PM / wakeirq: Avoid setting power.wakeirq too hastily

If dev_pm_attach_wake_irq() fails, the device's power.wakeirq field
should not be set to point to the struct wake_irq passed to that
function, as that object will be freed going forward.

For this reason, make dev_pm_attach_wake_irq() first call
device_wakeup_attach_irq() and only set the device's power.wakeirq
field if that's successful.

That requires device_wakeup_attach_irq() to be called under the
device's power.lock lock, but since dev_pm_attach_wake_irq() is
the only caller of it, the requisite changes are easy to make.

Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling)
Reported-by: Felipe Balbi <balbi@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
index 7470004..eb6e674 100644 (file)
--- a/drivers/base/power/wakeirq.c
+++ b/drivers/base/power/wakeirq.c
@@ -45,14 +45,12 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
                return -EEXIST;
        }
 
-       dev->power.wakeirq = wirq;
-       spin_unlock_irqrestore(&dev->power.lock, flags);
-
        err = device_wakeup_attach_irq(dev, wirq);
-       if (err)
-               return err;
+       if (!err)
+               dev->power.wakeirq = wirq;
 
-       return 0;
+       spin_unlock_irqrestore(&dev->power.lock, flags);
+       return err;
 }
 
 /**
@@ -105,10 +103,10 @@ void dev_pm_clear_wake_irq(struct device *dev)
                return;
 
        spin_lock_irqsave(&dev->power.lock, flags);
+       device_wakeup_detach_irq(dev);
        dev->power.wakeirq = NULL;
        spin_unlock_irqrestore(&dev->power.lock, flags);
 
-       device_wakeup_detach_irq(dev);
        if (wirq->dedicated_irq)
                free_irq(wirq->irq, wirq);
        kfree(wirq);

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 7332ebc..15d27d7 100644 (file)
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -247,32 +247,25 @@ EXPORT_SYMBOL_GPL(device_wakeup_enable);
  * Attach a device wakeirq to the wakeup source so the device
  * wake IRQ can be configured automatically for suspend and
  * resume.
+ *
+ * Call under the device's power.lock lock.
  */
 int device_wakeup_attach_irq(struct device *dev,
                             struct wake_irq *wakeirq)
 {
        struct wakeup_source *ws;
-       int ret = 0;
 
-       spin_lock_irq(&dev->power.lock);
        ws = dev->power.wakeup;
        if (!ws) {
                dev_err(dev, "forgot to call call device_init_wakeup?\n");
-               ret = -EINVAL;
-               goto unlock;
+               return -EINVAL;
        }
 
-       if (ws->wakeirq) {
-               ret = -EEXIST;
-               goto unlock;
-       }
+       if (ws->wakeirq)
+               return -EEXIST;
 
        ws->wakeirq = wakeirq;
-
-unlock:
-       spin_unlock_irq(&dev->power.lock);
-
-       return ret;
+       return 0;
 }
 
 /**
@@ -280,20 +273,16 @@ unlock:
  * @dev: Device to handle
  *
  * Removes a device wakeirq from the wakeup source.
+ *
+ * Call under the device's power.lock lock.
  */
 void device_wakeup_detach_irq(struct device *dev)
 {
        struct wakeup_source *ws;
 
-       spin_lock_irq(&dev->power.lock);
        ws = dev->power.wakeup;
-       if (!ws)
-               goto unlock;
-
-       ws->wakeirq = NULL;
-
-unlock:
-       spin_unlock_irq(&dev->power.lock);
+       if (ws)
+               ws->wakeirq = NULL;
 }
 
 /**