linux-kernel - Re: [PATCH 2/4] alarmtimer: Make alarmtimer platform device child of RTC device

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Date:   Wed, 15 Jan 2020 08:47:48 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Doug Anderson <dianders@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     John Stultz <john.stultz@...aro.org>,
        Ravi Chandra Sadineni <ravisadineni@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>
Subject: Re: [PATCH 2/4] alarmtimer: Make alarmtimer platform device child of RTC device

Quoting Thomas Gleixner (2020-01-15 02:07:09)
> Doug Anderson <dianders@...omium.org> writes:
> > On Thu, Jan 9, 2020 at 7:59 AM Stephen Boyd <swboyd@...omium.org> wrote:
> >> diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
> >> index 4b11f0309eee..ccb6aea4f1d4 100644
> >> --- a/kernel/time/alarmtimer.c
> >> +++ b/kernel/time/alarmtimer.c
> >> @@ -88,6 +88,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
> >>         unsigned long flags;
> >>         struct rtc_device *rtc = to_rtc_device(dev);
> >>         struct wakeup_source *__ws;
> >> +       struct platform_device *pdev;
> >>         int ret = 0;
> >>
> >>         if (rtcdev)
> >> @@ -99,6 +100,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
> >>                 return -1;
> >>
> >>         __ws = wakeup_source_register(dev, "alarmtimer");
> >> +       pdev = platform_device_register_data(dev, "alarmtimer", -1, NULL, 0);
> >
> > Don't you need to check for an error here?  If pdev is an error you'll
> > continue on your merry way.  Before your patch if you got an error
> > registering the device it would have caused probe to fail.
> 
> Yes, that return value should be checked
> 

Ok. Should __ws also be checked for error? I'm currently thinking of this patch
and then simplifying it in patch 3 of this series by removing __ws. Or
the series can swap patch 2 and 3.

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index ccb6aea4f1d4..3e1f4056e384 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -103,7 +103,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
 	pdev = platform_device_register_data(dev, "alarmtimer", -1, NULL, 0);
 
 	spin_lock_irqsave(&rtcdev_lock, flags);
-	if (!rtcdev) {
+	if (__ws && pdev && !rtcdev) {
 		if (!try_module_get(rtc->owner)) {
 			ret = -1;
 			goto unlock;
@@ -115,6 +115,8 @@ static int alarmtimer_rtc_add_device(struct device *dev,
 		ws = __ws;
 		__ws = NULL;
 		pdev = NULL;
+	} else {
+		ret = - 1;
 	}
 unlock:
 	spin_unlock_irqrestore(&rtcdev_lock, flags);