PCI: hotplug: Use global PCI rescan-remove locking

Multiple race conditions are possible between PCI hotplug and the generic
PCI bus rescan and device removal that can be triggered via sysfs.

To avoid those race conditions make PCI hotplug use global PCI
rescan-remove locking.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
index b7fc5c9..4796c15 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -398,7 +398,9 @@
 		return retval;
 
 	if (state == PRESENT) {
+		pci_lock_rescan_remove();
 		pcibios_add_pci_devices(slot->bus);
+		pci_unlock_rescan_remove();
 		slot->state = CONFIGURED;
 	} else if (state == EMPTY) {
 		slot->state = EMPTY;
@@ -418,7 +420,9 @@
 	if (slot->state == NOT_CONFIGURED)
 		return -EINVAL;
 
+	pci_lock_rescan_remove();
 	pcibios_remove_pci_devices(slot->bus);
+	pci_unlock_rescan_remove();
 	vm_unmap_aliases();
 
 	slot->state = NOT_CONFIGURED;