[SOCK]: Add some notes about per-bind-bucket sock lookup.

I was asked about "why don't we perform a sk_net filtering in
bind_conflict calls, like we do in other sock lookup places"
for a couple of times.

Can we please add a comment about why we do not need one?

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 8d70cfbacb78..828ea211ff21 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -55,6 +55,13 @@ int inet_csk_bind_conflict(const struct sock *sk,
         struct hlist_node *node;
         int reuse = sk->sk_reuse;
 
+        /*
+         * Unlike other sk lookup places we do not check
+         * for sk_net here, since _all_ the socks listed
+         * in tb->owners list belong to the same net - the
+         * one this bucket belongs to.
+         */
+
         sk_for_each_bound(sk2, node, &tb->owners) {
                 if (sk != sk2 &&
                     !inet_v6_ipv6only(sk2) &&