[PATCH 3/3] mach-u300: cleanup clockevent code

On Wed, 1 Jun 2011, Stephen Boyd wrote:

On 06/01/2011 03:03 AM, Thomas Gleixner wrote:

quoted

Something like the below should work for both UP and SMP

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index c027d4f..739801b 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c

@@ -173,6 +173,12 @@ static void clockevents_notify_released(void)
 	}
 }
 
+#ifdef CONFIG_SMP
+# define CPU_MASK_CHECK(x)		WARN_ON(!x)
+#else
+# define CPU_MASK_CHECK(x)		(!x)
+#endif
+
 /**
  * clockevents_register_device - register a clock event device
  * @dev:	device to register

@@ -182,7 +188,8 @@ void clockevents_register_device(struct clock_event_device *dev)
 	unsigned long flags;
 
 	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
-	BUG_ON(!dev->cpumask);
+	if (CPU_MASK_CHECK(dev->cpumask))
+		dev->cpumask = cpumask_of(smp_processor_id());
 
 	raw_spin_lock_irqsave(&clockevents_lock, flags);

Won't this print a big WARNING on SMP_ON_UP=y and is_smp() == false
kernels? Is there a generic cross-architecture way to check for SMP at

Need to check that.

runtime?

Also, I don't understand the original motivation for this change. The
assignment to cpumask was there in the u300 timer code already so the
commit text from Linus is a bit misleading/confusing.

The point is that we can remove these assignements for UP all over the
place and just do it in the core code.