ACPI: convert acpi_device_lock spinlock to mutex
Convert acpi_device_lock to a mutex to avoid
a potential race upon access to /proc/acpi/wakeup
Delete the lock entirely in wakeup.c
since it is not necessary (and can not sleep)
Found-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/wakeup.c b/drivers/acpi/wakeup.c
index 5aee8c2..88725dc 100644
--- a/drivers/acpi/wakeup.c
+++ b/drivers/acpi/wakeup.c
@@ -12,12 +12,14 @@
#include "internal.h"
#include "sleep.h"
+/*
+ * We didn't lock acpi_device_lock in the file, because it invokes oops in
+ * suspend/resume and isn't really required as this is called in S-state. At
+ * that time, there is no device hotplug
+ **/
#define _COMPONENT ACPI_SYSTEM_COMPONENT
ACPI_MODULE_NAME("wakeup_devices")
-extern struct list_head acpi_wakeup_device_list;
-extern spinlock_t acpi_device_lock;
-
/**
* acpi_enable_wakeup_device_prep - prepare wakeup devices
* @sleep_state: ACPI state
@@ -29,7 +31,6 @@
{
struct list_head *node, *next;
- spin_lock(&acpi_device_lock);
list_for_each_safe(node, next, &acpi_wakeup_device_list) {
struct acpi_device *dev = container_of(node,
struct acpi_device,
@@ -40,11 +41,8 @@
(sleep_state > (u32) dev->wakeup.sleep_state))
continue;
- spin_unlock(&acpi_device_lock);
acpi_enable_wakeup_device_power(dev, sleep_state);
- spin_lock(&acpi_device_lock);
}
- spin_unlock(&acpi_device_lock);
}
/**
@@ -60,7 +58,6 @@
* Caution: this routine must be invoked when interrupt is disabled
* Refer ACPI2.0: P212
*/
- spin_lock(&acpi_device_lock);
list_for_each_safe(node, next, &acpi_wakeup_device_list) {
struct acpi_device *dev =
container_of(node, struct acpi_device, wakeup_list);
@@ -74,22 +71,17 @@
if ((!dev->wakeup.state.enabled && !dev->wakeup.flags.prepared)
|| sleep_state > (u32) dev->wakeup.sleep_state) {
if (dev->wakeup.flags.run_wake) {
- spin_unlock(&acpi_device_lock);
/* set_gpe_type will disable GPE, leave it like that */
acpi_set_gpe_type(dev->wakeup.gpe_device,
dev->wakeup.gpe_number,
ACPI_GPE_TYPE_RUNTIME);
- spin_lock(&acpi_device_lock);
}
continue;
}
- spin_unlock(&acpi_device_lock);
if (!dev->wakeup.flags.run_wake)
acpi_enable_gpe(dev->wakeup.gpe_device,
dev->wakeup.gpe_number);
- spin_lock(&acpi_device_lock);
}
- spin_unlock(&acpi_device_lock);
}
/**
@@ -101,7 +93,6 @@
{
struct list_head *node, *next;
- spin_lock(&acpi_device_lock);
list_for_each_safe(node, next, &acpi_wakeup_device_list) {
struct acpi_device *dev =
container_of(node, struct acpi_device, wakeup_list);
@@ -112,19 +103,16 @@
if ((!dev->wakeup.state.enabled && !dev->wakeup.flags.prepared)
|| sleep_state > (u32) dev->wakeup.sleep_state) {
if (dev->wakeup.flags.run_wake) {
- spin_unlock(&acpi_device_lock);
acpi_set_gpe_type(dev->wakeup.gpe_device,
dev->wakeup.gpe_number,
ACPI_GPE_TYPE_WAKE_RUN);
/* Re-enable it, since set_gpe_type will disable it */
acpi_enable_gpe(dev->wakeup.gpe_device,
dev->wakeup.gpe_number);
- spin_lock(&acpi_device_lock);
}
continue;
}
- spin_unlock(&acpi_device_lock);
acpi_disable_wakeup_device_power(dev);
/* Never disable run-wake GPE */
if (!dev->wakeup.flags.run_wake) {
@@ -133,16 +121,14 @@
acpi_clear_gpe(dev->wakeup.gpe_device,
dev->wakeup.gpe_number, ACPI_NOT_ISR);
}
- spin_lock(&acpi_device_lock);
}
- spin_unlock(&acpi_device_lock);
}
int __init acpi_wakeup_device_init(void)
{
struct list_head *node, *next;
- spin_lock(&acpi_device_lock);
+ mutex_lock(&acpi_device_lock);
list_for_each_safe(node, next, &acpi_wakeup_device_list) {
struct acpi_device *dev = container_of(node,
struct acpi_device,
@@ -150,15 +136,13 @@
/* In case user doesn't load button driver */
if (!dev->wakeup.flags.run_wake || dev->wakeup.state.enabled)
continue;
- spin_unlock(&acpi_device_lock);
acpi_set_gpe_type(dev->wakeup.gpe_device,
dev->wakeup.gpe_number,
ACPI_GPE_TYPE_WAKE_RUN);
acpi_enable_gpe(dev->wakeup.gpe_device,
dev->wakeup.gpe_number);
dev->wakeup.state.enabled = 1;
- spin_lock(&acpi_device_lock);
}
- spin_unlock(&acpi_device_lock);
+ mutex_unlock(&acpi_device_lock);
return 0;
}