af_packet: use swap() instead of the open coded macro XC()

Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -2501,22 +2501,20 @@ static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
 	mutex_lock(&po->pg_vec_lock);
 	if (closing || atomic_read(&po->mapped) == 0) {
 		err = 0;
-#define XC(a, b) ({ __typeof__ ((a)) __t; __t = (a); (a) = (b); __t; })
 		spin_lock_bh(&rb_queue->lock);
-		pg_vec = XC(rb->pg_vec, pg_vec);
+		swap(rb->pg_vec, pg_vec);
 		rb->frame_max = (req->tp_frame_nr - 1);
 		rb->head = 0;
 		rb->frame_size = req->tp_frame_size;
 		spin_unlock_bh(&rb_queue->lock);
 
-		order = XC(rb->pg_vec_order, order);
-		req->tp_block_nr = XC(rb->pg_vec_len, req->tp_block_nr);
+		swap(rb->pg_vec_order, order);
+		swap(rb->pg_vec_len, req->tp_block_nr);
 
 		rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
 		po->prot_hook.func = (po->rx_ring.pg_vec) ?
 						tpacket_rcv : packet_rcv;
 		skb_queue_purge(rb_queue);
-#undef XC
 		if (atomic_read(&po->mapped))
 			pr_err("packet_mmap: vma is busy: %d\n",
 			       atomic_read(&po->mapped));