tcp: remove unused hash_size from struct tcp_out_options

hash_size is declared but never read. The MD5 path always uses a
fixed size of 16, and the TCP-AO path uses tcp_ao_maclen().

This closes a 7-byte hole and reduces the struct size from 96 to
88 bytes.

Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Keita Morisaki <kmta1236@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260307051619.51685-1-kmta1236@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f0ebcc7e287173be6198fd100130e7ba1a1dbf03..4377b3673da9549b4041c10e673a2ba11015cbd2 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -441,7 +441,6 @@ struct tcp_out_options {
        u8 ws;                  /* window scale, 0 to disable */
        u8 num_accecn_fields:7, /* number of AccECN fields needed */
           use_synack_ecn_bytes:1; /* Use synack_ecn_bytes or not */
-       u8 hash_size;           /* bytes in hash_location */
        __u8 *hash_location;    /* temporary pointer, overloaded */
        __u32 tsval, tsecr;     /* need to include OPTION_TS */
        struct tcp_fastopen_cookie *fastopen_cookie;    /* Fast open cookie */