netdev - Re: [PATCH v4 09/11] thermal: core: Stop polling DISABLED thermal devices

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Date:   Wed, 24 Jun 2020 12:02:19 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Andrzej Pietrasiewicz <andrzej.p@...labora.com>
Cc:     linux-pm@...r.kernel.org, linux-acpi@...r.kernel.org,
        netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-renesas-soc@...r.kernel.org,
        linux-rockchip@...ts.infradead.org,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Vishal Kulkarni <vishal@...lsio.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jiri Pirko <jiri@...lanox.com>,
        Ido Schimmel <idosch@...lanox.com>,
        Johannes Berg <johannes.berg@...el.com>,
        Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
        Luca Coelho <luciano.coelho@...el.com>,
        Intel Linux Wireless <linuxwifi@...el.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        Peter Kaestle <peter@...e.net>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Sebastian Reichel <sre@...nel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        Support Opensource <support.opensource@...semi.com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        Heiko Stuebner <heiko@...ech.de>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang7@...il.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Allison Randal <allison@...utok.net>,
        Enrico Weigelt <info@...ux.net>,
        Gayatri Kammela <gayatri.kammela@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>, kernel@...labora.com
Subject: Re: [PATCH v4 09/11] thermal: core: Stop polling DISABLED thermal
 devices



On 5/28/20 9:20 PM, Andrzej Pietrasiewicz wrote:
> Polling DISABLED devices is not desired, as all such "disabled" devices
> are meant to be handled by userspace. This patch introduces and uses
> should_stop_polling() to decide whether the device should be polled or not.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@...labora.com>

Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> ---
>  drivers/thermal/thermal_core.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 14baf0288759..e9c0b990e4a9 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -301,13 +301,22 @@ static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
>  		cancel_delayed_work(&tz->poll_queue);
>  }
>  
> +static inline bool should_stop_polling(struct thermal_zone_device *tz)
> +{
> +	return !thermal_zone_device_is_enabled(tz);
> +}
> +
>  static void monitor_thermal_zone(struct thermal_zone_device *tz)
>  {
> +	bool stop;
> +
> +	stop = should_stop_polling(tz);
> +
>  	mutex_lock(&tz->lock);
>  
> -	if (tz->passive)
> +	if (!stop && tz->passive)
>  		thermal_zone_device_set_polling(tz, tz->passive_delay);
> -	else if (tz->polling_delay)
> +	else if (!stop && tz->polling_delay)
>  		thermal_zone_device_set_polling(tz, tz->polling_delay);
>  	else
>  		thermal_zone_device_set_polling(tz, 0);
> @@ -517,6 +526,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz,
>  {
>  	int count;
>  
> +	if (should_stop_polling(tz))
> +		return;
> +
>  	if (atomic_read(&in_suspend))
>  		return;
>  
>