Merge tag 'batadv-net-pullrequest-20220916' of git://git.open-mesh.or…

…g/linux-merge

Simon Wunderlich says:

====================
Here is a batman-adv bugfix:

 - Fix hang up with small MTU hard-interface, by Shigeru Yoshida

* tag 'batadv-net-pullrequest-20220916' of git://git.open-mesh.org/linux-merge:
  batman-adv: Fix hang up with small MTU hard-interface
====================

Link: https://lore.kernel.org/r/20220916160931.1412407-1-sw@simonwunderlich.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/batman-adv/hard-interface.c

@@ -10,6 +10,7 @@
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
 #include <linux/container_of.h>
+#include <linux/errno.h>
 #include <linux/gfp.h>
 #include <linux/if.h>
 #include <linux/if_arp.h>
@@ -700,6 +701,9 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 	int max_header_len = batadv_max_header_len();
 	int ret;
 
+	if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len)
+		return -EINVAL;
+
 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 		goto out;