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Date: Sat,  1 Jun 2019 18:27:37 -0400
From: "Joel Fernandes (Google)" <joel@...lfernandes.org>
To: linux-kernel@...r.kernel.org
Cc: "Joel Fernandes (Google)" <joel@...lfernandes.org>,
	Alexey Kuznetsov <kuznet@....inr.ac.ru>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Borislav Petkov <bp@...en8.de>,
	"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>,
	Josh Triplett <josh@...htriplett.org>,
	keescook@...omium.org,
	kernel-hardening@...ts.openwall.com,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Len Brown <lenb@...nel.org>,
	linux-acpi@...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@...hat.com,
	"Paul E. McKenney" <paulmck@...ux.ibm.com>,
	Pavel Machek <pavel@....cz>,
	peterz@...radead.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	rcu@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>,
	Tejun Heo <tj@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Subject: [RFC 5/6] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator

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>
---
 arch/x86/pci/mmconfig-shared.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 7389db538c30..6fa42e9c4e6f 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 +55,7 @@ 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 +119,7 @@ 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.rc1.311.g5d7573a151-goog

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