netdevsim: correctly check return value of debugfs_create_dir

- Checking return value with IS_ERROR_OR_NULL
- Added error handling where it was not handled

Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 92678f5..3fd5679 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -151,6 +151,8 @@ static int nsim_init(struct net_device *dev)
 
 	ns->netdev = dev;
 	ns->ddir = debugfs_create_dir(netdev_name(dev), nsim_ddir);
+	if (IS_ERR_OR_NULL(ns->ddir))
+		return -ENOMEM;
 
 	err = nsim_bpf_init(ns);
 	if (err)
@@ -469,8 +471,8 @@ static int __init nsim_module_init(void)
 	int err;
 
 	nsim_ddir = debugfs_create_dir(DRV_NAME, NULL);
-	if (IS_ERR(nsim_ddir))
-		return PTR_ERR(nsim_ddir);
+	if (IS_ERR_OR_NULL(nsim_ddir))
+		return -ENOMEM;
 
 	err = bus_register(&nsim_bus);
 	if (err)