5.15-stable review patch. If anyone has any objections, please let me know.
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From: Martin Willi martin@strongswan.org
[ Upstream commit c5118072e228e7e4385fc5ac46b2e31cf6c4f2d3 ]
Broadcom switches supported by the b53 driver use a chip-wide jumbo frame configuration. In the commit referenced with the Fixes tag, the setting is applied just for the last port changing its MTU.
While configuring CPU ports accounts for tagger overhead, user ports do not. When setting the MTU for a user port, the chip-wide setting is reduced to not include the tagger overhead, resulting in an potentially insufficient chip-wide maximum frame size for the CPU port.
As, by design, the CPU port MTU is adjusted for any user port change, apply the chip-wide setting only for CPU ports. This aligns the driver to the behavior of other switch drivers.
Fixes: 6ae5834b983a ("net: dsa: b53: add MTU configuration support") Suggested-by: Vladimir Oltean olteanv@gmail.com Signed-off-by: Martin Willi martin@strongswan.org Reviewed-by: Vladimir Oltean olteanv@gmail.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/b53/b53_common.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c index 604f541126654..e23f184ffdda7 100644 --- a/drivers/net/dsa/b53/b53_common.c +++ b/drivers/net/dsa/b53/b53_common.c @@ -2223,6 +2223,9 @@ static int b53_change_mtu(struct dsa_switch *ds, int port, int mtu) if (is5325(dev) || is5365(dev)) return -EOPNOTSUPP;
+ if (!dsa_is_cpu_port(ds, port)) + return 0; + enable_jumbo = (mtu >= JMS_MIN_SIZE); allow_10_100 = (dev->chip_id == BCM583XX_DEVICE_ID);