RTC: Propagate error handling via rtc_timer_enqueue properly

In cases where RTC hardware does not support alarms, the virtualized
RTC interfaces did not have a way to propagate the error up to userland.

This patch extends rtc_timer_enqueue so it catches errors from the hardware
and returns them upwards to the virtualized interfaces. To simplify error
handling, it also internalizes the management of the timer->enabled bit
into rtc_timer_enqueue and rtc_timer_remove.

Also makes rtc_timer_enqueue and rtc_timer_remove static.

Reported-by: David Daney <ddaney@caviumnetworks.com>
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diagnosed-by: David Daney <ddaney@caviumnetworks.com>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
LKML-Reference: <1295565973-14358-1-git-send-email-john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 90384b9..f1ba2c6 100644 (file)
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -16,6 +16,9 @@
 #include <linux/log2.h>
 #include <linux/workqueue.h>
 
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
+
 static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
 {
        int err;
@@ -175,16 +178,14 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
                return err;
        if (rtc->aie_timer.enabled) {
                rtc_timer_remove(rtc, &rtc->aie_timer);
-               rtc->aie_timer.enabled = 0;
        }
        rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
        rtc->aie_timer.period = ktime_set(0, 0);
        if (alarm->enabled) {
-               rtc->aie_timer.enabled = 1;
-               rtc_timer_enqueue(rtc, &rtc->aie_timer);
+               err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
        }
        mutex_unlock(&rtc->ops_lock);
-       return 0;
+       return err;
 }
 EXPORT_SYMBOL_GPL(rtc_set_alarm);
 
@@ -195,15 +196,15 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
                return err;
 
        if (rtc->aie_timer.enabled != enabled) {
-               if (enabled) {
-                       rtc->aie_timer.enabled = 1;
-                       rtc_timer_enqueue(rtc, &rtc->aie_timer);
-               } else {
+               if (enabled)
+                       err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
+               else
                        rtc_timer_remove(rtc, &rtc->aie_timer);
-                       rtc->aie_timer.enabled = 0;
-               }
        }
 
+       if (err)
+               return err;
+
        if (!rtc->ops)
                err = -ENODEV;
        else if (!rtc->ops->alarm_irq_enable)
@@ -235,12 +236,9 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
                now = rtc_tm_to_ktime(tm);
                rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
                rtc->uie_rtctimer.period = ktime_set(1, 0);
-               rtc->uie_rtctimer.enabled = 1;
-               rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
-       } else {
+               err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
+       } else
                rtc_timer_remove(rtc, &rtc->uie_rtctimer);
-               rtc->uie_rtctimer.enabled = 0;
-       }
 
 out:
        mutex_unlock(&rtc->ops_lock);
@@ -488,10 +486,13 @@ EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
  * Enqueues a timer onto the rtc devices timerqueue and sets
  * the next alarm event appropriately.
  *
+ * Sets the enabled bit on the added timer.
+ *
  * Must hold ops_lock for proper serialization of timerqueue
  */
-void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
 {
+       timer->enabled = 1;
        timerqueue_add(&rtc->timerqueue, &timer->node);
        if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
                struct rtc_wkalrm alarm;
@@ -501,7 +502,13 @@ void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
                err = __rtc_set_alarm(rtc, &alarm);
                if (err == -ETIME)
                        schedule_work(&rtc->irqwork);
+               else if (err) {
+                       timerqueue_del(&rtc->timerqueue, &timer->node);
+                       timer->enabled = 0;
+                       return err;
+               }
        }
+       return 0;
 }
 
 /**
@@ -512,13 +519,15 @@ void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
  * Removes a timer onto the rtc devices timerqueue and sets
  * the next alarm event appropriately.
  *
+ * Clears the enabled bit on the removed timer.
+ *
  * Must hold ops_lock for proper serialization of timerqueue
  */
-void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
 {
        struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
        timerqueue_del(&rtc->timerqueue, &timer->node);
-
+       timer->enabled = 0;
        if (next == &timer->node) {
                struct rtc_wkalrm alarm;
                int err;
@@ -626,8 +635,7 @@ int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
        timer->node.expires = expires;
        timer->period = period;
 
-       timer->enabled = 1;
-       rtc_timer_enqueue(rtc, timer);
+       ret = rtc_timer_enqueue(rtc, timer);
 
        mutex_unlock(&rtc->ops_lock);
        return ret;
@@ -645,7 +653,6 @@ int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
        mutex_lock(&rtc->ops_lock);
        if (timer->enabled)
                rtc_timer_remove(rtc, timer);
-       timer->enabled = 0;
        mutex_unlock(&rtc->ops_lock);
        return ret;
 }

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index ea76069..a0b639f 100644 (file)
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -244,8 +244,6 @@ int rtc_register(rtc_task_t *task);
 int rtc_unregister(rtc_task_t *task);
 int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
 
-void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
-void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data);
 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
                        ktime_t expires, ktime_t period);