RTO connection timeout: coding style fixes and comments

This patch affects the retransmits_timed_out() function.

Changes:
1) Variables have more meaningful names
2) retransmits_timed_out() has an introductionary comment.
3) Small coding style changes.

Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e5319495f15e486063c280d2a32cd5dbc48953af..df50bc40b5fd244970d0287bb2a8b41286ab5066 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1252,22 +1252,27 @@ static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_bu
 #define tcp_for_write_queue_from_safe(skb, tmp, sk)                    \
        skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
 
+/* This function calculates a "timeout" which is equivalent to the timeout of a
+ * TCP connection after "boundary" unsucessful, exponentially backed-off
+ * retransmissions with an initial RTO of TCP_RTO_MIN.
+ */
 static inline bool retransmits_timed_out(const struct sock *sk,
                                         unsigned int boundary)
 {
-       int limit, K;
+       unsigned int timeout, linear_backoff_thresh;
+
        if (!inet_csk(sk)->icsk_retransmits)
                return false;
 
-       K = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
+       linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
 
-       if (boundary <= K)
-               limit = ((2 << boundary) - 1) * TCP_RTO_MIN;
+       if (boundary <= linear_backoff_thresh)
+               timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
        else
-               limit = ((2 << K) - 1) * TCP_RTO_MIN +
-                       (boundary - K) * TCP_RTO_MAX;
+               timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
+                         (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
 
-       return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= limit;
+       return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout;
 }
 
 static inline struct sk_buff *tcp_send_head(struct sock *sk)