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/class.c b/drivers/rtc/class.c
index 10ab3b7..4dfdf01 100644 (file)
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -153,6 +153,7 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev,
        mutex_init(&rtc->ops_lock);
        spin_lock_init(&rtc->irq_lock);
        spin_lock_init(&rtc->irq_task_lock);
+       init_waitqueue_head(&rtc->irq_queue);
 
        strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
        snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id);

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index ad66c6e..a43afa5 100644 (file)
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -210,6 +210,10 @@ int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
        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 @@ int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
        }
        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 @@ int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled
                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 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
                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) {

diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 005fff3..362400d 100644 (file)
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -238,17 +238,6 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
                break;
        }
 
-       /* avoid conflicting IRQ users */
-       if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
-               spin_lock_irq(&rtc->irq_task_lock);
-               if (rtc->irq_task)
-                       err = -EBUSY;
-               spin_unlock_irq(&rtc->irq_task_lock);
-
-               if (err < 0)
-                       return err;
-       }
-
        /* try the driver's ioctl interface */
        if (ops->ioctl) {
                err = ops->ioctl(rtc->dev.parent, cmd, arg);
@@ -338,18 +327,20 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
                err = rtc_set_time(rtc, &tm);
                break;
 
-       case RTC_IRQP_READ:
-               if (ops->irq_set_freq)
-                       err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
-               else
-                       err = -ENOTTY;
+       case RTC_PIE_ON:
+               err = rtc_irq_set_state(rtc, NULL, 1);
+               break;
+
+       case RTC_PIE_OFF:
+               err = rtc_irq_set_state(rtc, NULL, 0);
                break;
 
        case RTC_IRQP_SET:
-               if (ops->irq_set_freq)
-                       err = rtc_irq_set_freq(rtc, rtc->irq_task, arg);
-               else
-                       err = -ENOTTY;
+               err = rtc_irq_set_freq(rtc, NULL, arg);
+               break;
+
+       case RTC_IRQP_READ:
+               err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
                break;
 
 #if 0
@@ -449,8 +440,6 @@ void rtc_dev_prepare(struct rtc_device *rtc)
        rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
 
        mutex_init(&rtc->char_lock);
-       spin_lock_init(&rtc->irq_lock);
-       init_waitqueue_head(&rtc->irq_queue);
 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
        INIT_WORK(&rtc->uie_task, rtc_uie_task);
        setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);