From f5f80e32de12fad2813d37270e8364a03e6d3ef0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 20 Jul 2023 11:09:01 +0000 Subject: ipv6: remove hard coded limitation on ipv6_pinfo IPv6 inet sockets are supposed to have a "struct ipv6_pinfo" field at the end of their definition, so that inet6_sk_generic() can derive from socket size the offset of the "struct ipv6_pinfo". This is very fragile, and prevents adding bigger alignment in sockets, because inet6_sk_generic() does not work if the compiler adds padding after the ipv6_pinfo component. We are currently working on a patch series to reorganize TCP structures for better data locality and found issues similar to the one fixed in commit f5d547676ca0 ("tcp: fix tcp_inet6_sk() for 32bit kernels") Alternative would be to force an alignment on "struct ipv6_pinfo", greater or equal to __alignof__(any ipv6 sock) to ensure there is no padding. This does not look great. v2: fix typo in mptcp_proto_v6_init() (Paolo) Signed-off-by: Eric Dumazet Cc: Chao Wu Cc: Wei Wang Cc: Coco Li Cc: YiFei Zhu Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- net/l2tp/l2tp_ip6.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'net/l2tp/l2tp_ip6.c') diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index b1623f9c4f92..2eee95a00c05 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -36,9 +36,6 @@ struct l2tp_ip6_sock { u32 conn_id; u32 peer_conn_id; - /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see - * inet6_sk_generic - */ struct ipv6_pinfo inet6; }; @@ -730,6 +727,7 @@ static struct proto l2tp_ip6_prot = { .hash = l2tp_ip6_hash, .unhash = l2tp_ip6_unhash, .obj_size = sizeof(struct l2tp_ip6_sock), + .ipv6_pinfo_offset = offsetof(struct l2tp_ip6_sock, inet6), }; static const struct proto_ops l2tp_ip6_ops = { -- cgit v1.2.3-58-ga151