net: Add comment that early_demux can change via sysctl

Twice patches trying to constify inet{6}_protocol have been reverted:
39294c3df2a8 ("Revert "ipv6: constify inet6_protocol structures"") to
revert 3a3a4e3054137 and then 03157937fe0b5 ("Revert "ipv4: make
net_protocol const"") to revert aa8db499ea67.

Add a comment that the structures can not be const because the
early_demux field can change based on a sysctl.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index abba3bc2a3d9..38f76d8b231e 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1949,6 +1949,9 @@ struct proto tcpv6_prot = {
         .diag_destroy           = tcp_abort,
 };
 
+/* thinking of making this const? Don't.
+ * early_demux can change based on sysctl.
+ */
 static struct inet6_protocol tcpv6_protocol = {
         .early_demux    =       tcp_v6_early_demux,
         .early_demux_handler =  tcp_v6_early_demux,