[1/5] thermal: Initialize thermal subsystem earlier

Message ID 97b6f861e6e6a2ac7b50efb7211f3c8e7fe872b0.1568240476.git.amit.kucheria@linaro.org
State New
Headers show
Series
  • Initialise thermal framework earlier during boot
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Commit Message

Amit Kucheria Sept. 11, 2019, 10:32 p.m.
From: Lina Iyer <ilina@codeaurora.org>


Now that the thermal framework is built-in, in order to facilitate
thermal mitigation as early as possible in the boot cycle, move the
thermal framework initialization to core_initcall.

However, netlink initialization happens only as part of subsys_initcall.
At this time in the boot process, the userspace is not available yet. So
initialize the netlink events later in fs_initcall.

Signed-off-by: Lina Iyer <ilina@codeaurora.org>

[Rebased, refactored and moved to core_initcall]
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>

---
 drivers/thermal/thermal_core.c | 41 ++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 17 deletions(-)

-- 
2.17.1

Comments

Daniel Lezcano Sept. 16, 2019, 8 p.m. | #1
On 12/09/2019 00:32, Amit Kucheria wrote:
> From: Lina Iyer <ilina@codeaurora.org>

> 

> Now that the thermal framework is built-in, in order to facilitate

> thermal mitigation as early as possible in the boot cycle, move the

> thermal framework initialization to core_initcall.

> 

> However, netlink initialization happens only as part of subsys_initcall.

> At this time in the boot process, the userspace is not available yet. So

> initialize the netlink events later in fs_initcall.


Why not kill directly the netlink part, no one is using it in the kernel?


> Signed-off-by: Lina Iyer <ilina@codeaurora.org>

> [Rebased, refactored and moved to core_initcall]

> Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>

> ---

>  drivers/thermal/thermal_core.c | 41 ++++++++++++++++++++--------------

>  1 file changed, 24 insertions(+), 17 deletions(-)

> 

> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c

> index 6bab66e84eb5..b13e8a9298cc 100644

> --- a/drivers/thermal/thermal_core.c

> +++ b/drivers/thermal/thermal_core.c

> @@ -1468,6 +1468,8 @@ static struct genl_family thermal_event_genl_family __ro_after_init = {

>  	.n_mcgrps = ARRAY_SIZE(thermal_event_mcgrps),

>  };

>  

> +static bool allow_netlink_events;

> +

>  int thermal_generate_netlink_event(struct thermal_zone_device *tz,

>  				   enum events event)

>  {

> @@ -1482,6 +1484,9 @@ int thermal_generate_netlink_event(struct thermal_zone_device *tz,

>  	if (!tz)

>  		return -EINVAL;

>  

> +	if (!allow_netlink_events)

> +		return -ENODEV;

> +

>  	/* allocate memory */

>  	size = nla_total_size(sizeof(struct thermal_genl_event)) +

>  	       nla_total_size(0);

> @@ -1533,16 +1538,18 @@ EXPORT_SYMBOL_GPL(thermal_generate_netlink_event);

>  

>  static int __init genetlink_init(void)

>  {

> -	return genl_register_family(&thermal_event_genl_family);

> -}

> +	int ret;

>  

> -static void genetlink_exit(void)

> -{

> -	genl_unregister_family(&thermal_event_genl_family);

> +	ret = genl_register_family(&thermal_event_genl_family);

> +	if (!ret)

> +		allow_netlink_events = true;

> +	return ret;

>  }

> +

>  #else /* !CONFIG_NET */

>  static inline int genetlink_init(void) { return 0; }

> -static inline void genetlink_exit(void) {}

> +static inline int thermal_generate_netlink_event(struct thermal_zone_device *tz,

> +						 enum events event) { return -ENODEV; }

>  #endif /* !CONFIG_NET */

>  

>  static int thermal_pm_notify(struct notifier_block *nb,

> @@ -1591,19 +1598,15 @@ static int __init thermal_init(void)

>  	mutex_init(&poweroff_lock);

>  	result = thermal_register_governors();

>  	if (result)

> -		goto error;

> +		goto init_exit;

>  

>  	result = class_register(&thermal_class);

>  	if (result)

>  		goto unregister_governors;

>  

> -	result = genetlink_init();

> -	if (result)

> -		goto unregister_class;

> -

>  	result = of_parse_thermal_zones();

>  	if (result)

> -		goto exit_netlink;

> +		goto exit_zone_parse;

>  

>  	result = register_pm_notifier(&thermal_pm_nb);

>  	if (result)

> @@ -1612,13 +1615,11 @@ static int __init thermal_init(void)

>  

>  	return 0;

>  

> -exit_netlink:

> -	genetlink_exit();

> -unregister_class:

> +exit_zone_parse:

>  	class_unregister(&thermal_class);

>  unregister_governors:

>  	thermal_unregister_governors();

> -error:

> +init_exit:

>  	ida_destroy(&thermal_tz_ida);

>  	ida_destroy(&thermal_cdev_ida);

>  	mutex_destroy(&thermal_list_lock);

> @@ -1626,4 +1627,10 @@ static int __init thermal_init(void)

>  	mutex_destroy(&poweroff_lock);

>  	return result;

>  }

> -fs_initcall(thermal_init);

> +

> +static int __init thermal_netlink_init(void)

> +{

> +	return genetlink_init();

> +}

> +core_initcall(thermal_init);

> +fs_initcall(thermal_netlink_init);

> 



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Amit Kucheria Sept. 17, 2019, 9:18 a.m. | #2
On Tue, Sep 17, 2019 at 1:30 AM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>

> On 12/09/2019 00:32, Amit Kucheria wrote:

> > From: Lina Iyer <ilina@codeaurora.org>

> >

> > Now that the thermal framework is built-in, in order to facilitate

> > thermal mitigation as early as possible in the boot cycle, move the

> > thermal framework initialization to core_initcall.

> >

> > However, netlink initialization happens only as part of subsys_initcall.

> > At this time in the boot process, the userspace is not available yet. So

> > initialize the netlink events later in fs_initcall.

>

> Why not kill directly the netlink part, no one is using it in the kernel?


That's a good point. I wasn't sure if anybody was using it, but I can
remove it completely since no driver seems to be using the
thermal_generate_netlink_event() api.

Regards,
Amit

$ git grep thermal_generate_netlink_event
Documentation/thermal/sysfs-api.rst:just need to call
thermal_generate_netlink_event() with two arguments viz
drivers/thermal/thermal_core.c:int
thermal_generate_netlink_event(struct thermal_zone_device *tz,
drivers/thermal/thermal_core.c:EXPORT_SYMBOL_GPL(thermal_generate_netlink_event);
include/linux/thermal.h:extern int
thermal_generate_netlink_event(struct thermal_zone_device *tz,
include/linux/thermal.h:static inline int
thermal_generate_netlink_event(struct thermal_zone_device *tz,
Zhang Rui Sept. 19, 2019, 2:13 p.m. | #3
On Tue, 2019-09-17 at 14:48 +0530, Amit Kucheria wrote:
> On Tue, Sep 17, 2019 at 1:30 AM Daniel Lezcano

> <daniel.lezcano@linaro.org> wrote:

> > 

> > On 12/09/2019 00:32, Amit Kucheria wrote:

> > > From: Lina Iyer <ilina@codeaurora.org>

> > > 

> > > Now that the thermal framework is built-in, in order to

> > > facilitate

> > > thermal mitigation as early as possible in the boot cycle, move

> > > the

> > > thermal framework initialization to core_initcall.

> > > 

> > > However, netlink initialization happens only as part of

> > > subsys_initcall.

> > > At this time in the boot process, the userspace is not available

> > > yet. So

> > > initialize the netlink events later in fs_initcall.

> > 

> > Why not kill directly the netlink part, no one is using it in the

> > kernel?

> 

> That's a good point. I wasn't sure if anybody was using it, but I can

> remove it completely since no driver seems to be using the

> thermal_generate_netlink_event() api.


Interesting, I recalled that thermal_generate_netlink_event() is indeed
used by some thermal driver, but it's true that no one is using it now.

let's remove it and see if we get any complains.

thanks,
rui
> 

> Regards,

> Amit

> 

> $ git grep thermal_generate_netlink_event

> Documentation/thermal/sysfs-api.rst:just need to call

> thermal_generate_netlink_event() with two arguments viz

> drivers/thermal/thermal_core.c:int

> thermal_generate_netlink_event(struct thermal_zone_device *tz,

> drivers/thermal/thermal_core.c:EXPORT_SYMBOL_GPL(thermal_generate_net

> link_event);

> include/linux/thermal.h:extern int

> thermal_generate_netlink_event(struct thermal_zone_device *tz,

> include/linux/thermal.h:static inline int

> thermal_generate_netlink_event(struct thermal_zone_device *tz,

Patch

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 6bab66e84eb5..b13e8a9298cc 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1468,6 +1468,8 @@  static struct genl_family thermal_event_genl_family __ro_after_init = {
 	.n_mcgrps = ARRAY_SIZE(thermal_event_mcgrps),
 };
 
+static bool allow_netlink_events;
+
 int thermal_generate_netlink_event(struct thermal_zone_device *tz,
 				   enum events event)
 {
@@ -1482,6 +1484,9 @@  int thermal_generate_netlink_event(struct thermal_zone_device *tz,
 	if (!tz)
 		return -EINVAL;
 
+	if (!allow_netlink_events)
+		return -ENODEV;
+
 	/* allocate memory */
 	size = nla_total_size(sizeof(struct thermal_genl_event)) +
 	       nla_total_size(0);
@@ -1533,16 +1538,18 @@  EXPORT_SYMBOL_GPL(thermal_generate_netlink_event);
 
 static int __init genetlink_init(void)
 {
-	return genl_register_family(&thermal_event_genl_family);
-}
+	int ret;
 
-static void genetlink_exit(void)
-{
-	genl_unregister_family(&thermal_event_genl_family);
+	ret = genl_register_family(&thermal_event_genl_family);
+	if (!ret)
+		allow_netlink_events = true;
+	return ret;
 }
+
 #else /* !CONFIG_NET */
 static inline int genetlink_init(void) { return 0; }
-static inline void genetlink_exit(void) {}
+static inline int thermal_generate_netlink_event(struct thermal_zone_device *tz,
+						 enum events event) { return -ENODEV; }
 #endif /* !CONFIG_NET */
 
 static int thermal_pm_notify(struct notifier_block *nb,
@@ -1591,19 +1598,15 @@  static int __init thermal_init(void)
 	mutex_init(&poweroff_lock);
 	result = thermal_register_governors();
 	if (result)
-		goto error;
+		goto init_exit;
 
 	result = class_register(&thermal_class);
 	if (result)
 		goto unregister_governors;
 
-	result = genetlink_init();
-	if (result)
-		goto unregister_class;
-
 	result = of_parse_thermal_zones();
 	if (result)
-		goto exit_netlink;
+		goto exit_zone_parse;
 
 	result = register_pm_notifier(&thermal_pm_nb);
 	if (result)
@@ -1612,13 +1615,11 @@  static int __init thermal_init(void)
 
 	return 0;
 
-exit_netlink:
-	genetlink_exit();
-unregister_class:
+exit_zone_parse:
 	class_unregister(&thermal_class);
 unregister_governors:
 	thermal_unregister_governors();
-error:
+init_exit:
 	ida_destroy(&thermal_tz_ida);
 	ida_destroy(&thermal_cdev_ida);
 	mutex_destroy(&thermal_list_lock);
@@ -1626,4 +1627,10 @@  static int __init thermal_init(void)
 	mutex_destroy(&poweroff_lock);
 	return result;
 }
-fs_initcall(thermal_init);
+
+static int __init thermal_netlink_init(void)
+{
+	return genetlink_init();
+}
+core_initcall(thermal_init);
+fs_initcall(thermal_netlink_init);