RTC: periodic irq fix
Add kernel/kernel and kernel/user locking for the periodic irq feature of
the rtc class.
PIE ioctls are also supported.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index ad66c6e..a43afa5 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -210,6 +210,10 @@
if (task == NULL || task->func == NULL)
return -EINVAL;
+ /* Cannot register while the char dev is in use */
+ if (!(mutex_trylock(&rtc->char_lock)))
+ return -EBUSY;
+
spin_lock_irq(&rtc->irq_task_lock);
if (rtc->irq_task == NULL) {
rtc->irq_task = task;
@@ -217,13 +221,14 @@
}
spin_unlock_irq(&rtc->irq_task_lock);
+ mutex_unlock(&rtc->char_lock);
+
return retval;
}
EXPORT_SYMBOL_GPL(rtc_irq_register);
void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
{
-
spin_lock_irq(&rtc->irq_task_lock);
if (rtc->irq_task == task)
rtc->irq_task = NULL;
@@ -240,8 +245,10 @@
return -ENXIO;
spin_lock_irqsave(&rtc->irq_task_lock, flags);
+ if (rtc->irq_task != NULL && task == NULL)
+ err = -EBUSY;
if (rtc->irq_task != task)
- err = -ENXIO;
+ err = -EACCES;
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
if (err == 0)
@@ -260,8 +267,10 @@
return -ENXIO;
spin_lock_irqsave(&rtc->irq_task_lock, flags);
+ if (rtc->irq_task != NULL && task == NULL)
+ err = -EBUSY;
if (rtc->irq_task != task)
- err = -ENXIO;
+ err = -EACCES;
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
if (err == 0) {
