[PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem)

Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390
timer interrupt handler with this change.

Currently update_times() calculates ticks by "jiffies - wall_jiffies", but
callers of do_timer() should know how many ticks to update.  Passing ticks
get rid of this redundant calculation.  Also there are another redundancy
pointed out by Martin Schwidefsky.

This cleanup make a barrier added by
5aee405c66 needless.  So this patch removes
it.

As a bonus, this cleanup make wall_jiffies can be removed easily, since now
wall_jiffies is always synced with jiffies.  (This patch does not really
remove wall_jiffies.  It would be another cleanup patch)

Signed-off-by: Atsushi Nemoto <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: john stultz <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Acked-by: Russell King <[email protected]>
Cc: Ian Molton <[email protected]>
Cc: Mikael Starvik <[email protected]>
Acked-by: David Howells <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: Hirokazu Takata <[email protected]>
Acked-by: Ralf Baechle <[email protected]>
Cc: Kyle McMartin <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Kazumoto Kojima <[email protected]>
Cc: Richard Curnow <[email protected]>
Cc: William Lee Irwin III <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: Paolo 'Blaisorblade' Giarrusso <[email protected]>
Cc: Miles Bader <[email protected]>
Cc: Chris Zankel <[email protected]>
Acked-by: "Luck, Tony" <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Roman Zippel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

arch/alpha/kernel/time.c

@@ -132,7 +132,7 @@ irqreturn_t timer_interrupt(int irq, void *dev, struct pt_regs * regs)
 	nticks = delta >> FIX_SHIFT;
 
 	while (nticks > 0) {
-		do_timer(regs);
+		do_timer(1);
 #ifndef CONFIG_SMP
 		update_process_times(user_mode(regs));
 #endif