[CCID3]: Reorganise timeval handling

Introducing functions to add to or subtract from a timeval variable
and renaming now_delta to timeval_new_delta that calls do_gettimeofday
and then timeval_delta, that should be used when there are several
deltas made relative to the current time or setting variables to it,
so as to avoid calling do_gettimeofday excessively.

I'm leaving these "timeval_" prefixed funcions internal to DCCP for a
while till we're sure there are no subtle bugs in it.

It also is more correct as it checks if the number of usecs added to
or subtracted from a tv_usec field is more than 2 seconds.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 40 insertions, 4 deletions

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 6ba21509e797..5cd9e794bbe2 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -429,17 +429,53 @@ extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state);
 extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
                                          struct sock *sk, u64 ackno);
 
+static inline suseconds_t timeval_usecs(const struct timeval *tv)
+{
+        return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
+}
+
+static inline suseconds_t timeval_delta(const struct timeval *large,
+                                        const struct timeval *small)
+{
+        time_t      secs  = large->tv_sec  - small->tv_sec;
+        suseconds_t usecs = large->tv_usec - small->tv_usec;
+
+        if (usecs < 0) {
+                secs--;
+                usecs += USEC_PER_SEC;
+        }
+        return secs * USEC_PER_SEC + usecs;
+}
+
+static inline void timeval_add_usecs(struct timeval *tv,
+                                     const suseconds_t usecs)
+{
+        tv->tv_usec += usecs;
+        while (tv->tv_usec >= USEC_PER_SEC) {
+                tv->tv_sec++;
+                tv->tv_usec -= USEC_PER_SEC;
+        }
+}
+
+static inline void timeval_sub_usecs(struct timeval *tv,
+                                     const suseconds_t usecs)
+{
+        tv->tv_usec -= usecs;
+        while (tv->tv_usec < 0) {
+                tv->tv_sec--;
+                tv->tv_usec += USEC_PER_SEC;
+        }
+}
+
 /*
  * Returns the difference in usecs between timeval
  * passed in and current time
  */
-static inline u32 now_delta(struct timeval tv)
+static inline suseconds_t timeval_now_delta(const struct timeval *tv)
 {
         struct timeval now;
-        
         do_gettimeofday(&now);
-        return (now.tv_sec  - tv.tv_sec) * USEC_PER_SEC +
-               (now.tv_usec - tv.tv_usec);
+        return timeval_delta(&now, tv);
 }
 
 #ifdef CONFIG_IP_DCCP_DEBUG