From: Sven Eckelmann <sven@narfation.org>
To: b.a.t.m.a.n@lists.open-mesh.org
Subject: [PATCH RFC 2/3] batman-adv: Check hardif MTU against runtime MTU
Date: Thu, 27 Jul 2023 10:13:43 +0200 [thread overview]
Message-ID: <20230727-jumbo-mtu-v1-2-036ce1a6e33c@narfation.org> (raw)
In-Reply-To: <20230727-jumbo-mtu-v1-0-036ce1a6e33c@narfation.org>
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>
---
net/batman-adv/hard-interface.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 41c1ad33..5a4ff9a8 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);
--
2.39.2
next prev parent reply other threads:[~2023-07-27 8:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-27 8:13 [PATCH RFC 0/3] batman-adv: Enable support for jumbo frames Sven Eckelmann
2023-07-27 8:13 ` [PATCH RFC 1/3] batman-adv: Avoid magic value for minimum MTU Sven Eckelmann
2023-07-27 8:13 ` Sven Eckelmann [this message]
2023-07-27 8:13 ` [PATCH RFC 3/3] batman-adv: Add support for jumbo frames Sven Eckelmann
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