From ae0820e32026979a7b8aee3f19f0a8d925946636 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 15 Jul 2010 10:29:00 +0200
Subject: [PATCH 129/518] suspend: Prevent might sleep splats

timekeeping suspend/resume calls read_persistant_clock() which takes
rtc_lock. That results in might sleep warnings because at that point
we run with interrupts disabled.

We cannot convert rtc_lock to a raw spinlock as that would trigger
other might sleep warnings.

As a temporary workaround we disable the might sleep warnings by
setting system_state to SYSTEM_SUSPEND before calling sysdev_suspend()
and restoring it to SYSTEM_RUNNING afer sysdev_resume().

Needs to be revisited.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/kernel.h   | 1 +
 kernel/power/hibernate.c | 7 +++++++
 kernel/power/suspend.c   | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index a4ac278d02d0a..d1e54f3927807 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -533,6 +533,7 @@ extern enum system_states {
 	SYSTEM_HALT,
 	SYSTEM_POWER_OFF,
 	SYSTEM_RESTART,
+	SYSTEM_SUSPEND,
 } system_state;
 
 #define TAINT_PROPRIETARY_MODULE	0
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e97f2395e15d8..c9e8fd79ad3a9 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -292,6 +292,8 @@ static int create_image(int platform_mode)
 
 	local_irq_disable();
 
+	system_state = SYSTEM_SUSPEND;
+
 	error = syscore_suspend();
 	if (error) {
 		pr_err("Some system devices failed to power down, aborting hibernation\n");
@@ -322,6 +324,7 @@ static int create_image(int platform_mode)
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -454,6 +457,7 @@ static int resume_target_kernel(bool platform_mode)
 		goto Enable_cpus;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 
 	error = syscore_suspend();
 	if (error)
@@ -487,6 +491,7 @@ static int resume_target_kernel(bool platform_mode)
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -572,6 +577,7 @@ int hibernation_platform_enter(void)
 		goto Enable_cpus;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 	syscore_suspend();
 	if (pm_wakeup_pending()) {
 		error = -EAGAIN;
@@ -584,6 +590,7 @@ int hibernation_platform_enter(void)
 
  Power_up:
 	syscore_resume();
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index c0bc2c89697ac..0d3dab53c527b 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -428,6 +428,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 	arch_suspend_disable_irqs();
 	BUG_ON(!irqs_disabled());
 
+	system_state = SYSTEM_SUSPEND;
+
 	error = syscore_suspend();
 	if (!error) {
 		*wakeup = pm_wakeup_pending();
@@ -443,6 +445,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 		syscore_resume();
 	}
 
+	system_state = SYSTEM_RUNNING;
+
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
 
-- 
2.41.0

