Replace the per-flag inet_assign_bit() calls in sync_socket_options()
with a masked word-level copy of inet_sk()->inet_flags. Introduce
MPTCP_INET_FLAGS_MASK so further flags propagated by MPTCP can be
added by extending the mask rather than touching the call site.

No functional change.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David Carlier <devnexen@gmail.com>
---
 net/mptcp/sockopt.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 0efe40be2fde..41c9dc9cf95e 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -16,6 +16,10 @@
 
 #define MIN_INFO_OPTLEN_SIZE		16
 #define MIN_FULL_INFO_OPTLEN_SIZE	40
+#define MPTCP_INET_FLAGS_MASK \
+	(BIT(INET_FLAGS_TRANSPARENT) | \
+	 BIT(INET_FLAGS_FREEBIND) | \
+	 BIT(INET_FLAGS_BIND_ADDRESS_NO_PORT))
 
 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk)
 {
@@ -1536,6 +1540,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 {
 	static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
 	struct sock *sk = (struct sock *)msk;
+	unsigned long flags;
 	bool keep_open;
 
 	keep_open = sock_flag(sk, SOCK_KEEPOPEN);
@@ -1582,9 +1587,10 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 	tcp_sock_set_keepcnt(ssk, msk->keepalive_cnt);
 	tcp_sock_set_maxseg(ssk, msk->maxseg);
 
-	inet_assign_bit(TRANSPARENT, ssk, inet_test_bit(TRANSPARENT, sk));
-	inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
-	inet_assign_bit(BIND_ADDRESS_NO_PORT, ssk, inet_test_bit(BIND_ADDRESS_NO_PORT, sk));
+	flags = inet_sk(ssk)->inet_flags;
+	flags &= ~MPTCP_INET_FLAGS_MASK;
+	flags |= inet_sk(sk)->inet_flags & MPTCP_INET_FLAGS_MASK;
+	WRITE_ONCE(inet_sk(ssk)->inet_flags, flags);
 	WRITE_ONCE(inet_sk(ssk)->local_port_range, READ_ONCE(inet_sk(sk)->local_port_range));
 }
 
-- 
2.53.0