1 files changed, 55 insertions, 35 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 6c8c9509e03d..dbb5919f23e2 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -483,9 +483,8 @@ static void acpi_device_del(struct acpi_device *device)
 	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
 		if (!strcmp(acpi_device_bus_id->bus_id,
 			    acpi_device_hid(device))) {
-			if (acpi_device_bus_id->instance_no > 0)
-				acpi_device_bus_id->instance_no--;
-			else {
+			ida_simple_remove(&acpi_device_bus_id->instance_ida, device->pnp.instance_no);
+			if (ida_is_empty(&acpi_device_bus_id->instance_ida)) {
 				list_del(&acpi_device_bus_id->node);
 				kfree_const(acpi_device_bus_id->bus_id);
 				kfree(acpi_device_bus_id);
@@ -587,6 +586,8 @@ static int acpi_get_device_data(acpi_handle handle, struct acpi_device **device,
 	if (!device)
 		return -EINVAL;
 
+	*device = NULL;
+
 	status = acpi_get_data_full(handle, acpi_scan_drop_device,
 				    (void **)device, callback);
 	if (ACPI_FAILURE(status) || !*device) {
@@ -622,12 +623,38 @@ void acpi_bus_put_acpi_device(struct acpi_device *adev)
 	put_device(&adev->dev);
 }
 
+static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id)
+{
+	struct acpi_device_bus_id *acpi_device_bus_id;
+
+	/* Find suitable bus_id and instance number in acpi_bus_id_list. */
+	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
+		if (!strcmp(acpi_device_bus_id->bus_id, dev_id))
+			return acpi_device_bus_id;
+	}
+	return NULL;
+}
+
+static int acpi_device_set_name(struct acpi_device *device,
+				struct acpi_device_bus_id *acpi_device_bus_id)
+{
+	struct ida *instance_ida = &acpi_device_bus_id->instance_ida;
+	int result;
+
+	result = ida_simple_get(instance_ida, 0, ACPI_MAX_DEVICE_INSTANCES, GFP_KERNEL);
+	if (result < 0)
+		return result;
+
+	device->pnp.instance_no = result;
+	dev_set_name(&device->dev, "%s:%02x", acpi_device_bus_id->bus_id, result);
+	return 0;
+}
+
 int acpi_device_add(struct acpi_device *device,
 		    void (*release)(struct device *))
 {
+	struct acpi_device_bus_id *acpi_device_bus_id;
 	int result;
-	struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
-	int found = 0;
 
 	if (device->handle) {
 		acpi_status status;
@@ -653,41 +680,38 @@ int acpi_device_add(struct acpi_device *device,
 	INIT_LIST_HEAD(&device->del_list);
 	mutex_init(&device->physical_node_lock);
 
-	new_bus_id = kzalloc(sizeof(struct acpi_device_bus_id), GFP_KERNEL);
-	if (!new_bus_id) {
-		pr_err(PREFIX "Memory allocation error\n");
-		result = -ENOMEM;
-		goto err_detach;
-	}
-
 	mutex_lock(&acpi_device_lock);
-	/*
-	 * Find suitable bus_id and instance number in acpi_bus_id_list
-	 * If failed, create one and link it into acpi_bus_id_list
-	 */
-	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
-		if (!strcmp(acpi_device_bus_id->bus_id,
-			    acpi_device_hid(device))) {
-			acpi_device_bus_id->instance_no++;
-			found = 1;
-			kfree(new_bus_id);
-			break;
+
+	acpi_device_bus_id = acpi_device_bus_id_match(acpi_device_hid(device));
+	if (acpi_device_bus_id) {
+		result = acpi_device_set_name(device, acpi_device_bus_id);
+		if (result)
+			goto err_unlock;
+	} else {
+		acpi_device_bus_id = kzalloc(sizeof(*acpi_device_bus_id),
+					     GFP_KERNEL);
+		if (!acpi_device_bus_id) {
+			result = -ENOMEM;
+			goto err_unlock;
 		}
-	}
-	if (!found) {
-		acpi_device_bus_id = new_bus_id;
 		acpi_device_bus_id->bus_id =
 			kstrdup_const(acpi_device_hid(device), GFP_KERNEL);
 		if (!acpi_device_bus_id->bus_id) {
-			pr_err(PREFIX "Memory allocation error for bus id\n");
+			kfree(acpi_device_bus_id);
 			result = -ENOMEM;
-			goto err_free_new_bus_id;
+			goto err_unlock;
+		}
+
+		ida_init(&acpi_device_bus_id->instance_ida);
+
+		result = acpi_device_set_name(device, acpi_device_bus_id);
+		if (result) {
+			kfree(acpi_device_bus_id);
+			goto err_unlock;
 		}
 
-		acpi_device_bus_id->instance_no = 0;
 		list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
 	}
-	dev_set_name(&device->dev, "%s:%02x", acpi_device_bus_id->bus_id, acpi_device_bus_id->instance_no);
 
 	if (device->parent)
 		list_add_tail(&device->node, &device->parent->children);
@@ -719,13 +743,9 @@ int acpi_device_add(struct acpi_device *device,
 		list_del(&device->node);
 	list_del(&device->wakeup_list);
 
- err_free_new_bus_id:
-	if (!found)
-		kfree(new_bus_id);
-
+ err_unlock:
 	mutex_unlock(&acpi_device_lock);
 
- err_detach:
 	acpi_detach_data(device->handle, acpi_scan_drop_device);
 	return result;
 }