s390/pci: fix hotplug module init

Loading the pci hotplug module when no devices are present will fail
but unfortunately some hotplug callbacks stay registered to the pci
bus level. Fix this by not letting module loading fail when no pci
devices are present and provide proper {de}registration functions
for these callbacks.

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, 25 insertions, 33 deletions

diff --git a/drivers/pci/hotplug/s390_pci_hpc.c b/drivers/pci/hotplug/s390_pci_hpc.c
index 8fe2a8aa89a1..7db249a25016 100644
--- a/drivers/pci/hotplug/s390_pci_hpc.c
+++ b/drivers/pci/hotplug/s390_pci_hpc.c
@@ -172,25 +172,6 @@ error:
 	return -ENOMEM;
 }
 
-static int __init init_pci_slots(void)
-{
-	struct zpci_dev *zdev;
-	int device = 0;
-
-	/*
-	 * Create a structure for each slot, and register that slot
-	 * with the pci_hotplug subsystem.
-	 */
-	mutex_lock(&zpci_list_lock);
-	list_for_each_entry(zdev, &zpci_list, entry) {
-		init_pci_slot(zdev);
-		device++;
-	}
-
-	mutex_unlock(&zpci_list_lock);
-	return (device) ? 0 : -ENODEV;
-}
-
 static void exit_pci_slot(struct zpci_dev *zdev)
 {
 	struct list_head *tmp, *n;
@@ -205,6 +186,26 @@ static void exit_pci_slot(struct zpci_dev *zdev)
 	}
 }
 
+static struct pci_hp_callback_ops hp_ops = {
+	.create_slot = init_pci_slot,
+	.remove_slot = exit_pci_slot,
+};
+
+static void __init init_pci_slots(void)
+{
+	struct zpci_dev *zdev;
+
+	/*
+	 * Create a structure for each slot, and register that slot
+	 * with the pci_hotplug subsystem.
+	 */
+	mutex_lock(&zpci_list_lock);
+	list_for_each_entry(zdev, &zpci_list, entry) {
+		init_pci_slot(zdev);
+	}
+	mutex_unlock(&zpci_list_lock);
+}
+
 static void __exit exit_pci_slots(void)
 {
 	struct list_head *tmp, *n;
@@ -224,28 +225,19 @@ static void __exit exit_pci_slots(void)
 
 static int __init pci_hotplug_s390_init(void)
 {
-	/*
-	 * Do specific initialization stuff for your driver here
-	 * like initializing your controller hardware (if any) and
-	 * determining the number of slots you have in the system
-	 * right now.
-	 */
-
 	if (!s390_pci_probe)
 		return -EOPNOTSUPP;
 
-	/* register callbacks for slot handling from arch code */
-	mutex_lock(&zpci_list_lock);
-	hotplug_ops.create_slot = init_pci_slot;
-	hotplug_ops.remove_slot = exit_pci_slot;
-	mutex_unlock(&zpci_list_lock);
-	pr_info("registered hotplug slot callbacks\n");
-	return init_pci_slots();
+	zpci_register_hp_ops(&hp_ops);
+	init_pci_slots();
+
+	return 0;
 }
 
 static void __exit pci_hotplug_s390_exit(void)
 {
 	exit_pci_slots();
+	zpci_deregister_hp_ops();
 }
 
 module_init(pci_hotplug_s390_init);