staging: gpib: hp_82341: Handle gpib_register_driver() errors

The function gpib_register_driver() can fail, resulting in a
semi-registered module and does not return an error value if it
fails.

Return the error value if the first gpib_register_driver() fails
and if the second gpib_register_driver() fails unregister the first
gpib_register_driver() and return the error value. Add pr_err()
statements indicating the fail and the error value.

Signed-off-by: Nihar Chaithanya <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: niharcy

drivers/staging/gpib/hp_82341/hp_82341.c

@@ -807,8 +807,21 @@ MODULE_DEVICE_TABLE(pnp, hp_82341_pnp_table);
 
 static int __init hp_82341_init_module(void)
 {
-	gpib_register_driver(&hp_82341_unaccel_interface, THIS_MODULE);
-	gpib_register_driver(&hp_82341_interface, THIS_MODULE);
+	int ret;
+
+	ret = gpib_register_driver(&hp_82341_unaccel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("hp_82341: gpib_register_driver failed: error = %d\n", ret);
+		return ret;
+	}
+
+	ret = gpib_register_driver(&hp_82341_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("hp_82341: gpib_register_driver failed: error = %d\n", ret);
+		gpib_unregister_driver(&hp_82341_unaccel_interface);
+		return ret;
+	}
+
 	return 0;
 }