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authorSven Eckelmann <sven@narfation.org>2023-07-27 10:13:43 +0200
committerSimon Wunderlich <sw@simonwunderlich.de>2023-08-03 21:11:42 +0200
commit112cbcb4af90c4b108b120a28089872d2234a350 (patch)
treeceee6971b2cb36529ea02c892675f6a1894e2c6e /net/batman-adv
parente4b817804579624b47823d87e647ec6c3d3ab827 (diff)
batman-adv: Check hardif MTU against runtime MTU
If the MTU of the soft/mesh interface was already reduced (enough), it is not necessary to print a warning about a hard interface not having a MTU to transport ethernet payloads of 1500 bytes. Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/hard-interface.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 41c1ad33d009..5a4ff9a81e74 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -9,6 +9,7 @@
#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
+#include <linux/compiler.h>
#include <linux/container_of.h>
#include <linux/errno.h>
#include <linux/gfp.h>
@@ -699,9 +700,14 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
struct batadv_priv *bat_priv;
__be16 ethertype = htons(ETH_P_BATMAN);
int max_header_len = batadv_max_header_len();
+ unsigned int required_mtu;
+ unsigned int hardif_mtu;
int ret;
- if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len)
+ hardif_mtu = READ_ONCE(hard_iface->net_dev->mtu);
+ required_mtu = READ_ONCE(soft_iface->mtu) + max_header_len;
+
+ if (hardif_mtu < ETH_MIN_MTU + max_header_len)
return -EINVAL;
if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
@@ -734,18 +740,18 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
hard_iface->net_dev->name);
if (atomic_read(&bat_priv->fragmentation) &&
- hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
+ hardif_mtu < required_mtu)
batadv_info(hard_iface->soft_iface,
"The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %i would solve the problem.\n",
- hard_iface->net_dev->name, hard_iface->net_dev->mtu,
- ETH_DATA_LEN + max_header_len);
+ hard_iface->net_dev->name, hardif_mtu,
+ required_mtu);
if (!atomic_read(&bat_priv->fragmentation) &&
- hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
+ hardif_mtu < required_mtu)
batadv_info(hard_iface->soft_iface,
"The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %i.\n",
- hard_iface->net_dev->name, hard_iface->net_dev->mtu,
- ETH_DATA_LEN + max_header_len);
+ hard_iface->net_dev->name, hardif_mtu,
+ required_mtu);
if (batadv_hardif_is_iface_up(hard_iface))
batadv_hardif_activate_interface(hard_iface);