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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 56347C43610 for ; Thu, 15 Nov 2018 08:54:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A9862077C for ; Thu, 15 Nov 2018 08:54:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A9862077C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387784AbeKOTBT (ORCPT ); Thu, 15 Nov 2018 14:01:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59216 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728564AbeKOTBT (ORCPT ); Thu, 15 Nov 2018 14:01:19 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 980BA30024FC; Thu, 15 Nov 2018 08:54:24 +0000 (UTC) Received: from localhost (ovpn-8-23.pek2.redhat.com [10.72.8.23]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B4F55D739; Thu, 15 Nov 2018 08:54:13 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ming Lei , Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , Theodore Ts'o , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com Subject: [PATCH V10 04/19] block: use bio_for_each_bvec() to map sg Date: Thu, 15 Nov 2018 16:52:51 +0800 Message-Id: <20181115085306.9910-5-ming.lei@redhat.com> In-Reply-To: <20181115085306.9910-1-ming.lei@redhat.com> References: <20181115085306.9910-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Thu, 15 Nov 2018 08:54:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is more efficient to use bio_for_each_bvec() to map sg, meantime we have to consider splitting multipage bvec as done in blk_bio_segment_split(). Cc: Dave Chinner Cc: Kent Overstreet Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Shaohua Li Cc: linux-raid@vger.kernel.org Cc: linux-erofs@lists.ozlabs.org Cc: David Sterba Cc: linux-btrfs@vger.kernel.org Cc: Darrick J. Wong Cc: linux-xfs@vger.kernel.org Cc: Gao Xiang Cc: Christoph Hellwig Cc: Theodore Ts'o Cc: linux-ext4@vger.kernel.org Cc: Coly Li Cc: linux-bcache@vger.kernel.org Cc: Boaz Harrosh Cc: Bob Peterson Cc: cluster-devel@redhat.com Signed-off-by: Ming Lei --- block/blk-merge.c | 72 +++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 52 insertions(+), 20 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 6f7deb94a23f..cb9f49bcfd36 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -473,6 +473,56 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, return biovec_phys_mergeable(q, &end_bv, &nxt_bv); } +static struct scatterlist *blk_next_sg(struct scatterlist **sg, + struct scatterlist *sglist) +{ + if (!*sg) + return sglist; + else { + /* + * If the driver previously mapped a shorter + * list, we could see a termination bit + * prematurely unless it fully inits the sg + * table on each mapping. We KNOW that there + * must be more entries here or the driver + * would be buggy, so force clear the + * termination bit to avoid doing a full + * sg_init_table() in drivers for each command. + */ + sg_unmark_end(*sg); + return sg_next(*sg); + } +} + +static unsigned blk_bvec_map_sg(struct request_queue *q, + struct bio_vec *bvec, struct scatterlist *sglist, + struct scatterlist **sg) +{ + unsigned nbytes = bvec->bv_len; + unsigned nsegs = 0, total = 0; + + while (nbytes > 0) { + unsigned seg_size; + struct page *pg; + unsigned offset, idx; + + *sg = blk_next_sg(sg, sglist); + + seg_size = min(nbytes, queue_max_segment_size(q)); + offset = (total + bvec->bv_offset) % PAGE_SIZE; + idx = (total + bvec->bv_offset) / PAGE_SIZE; + pg = nth_page(bvec->bv_page, idx); + + sg_set_page(*sg, pg, seg_size, offset); + + total += seg_size; + nbytes -= seg_size; + nsegs++; + } + + return nsegs; +} + static inline void __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, struct scatterlist *sglist, struct bio_vec *bvprv, @@ -490,25 +540,7 @@ __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, (*sg)->length += nbytes; } else { new_segment: - if (!*sg) - *sg = sglist; - else { - /* - * If the driver previously mapped a shorter - * list, we could see a termination bit - * prematurely unless it fully inits the sg - * table on each mapping. We KNOW that there - * must be more entries here or the driver - * would be buggy, so force clear the - * termination bit to avoid doing a full - * sg_init_table() in drivers for each command. - */ - sg_unmark_end(*sg); - *sg = sg_next(*sg); - } - - sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); - (*nsegs)++; + (*nsegs) += blk_bvec_map_sg(q, bvec, sglist, sg); } *bvprv = *bvec; } @@ -530,7 +562,7 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, int cluster = blk_queue_cluster(q), nsegs = 0; for_each_bio(bio) - bio_for_each_segment(bvec, bio, iter) + bio_for_each_bvec(bvec, bio, iter) __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, &nsegs, &cluster); -- 2.9.5