net: introduce lockdep_is_held and update various places to use it

The socket is either locked if we hold the slock spin_lock for
lock_sock_fast and unlock_sock_fast or we own the lock (sk_lock.owned
!= 0). Check for this and at the same time improve that the current
thread/cpu is really holding the lock.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index a38b991..8217cd2 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1107,7 +1107,7 @@
 	struct ip_options_rcu *inet_opt;
 
 	inet_opt = rcu_dereference_protected(inet->inet_opt,
-					     sock_owned_by_user(sk));
+					     lockdep_sock_is_held(sk));
 	if (inet_opt && inet_opt->opt.srr)
 		daddr = inet_opt->opt.faddr;
 
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index bdb2a07..40d6b87 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1933,7 +1933,8 @@
 
 	sk_inet = inet_sk(sk);
 
-	old = rcu_dereference_protected(sk_inet->inet_opt, sock_owned_by_user(sk));
+	old = rcu_dereference_protected(sk_inet->inet_opt,
+					lockdep_sock_is_held(sk));
 	if (sk_inet->is_icsk) {
 		sk_conn = inet_csk(sk);
 		if (old)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 1b7c077..89b5f3b 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -642,7 +642,7 @@
 		if (err)
 			break;
 		old = rcu_dereference_protected(inet->inet_opt,
-						sock_owned_by_user(sk));
+						lockdep_sock_is_held(sk));
 		if (inet->is_icsk) {
 			struct inet_connection_sock *icsk = inet_csk(sk);
 #if IS_ENABLED(CONFIG_IPV6)
@@ -1302,7 +1302,7 @@
 		struct ip_options_rcu *inet_opt;
 
 		inet_opt = rcu_dereference_protected(inet->inet_opt,
-						     sock_owned_by_user(sk));
+						     lockdep_sock_is_held(sk));
 		opt->optlen = 0;
 		if (inet_opt)
 			memcpy(optbuf, &inet_opt->opt,
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 456ff3d..f4f2a0a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -157,7 +157,7 @@
 
 	nexthop = daddr = usin->sin_addr.s_addr;
 	inet_opt = rcu_dereference_protected(inet->inet_opt,
-					     sock_owned_by_user(sk));
+					     lockdep_sock_is_held(sk));
 	if (inet_opt && inet_opt->opt.srr) {
 		if (!daddr)
 			return -EINVAL;
@@ -882,8 +882,7 @@
 
 	/* caller either holds rcu_read_lock() or socket lock */
 	md5sig = rcu_dereference_check(tp->md5sig_info,
-				       sock_owned_by_user(sk) ||
-				       lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
+				       lockdep_sock_is_held(sk));
 	if (!md5sig)
 		return NULL;
 #if IS_ENABLED(CONFIG_IPV6)
@@ -928,8 +927,7 @@
 	}
 
 	md5sig = rcu_dereference_protected(tp->md5sig_info,
-					   sock_owned_by_user(sk) ||
-					   lockdep_is_held(&sk->sk_lock.slock));
+					   lockdep_sock_is_held(sk));
 	if (!md5sig) {
 		md5sig = kmalloc(sizeof(*md5sig), gfp);
 		if (!md5sig)