sock: struct proto hash function may error

In order to support fast reuseport lookups in TCP, the hash function
defined in struct proto must be capable of returning an error code.
This patch changes the function signature of all related hash functions
to return an integer and handles or propagates this return value at
all call sites.

Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 44 insertions, 17 deletions

diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
index a548be2..e0bd013 100644
--- a/net/ieee802154/socket.c
+++ b/net/ieee802154/socket.c
@@ -182,12 +182,14 @@ static int ieee802154_sock_ioctl(struct socket *sock, unsigned int cmd,
 static HLIST_HEAD(raw_head);
 static DEFINE_RWLOCK(raw_lock);
 
-static void raw_hash(struct sock *sk)
+static int raw_hash(struct sock *sk)
 {
 	write_lock_bh(&raw_lock);
 	sk_add_node(sk, &raw_head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock_bh(&raw_lock);
+
+	return 0;
 }
 
 static void raw_unhash(struct sock *sk)
@@ -462,12 +464,14 @@ static inline struct dgram_sock *dgram_sk(const struct sock *sk)
 	return container_of(sk, struct dgram_sock, sk);
 }
 
-static void dgram_hash(struct sock *sk)
+static int dgram_hash(struct sock *sk)
 {
 	write_lock_bh(&dgram_lock);
 	sk_add_node(sk, &dgram_head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock_bh(&dgram_lock);
+
+	return 0;
 }
 
 static void dgram_unhash(struct sock *sk)
@@ -1026,8 +1030,13 @@ static int ieee802154_create(struct net *net, struct socket *sock,
 	/* Checksums on by default */
 	sock_set_flag(sk, SOCK_ZAPPED);
 
-	if (sk->sk_prot->hash)
-		sk->sk_prot->hash(sk);
+	if (sk->sk_prot->hash) {
+		rc = sk->sk_prot->hash(sk);
+		if (rc) {
+			sk_common_release(sk);
+			goto out;
+		}
+	}
 
 	if (sk->sk_prot->init) {
 		rc = sk->sk_prot->init(sk);
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 5c5db66..eade66d 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -370,7 +370,11 @@ lookup_protocol:
 		 */
 		inet->inet_sport = htons(inet->inet_num);
 		/* Add to protocol hash chains. */
-		sk->sk_prot->hash(sk);
+		err = sk->sk_prot->hash(sk);
+		if (err) {
+			sk_common_release(sk);
+			goto out;
+		}
 	}
 
 	if (sk->sk_prot->init) {
@@ -1142,8 +1146,7 @@ static int inet_sk_reselect_saddr(struct sock *sk)
 	 * Besides that, it does not check for connection
 	 * uniqueness. Wait for troubles.
 	 */
-	__sk_prot_rehash(sk);
-	return 0;
+	return __sk_prot_rehash(sk);
 }
 
 int inet_sk_rebuild_header(struct sock *sk)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 9b17c179..12c8d38 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -734,6 +734,7 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct inet_sock *inet = inet_sk(sk);
+	int err = -EADDRINUSE;
 
 	reqsk_queue_alloc(&icsk->icsk_accept_queue);
 
@@ -751,13 +752,14 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
 		inet->inet_sport = htons(inet->inet_num);
 
 		sk_dst_reset(sk);
-		sk->sk_prot->hash(sk);
+		err = sk->sk_prot->hash(sk);
 
-		return 0;
+		if (likely(!err))
+			return 0;
 	}
 
 	sk->sk_state = TCP_CLOSE;
-	return -EADDRINUSE;
+	return err;
 }
 EXPORT_SYMBOL_GPL(inet_csk_listen_start);
 
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index ccc5980..b6023b7 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -468,13 +468,15 @@ void __inet_hash(struct sock *sk, struct sock *osk)
 }
 EXPORT_SYMBOL(__inet_hash);
 
-void inet_hash(struct sock *sk)
+int inet_hash(struct sock *sk)
 {
 	if (sk->sk_state != TCP_CLOSE) {
 		local_bh_disable();
 		__inet_hash(sk, NULL);
 		local_bh_enable();
 	}
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(inet_hash);
 
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index c117b21..f6f93fc 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -145,10 +145,12 @@ fail:
 }
 EXPORT_SYMBOL_GPL(ping_get_port);
 
-void ping_hash(struct sock *sk)
+int ping_hash(struct sock *sk)
 {
 	pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 	BUG(); /* "Please do not press this button again." */
+
+	return 0;
 }
 
 void ping_unhash(struct sock *sk)
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index bc35f18..d635251 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -93,7 +93,7 @@ static struct raw_hashinfo raw_v4_hashinfo = {
 	.lock = __RW_LOCK_UNLOCKED(raw_v4_hashinfo.lock),
 };
 
-void raw_hash_sk(struct sock *sk)
+int raw_hash_sk(struct sock *sk)
 {
 	struct raw_hashinfo *h = sk->sk_prot->h.raw_hash;
 	struct hlist_head *head;
@@ -104,6 +104,8 @@ void raw_hash_sk(struct sock *sk)
 	sk_add_node(sk, head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock_bh(&h->lock);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(raw_hash_sk);
 
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 9f5137c..b11c37c 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -235,7 +235,11 @@ lookup_protocol:
 		 * creation time automatically shares.
 		 */
 		inet->inet_sport = htons(inet->inet_num);
-		sk->sk_prot->hash(sk);
+		err = sk->sk_prot->hash(sk);
+		if (err) {
+			sk_common_release(sk);
+			goto out;
+		}
 	}
 	if (sk->sk_prot->init) {
 		err = sk->sk_prot->init(sk);
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index d575ef4..ffd5f22 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -140,13 +140,15 @@ void pn_deliver_sock_broadcast(struct net *net, struct sk_buff *skb)
 	rcu_read_unlock();
 }
 
-void pn_sock_hash(struct sock *sk)
+int pn_sock_hash(struct sock *sk)
 {
 	struct hlist_head *hlist = pn_hash_list(pn_sk(sk)->sobject);
 
 	mutex_lock(&pnsocks.lock);
 	sk_add_node_rcu(sk, hlist);
 	mutex_unlock(&pnsocks.lock);
+
+	return 0;
 }
 EXPORT_SYMBOL(pn_sock_hash);
 
@@ -200,7 +202,7 @@ static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
 	pn->resource = spn->spn_resource;
 
 	/* Enable RX on the socket */
-	sk->sk_prot->hash(sk);
+	err = sk->sk_prot->hash(sk);
 out_port:
 	mutex_unlock(&port_mutex);
 out:
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 5ca2ebf..6427b9d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6101,9 +6101,10 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname,
 	return retval;
 }
 
-static void sctp_hash(struct sock *sk)
+static int sctp_hash(struct sock *sk)
 {
 	/* STUB */
+	return 0;
 }
 
 static void sctp_unhash(struct sock *sk)