[PATCH] /proc/stat:btime fix

From: George Anzinger <george@mvista.com>,
      Petri Kaukasoina <kaukasoi@elektroni.ee.tut.fi>

btime in /proc/stat does not stay constant but decreases at a rate of 15
secs/day, because we're assuming that HZ is exactly 100.  Use the correct
adjustments to fix that up.

fs/proc/proc_misc.c

@@ -360,23 +360,12 @@ int show_stat(struct seq_file *p, void *v)
 {
 	int i;
 	extern unsigned long total_forks;
-	u64 jif;
+	unsigned long jif;
 	unsigned int sum = 0, user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0;
-	struct timeval now; 
-	unsigned long seq;
 
-	/* Atomically read jiffies and time of day */ 
-	do {
-		seq = read_seqbegin(&xtime_lock);
-
-		jif = get_jiffies_64();
-		do_gettimeofday(&now);
-	} while (read_seqretry(&xtime_lock, seq));
-
-	/* calc # of seconds since boot time */
-	jif -= INITIAL_JIFFIES;
-	jif = ((u64)now.tv_sec * HZ) + (now.tv_usec/(1000000/HZ)) - jif;
-	do_div(jif, HZ);
+	jif = - wall_to_monotonic.tv_sec;
+	if (wall_to_monotonic.tv_nsec)
+		--jif;
 
 	for_each_cpu(i) {
 		int j;