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authorJonas Gorski <jonas.gorski@gmail.com>2024-10-04 10:47:17 +0200
committerPaolo Abeni <pabeni@redhat.com>2024-10-08 10:42:27 +0200
commit42fb3acf6826c6764ba79feb6e15229b43fd2f9f (patch)
tree57092f85d6522f4355a9ec4dede45be87d857dd4 /drivers
parent60ed96bd1e69764f6b4bdf28ce9399d6a79f497b (diff)
downloadlwn-42fb3acf6826c6764ba79feb6e15229b43fd2f9f.tar.gz
lwn-42fb3acf6826c6764ba79feb6e15229b43fd2f9f.zip
net: dsa: b53: fix jumbo frame mtu check
JMS_MIN_SIZE is the full ethernet frame length, while mtu is just the data payload size. Comparing these two meant that mtus between 1500 and 1518 did not trigger enabling jumbo frames. So instead compare the set mtu ETH_DATA_LEN, which is equal to JMS_MIN_SIZE - ETH_HLEN - ETH_FCS_LEN; Also do a check that the requested mtu is actually greater than the minimum length, else we do not need to enable jumbo frames. In practice this only introduced a very small range of mtus that did not work properly. Newer chips allow 2000 byte large frames by default, and older chips allow 1536 bytes long, which is equivalent to an mtu of 1514. So effectivly only mtus of 1515~1517 were broken. Fixes: 6ae5834b983a ("net: dsa: b53: add MTU configuration support") Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/dsa/b53/b53_common.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 0783fc121bbb..57df00ad9dd4 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2259,7 +2259,7 @@ static int b53_change_mtu(struct dsa_switch *ds, int port, int mtu)
if (!dsa_is_cpu_port(ds, port))
return 0;
- enable_jumbo = (mtu >= JMS_MIN_SIZE);
+ enable_jumbo = (mtu > ETH_DATA_LEN);
allow_10_100 = (dev->chip_id == BCM583XX_DEVICE_ID);
return b53_set_jumbo(dev, enable_jumbo, allow_10_100);