From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: [PATCH net-next] net: Reflect RX hash for transmit Date: Sun, 15 Feb 2015 10:37:18 -0800 Message-ID: <1424025438-1659-1-git-send-email-therbert@google.com> To: davem@davemloft.net, netdev@vger.kernel.org Return-path: Received: from mail-ig0-f179.google.com ([209.85.213.179]:33001 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754390AbbBOShh (ORCPT ); Sun, 15 Feb 2015 13:37:37 -0500 Received: by mail-ig0-f179.google.com with SMTP id l13so19847639iga.0 for ; Sun, 15 Feb 2015 10:37:36 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: This patch allows a driver to request that the receive hash it provides to the stack is reflected back in skb->hash for packets transmitted on the associated connection. The hash value returned by a device could have meaning when used in transmit to identify a flow, for instance the hash may by a flow ID for a flow created in a (virtual) device. With the flow ID provided on transmit this can obviate the need to create the hash and do the lookup on the fly in transmit. Note that this is an opportunistic optimization, there is no separate negotiation between the stack and driver/device for the hash used in either TX or RX. Signed-off-by: Tom Herbert --- include/linux/skbuff.h | 3 ++- include/net/sock.h | 2 ++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1bb36ed..f792a0d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -605,7 +605,8 @@ struct sk_buff { __u8 ipvs_property:1; __u8 inner_protocol_type:1; __u8 remcsum_offload:1; - /* 3 or 5 bit hole */ + __u8 reflect_hash:1; + /* 2 or 4 bit hole */ #ifdef CONFIG_NET_SCHED __u16 tc_index; /* traffic control index */ diff --git a/include/net/sock.h b/include/net/sock.h index e138245..133fc51 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -871,6 +871,8 @@ static inline void sock_rps_save_rxhash(struct sock *sk, if (unlikely(sk->sk_rxhash != skb->hash)) sk->sk_rxhash = skb->hash; #endif + if (unlikely(skb->reflect_hash && sk->sk_txhash != skb->hash)) + sk->sk_txhash = skb->hash; } static inline void sock_rps_reset_rxhash(struct sock *sk) -- 2.2.0.rc0.207.ga3a616c