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 ADE23C33CAF for ; Thu, 16 Jan 2020 19:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F6652072E for ; Thu, 16 Jan 2020 19:07:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579201657; bh=VH6Ot6iZUhwLCZjJgw6dRkJxF8WjyXnJUUWjVLlB6WM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rFVQ3/L9fGfWIX3SfT8Xx/1JyShwMS6gzZgKHgnzePhJWxyfW7bqiIOSwZ+8Ydc0b 3vGXHoJHGdJYPl9wWo0TxAXlR/HQoiCEUNxrZFRN/en4/2/z+WABMyBnmUg8/p7S5r RsqBccRYByG8TMjbemwQ8Bcw6JvkuwS9PtivbNWo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437383AbgAPTHg (ORCPT ); Thu, 16 Jan 2020 14:07:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:52058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388049AbgAPRBP (ORCPT ); Thu, 16 Jan 2020 12:01:15 -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 C806520730; Thu, 16 Jan 2020 17:01:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194075; bh=VH6Ot6iZUhwLCZjJgw6dRkJxF8WjyXnJUUWjVLlB6WM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U1fG0Y0vF60f94ebjswDzcvAHvcknAN8jiF0vHmCB/Qz6y5w9WpZPi0tLE9GMcj6u 40ny+6XWbBIfXDzcZT+aDAi2tICToAltw6xgx/ZeNOzcIE9YDWXnZyw669V9nv77XK N8Xdr+SNe7mlGfzvICElV1jo6wCzr+csG9uZOhyY= 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 4.19 182/671] block: don't use bio->bi_vcnt to figure out segment number Date: Thu, 16 Jan 2020 11:51:31 -0500 Message-Id: <20200116165940.10720-65-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116165940.10720-1-sashal@kernel.org> References: <20200116165940.10720-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 2776ee6c5c3d..7efa8c3e2b72 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -309,13 +309,7 @@ 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