tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled

commit ba67b510035141bd89b40bf65efa0a79834311ca upstream.

The patch fixes a problem with dropped jumbo frames after usage of
'ethtool -G ... rx'.

Scenario:
1. ip link set eth0 up
2. ethtool -G eth0 rx N # <- This zeroes rx-jumbo
3. ip link set mtu 9000 dev eth0

The ethtool command set rx_jumbo_pending to zero so any received jumbo
packets are dropped and you need to use 'ethtool -G eth0 rx-jumbo N'
to workaround the issue.
The patch changes the logic so rx_jumbo_pending value is changed only if
jumbo frames are enabled (MTU > 1500).

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index c77c462..2615433 100644 (file)
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -10656,7 +10656,9 @@ static int tg3_set_ringparam(struct net_device *dev, struct ethtool_ringparam *e
        if (tg3_flag(tp, MAX_RXPEND_64) &&
            tp->rx_pending > 63)
                tp->rx_pending = 63;
-       tp->rx_jumbo_pending = ering->rx_jumbo_pending;
+
+       if (tg3_flag(tp, JUMBO_RING_ENABLE))
+               tp->rx_jumbo_pending = ering->rx_jumbo_pending;
 
        for (i = 0; i < tp->irq_max; i++)
                tp->napi[i].tx_pending = ering->tx_pending;