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authorLawrence Brakmo <brakmo@fb.com>2016-05-07 03:35:35 (GMT)
committerDavid S. Miller <davem@davemloft.net>2016-05-09 04:03:26 (GMT)
commitb75803d52a2ce1f6cbaf7ae0ae40a369210070cf (patch)
tree87760e042352445348961f6e4326d11a0e6b4a20 /include/net
parent7d945796754a0394b0c5c35d8f80a4a805c7dbb9 (diff)
downloadlinux-b75803d52a2ce1f6cbaf7ae0ae40a369210070cf.tar.xz
tcp: refactor struct tcp_skb_cb
Refactor tcp_skb_cb to create two overlaping areas to store state for incoming or outgoing skbs based on comments by Neal Cardwell to tcp_nv patch: AFAICT this patch would not require an increase in the size of sk_buff cb[] if it were to take advantage of the fact that the tcp_skb_cb header.h4 and header.h6 fields are only used in the packet reception code path, and this in_flight field is only used on the transmit side. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/tcp.h11
1 files changed, 8 insertions, 3 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 24ec804..4775a1b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -765,11 +765,16 @@ struct tcp_skb_cb {
unused:6;
__u32 ack_seq; /* Sequence number ACK'd */
union {
- struct inet_skb_parm h4;
+ struct {
+ /* There is space for up to 20 bytes */
+ } tx; /* only used for outgoing skbs */
+ union {
+ struct inet_skb_parm h4;
#if IS_ENABLED(CONFIG_IPV6)
- struct inet6_skb_parm h6;
+ struct inet6_skb_parm h6;
#endif
- } header; /* For incoming frames */
+ } header; /* For incoming skbs */
+ };
};
#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))