Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 7389db5..6fa42e9 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 @@
 	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 *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;