From patchwork Mon Jan 21 08:17:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 10773127 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8111F13BF for ; Mon, 21 Jan 2019 08:19:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7305B28BEB for ; Mon, 21 Jan 2019 08:19:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6649D29E63; Mon, 21 Jan 2019 08:19:01 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI 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 1BA8529E65 for ; Mon, 21 Jan 2019 08:19:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729051AbfAUISz (ORCPT ); Mon, 21 Jan 2019 03:18:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44980 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728673AbfAUISy (ORCPT ); Mon, 21 Jan 2019 03:18:54 -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 264568535D; Mon, 21 Jan 2019 08:18:54 +0000 (UTC) Received: from localhost (ovpn-8-22.pek2.redhat.com [10.72.8.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 78F0E5D737; Mon, 21 Jan 2019 08:18:35 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Theodore Ts'o , Omar Sandoval , Sagi Grimberg , Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com, Ming Lei Subject: [PATCH V14 02/18] block: don't use bio->bi_vcnt to figure out segment number Date: Mon, 21 Jan 2019 16:17:49 +0800 Message-Id: <20190121081805.32727-3-ming.lei@redhat.com> In-Reply-To: <20190121081805.32727-1-ming.lei@redhat.com> References: <20190121081805.32727-1-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 [10.5.110.25]); Mon, 21 Jan 2019 08:18:54 +0000 (UTC) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It is wrong to use bio->bi_vcnt to figure out how many segments there are in the bio even though CLONED flag isn't set on this bio, because this bio may be splitted or advanced. So always use bio_segments() in blk_recount_segments(), and it shouldn't cause any performance loss now because the physical segment number is figured out in blk_queue_split() and BIO_SEG_VALID is set meantime since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"). Reviewed-by: Omar Sandoval Reviewed-by: Christoph Hellwig Fixes: 76d8137a3113 ("blk-merge: recaculate segment if it isn't less than max segments") Signed-off-by: Ming Lei --- block/blk-merge.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 71e9ac03f621..f85d878f313d 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -367,13 +367,7 @@ void blk_recalc_rq_segments(struct request *rq) void blk_recount_segments(struct request_queue *q, struct bio *bio) { - unsigned short seg_cnt; - - /* estimate segment number by bi_vcnt for non-cloned bio */ - if (bio_flagged(bio, BIO_CLONED)) - seg_cnt = bio_segments(bio); - else - seg_cnt = bio->bi_vcnt; + unsigned short seg_cnt = bio_segments(bio); if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && (seg_cnt < queue_max_segments(q)))