net/core: Collapse redundant sk_timer callback data assignments

The core sk_timer initializer can provide the common .data assignment
instead of it being set separately in users.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linzhang <xiaolou4617@gmail.com>
Cc: netdev@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-x25@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -2683,7 +2683,7 @@ void sock_init_data(struct socket *sock, struct sock *sk)
 	sk_init_common(sk);
 	sk->sk_send_head	=	NULL;
 
-	init_timer(&sk->sk_timer);
+	setup_timer(&sk->sk_timer, NULL, (unsigned long)sk);
 
 	sk->sk_allocation	=	GFP_KERNEL;
 	sk->sk_rcvbuf		=	sysctl_rmem_default;

net/netrom/nr_timer.c

@@ -45,7 +45,6 @@ void nr_init_timers(struct sock *sk)
 	setup_timer(&nr->idletimer, nr_idletimer_expiry, (unsigned long)sk);
 
 	/* initialized by sock_init_data */
-	sk->sk_timer.data     = (unsigned long)sk;
 	sk->sk_timer.function = &nr_heartbeat_expiry;
 }
 

net/rose/rose_timer.c

@@ -36,7 +36,6 @@ void rose_start_heartbeat(struct sock *sk)
 {
 	del_timer(&sk->sk_timer);
 
-	sk->sk_timer.data     = (unsigned long)sk;
 	sk->sk_timer.function = &rose_heartbeat_expiry;
 	sk->sk_timer.expires  = jiffies + 5 * HZ;
 

net/x25/af_x25.c

@@ -414,7 +414,6 @@ static void __x25_destroy_socket(struct sock *sk)
 		/* Defer: outstanding buffers */
 		sk->sk_timer.expires  = jiffies + 10 * HZ;
 		sk->sk_timer.function = x25_destroy_timer;
-		sk->sk_timer.data = (unsigned long)sk;
 		add_timer(&sk->sk_timer);
 	} else {
 		/* drop last reference so sock_put will free */

net/x25/x25_timer.c

@@ -36,7 +36,6 @@ void x25_init_timers(struct sock *sk)
 	setup_timer(&x25->timer, x25_timer_expiry, (unsigned long)sk);
 
 	/* initialized by sock_init_data */
-	sk->sk_timer.data     = (unsigned long)sk;
 	sk->sk_timer.function = &x25_heartbeat_expiry;
 }