From abf111ce0518ae09e6fe6e776bcb402db26e78be Mon Sep 17 00:00:00 2001 From: Dave Stevenson Date: Tue, 10 Apr 2018 13:08:36 +0100 Subject: [PATCH] net: lan78xx: Reduce s/w csum check on VLANs With HW_VLAN_CTAG_RX enabled we don't observe the checksum issue, so amend the workaround to only drop back to s/w checksums if VLAN offload is disabled. See #2458. Signed-off-by: Dave Stevenson --- drivers/net/usb/lan78xx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index bac0bd4e898615..0c9b9da6cf09b9 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2997,12 +2997,13 @@ static void lan78xx_rx_csum_offload(struct lan78xx_net *dev, struct sk_buff *skb, u32 rx_cmd_a, u32 rx_cmd_b) { - /* Checksum offload appears to be flawed if used with VLANs. - * Elect for sw checksum check instead. + /* HW Checksum offload appears to be flawed if used when not stripping + * VLAN headers. */ if (!(dev->net->features & NETIF_F_RXCSUM) || unlikely(rx_cmd_a & RX_CMD_A_ICSM_) || - (rx_cmd_a & RX_CMD_A_FVTG_)) { + ((rx_cmd_a & RX_CMD_A_FVTG_) && + !(dev->net->features & NETIF_F_HW_VLAN_CTAG_RX))) { skb->ip_summed = CHECKSUM_NONE; } else { skb->csum = ntohs((u16)(rx_cmd_b >> RX_CMD_B_CSUM_SHIFT_));