[PATCH] PM / sleep: cancel the synchronous restriction of pm-trace

["Fu, Zhonghui" <zhonghui.fu@linux.intel.com>]

Some system-hang occur only when multiple device PM methods
are running asynchronously. So should cancel the synchronization
of pm-trace, and make it suitable for asynchronous PM environment.

Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
---
 drivers/base/power/main.c |   53 +++++++++++++++++++++-----------------------
 include/linux/pm-trace.h  |   24 ++++++++++++--------
 kernel/power/main.c       |    2 +
 3 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 3d874ec..40daf48 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -476,9 +476,6 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
 	char *info = NULL;
 	int error = 0;
 
-	TRACE_DEVICE(dev);
-	TRACE_RESUME(0);
-
 	if (dev->power.syscore || dev->power.direct_complete)
 		goto Out;
 
@@ -506,19 +503,21 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
 		callback = pm_noirq_op(dev->driver->pm, state);
 	}
 
+	TRACE_DEVICE_START(dev);
+	TRACE_RESUME(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 	dev->power.is_noirq_suspended = false;
 
+	TRACE_DEVICE_END();
  Out:
 	complete_all(&dev->power.completion);
-	TRACE_RESUME(error);
 	return error;
 }
 
 static bool is_async(struct device *dev)
 {
-	return dev->power.async_suspend && pm_async_enabled
-		&& !pm_trace_is_enabled();
+	return dev->power.async_suspend && pm_async_enabled;
 }
 
 static void async_resume_noirq(void *data, async_cookie_t cookie)
@@ -605,9 +604,6 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
 	char *info = NULL;
 	int error = 0;
 
-	TRACE_DEVICE(dev);
-	TRACE_RESUME(0);
-
 	if (dev->power.syscore || dev->power.direct_complete)
 		goto Out;
 
@@ -635,12 +631,14 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
 		callback = pm_late_early_op(dev->driver->pm, state);
 	}
 
+	TRACE_DEVICE_START(dev);
+	TRACE_RESUME(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 	dev->power.is_late_suspended = false;
 
+	TRACE_DEVICE_END();
  Out:
-	TRACE_RESUME(error);
-
 	pm_runtime_enable(dev);
 	complete_all(&dev->power.completion);
 	return error;
@@ -734,9 +732,6 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 	int error = 0;
 	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
-	TRACE_DEVICE(dev);
-	TRACE_RESUME(0);
-
 	if (dev->power.syscore)
 		goto Complete;
 
@@ -801,9 +796,13 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 	}
 
  End:
+	TRACE_DEVICE_START(dev);
+	TRACE_RESUME(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 	dev->power.is_suspended = false;
 
+	TRACE_DEVICE_END();
  Unlock:
 	device_unlock(dev);
 	dpm_watchdog_clear(&wd);
@@ -811,8 +810,6 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
  Complete:
 	complete_all(&dev->power.completion);
 
-	TRACE_RESUME(error);
-
 	return error;
 }
 
@@ -1017,9 +1014,6 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 	char *info = NULL;
 	int error = 0;
 
-	TRACE_DEVICE(dev);
-	TRACE_SUSPEND(0);
-
 	if (async_error)
 		goto Complete;
 
@@ -1052,15 +1046,18 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
 		callback = pm_noirq_op(dev->driver->pm, state);
 	}
 
+	TRACE_DEVICE_START(dev);
+	TRACE_SUSPEND(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 	if (!error)
 		dev->power.is_noirq_suspended = true;
 	else
 		async_error = error;
 
+	TRACE_DEVICE_END();
 Complete:
 	complete_all(&dev->power.completion);
-	TRACE_SUSPEND(error);
 	return error;
 }
 
@@ -1161,9 +1158,6 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
 	char *info = NULL;
 	int error = 0;
 
-	TRACE_DEVICE(dev);
-	TRACE_SUSPEND(0);
-
 	__pm_runtime_disable(dev, false);
 
 	if (async_error)
@@ -1198,14 +1192,17 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
 		callback = pm_late_early_op(dev->driver->pm, state);
 	}
 
+	TRACE_DEVICE_START(dev);
+	TRACE_SUSPEND(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 	if (!error)
 		dev->power.is_late_suspended = true;
 	else
 		async_error = error;
 
+	TRACE_DEVICE_END();
 Complete:
-	TRACE_SUSPEND(error);
 	complete_all(&dev->power.completion);
 	return error;
 }
@@ -1346,9 +1343,6 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	int error = 0;
 	DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
-	TRACE_DEVICE(dev);
-	TRACE_SUSPEND(0);
-
 	dpm_wait_for_children(dev, async);
 
 	if (async_error)
@@ -1428,8 +1422,12 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 		callback = pm_op(dev->driver->pm, state);
 	}
 
+	TRACE_DEVICE_START(dev);
+	TRACE_SUSPEND(0);
+
 	error = dpm_run_callback(callback, dev, state, info);
 
+	TRACE_DEVICE_END();
  End:
 	if (!error) {
 		struct device *parent = dev->parent;
@@ -1455,7 +1453,6 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (error)
 		async_error = error;
 
-	TRACE_SUSPEND(error);
 	return error;
 }
 
diff --git a/include/linux/pm-trace.h b/include/linux/pm-trace.h
index ecbde7a..aa480b1 100644
--- a/include/linux/pm-trace.h
+++ b/include/linux/pm-trace.h
@@ -6,29 +6,33 @@
 #include <linux/types.h>
 
 extern int pm_trace_enabled;
-
-static inline int pm_trace_is_enabled(void)
-{
-       return pm_trace_enabled;
-}
+extern struct mutex pt_mutex;
 
 struct device;
 extern void set_trace_device(struct device *);
 extern void generate_pm_trace(const void *tracedata, unsigned int user);
 extern int show_trace_dev_match(char *buf, size_t size);
 
-#define TRACE_DEVICE(dev) do { \
+#define TRACE_DEVICE_START(dev) do { \
 	if (pm_trace_enabled) \
+		mutex_lock(&pt_mutex); \
 		set_trace_device(dev); \
 	} while(0)
 
+#define TRACE_DEVICE_END() \
+do { \
+	if (pm_trace_enabled) { \
+		mutex_unlock(&pt_mutex); \
+	} \
+} while (0)
+
 #else
 
-static inline int pm_trace_is_enabled(void) { return 0; }
+#define TRACE_DEVICE_START(dev) do { } while (0)
+#define TRACE_DEVICE_END() do { } while (0)
 
-#define TRACE_DEVICE(dev) do { } while (0)
-#define TRACE_RESUME(dev) do { } while (0)
-#define TRACE_SUSPEND(dev) do { } while (0)
+#define TRACE_RESUME(user) do { } while (0)
+#define TRACE_SUSPEND(user) do { } while (0)
 
 #endif
 
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 86e8157..ffd5145 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -515,6 +515,7 @@ power_attr(wake_unlock);
 
 #ifdef CONFIG_PM_TRACE
 int pm_trace_enabled;
+struct mutex pt_mutex;
 
 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 			     char *buf)
@@ -533,6 +534,7 @@ pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 		if (pm_trace_enabled) {
 			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
 				"PM: Correct system time has to be restored manually after resume.\n");
+			mutex_init(&pt_mutex);
 		}
 		return n;
 	}
-- 1.7.1