[PATCH net-next] net: udp Allow CHECKSUM_UNNECESSARY packets to do GRO.

[Mao Wenan]

When udp4_gro_receive() get one packet that uh->check=0,
skb_gro_checksum_validate_zero_check() will set the
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->csum_level = 0;
Then udp_gro_receive() will flush the packet which is not CHECKSUM_PARTIAL,
It is not our expect,  because check=0 in udp header indicates this
packet is no need to caculate checksum, we should go further to do GRO.

This patch changes the value of csum_cnt according to skb->csum_level.
---
 include/linux/netdevice.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1377d08..9c819f1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2764,6 +2764,7 @@ static inline void skb_gro_incr_csum_unnecessary(struct 
sk_buff *skb)
                 * during GRO. This saves work if we fallback to normal path.
                 */
                __skb_incr_checksum_unnecessary(skb);
+               NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
        }
 }
 
-- 
1.8.3.1