned max_segs) > + unsigned *nsegs, unsigned *sectors, unsigned max_segs) > { > unsigned len = bv->bv_len; > unsigned total_len = 0; > @@ -185,28 +184,12 @@ static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv, > break; > } > > - if (!new_nsegs) > - return !!len; > - > - /* update front segment size */ > - if (!*nsegs) { > - unsigned first_seg_size; > - > - if (new_nsegs == 1) > - first_seg_size = get_max_segment_size(q, bv->bv_offset); > - else > - first_seg_size = queue_max_segment_size(q); > - > - if (*front_seg_size < first_seg_size) > - *front_seg_size = first_seg_size; > + if (new_nsegs) { > + *nsegs += new_nsegs; > + if (sectors) > + *sectors += total_len >> 9; > } > > - /* update other varibles */ > - *last_seg_size = seg_size; > - *nsegs += new_nsegs; > - if (sectors) > - *sectors += total_len >> 9; > - > /* split in the middle of the bvec if len != 0 */ > return !!len; > } > @@ -218,8 +201,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, > { > struct bio_vec bv, bvprv, *bvprvp = NULL; > struct bvec_iter iter; > - unsigned seg_size = 0, nsegs = 0, sectors = 0; > - unsigned front_seg_size = bio->bi_seg_front_size; > + unsigned nsegs = 0, sectors = 0; > bool do_split = true; > struct bio *new = NULL; > const unsigned max_sectors = get_max_io_size(q, bio); > @@ -243,8 +225,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, > /* split in the middle of bvec */ > bv.bv_len = (max_sectors - sectors) << 9; > bvec_split_segs(q, &bv, &nsegs, > - &seg_size, > - &front_seg_size, > §ors, max_segs); > } > goto split; > @@ -258,12 +238,9 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, > > if (bv.bv_offset + bv.bv_len <= PAGE_SIZE) { > nsegs++; > - seg_size = bv.bv_len; > sectors += bv.bv_len >> 9; > - if (nsegs == 1 && seg_size > front_seg_size) > - front_seg_size = seg_size; > - } else if (bvec_split_segs(q, &bv, &nsegs, &seg_size, > - &front_seg_size, §ors, max_segs)) { > + } else if (bvec_split_segs(q, &bv, &nsegs, §ors, > + max_segs)) { > goto split; > } > } > @@ -278,10 +255,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, > bio = new; > } > > - bio->bi_seg_front_size = front_seg_size; > - if (seg_size > bio->bi_seg_back_size) > - bio->bi_seg_back_size = seg_size; > - > return do_split ? new : NULL; > } > > @@ -336,17 +309,13 @@ EXPORT_SYMBOL(blk_queue_split); > static unsigned int __blk_recalc_rq_segments(struct request_queue *q, > struct bio *bio) > { > - struct bio_vec uninitialized_var(bv), bvprv = { NULL }; > - unsigned int seg_size, nr_phys_segs; > - unsigned front_seg_size; > - struct bio *fbio, *bbio; > + unsigned int nr_phys_segs = 0; > struct bvec_iter iter; > + struct bio_vec bv; > > if (!bio) > return 0; > > - front_seg_size = bio->bi_seg_front_size; > - > switch (bio_op(bio)) { > case REQ_OP_DISCARD: > case REQ_OP_SECURE_ERASE: > @@ -356,23 +325,11 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, > return 1; > } > > - fbio = bio; > - seg_size = 0; > - nr_phys_segs = 0; > for_each_bio(bio) { > - bio_for_each_bvec(bv, bio, iter) { > - bvec_split_segs(q, &bv, &nr_phys_segs, &seg_size, > - &front_seg_size, NULL, UINT_MAX); > - } > - bbio = bio; > - if (likely(bio->bi_iter.bi_size)) > - bvprv = bv; > + bio_for_each_bvec(bv, bio, iter) > + bvec_split_segs(q, &bv, &nr_phys_segs, NULL, UINT_MAX); > } > > - fbio->bi_seg_front_size = front_seg_size; > - if (seg_size > bbio->bi_seg_back_size) > - bbio->bi_seg_back_size = seg_size; > - > return nr_phys_segs; > } > > @@ -392,24 +349,6 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio) > bio_set_flag(bio, BIO_SEG_VALID); > } > > -static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, > - struct bio *nxt) > -{ > - struct bio_vec end_bv = { NULL }, nxt_bv; > - > - if (bio->bi_seg_back_size + nxt->bi_seg_front_size > > - queue_max_segment_size(q)) > - return 0; > - > - if (!bio_has_data(bio)) > - return 1; > - > - bio_get_last_bvec(bio, &end_bv); > - bio_get_first_bvec(nxt, &nxt_bv); > - > - return biovec_phys_mergeable(q, &end_bv, &nxt_bv); > -} > - > static inline struct scatterlist *blk_next_sg(struct scatterlist **sg, > struct scatterlist *sglist) > { > @@ -669,8 +608,6 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, > struct request *next) > { > int total_phys_segments; > - unsigned int seg_size = > - req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; > > if (req_gap_back_merge(req, next->bio)) > return 0; > @@ -683,13 +620,6 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, > return 0; > > total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; > - if (blk_phys_contig_segment(q, req->biotail, next->bio)) { > - if (req->nr_phys_segments == 1) > - req->bio->bi_seg_front_size = seg_size; > - if (next->nr_phys_segments == 1) > - next->biotail->bi_seg_back_size = seg_size; > - } > - > if (total_phys_segments > queue_max_segments(q)) > return 0; > > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index be418275763c..95202f80676c 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -159,13 +159,6 @@ struct bio { > */ > unsigned int bi_phys_segments; > > - /* > - * To keep track of the max segment size, we account for the > - * sizes of the first and last mergeable segments in this bio. > - */ > - unsigned int bi_seg_front_size; > - unsigned int bi_seg_back_size; > - > struct bvec_iter bi_iter; > > atomic_t __bi_remaining; > -- > 2.20.1 > Reviewed-by: Ming Lei Thanks, Ming