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=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 E069BC433E0 for ; Sat, 27 Jun 2020 07:32:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD1DF2088E for ; Sat, 27 Jun 2020 07:32:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Y+/+SN3N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726432AbgF0Hcr (ORCPT ); Sat, 27 Jun 2020 03:32:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725994AbgF0Hco (ORCPT ); Sat, 27 Jun 2020 03:32:44 -0400 Received: from casper.infradead.org (unknown [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47DE9C03E979; Sat, 27 Jun 2020 00:32:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=LREORKkL9EawusRPfY+RfGgkga9SJryaB1y7sBbv+3c=; b=Y+/+SN3Nj38jfxO2i3lNtkEEEh p5PU9kxKUEStA039sBaU80FUIIvTpcHFt36RI1FknpmJhMWGKFgiwg7s+Ms4DQI1MtXDPeUM0wIlV 38tOKbh9wlcT5Kj6Ny5CNIX5um8hs4EbmbRw5gwgMH3tffQVM7ubNGIG8NC+S/yEQMYZDHuLWxqmi 9IPc4iePF4IzCvsADXfxFap/nSeBhF4g2Upoi5yYBu1877xEsCRJU4tl1kUnbUmTivqgDceaxmw7y X4I/EqORE71u36SwJMR6c7nexLlV+8Lg6IfBUPe9FwHt6SC1jFfbKqSNrFRrIuHZR74kmPbEayDff UkYW2/YQ==; Received: from [2001:4bb8:184:76e3:595:ba65:ae56:65a6] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jp5Jt-0006mN-VO; Sat, 27 Jun 2020 07:32:14 +0000 From: Christoph Hellwig To: Jens Axboe , Tejun Heo Cc: Dennis Zhou , Li Zefan , Johannes Weiner , dm-devel@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 04/14] block: merge __bio_associate_blkg into bio_associate_blkg_from_css Date: Sat, 27 Jun 2020 09:31:49 +0200 Message-Id: <20200627073159.2447325-5-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200627073159.2447325-1-hch@lst.de> References: <20200627073159.2447325-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Merge __bio_associate_blkg into the only caller, which allows to slightly reduce the RCU crticial section and better explain the code flow. Signed-off-by: Christoph Hellwig --- block/bio.c | 45 +++++++++++++-------------------------------- 1 file changed, 13 insertions(+), 32 deletions(-) diff --git a/block/bio.c b/block/bio.c index e1d01acce8070c..bc8de2432e3645 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1628,52 +1628,33 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src) EXPORT_SYMBOL(bioset_init_from_src); #ifdef CONFIG_BLK_CGROUP - -/** - * __bio_associate_blkg - associate a bio with the a blkg - * @bio: target bio - * @blkg: the blkg to associate - * - * This tries to associate @bio with the specified @blkg. Association failure - * is handled by walking up the blkg tree. Therefore, the blkg associated can - * be anything between @blkg and the root_blkg. This situation only happens - * when a cgroup is dying and then the remaining bios will spill to the closest - * alive blkg. - * - * A reference will be taken on the @blkg and will be released when @bio is - * freed. - */ -static void __bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) -{ - if (bio->bi_blkg) - blkg_put(bio->bi_blkg); - bio->bi_blkg = blkg_tryget_closest(blkg); -} - /** * bio_associate_blkg_from_css - associate a bio with a specified css * @bio: target bio * @css: target css * * Associate @bio with the blkg found by combining the css's blkg and the - * request_queue of the @bio. This falls back to the queue's root_blkg if - * the association fails with the css. + * request_queue of the @bio. An association failure is handled by walking up + * the blkg tree. Therefore, the blkg associated can be anything between @blkg + * and q->root_blkg. This situation only happens when a cgroup is dying and + * then the remaining bios will spill to the closest alive blkg. + * + * A reference will be taken on the blkg and will be released when @bio is + * freed. */ void bio_associate_blkg_from_css(struct bio *bio, struct cgroup_subsys_state *css) { struct request_queue *q = bio->bi_disk->queue; - struct blkcg_gq *blkg; + struct blkcg_gq *blkg = q->root_blkg; - rcu_read_lock(); + if (bio->bi_blkg) + blkg_put(bio->bi_blkg); - if (!css || !css->parent) - blkg = q->root_blkg; - else + rcu_read_lock(); + if (css && css->parent) blkg = blkg_lookup_create(css_to_blkcg(css), q); - - __bio_associate_blkg(bio, blkg); - + bio->bi_blkg = blkg_tryget_closest(blkg); rcu_read_unlock(); } EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); -- 2.26.2