net: Set ping saddr after we successfully get the ping port

We can defer set ping saddr until we successfully get the ping port. So we
can avoid clear saddr when failed. Since ping_clear_saddr() is not used
anymore now, remove it.
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ping.c

@@ -383,20 +383,6 @@ static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 	}
 }
 
-static void ping_clear_saddr(struct sock *sk, int dif)
-{
-	sk->sk_bound_dev_if = dif;
-	if (sk->sk_family == AF_INET) {
-		struct inet_sock *isk = inet_sk(sk);
-		isk->inet_rcv_saddr = isk->inet_saddr = 0;
-#if IS_ENABLED(CONFIG_IPV6)
-	} else if (sk->sk_family == AF_INET6) {
-		struct ipv6_pinfo *np = inet6_sk(sk);
-		memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
-		memset(&np->saddr, 0, sizeof(np->saddr));
-#endif
-	}
-}
 /*
  * We need our own bind because there are no privileged id's == local ports.
  * Moreover, we don't allow binding to multi- and broadcast addresses.
@@ -420,12 +406,13 @@ int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 		goto out;
 
 	err = -EADDRINUSE;
-	ping_set_saddr(sk, uaddr);
 	snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 	if (ping_get_port(sk, snum) != 0) {
-		ping_clear_saddr(sk, dif);
+		/* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
+		sk->sk_bound_dev_if = dif;
 		goto out;
 	}
+	ping_set_saddr(sk, uaddr);
 
 	pr_debug("after bind(): num = %hu, dif = %d\n",
 		 isk->inet_num,