From fe79bd65c819cc520aa66de65caae8e4cea29c5a Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 19 May 2023 14:30:36 +0100 Subject: [PATCH] net/tcp: refactor tcp_inet6_sk() Don't keep hand coded offset caluclations and replace it with container_of(). It should be type safer and a bit less confusing. It also makes it with a macro instead of inline function to preserve constness, which was previously casted out like in case of tcp_v6_send_synack(). Signed-off-by: Pavel Begunkov Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- net/ipv6/tcp_ipv6.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7132eb2..d657713 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -93,12 +93,8 @@ static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk, * This avoids a dereference and allow compiler optimizations. * It is a specialized version of inet6_sk_generic(). */ -static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk) -{ - unsigned int offset = sizeof(struct tcp6_sock) - sizeof(struct ipv6_pinfo); - - return (struct ipv6_pinfo *)(((u8 *)sk) + offset); -} +#define tcp_inet6_sk(sk) (&container_of_const(tcp_sk(sk), \ + struct tcp6_sock, tcp)->inet6) static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) { @@ -533,7 +529,7 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, struct sk_buff *syn_skb) { struct inet_request_sock *ireq = inet_rsk(req); - struct ipv6_pinfo *np = tcp_inet6_sk(sk); + const struct ipv6_pinfo *np = tcp_inet6_sk(sk); struct ipv6_txoptions *opt; struct flowi6 *fl6 = &fl->u.ip6; struct sk_buff *skb; -- 2.7.4