Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
posix_timer: Fix error path in timer_create
hrtimer: Avoid double seqlock
timers: Move local variable into else section
timers: Fix slack calculation really

kernel/hrtimer.c

···
 
 	do {
 		seq = read_seqbegin(&xtime_lock);
-		xts = current_kernel_time();
+		xts = __current_kernel_time();
 		tom = wall_to_monotonic;
 	} while (read_seqretry(&xtime_lock, seq));
 

kernel/posix-timers.c

···
 	new_timer->it_id = (timer_t) new_timer_id;
 	new_timer->it_clock = which_clock;
 	new_timer->it_overrun = -1;
-	error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
-	if (error)
-		goto out;
 
-	/*
-	 * return the timer_id now.  The next step is hard to
-	 * back out if there is an error.
-	 */
 	if (copy_to_user(created_timer_id,
 			 &new_timer_id, sizeof (new_timer_id))) {
 		error = -EFAULT;
···
 	new_timer->sigq->info.si_value = event.sigev_value;
 	new_timer->sigq->info.si_tid   = new_timer->it_id;
 	new_timer->sigq->info.si_code  = SI_TIMER;
+
+	error = CLOCK_DISPATCH(which_clock, timer_create, (new_timer));
+	if (error)
+		goto out;
 
 	spin_lock_irq(&current->sighand->siglock);
 	new_timer->it_signal = current->signal;

kernel/timer.c

···
 
 	expires_limit = expires;
 
-	if (timer->slack > -1)
+	if (timer->slack >= 0) {
 		expires_limit = expires + timer->slack;
-	else if (time_after(expires, jiffies)) /* auto slack: use 0.4% */
-		expires_limit = expires + (expires - jiffies)/256;
+	} else {
+		unsigned long now = jiffies;
 
+		/* No slack, if already expired else auto slack 0.4% */
+		if (time_after(expires, now))
+			expires_limit = expires + (expires - now)/256;
+	}
 	mask = expires ^ expires_limit;
 	if (mask == 0)
 		return expires;