[PATCH 3.4 023/214] tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled

Greg Kroah-Hartman
2014-06-05T05:13:29Z

From: Ivan Vecera <ivecera@redhat.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/broadcom/tg3.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -10861,7 +10861,9 @@ static int tg3_set_ringparam(struct net_
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;