net: fec: fix receive VLAN CTAG HW acceleration issue

[ Upstream commit af5cbc9822f6bbe399925760a4d5ee82c21f258c ]

The current driver support receive VLAN CTAG HW acceleration feature
(NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
have overlap between the two memory data point range. The patch just fix
the issue.

V2:
Michael Grzeschik suggest to use memmove() instead of skb_copy_to_linear_data_offset().

Reported-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Fixes: 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx performance")
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index bba87775419dc9c0d5adadcdda8c1e634dc8e04d..fd655df63accae246e512c94dc80f52410642085 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1448,8 +1448,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
 
                        vlan_packet_rcvd = true;
 
-                       skb_copy_to_linear_data_offset(skb, VLAN_HLEN,
-                                                      data, (2 * ETH_ALEN));
+                       memmove(skb->data + VLAN_HLEN, data, ETH_ALEN * 2);
                        skb_pull(skb, VLAN_HLEN);
                }