[PATCH v2 net-next 1/3] net: Make locking in sock_bindtoindex optional

[Ferenc Fejes]

The sock_bindtoindex intended for kernel wide usage however
it will lock the socket regardless of the context. This modification
relax this behavior optionally: locking the socket will be optional
by calling the sock_bindtoindex with lock_sk = true.

The modification applied to all users of the sock_bindtoindex.

Signed-off-by: Ferenc Fejes <fejes@xxxxxxxxxxx>
---
 include/net/sock.h        |  2 +-
 net/core/sock.c           | 10 ++++++----
 net/ipv4/udp_tunnel.c     |  2 +-
 net/ipv6/ip6_udp_tunnel.c |  2 +-
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index d994daa418ec..098d97d9fe72 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2688,7 +2688,7 @@ static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)
 
 void sock_def_readable(struct sock *sk);
 
-int sock_bindtoindex(struct sock *sk, int ifindex);
+int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
 void sock_enable_timestamps(struct sock *sk);
 void sock_no_linger(struct sock *sk);
 void sock_set_keepalive(struct sock *sk);
diff --git a/net/core/sock.c b/net/core/sock.c
index 2ca3425b519c..c7ee722cfbe9 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -594,13 +594,15 @@ static int sock_bindtoindex_locked(struct sock *sk, int ifindex)
 	return ret;
 }
 
-int sock_bindtoindex(struct sock *sk, int ifindex)
+int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk)
 {
 	int ret;
 
-	lock_sock(sk);
+	if (lock_sk)
+		lock_sock(sk);
 	ret = sock_bindtoindex_locked(sk, ifindex);
-	release_sock(sk);
+	if (lock_sk)
+		release_sock(sk);
 
 	return ret;
 }
@@ -646,7 +648,7 @@ static int sock_setbindtodevice(struct sock *sk, char __user *optval,
 			goto out;
 	}
 
-	return sock_bindtoindex(sk, index);
+	return sock_bindtoindex(sk, index, true);
 out:
 #endif
 
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 2158e8bddf41..3eecba0874aa 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -22,7 +22,7 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
 		goto error;
 
 	if (cfg->bind_ifindex) {
-		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex);
+		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true);
 		if (err < 0)
 			goto error;
 	}
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 2e0ad1bc84a8..cdc4d4ee2420 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -30,7 +30,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 			goto error;
 	}
 	if (cfg->bind_ifindex) {
-		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex);
+		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true);
 		if (err < 0)
 			goto error;
 	}
-- 
2.17.1