x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator

The pcm_mmcfg_list is traversed by list_for_each_entry_rcu() outside
of an RCU read-side critical section, which is safe because the
pci_mmcfg_lock is held.  This commit therefore adds a lockdep expression
to list_for_each_entry_rcu() in order t avoid lockdep warnings.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 7389db5..6fa42e9 100644 (file)
--- 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;