diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c
index 40baeac594a9..cf81a6128f55 100644
--- a/drivers/ata/pata_parport/pata_parport.c
+++ b/drivers/ata/pata_parport/pata_parport.c
@@ -618,8 +618,9 @@ void pata_parport_unregister_driver(struct pi_protocol *pr)
 			break;
 	}
 	idr_remove(&protocols, id);
-	mutex_unlock(&pi_mutex);
 	driver_unregister(&pr->driver);
+	mutex_unlock(&pi_mutex);
+
 }
 EXPORT_SYMBOL_GPL(pata_parport_unregister_driver);
 
@@ -646,18 +647,18 @@ static ssize_t new_device_store(const struct bus_type *bus, const char *buf, siz
 		port_wanted = -1;
 	}
 
+	mutex_lock(&pi_mutex);
 	drv = driver_find(protocol, &pata_parport_bus_type);
 	if (!drv) {
 		if (strcmp(protocol, "auto")) {
 			pr_err("protocol %s not found\n", protocol);
+			mutex_unlock(&pi_mutex);
 			return -EINVAL;
 		}
 		pr_wanted = NULL;
 	} else {
 		pr_wanted = container_of(drv, struct pi_protocol, driver);
 	}
-
-	mutex_lock(&pi_mutex);
 	/* walk all parports */
 	idr_for_each_entry(&parport_list, parport, port_num) {
 		if (port_num == port_wanted || port_wanted == -1) {