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 31576C2D0DB for ; Tue, 28 Jan 2020 14:38:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F292C20716 for ; Tue, 28 Jan 2020 14:38:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580222281; bh=a7hZ0I9DVi8FQ2vUmwYlY7OO1gbwxmdrjRY9e4lKIj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hFvK+EbPhhYrAzIrnJmBgkd0i0Yd0Gjm5z8l9BC4tmNKNbffp8ibukBZTkCU6MVMk u4gVa0n1lg1nPvKf656Ve4v9w+sp18KKD+LMDPEF+l8WJll8gQHbvfA08QfdTUD+nf QEF0IaFy6gJFbhjLVMor+zoC2nJzSzIBOVxk/xEM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730860AbgA1OTU (ORCPT ); Tue, 28 Jan 2020 09:19:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:43550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729866AbgA1OTO (ORCPT ); Tue, 28 Jan 2020 09:19:14 -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 EC17724681; Tue, 28 Jan 2020 14:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580221154; bh=a7hZ0I9DVi8FQ2vUmwYlY7OO1gbwxmdrjRY9e4lKIj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a18755Vb178SkAtxCkIeE1ybA5KhadM5M/CpwL+fBLvHb+BEZ6WAHZoRreyB6Sk5r DEEV4BIDD6B+lri9fAmA86sUmDeeTZAug+/rbWM9KKO7Q2IQ9w/hSP1PBLUc7S/mDf 2xbDq32WqZE8Kj14N93GqSpxuKUUF57Ot7z0Ry48= 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 4.9 073/271] block: dont use bio->bi_vcnt to figure out segment number Date: Tue, 28 Jan 2020 15:03:42 +0100 Message-Id: <20200128135858.012132990@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135852.449088278@linuxfoundation.org> References: <20200128135852.449088278@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 2642e5fc8b69a..66795cca662a3 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -305,13 +305,7 @@ 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