net: sock: make sock_tx_timestamp void

Currently, sock_tx_timestamp() always returns 0. The comment that
describes the sock_tx_timestamp() function wrongly says that it
returns an error when an invalid argument is passed (from commit
20d4947353be, ``net: socket infrastructure for SO_TIMESTAMPING'').
Make the function void, so that we can also remove all the unneeded
if conditions that check for such a _non-existant_ error case in the
output path.

Signed-off-by: Daniel Borkmann <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/sock.h

···
  * @sk:		socket sending this packet
  * @tx_flags:	filled with instructions for time stamping
  *
- * Currently only depends on SOCK_TIMESTAMPING* flags. Returns error code if
- * parameters are invalid.
+ * Currently only depends on SOCK_TIMESTAMPING* flags.
  */
-extern int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
+extern void sock_tx_timestamp(struct sock *sk, __u8 *tx_flags);
 
 /**
  * sk_eat_skb - Release a skb if it is no longer needed

net/can/raw.c

···
 	err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 	if (err < 0)
 		goto free_skb;
-	err = sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
-	if (err < 0)
-		goto free_skb;
+
+	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
 
 	skb->dev = dev;
 	skb->sk  = sk;

net/ipv4/ping.c

···
 	ipc.opt = NULL;
 	ipc.oif = sk->sk_bound_dev_if;
 	ipc.tx_flags = 0;
-	err = sock_tx_timestamp(sk, &ipc.tx_flags);
-	if (err)
-		return err;
+
+	sock_tx_timestamp(sk, &ipc.tx_flags);
 
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sock_net(sk), msg, &ipc);

net/ipv4/udp.c

···
 	ipc.addr = inet->inet_saddr;
 
 	ipc.oif = sk->sk_bound_dev_if;
-	err = sock_tx_timestamp(sk, &ipc.tx_flags);
-	if (err)
-		return err;
+
+	sock_tx_timestamp(sk, &ipc.tx_flags);
+
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
 		if (err)

net/ipv6/ip6_output.c

···
 	}
 
 	/* For UDP, check if TX timestamp is enabled */
-	if (sk->sk_type == SOCK_DGRAM) {
-		err = sock_tx_timestamp(sk, &tx_flags);
-		if (err)
-			goto error;
-	}
+	if (sk->sk_type == SOCK_DGRAM)
+		sock_tx_timestamp(sk, &tx_flags);
 
 	/*
 	 * Let's try using as much space as possible.

net/packet/af_packet.c

···
 	skb->dev = dev;
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
-	err = sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
-	if (err < 0)
-		goto out_unlock;
+
+	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
 
 	if (unlikely(extra_len == 4))
 		skb->no_fcs = 1;
···
 	err = skb_copy_datagram_from_iovec(skb, offset, msg->msg_iov, 0, len);
 	if (err)
 		goto out_free;
-	err = sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
-	if (err < 0)
-		goto out_free;
+
+	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
 
 	if (!gso_type && (len > dev->mtu + reserve + extra_len)) {
 		/* Earlier code assumed this would be a VLAN pkt,

net/socket.c

···
 }
 EXPORT_SYMBOL(sock_release);
 
-int sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
+void sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
 {
 	*tx_flags = 0;
 	if (sock_flag(sk, SOCK_TIMESTAMPING_TX_HARDWARE))
···
 		*tx_flags |= SKBTX_SW_TSTAMP;
 	if (sock_flag(sk, SOCK_WIFI_STATUS))
 		*tx_flags |= SKBTX_WIFI_STATUS;
-	return 0;
 }
 EXPORT_SYMBOL(sock_tx_timestamp);