inet6: Remove inet6_destroy_sock() in sk->sk_prot->destroy().

After commit d38afeec26 ("tcp/udp: Call inet6_destroy_sock()
in IPv6 sk->sk_destruct()."), we call inet6_destroy_sock() in
sk->sk_destruct() by setting inet6_sock_destruct() to it to make
sure we do not leak inet6-specific resources.

Now we can remove unnecessary inet6_destroy_sock() calls in
sk->sk_prot->destroy().

DCCP and SCTP have their own sk->sk_destruct() function, so we
change them separately in the following patches.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ping.c

@@ -23,11 +23,6 @@
 #include <linux/bpf-cgroup.h>
 #include <net/ping.h>
 
-static void ping_v6_destroy(struct sock *sk)
-{
-	inet6_destroy_sock(sk);
-}
-
 /* Compatibility glue so we can support IPv6 when it's compiled as a module */
 static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
 				 int *addr_len)
@@ -205,7 +200,6 @@ struct proto pingv6_prot = {
 	.owner =	THIS_MODULE,
 	.init =		ping_init_sock,
 	.close =	ping_close,
-	.destroy =	ping_v6_destroy,
 	.pre_connect =	ping_v6_pre_connect,
 	.connect =	ip6_datagram_connect_v6_only,
 	.disconnect =	__udp_disconnect,

net/ipv6/raw.c

@@ -1173,8 +1173,6 @@ static void raw6_destroy(struct sock *sk)
 	lock_sock(sk);
 	ip6_flush_pending_frames(sk);
 	release_sock(sk);
-
-	inet6_destroy_sock(sk);
 }
 
 static int rawv6_init_sk(struct sock *sk)

net/ipv6/tcp_ipv6.c

@@ -1966,12 +1966,6 @@ static int tcp_v6_init_sock(struct sock *sk)
 	return 0;
 }
 
-static void tcp_v6_destroy_sock(struct sock *sk)
-{
-	tcp_v4_destroy_sock(sk);
-	inet6_destroy_sock(sk);
-}
-
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCPv6 sock list dumping. */
 static void get_openreq6(struct seq_file *seq,
@@ -2164,7 +2158,7 @@ struct proto tcpv6_prot = {
 	.accept			= inet_csk_accept,
 	.ioctl			= tcp_ioctl,
 	.init			= tcp_v6_init_sock,
-	.destroy		= tcp_v6_destroy_sock,
+	.destroy		= tcp_v4_destroy_sock,
 	.shutdown		= tcp_shutdown,
 	.setsockopt		= tcp_setsockopt,
 	.getsockopt		= tcp_getsockopt,

net/ipv6/udp.c

@@ -1661,8 +1661,6 @@ void udpv6_destroy_sock(struct sock *sk)
 			udp_encap_disable();
 		}
 	}
-
-	inet6_destroy_sock(sk);
 }
 
 /*

net/l2tp/l2tp_ip6.c

@@ -257,8 +257,6 @@ static void l2tp_ip6_destroy_sock(struct sock *sk)
 
 	if (tunnel)
 		l2tp_tunnel_delete(tunnel);
-
-	inet6_destroy_sock(sk);
 }
 
 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)

net/mptcp/protocol.c

@@ -3898,12 +3898,6 @@ static const struct proto_ops mptcp_v6_stream_ops = {
 
 static struct proto mptcp_v6_prot;
 
-static void mptcp_v6_destroy(struct sock *sk)
-{
-	mptcp_destroy(sk);
-	inet6_destroy_sock(sk);
-}
-
 static struct inet_protosw mptcp_v6_protosw = {
 	.type		= SOCK_STREAM,
 	.protocol	= IPPROTO_MPTCP,
@@ -3919,7 +3913,6 @@ int __init mptcp_proto_v6_init(void)
 	mptcp_v6_prot = mptcp_prot;
 	strcpy(mptcp_v6_prot.name, "MPTCPv6");
 	mptcp_v6_prot.slab = NULL;
-	mptcp_v6_prot.destroy = mptcp_v6_destroy;
 	mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock);
 
 	err = proto_register(&mptcp_v6_prot, 1);