s390/pci: prevent inadvertently triggered bus scans

Initialization and scanning of the pci bus is omitted on older
machines without pci support or if pci=off was specified. Remember
the fact that we ran without pci support and prevent further bus
scans during resume from hibernate or after receiving hotplug
notifications.

Reported-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index bf7c73d71eef..e3265b50f3ae 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -920,6 +920,7 @@ static void zpci_mem_exit(void)
 }
 
 static unsigned int s390_pci_probe;
+static unsigned int s390_pci_initialized;
 
 char * __init pcibios_setup(char *str)
 {
@@ -930,6 +931,11 @@ char * __init pcibios_setup(char *str)
 	return str;
 }
 
+bool zpci_is_enabled(void)
+{
+	return s390_pci_initialized;
+}
+
 static int __init pci_base_init(void)
 {
 	int rc;
@@ -961,6 +967,7 @@ static int __init pci_base_init(void)
 	if (rc)
 		goto out_find;
 
+	s390_pci_initialized = 1;
 	return 0;
 
 out_find:
@@ -978,5 +985,6 @@ subsys_initcall_sync(pci_base_init);
 
 void zpci_rescan(void)
 {
-	clp_rescan_pci_devices_simple();
+	if (zpci_is_enabled())
+		clp_rescan_pci_devices_simple();
 }