From 25891ba732fa3c2fbfc9e47848f05161b5f68a52 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 15 Jul 2010 10:29:00 +0200
Subject: [PATCH 038/414] 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 11fdfda99b3c..30e07e57ab73 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -425,6 +425,7 @@ 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 7ef5244c3164..9c312eda409f 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -275,6 +275,8 @@ static int create_image(int platform_mode)
 
 	local_irq_disable();
 
+	system_state = SYSTEM_SUSPEND;
+
 	error = syscore_suspend();
 	if (error) {
 		printk(KERN_ERR "PM: Some system devices failed to power down, "
@@ -302,6 +304,7 @@ static int create_image(int platform_mode)
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -427,6 +430,7 @@ static int resume_target_kernel(bool platform_mode)
 		goto Enable_cpus;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 
 	error = syscore_suspend();
 	if (error)
@@ -460,6 +464,7 @@ static int resume_target_kernel(bool platform_mode)
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -548,6 +553,7 @@ int hibernation_platform_enter(void)
 		goto Platform_finish;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 	syscore_suspend();
 	if (pm_wakeup_pending()) {
 		error = -EAGAIN;
@@ -560,6 +566,7 @@ int hibernation_platform_enter(void)
 
  Power_up:
 	syscore_resume();
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 	enable_nonboot_cpus();
 
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 5455d5c3c149..c2372edf5857 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -210,6 +210,8 @@ 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();
@@ -220,6 +222,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
 		syscore_resume();
 	}
 
+	system_state = SYSTEM_RUNNING;
+
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
 
-- 
2.10.2

