Re: [PATCH] PCI / PM: Block races between runtime PM and system sleep

OK, so what about the appended patch (the last hunk is necessary to make the
SCSI error handling work when runtime PM is disabled, it should be a separate
patch)?

Rafael

---
 drivers/base/power/main.c    |   27 ++++++++++++++++++++++-----
 drivers/base/power/runtime.c |   10 ++++++----
 2 files changed, 28 insertions(+), 9 deletions(-)

Index: linux-2.6/drivers/base/power/main.c
===================================================================

--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c

@@ -505,6 +505,7 @@ static int legacy_resume(struct device *
 static int device_resume(struct device *dev, pm_message_t state, bool async)
 {
 	int error = 0;
+	bool put = false;
 
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);

@@ -521,6 +522,9 @@ static int device_resume(struct device *
 	if (!dev->power.is_suspended)
 		goto Unlock;
 
+	pm_runtime_enable(dev);
+	put = true;
+
 	if (dev->pwr_domain) {
 		pm_dev_dbg(dev, state, "power domain ");
 		error = pm_op(dev, &dev->pwr_domain->ops, state);

@@ -563,6 +567,10 @@ static int device_resume(struct device *
 	complete_all(&dev->power.completion);
 
 	TRACE_RESUME(error);
+
+	if (put)
+		pm_runtime_put_sync(dev);
+
 	return error;
 }
 

@@ -843,16 +851,22 @@ static int __device_suspend(struct devic
 	int error = 0;
 
 	dpm_wait_for_children(dev, async);
-	device_lock(dev);
 
 	if (async_error)
-		goto Unlock;
+		return 0;
+
+	pm_runtime_get_noresume(dev);
+	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
+		pm_wakeup_event(dev, 0);
 
 	if (pm_wakeup_pending()) {
+		pm_runtime_put_sync(dev);
 		async_error = -EBUSY;
-		goto Unlock;
+		return 0;
 	}
 
+	device_lock(dev);
+
 	if (dev->pwr_domain) {
 		pm_dev_dbg(dev, state, "power domain ");
 		error = pm_op(dev, &dev->pwr_domain->ops, state);

@@ -890,12 +904,15 @@ static int __device_suspend(struct devic
  End:
 	dev->power.is_suspended = !error;
 
- Unlock:
 	device_unlock(dev);
 	complete_all(&dev->power.completion);
 
-	if (error)
+	if (error) {
+		pm_runtime_put_sync(dev);
 		async_error = error;
+	} else if (dev->power.is_suspended) {
+		__pm_runtime_disable(dev, false);
+	}
 
 	return error;
 }

Index: linux-2.6/drivers/base/power/runtime.c
===================================================================

--- linux-2.6.orig/drivers/base/power/runtime.c
+++ linux-2.6/drivers/base/power/runtime.c

@@ -455,12 +455,14 @@ static int rpm_resume(struct device *dev
 	dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
 
  repeat:
-	if (dev->power.runtime_error)
+	if (dev->power.runtime_error) {
 		retval = -EINVAL;
-	else if (dev->power.disable_depth > 0)
-		retval = -EAGAIN;
-	if (retval)
 		goto out;
+	} else if (dev->power.disable_depth > 0) {
+		if (!(rpmflags & RPM_GET_PUT))
+			retval = -EAGAIN;

+		goto out;
+	}
 
 	/*
 	 * Other scheduled or pending requests need to be canceled.  Small