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>

include/net/sock.h

@@ -1360,6 +1360,14 @@ do {									\
 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
 } while (0)
 
+static bool lockdep_sock_is_held(const struct sock *csk)
+{
+	struct sock *sk = (struct sock *)csk;
+
+	return lockdep_is_held(&sk->sk_lock) ||
+	       lockdep_is_held(&sk->sk_lock.slock);
+}
+
 void lock_sock_nested(struct sock *sk, int subclass);
 
 static inline void lock_sock(struct sock *sk)
@@ -1598,8 +1606,8 @@ static inline void sk_rethink_txhash(struct sock *sk)
 static inline struct dst_entry *
 __sk_dst_get(struct sock *sk)
 {
-	return rcu_dereference_check(sk->sk_dst_cache, sock_owned_by_user(sk) ||
-						       lockdep_is_held(&sk->sk_lock.slock));
+	return rcu_dereference_check(sk->sk_dst_cache,
+				     lockdep_sock_is_held(sk));
 }
 
 static inline struct dst_entry *

net/dccp/ipv4.c

@@ -62,7 +62,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	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 != NULL && inet_opt->opt.srr) {
 		if (daddr == 0)
 			return -EINVAL;

net/dccp/ipv6.c

@@ -868,7 +868,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	fl6.fl6_sport = inet->inet_sport;
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
-	opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 	final_p = fl6_update_dst(&fl6, opt, &final);
 
 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p);

net/ipv4/af_inet.c

@@ -1107,7 +1107,7 @@ static int inet_sk_reselect_saddr(struct sock *sk)
 	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;
 

net/ipv4/cipso_ipv4.c

@@ -1933,7 +1933,8 @@ int cipso_v4_sock_setattr(struct sock *sk,
 
 	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)

net/ipv4/ip_sockglue.c

@@ -642,7 +642,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 		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 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
 		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,

net/ipv4/tcp_ipv4.c

@@ -157,7 +157,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 
 	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 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 
 	/* 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 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 	}
 
 	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)

net/ipv6/ipv6_sockglue.c

@@ -407,7 +407,8 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		if (optname != IPV6_RTHDR && !ns_capable(net->user_ns, CAP_NET_RAW))
 			break;
 
-		opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+		opt = rcu_dereference_protected(np->opt,
+						lockdep_sock_is_held(sk));
 		opt = ipv6_renew_options(sk, opt, optname,
 					 (struct ipv6_opt_hdr __user *)optval,
 					 optlen);
@@ -1124,7 +1125,8 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		struct ipv6_txoptions *opt;
 
 		lock_sock(sk);
-		opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+		opt = rcu_dereference_protected(np->opt,
+						lockdep_sock_is_held(sk));
 		len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len);
 		release_sock(sk);
 		/* check if ipv6_getsockopt_sticky() returns err code */

net/ipv6/tcp_ipv6.c

@@ -234,7 +234,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	fl6.fl6_dport = usin->sin6_port;
 	fl6.fl6_sport = inet->inet_sport;
 
-	opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+	opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
 	final_p = fl6_update_dst(&fl6, opt, &final);
 
 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));

net/socket.c

@@ -1046,7 +1046,7 @@ static int sock_fasync(int fd, struct file *filp, int on)
 		return -EINVAL;
 
 	lock_sock(sk);
-	wq = rcu_dereference_protected(sock->wq, sock_owned_by_user(sk));
+	wq = rcu_dereference_protected(sock->wq, lockdep_sock_is_held(sk));
 	fasync_helper(fd, filp, on, &wq->fasync_list);
 
 	if (!wq->fasync_list)