drivers/rtc/interface.c: check the error after __rtc_read_time()

PATCH In review Hyogi Gim 2 participants 3 messages Dec 17, 2014 – Dec 22, 2014 Real time clock (RTC)

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Hyogi Gim

author

2014-12-17 03:17 UTC #0 lore raw

PATCH 1/1 drivers/rtc/interface.c: check the error after __rtc_read_time()

Add the verification code for returned __rtc_read_time() error in rtc_update_irq_enable() and rtc_timer_do_work().

Signed-off-by Hyogi Gim <[email protected]>

---
 drivers/rtc/interface.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

drivers/rtc/interface.c +10 -3

index 45bfc28ee..fa1f119 100644
@@ -489,7 +489,10 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
 		struct rtc_time tm;
 		ktime_t now, onesec;
 
-		__rtc_read_time(rtc, &tm);
+		err = __rtc_read_time(rtc, &tm);
+		if (err < 0)
+			goto out;
+
 		onesec = ktime_set(1, 0);
 		now = rtc_tm_to_ktime(tm);
 		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);

@@ -867,13 +870,17 @@ void rtc_timer_do_work(struct work_struct *work)
 	struct timerqueue_node *next;
 	ktime_t now;
 	struct rtc_time tm;
+	int err = 0;
 
 	struct rtc_device *rtc =
 		container_of(work, struct rtc_device, irqwork);
 
 	mutex_lock(&rtc->ops_lock);
 again:
-	__rtc_read_time(rtc, &tm);
+	err = __rtc_read_time(rtc, &tm);
+	if (err < 0)
+		goto out;
+
 	now = rtc_tm_to_ktime(tm);
 	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
 		if (next->expires.tv64 > now.tv64)

@@ -898,7 +905,6 @@ again:
 	/* Set next alarm */
 	if (next) {
 		struct rtc_wkalrm alarm;
-		int err;
 		int retry = 3;
 
 		alarm.time = rtc_ktime_to_tm(next->expires);

@@ -920,6 +926,7 @@ reprogram:
 	} else
 		rtc_alarm_disable(rtc);
 
+out:
 	pm_relax(rtc->dev.parent);
 	mutex_unlock(&rtc->ops_lock);
 }

Signature · 5 lines

1.8.3.2


-- 
Hyogi

Andrew Morton

2014-12-17 21:51 UTC #1 lore raw

Quoted 4 lines · On Wed, 17 Dec 2014 12:15:24 +0900 Hyogi Gim <[email protected]> wrote:

Add the verification code for returned __rtc_read_time() error in rtc_update_irq_enable() and rtc_timer_do_work().
...

Quoted 4 lines

drivers/rtc/interface.c +0 -0

@@ -489,7 +489,10 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
 		struct rtc_time tm;

drivers/rtc/interface.c int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) · line 498

Quoted 10 lines

drivers/rtc/interface.c +4 -1

 		ktime_t now, onesec;
 
-		__rtc_read_time(rtc, &tm);
+		err = __rtc_read_time(rtc, &tm);
+		if (err < 0)
+			goto out;
+
 		onesec = ktime_set(1, 0);
 		now = rtc_tm_to_ktime(tm);
 		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);

I'm not sure about this part. If __rtc_read_time() returns -EINVAL (due to !rtc->ops->read_time) then rtc_update_irq_enable() will go and call rtc_dev_update_irq_enable_emul(), inappropriately.

On the other hand, if __rtc_read_time() returns -EINVAL because that's what rtc->ops->read_time() returned then perhaps rtc_update_irq_enable() *should* call rtc_dev_update_irq_enable_emul().

Messy.

Hyogi Gim

author

2014-12-22 02:45 UTC #2 lore raw

Quoted 26 lines · Andrew Morton

Quoted 4 lines · On Wed, 17 Dec 2014 12:15:24 +0900 Hyogi Gim <[email protected]> wrote:
Add the verification code for returned __rtc_read_time() error in rtc_update_irq_enable() and rtc_timer_do_work().
...
L
Quoted 4 lines
drivers/rtc/interface.c +0 -0
@@ -489,7 +489,10 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
 		struct rtc_time tm;
drivers/rtc/interface.c int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) · line 498
Quoted 10 lines
drivers/rtc/interface.c +4 -1
 		ktime_t now, onesec;
 
-		__rtc_read_time(rtc, &tm);
+		err = __rtc_read_time(rtc, &tm);
+		if (err < 0)
+			goto out;
+
 		onesec = ktime_set(1, 0);
 		now = rtc_tm_to_ktime(tm);
 		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
I'm not sure about this part. If __rtc_read_time() returns -EINVAL (due to !rtc->ops->read_time) then rtc_update_irq_enable() will go and call rtc_dev_update_irq_enable_emul(), inappropriately.

Quoted 6 lines

On the other hand, if __rtc_read_time() returns -EINVAL because that's what rtc->ops->read_time() returned then perhaps rtc_update_irq_enable() *should* call rtc_dev_update_irq_enable_emul().
Messy.

As you said, if rtc driver has no read_time callback, rtc_read_time() is failed in rtc_dev_update_irq_enable_emul() anyway.

rtc_dev_update_irq_enable_emul()
|_ set_uie()

     |_ rtc_read_time()

What I worried about the error from rtc->ops->read_time(). If rtc->ops->read_time() returns another type of error except -EINVAL, then rtc interface can't run rtc_dev_update_irq_enable_emul().

I think it needs to be changed that check to ensure error for rtc_dev_update_irq_enable_emul().