Messages in this thread | | | Date | Mon, 22 Dec 2014 11:43:25 +0900 | From | Hyogi Gim <> | Subject | Re: [PATCH] drivers/rtc/interface.c: check the error after __rtc_read_time() |
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On Wed, Dec 17, 2014 at 01:51:50PM -0800, Andrew Morton wrote: > On Wed, 17 Dec 2014 12:15:24 +0900 Hyogi Gim <hyogi.gim@lge.com> wrote: > > > Add the verification code for returned __rtc_read_time() error in > > rtc_update_irq_enable() and rtc_timer_do_work(). > > > > ... > L > > --- a/drivers/rtc/interface.c > > +++ b/drivers/rtc/interface.c > > @@ -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); > > 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. >
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().
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