mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-25 16:31:13 +00:00
47 lines
2.0 KiB
Diff
47 lines
2.0 KiB
Diff
From 65258b9d8cde45689bdc86ca39b50f01f983733b Mon Sep 17 00:00:00 2001
|
|
From: Robert Marko <robert.marko@sartura.hr>
|
|
Date: Fri, 19 Nov 2021 03:03:50 +0100
|
|
Subject: [PATCH] net: dsa: qca8k: fix MTU calculation
|
|
|
|
qca8k has a global MTU, so its tracking the MTU per port to make sure
|
|
that the largest MTU gets applied.
|
|
Since it uses the frame size instead of MTU the driver MTU change function
|
|
will then add the size of Ethernet header and checksum on top of MTU.
|
|
|
|
The driver currently populates the per port MTU size as Ethernet frame
|
|
length + checksum which equals 1518.
|
|
|
|
The issue is that then MTU change function will go through all of the
|
|
ports, find the largest MTU and apply the Ethernet header + checksum on
|
|
top of it again, so for a desired MTU of 1500 you will end up with 1536.
|
|
|
|
This is obviously incorrect, so to correct it populate the per port struct
|
|
MTU with just the MTU and not include the Ethernet header + checksum size
|
|
as those will be added by the MTU change function.
|
|
|
|
Fixes: f58d2598cf70 ("net: dsa: qca8k: implement the port MTU callbacks")
|
|
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
|
|
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
|
|
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
---
|
|
drivers/net/dsa/qca8k.c | 6 +++++-
|
|
1 file changed, 5 insertions(+), 1 deletion(-)
|
|
|
|
--- a/drivers/net/dsa/qca8k.c
|
|
+++ b/drivers/net/dsa/qca8k.c
|
|
@@ -1256,8 +1256,12 @@ qca8k_setup(struct dsa_switch *ds)
|
|
/* Set initial MTU for every port.
|
|
* We have only have a general MTU setting. So track
|
|
* every port and set the max across all port.
|
|
+ * Set per port MTU to 1500 as the MTU change function
|
|
+ * will add the overhead and if its set to 1518 then it
|
|
+ * will apply the overhead again and we will end up with
|
|
+ * MTU of 1536 instead of 1518
|
|
*/
|
|
- priv->port_mtu[i] = ETH_FRAME_LEN + ETH_FCS_LEN;
|
|
+ priv->port_mtu[i] = ETH_DATA_LEN;
|
|
}
|
|
|
|
/* Special GLOBAL_FC_THRESH value are needed for ar8327 switch */
|