[TIME]: Put jiffies_to_usecs in time.h

Move local version put in tcp_diag.c into time.h
where it belongs.  Also, make it smarted about HZ
values math.

Based upon suggestions from Joe Perches <joe@Perches.com>
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/time.h

@@ -194,6 +194,18 @@ static inline unsigned int jiffies_to_msecs(const unsigned long j)
 	return (j * 1000) / HZ;
 #endif
 }
+
+static inline unsigned int jiffies_to_usecs(const unsigned long j)
+{
+#if HZ <= 1000 && !(1000 % HZ)
+	return (1000000 / HZ) * j;
+#elif HZ > 1000 && !(HZ % 1000)
+	return (j*1000 + (HZ - 1000))/(HZ / 1000);
+#else
+	return (j * 1000000) / HZ;
+#endif
+}
+
 static inline unsigned long msecs_to_jiffies(const unsigned int m)
 {
 #if HZ <= 1000 && !(1000 % HZ)

net/ipv4/tcp_diag.c

@@ -41,12 +41,6 @@ static struct sock *tcpnl;
    rta->rta_len = rtalen;                   \
    RTA_DATA(rta); })
 
-static inline unsigned int jiffies_to_usecs(const unsigned long j)
-{
-	return 1000*jiffies_to_msecs(j);
-}
-
-
 /* Return information about state of tcp endpoint in API format. */
 void tcp_get_info(struct sock *sk, struct tcp_info *info)
 {