From patchwork Sat Oct 29 08:08:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 9403211 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 177236070E for ; Sat, 29 Oct 2016 08:15:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02BEF2A597 for ; Sat, 29 Oct 2016 08:15:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EB9E82A5EA; Sat, 29 Oct 2016 08:15:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,FREEMAIL_FROM,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8A1FE2A597 for ; Sat, 29 Oct 2016 08:15:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934089AbcJ2IP0 (ORCPT ); Sat, 29 Oct 2016 04:15:26 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:33282 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938605AbcJ2IPV (ORCPT ); Sat, 29 Oct 2016 04:15:21 -0400 Received: by mail-pf0-f193.google.com with SMTP id a136so2852pfa.0; Sat, 29 Oct 2016 01:15:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=OegHRT2bTP7Zr2dkh/52Y4tLxCGUwHOCAxAMWABB3xI=; b=qDzk9ReJEnr4UPJ0y92nTPZhxYO+E+otOtetCujdYBI2qpump7Ldveyq25LBsHvASS ivPPECXizVHi9xjh94stermbvsLuZnJSwJ6gP7BRQp4xgWCmrsTDOrWlCs83DGkbAaw0 9VppOU6z9siMAZTv3sqEhY01Mv3l2WGBS02GSIx5H5GBgu4LT7/B5jhWCsoDvmMGUOro RTERKS7Mi/X6Ll+DwYsd1aKohiNX7lgV+EQmcTqiV79qkXRa9G9FB2vgsN4T/g6M93th dWpYEQ7axbN7jr3ZqMpIRQIFJ/ijgqu5TiFU6y5QSiXqVXO1/+895XzsqPrOsCM/vwxD dxNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=OegHRT2bTP7Zr2dkh/52Y4tLxCGUwHOCAxAMWABB3xI=; b=VzXYrmq3a+Rt3hY9dZLGPuLg9jH+2nHQEsyqaCrfXBlobBKP7c9i4G0M+qDEinW95f s9Jw3mW38f/GXhHF56+GKZ/FOoR3eAVM9qUI+neU76haMR0aX77ctkNk+eVWhtaKH2tK E3DBm+rx3hSl2QO3fbPiSeejC2usruJWFP4uNuEZUaOgWwbDlzX8SCQV4ao8GcYaqnx2 QkHSnq0Gd6YM+XhKx27fx1w769xHwCn9zjvW7UjaVRrDmkojq3J+QjodrbjCYFiCwFRD FRQBTU9XPJD2xL66NtqoDNmIChNQ2JT9dDevKAMviqw2N/G1iowRDeP2uuxpYLEmv3B5 wCFA== X-Gm-Message-State: ABUngvdYtb0UnMy5EJCpErQ91rwj9tCOnLLVc+CeiTOEYH6v7TC7Lc2VAaTSGE1VnzcITA== X-Received: by 10.98.138.219 with SMTP id o88mr32197646pfk.52.1477728915321; Sat, 29 Oct 2016 01:15:15 -0700 (PDT) Received: from localhost ([45.34.23.101]) by smtp.gmail.com with ESMTPSA id u10sm23562806pau.32.2016.10.29.01.15.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 29 Oct 2016 01:15:14 -0700 (PDT) From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , "Kirill A . Shutemov" , Ming Lei , Jens Axboe Subject: [PATCH 43/60] block: use bio_for_each_segment_mp() to map sg Date: Sat, 29 Oct 2016 16:08:42 +0800 Message-Id: <1477728600-12938-44-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> References: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It is more efficient to use bio_for_each_segment_mp() for mapping sg, meantime we have to consider splitting multipage bvec as done in blk_bio_segment_split(). 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 9142f1fc914b..e3b8cbc8b675 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -442,6 +442,56 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, return 0; } +static inline 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 inline 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, @@ -475,25 +525,7 @@ __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); /* for making iterator happy */ bvec->bv_offset -= advance; @@ -536,7 +568,7 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, } for_each_bio(bio) - bio_for_each_segment(bvec, bio, iter) + bio_for_each_segment_mp(bvec, bio, iter) __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, &nsegs, &cluster);