openwrt/target/linux/brcm2708/patches-4.14/950-0272-net-lan78xx-Reduce...

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Diff

From 126c6760f56d2d7a82c605a54c402a886ae9b5bf Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.org>
Date: Tue, 10 Apr 2018 13:08:36 +0100
Subject: [PATCH 272/454] 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 <dave.stevenson@raspberrypi.org>
---
drivers/net/usb/lan78xx.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2968,12 +2968,13 @@ static void lan78xx_rx_csum_offload(stru
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_));