linux-kernel - [PATCH 45/50] intel_idle: remove redundant local_irq

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Date:	Tue, 17 Jan 2012 07:21:37 -0500
From:	Len Brown <lenb@...nel.org>
To:	linux-acpi@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org
Cc:	Yanmin Zhang <yanmin_zhang@...ux.intel.com>,
	Mingming Zhang <mingmingx.zhang@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Len Brown <len.brown@...el.com>
Subject: [PATCH 45/50] intel_idle: remove redundant local_irq_disable() call

From: Yanmin Zhang <yanmin_zhang@...ux.intel.com>

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@...ux-foundation.org: add comment]
Signed-off-by: Mingming Zhang <mingmingx.zhang@...el.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Len Brown <len.brown@...el.com>
---
 drivers/idle/intel_idle.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 38da9f8..27e41cc 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -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.
-- 
1.7.9.rc1

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