Commit b75803d5 authored by Lawrence Brakmo's avatar Lawrence Brakmo Committed by David S. Miller

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: default avatarLawrence Brakmo <brakmo@fb.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7d945796
...@@ -765,11 +765,16 @@ struct tcp_skb_cb { ...@@ -765,11 +765,16 @@ struct tcp_skb_cb {
unused:6; unused:6;
__u32 ack_seq; /* Sequence number ACK'd */ __u32 ack_seq; /* Sequence number ACK'd */
union { 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) #if IS_ENABLED(CONFIG_IPV6)
struct inet6_skb_parm h6; struct inet6_skb_parm h6;
#endif #endif
} header; /* For incoming frames */ } header; /* For incoming skbs */
};
}; };
#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
......
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