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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 0D373C33CAF for ; Thu, 16 Jan 2020 18:11:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D46B1214AF for ; Thu, 16 Jan 2020 18:11:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579198316; bh=zNChFXR08NdTIOFIg1dr2d7/a8LewamvBVxJDlfieJM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Xfq+mbEgmhZaiTAN8kEudygwhhBhUoYcnWlQI/88NwPzjyqZkyMMPIyey96K1H3EH dg0UKXXF80npMK73J1jkQRyT1vmuLcxH4zQCUcKuNKS+IELdIKv4eSrn9DGPxSLSM4 1Wt7bvjk0oFv0ZvKcyg05oBJfhiijEeE5wr7C+ZY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393191AbgAPRhX (ORCPT ); Thu, 16 Jan 2020 12:37:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:52554 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393187AbgAPRhW (ORCPT ); Thu, 16 Jan 2020 12:37:22 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D3EB6246C3; Thu, 16 Jan 2020 17:37:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579196241; bh=zNChFXR08NdTIOFIg1dr2d7/a8LewamvBVxJDlfieJM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=suY6Obn9fy1p8RM/CzuTSTPFpr+9tbi0V9T3cPxZbHf4aVwGqmdf6JTnp2HRHyoGN PaIvkFTm29geO6MsFNpuwt+wuSGmYSqQRXWLBiNEfHgMcVkdhFO9RpjK3UGuV40VVy mRT/ddFbQ4zpes0h+mlwJgg78+Z1a9W8serRzPyY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ming Lei , Omar Sandoval , Christoph Hellwig , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 071/251] block: don't use bio->bi_vcnt to figure out segment number Date: Thu, 16 Jan 2020 12:33:40 -0500 Message-Id: <20200116173641.22137-31-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116173641.22137-1-sashal@kernel.org> References: <20200116173641.22137-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@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 2642e5fc8b69..66795cca662a 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