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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 16 Jul 2019 19:42:54 +0100 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x6GIgsHl52756968 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Jul 2019 18:42:54 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EF32DB205F; Tue, 16 Jul 2019 18:42:53 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9394AB2065; Tue, 16 Jul 2019 18:42:53 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.80.225.134]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 16 Jul 2019 18:42:53 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id A30AF16C8F09; Tue, 16 Jul 2019 11:42:53 -0700 (PDT) Date: Tue, 16 Jul 2019 11:42:53 -0700 From: "Paul E. McKenney" To: Joel Fernandes Cc: Bjorn Helgaas , 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 , 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) Reply-To: paulmck@linux.ibm.com References: <20190715143705.117908-1-joel@joelfernandes.org> <20190715143705.117908-8-joel@joelfernandes.org> <20190715200235.GG46935@google.com> <20190716040303.GA73383@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190716040303.GA73383@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19071618-0060-0000-0000-0000035F2730 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011440; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01233109; UDB=6.00649719; IPR=6.01014420; MB=3.00027748; MTD=3.00000008; XFM=3.00000015; UTC=2019-07-16 18:43:02 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19071618-0061-0000-0000-00004A2A24B5 Message-Id: <20190716184253.GI14271@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-16_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907160229 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tue, Jul 16, 2019 at 12:03:03AM -0400, Joel Fernandes wrote: > 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: I am OK with this going either way, but it does depend on an earlier patch. Thanx, Paul > ---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 >