net: annotate accesses to sk->sk_rx_queue_mapping

sk->sk_rx_queue_mapping can be modified locklessly,
add a couple of READ_ONCE()/WRITE_ONCE() to document this fact.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/sock.h

@@ -1925,15 +1925,19 @@ static inline void sk_rx_queue_set(struct sock *sk, const struct sk_buff *skb)
 static inline void sk_rx_queue_clear(struct sock *sk)
 {
 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
-	sk->sk_rx_queue_mapping = NO_QUEUE_MAPPING;
+	WRITE_ONCE(sk->sk_rx_queue_mapping, NO_QUEUE_MAPPING);
 #endif
 }
 
 static inline int sk_rx_queue_get(const struct sock *sk)
 {
 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
-	if (sk && sk->sk_rx_queue_mapping != NO_QUEUE_MAPPING)
-		return sk->sk_rx_queue_mapping;
+	if (sk) {
+		int res = READ_ONCE(sk->sk_rx_queue_mapping);
+
+		if (res != NO_QUEUE_MAPPING)
+			return res;
+	}
 #endif
 
 	return -1;