platform/x86/dell/dell-rbtn: Fix resources leaking on error path

Currently rbtn_add() in case of failure is leaking resources. Fix this
by adding a proper rollback. Move devm_kzalloc() before rbtn_acquire(),
so it doesn't require rollback in case of failure. While at it, remove
unnecessary assignment of NULL to device->driver_data and unnecessary
whitespace, plus add a break for the default case in a switch.

Suggested-by: Ilpo Järvinen <[email protected]>
Suggested-by: Pali Rohár <[email protected]>
Fixes: 817a5cd ("dell-rbtn: Dell Airplane Mode Switch driver")
Signed-off-by: Michal Wilczynski <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Pali Rohár <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>

Author: mwilczy

drivers/platform/x86/dell/dell-rbtn.c

@@ -395,16 +395,16 @@ static int rbtn_add(struct acpi_device *device)
 		return -EINVAL;
 	}
 
+	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
+	if (!rbtn_data)
+		return -ENOMEM;
+
 	ret = rbtn_acquire(device, true);
 	if (ret < 0) {
 		dev_err(&device->dev, "Cannot enable device\n");
 		return ret;
 	}
 
-	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
-	if (!rbtn_data)
-		return -ENOMEM;
-
 	rbtn_data->type = type;
 	device->driver_data = rbtn_data;
 
@@ -420,10 +420,12 @@ static int rbtn_add(struct acpi_device *device)
 		break;
 	default:
 		ret = -EINVAL;
+		break;
 	}
+	if (ret)
+		rbtn_acquire(device, false);
 
 	return ret;
-
 }
 
 static void rbtn_remove(struct acpi_device *device)
@@ -442,7 +444,6 @@ static void rbtn_remove(struct acpi_device *device)
 	}
 
 	rbtn_acquire(device, false);
-	device->driver_data = NULL;
 }
 
 static void rbtn_notify(struct acpi_device *device, u32 event)