net/packet: convert po->tp_tx_has_off to an atomic flag

This is to use existing space in po->flags, and reclaim
the storage used by the non atomic bit fields.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -2672,7 +2672,7 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame,
 		return -EMSGSIZE;
 	}
 
-	if (unlikely(po->tp_tx_has_off)) {
+	if (unlikely(packet_sock_flag(po, PACKET_SOCK_TX_HAS_OFF))) {
 		int off_min, off_max;
 
 		off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
@@ -3993,7 +3993,7 @@ packet_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval,
 
 		lock_sock(sk);
 		if (!po->rx_ring.pg_vec && !po->tx_ring.pg_vec)
-			po->tp_tx_has_off = !!val;
+			packet_sock_flag_set(po, PACKET_SOCK_TX_HAS_OFF, val);
 
 		release_sock(sk);
 		return 0;
@@ -4120,7 +4120,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
 		lv = sizeof(rstats);
 		break;
 	case PACKET_TX_HAS_OFF:
-		val = po->tp_tx_has_off;
+		val = packet_sock_flag(po, PACKET_SOCK_TX_HAS_OFF);
 		break;
 	case PACKET_QDISC_BYPASS:
 		val = packet_use_direct_xmit(po);

net/packet/internal.h

@@ -119,8 +119,7 @@ struct packet_sock {
 	unsigned long		flags;
 	unsigned int		running;	/* bind_lock must be held */
 	unsigned int		has_vnet_hdr:1, /* writer must hold sock lock */
-				tp_loss:1,
-				tp_tx_has_off:1;
+				tp_loss:1;
 	int			pressure;
 	int			ifindex;	/* bound device		*/
 	__be16			num;
@@ -146,6 +145,7 @@ static inline struct packet_sock *pkt_sk(struct sock *sk)
 enum packet_sock_flags {
 	PACKET_SOCK_ORIGDEV,
 	PACKET_SOCK_AUXDATA,
+	PACKET_SOCK_TX_HAS_OFF,
 };
 
 static inline void packet_sock_flag_set(struct packet_sock *po,