intel_idle: remove redundant local_irq_disable() call
Yanmin Zhang [Tue, 10 Jan 2012 23:48:21 +0000 (15:48 -0800)]
irq disabling happens earlier in process_32.c:cpu_idle.  Basically,
cpuidle_state->enter is called, cpu irq is disabled.  cpuidle_state->enter
would turn on irq when exiting.

intel_idle doesn't follow this assumption.  Although it doesn't cause real
issue, it misleads developers.  Remove the call to local_irq_disable() at
entry.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Mingming Zhang <mingmingx.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/idle/intel_idle.c

index af0b4a5..920c61c 100644 (file)
@@ -232,6 +232,7 @@ static int get_driver_data(int cstate)
  * @drv: cpuidle driver
  * @index: index of cpuidle state
  *
+ * Must be called under local_irq_disable().
  */
 static int intel_idle(struct cpuidle_device *dev,
                struct cpuidle_driver *drv, int index)
@@ -247,8 +248,6 @@ static int intel_idle(struct cpuidle_device *dev,
 
        cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
 
-       local_irq_disable();
-
        /*
         * leave_mm() to avoid costly and often unnecessary wakeups
         * for flushing the user TLB's associated with the active mm.