From: Christoph Paasch <cpaa...@apple.com>
Date: Wed, 31 Jan 2018 16:07:04 -0800
> An upcoming patch adds a configurable, per-socket list of TCP options to
> populate in the TCP header. This requires tcp_options_write() to know the
> socket (to use the options list) and the skb (to provide visibility to the
> packet data for options like TCP_MD5SIG).
>
> Signed-off-by: Christoph Paasch <cpaa...@apple.com>
> Reviewed-by: Mat Martineau <mathew.j.martin...@linux.intel.com>
> ---
> net/ipv4/tcp_output.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> index df50c7dc1a43..e598bf54e3fb 100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -444,10 +444,14 @@ struct tcp_out_options {
> * At least SACK_PERM as the first option is known to lead to a disaster
> * (but it may well be that other scenarios fail similarly).
> */
> -static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
> +static void tcp_options_write(__be32 *ptr, struct sk_buff *skb, struct sock
> *sk,
> struct tcp_out_options *opts)
> {
> u16 options = opts->options; /* mungable copy */
> + struct tcp_sock *tp = NULL;
> +
> + if (sk_fullsock(sk))
> + tp = tcp_sk(sk);
This adds a new test to the packet header building fast path,
and all of the call sites know whether they are dealing with
a full sock or not so the test is superfluous.
