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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 9D30EC2D0DB for ; Tue, 28 Jan 2020 14:09:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67AFE2468E for ; Tue, 28 Jan 2020 14:09:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220549; bh=a12u6ZQno3SEARFE81JCmxqRlDgmupD0ZouyyLFAnR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zxXoFqR5l20APuGYI+fgH8T1nqwV9RXJbFs12qpEUIXUnL+R6BTd0lH2jrR4Slwg1 19Y7E9evu+4Pdk43sKjseYHKX2Z097/GIHsiDnlNJL7c0Ms1Lj8GxgX4v7d+G3k0a7 9YsDk/Lh6oXG9E2PybUNYZOV9CKCkN7KHkS08pZg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728208AbgA1OJI (ORCPT ); Tue, 28 Jan 2020 09:09:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:57172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727191AbgA1OI5 (ORCPT ); Tue, 28 Jan 2020 09:08:57 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6BB0624681; Tue, 28 Jan 2020 14:08:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580220536; bh=a12u6ZQno3SEARFE81JCmxqRlDgmupD0ZouyyLFAnR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tDb9f86vV5I0R4QCuhBeLL4n88AtnUeGbbOtt2hUoAOlVrywBFx+tOwhESKhltsbh KdKaw6Db+xORjLW7XwRSaJOLffV6vV/T3fRgwW7j/b/h5OKJl1U3B8KsDT7+3LV/qX MigbzUVD01nx0JFYV1fKnBLsZ+ugbCXglT44eC5A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Omar Sandoval , Christoph Hellwig , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 4.4 047/183] block: dont use bio->bi_vcnt to figure out segment number Date: Tue, 28 Jan 2020 15:04:26 +0100 Message-Id: <20200128135834.659113318@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135829.486060649@linuxfoundation.org> References: <20200128135829.486060649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei [ Upstream commit 1a67356e9a4829da2935dd338630a550c59c8489 ] 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 Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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 7225511cf0b48..b8f1eaeeaac25 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -296,13 +296,7 @@ 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))) -- 2.20.1