tcp: tsq: add tsq_flags / tsq_enum

This is a cleanup, to ease code review of following patches.

Old 'enum tsq_flags' is renamed, and a new enumeration is added
with the flags used in cmpxchg() operations as opposed to
single bit operations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c7adcb5..8f0289b 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -784,10 +784,10 @@ static void tcp_tasklet_func(unsigned long data)
 	}
 }
 
-#define TCP_DEFERRED_ALL ((1UL << TCP_TSQ_DEFERRED) |		\
-			  (1UL << TCP_WRITE_TIMER_DEFERRED) |	\
-			  (1UL << TCP_DELACK_TIMER_DEFERRED) |	\
-			  (1UL << TCP_MTU_REDUCED_DEFERRED))
+#define TCP_DEFERRED_ALL (TCPF_TSQ_DEFERRED |		\
+			  TCPF_WRITE_TIMER_DEFERRED |	\
+			  TCPF_DELACK_TIMER_DEFERRED |	\
+			  TCPF_MTU_REDUCED_DEFERRED)
 /**
  * tcp_release_cb - tcp release_sock() callback
  * @sk: socket
@@ -808,7 +808,7 @@ void tcp_release_cb(struct sock *sk)
 		nflags = flags & ~TCP_DEFERRED_ALL;
 	} while (cmpxchg(&tp->tsq_flags, flags, nflags) != flags);
 
-	if (flags & (1UL << TCP_TSQ_DEFERRED))
+	if (flags & TCPF_TSQ_DEFERRED)
 		tcp_tsq_handler(sk);
 
 	/* Here begins the tricky part :
@@ -822,15 +822,15 @@ void tcp_release_cb(struct sock *sk)
 	 */
 	sock_release_ownership(sk);
 
-	if (flags & (1UL << TCP_WRITE_TIMER_DEFERRED)) {
+	if (flags & TCPF_WRITE_TIMER_DEFERRED) {
 		tcp_write_timer_handler(sk);
 		__sock_put(sk);
 	}
-	if (flags & (1UL << TCP_DELACK_TIMER_DEFERRED)) {
+	if (flags & TCPF_DELACK_TIMER_DEFERRED) {
 		tcp_delack_timer_handler(sk);
 		__sock_put(sk);
 	}
-	if (flags & (1UL << TCP_MTU_REDUCED_DEFERRED)) {
+	if (flags & TCPF_MTU_REDUCED_DEFERRED) {
 		inet_csk(sk)->icsk_af_ops->mtu_reduced(sk);
 		__sock_put(sk);
 	}