linux-kernel - Re: [PATCH] alarmtimer: Fix rebind failure

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Date:   Wed, 20 Sep 2023 15:26:53 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Biju Das <biju.das.jz@...renesas.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        John Stultz <jstultz@...gle.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Biju Das <biju.das.au@...il.com>, linux-rtc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH] alarmtimer: Fix rebind failure

On 20/09/2023 12:59:35+0100, Biju Das wrote:
> The resources allocated in alarmtimer_rtc_add_device() are not freed
> leading to re-bind failure for the endpoint driver. Fix this issue
> by adding alarmtimer_rtc_remove_device().
> 
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> ---
> This issue is found while adding irq support for built in RTC
> found on Renesas PMIC RAA215300 device. This issue should present
> on all RTC drivers which calls device_init_wakeup() in probe(). 
> ---
>  kernel/time/alarmtimer.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
> index 8d9f13d847f0..592668136bb5 100644
> --- a/kernel/time/alarmtimer.c
> +++ b/kernel/time/alarmtimer.c
> @@ -61,6 +61,7 @@ static DEFINE_SPINLOCK(freezer_delta_lock);
>  /* rtc timer and device for setting alarm wakeups at suspend */
>  static struct rtc_timer		rtctimer;
>  static struct rtc_device	*rtcdev;
> +static struct platform_device	*rtc_pdev;

This is the alarmtimer pdev, not the RTC one, right?

>  static DEFINE_SPINLOCK(rtcdev_lock);
>  
>  /**
> @@ -109,6 +110,7 @@ static int alarmtimer_rtc_add_device(struct device *dev)
>  		}
>  
>  		rtcdev = rtc;
> +		rtc_pdev = pdev;
>  		/* hold a reference so it doesn't go away */
>  		get_device(dev);
>  		pdev = NULL;
> @@ -123,6 +125,23 @@ static int alarmtimer_rtc_add_device(struct device *dev)
>  	return ret;
>  }
>  
> +static void alarmtimer_rtc_remove_device(struct device *dev)
> +{
> +	struct rtc_device *rtc = to_rtc_device(dev);
> +
> +	if (rtc_pdev) {
> +		module_put(rtc->owner);
> +		if (device_may_wakeup(rtc->dev.parent))
> +			device_init_wakeup(&rtc_pdev->dev, false);
> +
> +		platform_device_unregister(rtc_pdev);
> +		put_device(dev);
> +	}
> +
> +	rtcdev = NULL;
> +	rtc_pdev = NULL;
> +}
> +
>  static inline void alarmtimer_rtc_timer_init(void)
>  {
>  	rtc_timer_init(&rtctimer, NULL, NULL);
> @@ -130,6 +149,7 @@ static inline void alarmtimer_rtc_timer_init(void)
>  
>  static struct class_interface alarmtimer_rtc_interface = {
>  	.add_dev = &alarmtimer_rtc_add_device,
> +	.remove_dev = &alarmtimer_rtc_remove_device,
>  };
>  
>  static int alarmtimer_rtc_interface_setup(void)
> -- 
> 2.25.1
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com