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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 9B6A2C76195 for ; Tue, 16 Jul 2019 04:03:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 745F921721 for ; Tue, 16 Jul 2019 04:03:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="EUayzWAA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726463AbfGPEDH (ORCPT ); Tue, 16 Jul 2019 00:03:07 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:32904 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725770AbfGPEDH (ORCPT ); Tue, 16 Jul 2019 00:03:07 -0400 Received: by mail-pg1-f194.google.com with SMTP id m4so8744604pgk.0 for ; Mon, 15 Jul 2019 21:03:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=emWs4O8hlB2TIuNtkX4TCZFbfAkCg1SZuUU8yDd2sEA=; b=EUayzWAAPKzWkqzvEU0EkCIPVbFaXgTPLnhPDPXNEGqZowkwVyB0fuRja+ukvx2jRx /JsAJvv2ngG4+HyMb/ksTKGTTuCNw6tiK8jigG3DyiGHLTshKdgdlpd3cg/yvXQ34IXh LxYQ1MLKK8X//mQ7Xm/s6D4lgquYO/nzn6BMw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=emWs4O8hlB2TIuNtkX4TCZFbfAkCg1SZuUU8yDd2sEA=; b=dceGd1TnifJ24B3el4lADlrY3vcrbmnN1N54PqrLilxaLsV73rHaF0yjH6lTJ+woQr tmAWSBDvQL8Wjlzuh9olSArG75dcUYehBAgc9U+k7WIV5cJWs1Yuluq7Xl8AEjFDffYn DBAJ3oYNfmzgUMCqb536Z5EtSailIhdU5S4Hk5cIZEvvRKCsK9xcUCKs8Ick8p19wK75 +zT0WsFE1QLZDCY8WMtPI9nVGLXwmC/gR9N+bUop8b16HxffFCOZcXwEpxJwPaW6I7TY b3W7uMkvCGn1KGdM4SOnK022lTNz42qS+60b4Arv1WswP5o5xRcMARFaCc5eJQZ6vE1V 3yOg== X-Gm-Message-State: APjAAAUZUs3l1eAF0anJ81mXBWZyvIRGt4AU5BSMgFVA11NahuEQveVo Y8RjhvicKvjlakyemGjckEc= X-Google-Smtp-Source: APXvYqxyHJD5IpHHcJaM1ojDiiimToJpqwPzyUOe3rbN2WwHYdOcsvYOosL3yD4qnxS7tzykZLERPg== X-Received: by 2002:a17:90a:374a:: with SMTP id u68mr33288835pjb.4.1563249786384; Mon, 15 Jul 2019 21:03:06 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id y133sm21032895pfb.28.2019.07.15.21.03.04 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 15 Jul 2019 21:03:05 -0700 (PDT) Date: Tue, 16 Jul 2019 00:03:03 -0400 From: Joel Fernandes To: Bjorn Helgaas Cc: linux-kernel@vger.kernel.org, Alexey Kuznetsov , Borislav Petkov , c0d1n61at3@gmail.com, "David S. Miller" , edumazet@google.com, Greg Kroah-Hartman , Hideaki YOSHIFUJI , "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Josh Triplett , keescook@chromium.org, kernel-hardening@lists.openwall.com, kernel-team@android.com, Lai Jiangshan , Len Brown , linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Mathieu Desnoyers , neilb@suse.com, netdev@vger.kernel.org, Oleg Nesterov , "Paul E. McKenney" , Pavel Machek , peterz@infradead.org, "Rafael J. Wysocki" , Rasmus Villemoes , rcu@vger.kernel.org, Steven Rostedt , Tejun Heo , Thomas Gleixner , will@kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator (v1) Message-ID: <20190716040303.GA73383@google.com> References: <20190715143705.117908-1-joel@joelfernandes.org> <20190715143705.117908-8-joel@joelfernandes.org> <20190715200235.GG46935@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190715200235.GG46935@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Mon, Jul 15, 2019 at 03:02:35PM -0500, Bjorn Helgaas wrote: > On Mon, Jul 15, 2019 at 10:37:03AM -0400, Joel Fernandes (Google) wrote: > > The pcm_mmcfg_list is traversed with list_for_each_entry_rcu without a > > reader-lock held, because the pci_mmcfg_lock is already held. Make this > > known to the list macro so that it fixes new lockdep warnings that > > trigger due to lockdep checks added to list_for_each_entry_rcu(). > > > > Signed-off-by: Joel Fernandes (Google) > > Ingo takes care of most patches to this file, but FWIW, > > Acked-by: Bjorn Helgaas Thanks. > I would personally prefer if you capitalized the subject to match the > "x86/PCI:" convention that's used fairly consistently in > arch/x86/pci/. > > Also, I didn't apply this to be sure, but it looks like this might > make a line or two wider than 80 columns, which I would rewrap if I > were applying this. Updated below is the patch with the nits corrected: ---8<----------------------- >From 73fab09d7e33ca2110c24215f8ed428c12625dbe Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Sat, 1 Jun 2019 15:05:49 -0400 Subject: [PATCH] x86/PCI: Pass lockdep condition to pcm_mmcfg_list iterator (v1) The pcm_mmcfg_list is traversed with list_for_each_entry_rcu without a reader-lock held, because the pci_mmcfg_lock is already held. Make this known to the list macro so that it fixes new lockdep warnings that trigger due to lockdep checks added to list_for_each_entry_rcu(). Acked-by: Bjorn Helgaas Signed-off-by: Joel Fernandes (Google) --- arch/x86/pci/mmconfig-shared.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c index 7389db538c30..9e3250ec5a37 100644 --- a/arch/x86/pci/mmconfig-shared.c +++ b/arch/x86/pci/mmconfig-shared.c @@ -29,6 +29,7 @@ static bool pci_mmcfg_running_state; static bool pci_mmcfg_arch_init_failed; static DEFINE_MUTEX(pci_mmcfg_lock); +#define pci_mmcfg_lock_held() lock_is_held(&(pci_mmcfg_lock).dep_map) LIST_HEAD(pci_mmcfg_list); @@ -54,7 +55,8 @@ static void list_add_sorted(struct pci_mmcfg_region *new) struct pci_mmcfg_region *cfg; /* keep list sorted by segment and starting bus number */ - list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) { + list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list, + pci_mmcfg_lock_held()) { if (cfg->segment > new->segment || (cfg->segment == new->segment && cfg->start_bus >= new->start_bus)) { @@ -118,7 +120,8 @@ struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus) { struct pci_mmcfg_region *cfg; - list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) + list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list + pci_mmcfg_lock_held()) if (cfg->segment == segment && cfg->start_bus <= bus && bus <= cfg->end_bus) return cfg; -- 2.22.0.510.g264f2c817a-goog