linux-kernel - Re: [PATCHv2 1/1] thermal: core: call thermal_zone_device

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Date:	Wed, 22 Jun 2016 07:36:11 -0700
From:	Eduardo Valentin <edubezval@...il.com>
To:	Keerthy <a0393675@...com>
Cc:	Rui Zhang <rui.zhang@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
	"Lee, Chun-Yi" <jlee@...e.com>, Darren Hart <dvhart@...radead.org>,
	Keerthy <j-keerthy@...com>, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org, platform-driver-x86@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCHv2 1/1] thermal: core: call thermal_zone_device_update()
 after mode update

On Wed, Jun 22, 2016 at 03:03:45PM +0530, Keerthy wrote:
> 
> 
> On Wednesday 22 June 2016 10:45 AM, Eduardo Valentin wrote:
> >Because several drivers do the following pattern:
> >.set_mode()
> >    ...
> >    local_data->mode = new_mode;
> >    thermal_zone_device_update(tz);
> >
> >makes sense to simply do the thermal_zone_device_update()
> >in thermal core, after setting the new mode.
> 
> http://pastebin.ubuntu.com/17687601/
> 
> linux-next + current v2 of the patch.
> The back trace still comes.

I confirm this. Please check V3 I just sent. On V2 I focused
on thermal_zone_device_update(), but for OF thermal specifically,
we also hold the lock for protecting other accesses. Now they
are removed.

> 
> Regards,
> Keerthy
> 
> >
> >Also, this patch also remove deadlocks on drivers that
> >call thermal_zone_device_update() on .set_mode(),
> >as .set_mode()  is now called always with tz->lock held.
> >
> >Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> >Cc: Len Brown <lenb@...nel.org>
> >Cc: linux-acpi@...r.kernel.org
> >Cc: "Lee, Chun-Yi" <jlee@...e.com>
> >Cc: Darren Hart <dvhart@...radead.org>
> >Cc: Zhang Rui <rui.zhang@...el.com>
> >Cc: Keerthy <j-keerthy@...com>
> >Cc: linux-kernel@...r.kernel.org
> >Cc: linux-omap@...r.kernel.org
> >Cc: platform-driver-x86@...r.kernel.org
> >Cc: linux-pm@...r.kernel.org
> >Signed-off-by: Eduardo Valentin <edubezval@...il.com>
> >---
> >Please ignore last version.
> >
> >V1-> V2:
> >Cleaned the patch and remove unrelated changes.
> >---
> >
> >  drivers/acpi/thermal.c                             | 2 --
> >  drivers/platform/x86/acerhdf.c                     | 1 -
> >  drivers/thermal/imx_thermal.c                      | 1 -
> >  drivers/thermal/of-thermal.c                       | 1 -
> >  drivers/thermal/thermal_sysfs.c                    | 1 +
> >  drivers/thermal/ti-soc-thermal/ti-thermal-common.c | 1 -
> >  6 files changed, 1 insertion(+), 6 deletions(-)
> >
> >diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> >index 82707f9..8582b88 100644
> >--- a/drivers/acpi/thermal.c
> >+++ b/drivers/acpi/thermal.c
> >@@ -519,8 +519,6 @@ static void acpi_thermal_check(void *data)
> >
> >  	if (!tz->tz_enabled)
> >  		return;
> >-
> >-	thermal_zone_device_update(tz->thermal_zone);
> >  }
> >
> >  /* sys I/F for generic thermal sysfs support */
> >diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
> >index 460fa67..aee33ba 100644
> >--- a/drivers/platform/x86/acerhdf.c
> >+++ b/drivers/platform/x86/acerhdf.c
> >@@ -405,7 +405,6 @@ static inline void acerhdf_enable_kernelmode(void)
> >  	kernelmode = 1;
> >
> >  	thz_dev->polling_delay = interval*1000;
> >-	thermal_zone_device_update(thz_dev);
> >  	pr_notice("kernel mode fan control ON\n");
> >  }
> >
> >diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> >index c5547bd..a413eb6 100644
> >--- a/drivers/thermal/imx_thermal.c
> >+++ b/drivers/thermal/imx_thermal.c
> >@@ -246,7 +246,6 @@ static int imx_set_mode(struct thermal_zone_device *tz,
> >  	}
> >
> >  	data->mode = mode;
> >-	thermal_zone_device_update(tz);
> >
> >  	return 0;
> >  }
> >diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
> >index b8e509c..4602e2e 100644
> >--- a/drivers/thermal/of-thermal.c
> >+++ b/drivers/thermal/of-thermal.c
> >@@ -292,7 +292,6 @@ static int of_thermal_set_mode(struct thermal_zone_device *tz,
> >  	mutex_unlock(&tz->lock);
> >
> >  	data->mode = mode;
> >-	thermal_zone_device_update(tz);
> >
> >  	return 0;
> >  }
> >diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
> >index 743df50..3d0dc30 100644
> >--- a/drivers/thermal/thermal_sysfs.c
> >+++ b/drivers/thermal/thermal_sysfs.c
> >@@ -100,6 +100,7 @@ mode_store(struct device *dev, struct device_attribute *attr,
> >  	mutex_lock(&tz->lock);
> >  	result = tz->ops->set_mode(tz, mode);
> >  	mutex_unlock(&tz->lock);
> >+	thermal_zone_device_update(tz);
> >
> >  	if (result)
> >  		return result;
> >diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> >index 15c0a9a..9a5a3a3 100644
> >--- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> >+++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
> >@@ -205,7 +205,6 @@ static int ti_thermal_set_mode(struct thermal_zone_device *thermal,
> >  	data->mode = mode;
> >  	ti_bandgap_write_update_interval(bgp, data->sensor_id,
> >  					data->ti_thermal->polling_delay);
> >-	thermal_zone_device_update(data->ti_thermal);
> >  	dev_dbg(&thermal->device, "thermal polling set for duration=%d msec\n",
> >  		data->ti_thermal->polling_delay);
> >
> >