Merge bk://kernel.bkbits.net/davem/sparc-2.5

into home.osdl.org:/home/torvalds/v2.5/linux

arch/i386/kernel/timers/timer_tsc.c

@@ -321,7 +321,7 @@ time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 {
 	struct cpufreq_freqs *freq = data;
 
-	write_seqlock(&xtime_lock);
+	write_seqlock_irq(&xtime_lock);
 	if (!ref_freq) {
 		ref_freq = freq->old;
 		loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
@@ -342,7 +342,7 @@ time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 		}
 #endif
 	}
-	write_sequnlock(&xtime_lock);
+	write_sequnlock_irq(&xtime_lock);
 
 	return 0;
 }

kernel/timer.c

@@ -315,23 +315,30 @@ EXPORT_SYMBOL(del_timer);
  * the timer it also makes sure the handler has finished executing on other
  * CPUs.
  *
- * Synchronization rules: callers must prevent restarting of the timer,
- * otherwise this function is meaningless. It must not be called from
- * interrupt contexts. Upon exit the timer is not queued and the handler
- * is not running on any CPU.
+ * Synchronization rules: callers must prevent restarting of the timer
+ * (except restarting the timer from the timer function itself), otherwise
+ * this function is meaningless. It must not be called from interrupt
+ * contexts. Upon exit the timer is not queued and the handler is not
+ * running on any CPU.
  *
- * The function returns whether it has deactivated a pending timer or not.
+ * The function returns the number of times it has deactivated a pending
+ * timer.
  */
 int del_timer_sync(struct timer_list *timer)
 {
+	int i, ret = 0, again;
+	unsigned long flags;
 	tvec_base_t *base;
-	int i, ret = 0;
 
 	check_timer(timer);
 
 del_again:
 	ret += del_timer(timer);
 
+	/*
+	 * First do a lighter but racy check, whether the
+	 * timer is running on any other CPU:
+	 */
 	for (i = 0; i < NR_CPUS; i++) {
 		if (!cpu_online(i))
 			continue;
@@ -345,8 +352,33 @@ int del_timer_sync(struct timer_list *timer)
 			break;
 		}
 	}
-	smp_rmb();
+
+	/*
+	 * Do a heavy but race-free re-check to make sure both that
+	 * the timer is neither running nor pending:
+	 */
+	again = 0;
+	local_irq_save(flags);
+
+	for (i = 0; i < NR_CPUS; i++)
+		if (cpu_online(i))
+			spin_lock(&per_cpu(tvec_bases, i).lock);
+
 	if (timer_pending(timer))
+		again = 1;
+	else
+		for (i = 0; i < NR_CPUS; i++)
+			if (cpu_online(i) &&
+				(per_cpu(tvec_bases, i).running_timer == timer))
+					again = 1;
+
+	for (i = 0; i < NR_CPUS; i++)
+		if (cpu_online(i))
+			spin_unlock(&per_cpu(tvec_bases, i).lock);
+
+	local_irq_restore(flags);
+
+	if (again)
 		goto del_again;
 
 	return ret;