[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190716184253.GI14271@linux.ibm.com>
Date: Tue, 16 Jul 2019 11:42:53 -0700
From: "Paul E. McKenney" <paulmck@...ux.ibm.com>
To: Joel Fernandes <joel@...lfernandes.org>
Cc: Bjorn Helgaas <helgaas@...nel.org>, linux-kernel@...r.kernel.org,
Alexey Kuznetsov <kuznet@....inr.ac.ru>,
Borislav Petkov <bp@...en8.de>, c0d1n61at3@...il.com,
"David S. Miller" <davem@...emloft.net>, edumazet@...gle.com,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
Jonathan Corbet <corbet@....net>,
Josh Triplett <josh@...htriplett.org>, keescook@...omium.org,
kernel-hardening@...ts.openwall.com, kernel-team@...roid.com,
Lai Jiangshan <jiangshanlai@...il.com>, Len Brown <lenb@...nel.org>,
linux-acpi@...r.kernel.org, linux-doc@...r.kernel.org,
linux-pci@...r.kernel.org, linux-pm@...r.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, neilb@...e.com,
netdev@...r.kernel.org, Oleg Nesterov <oleg@...hat.com>,
Pavel Machek <pavel@....cz>, peterz@...radead.org,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Rasmus Villemoes <rasmus.villemoes@...vas.dk>, rcu@...r.kernel.org,
Steven Rostedt <rostedt@...dmis.org>, Tejun Heo <tj@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>, will@...nel.org,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>
Subject: Re: [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list
iterator (v1)
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) <joel@...lfernandes.org>
> >
> > Ingo takes care of most patches to this file, but FWIW,
> >
> > Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
>
> 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)" <joel@...lfernandes.org>
> 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 <bhelgaas@...gle.com>
> Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
> ---
> 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
>
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
