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[PATCH 04/20] hwmon/coretemp: Convert to hotplug state machine

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  [PATCH 04/20] hwmon/coretemp: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-17 19:40 +0100
    Re: [04/20] hwmon/coretemp: Convert to hotplug state machine Guenter Roeck <linux@roeck-us.net> - 2016-11-20 23:40 +0100
      Re: [04/20] hwmon/coretemp: Convert to hotplug state machine Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-11-21 23:40 +0100
    [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state machine tip-bot for Sebastian Andrzej Siewior <tipbot@zytor.com> - 2016-11-21 17:00 +0100
      Re: [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state  machine Thomas Gleixner <tglx@linutronix.de> - 2016-11-21 23:00 +0100
      Re: [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state  machine Guenter Roeck <linux@roeck-us.net> - 2016-11-21 23:20 +0100

#1524692 — [PATCH 04/20] hwmon/coretemp: Convert to hotplug state machine

Install the callbacks via the state machine. Setup and teardown are handled
by the hotplug core.

Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/hwmon/coretemp.c | 74 +++++++++++++++---------------------------------
 1 file changed, 23 insertions(+), 51 deletions(-)

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 6a27eb2fed17..390038884f9e 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -676,7 +676,7 @@ static bool is_any_core_online(struct platform_data *pdata)
 	return false;
 }
 
-static void get_core_online(unsigned int cpu)
+static int coretemp_cpu_online(unsigned int cpu)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	struct platform_device *pdev = coretemp_get_pdev(cpu);
@@ -688,12 +688,12 @@ static void get_core_online(unsigned int cpu)
 	 * without thermal sensors will be filtered out.
 	 */
 	if (!cpu_has(c, X86_FEATURE_DTHERM))
-		return;
+		return 0;
 
 	if (!pdev) {
 		/* Check the microcode version of the CPU */
 		if (chk_ucode_version(cpu))
-			return;
+			return 0;
 
 		/*
 		 * Alright, we have DTS support.
@@ -703,7 +703,7 @@ static void get_core_online(unsigned int cpu)
 		 */
 		err = coretemp_device_add(cpu);
 		if (err)
-			return;
+			return 0;
 		/*
 		 * Check whether pkgtemp support is available.
 		 * If so, add interfaces for pkgtemp.
@@ -716,9 +716,10 @@ static void get_core_online(unsigned int cpu)
 	 * So, just add interfaces for this core.
 	 */
 	coretemp_add_core(cpu, 0);
+	return 0;
 }
 
-static void put_core_offline(unsigned int cpu)
+static int coretemp_cpu_offline(unsigned int cpu)
 {
 	int i, indx;
 	struct platform_data *pdata;
@@ -726,7 +727,7 @@ static void put_core_offline(unsigned int cpu)
 
 	/* If the physical CPU device does not exist, just return */
 	if (!pdev)
-		return;
+		return 0;
 
 	pdata = platform_get_drvdata(pdev);
 
@@ -734,7 +735,7 @@ static void put_core_offline(unsigned int cpu)
 
 	/* The core id is too big, just return */
 	if (indx > MAX_CORE_DATA - 1)
-		return;
+		return 0;
 
 	if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu)
 		coretemp_remove_core(pdata, indx);
@@ -747,7 +748,7 @@ static void put_core_offline(unsigned int cpu)
 	 */
 	for_each_sibling(i, cpu) {
 		if (i != cpu) {
-			get_core_online(i);
+			coretemp_cpu_online(i);
 			/*
 			 * Display temperature sensor data for one HT sibling
 			 * per core only, so abort the loop after one such
@@ -764,38 +765,20 @@ static void put_core_offline(unsigned int cpu)
 	 */
 	if (!is_any_core_online(pdata))
 		coretemp_device_remove(cpu);
+	return 0;
 }
 
-static int coretemp_cpu_callback(struct notifier_block *nfb,
-				 unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long) hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_DOWN_FAILED:
-		get_core_online(cpu);
-		break;
-	case CPU_DOWN_PREPARE:
-		put_core_offline(cpu);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block coretemp_cpu_notifier __refdata = {
-	.notifier_call = coretemp_cpu_callback,
-};
-
 static const struct x86_cpu_id __initconst coretemp_ids[] = {
 	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_DTHERM },
 	{}
 };
 MODULE_DEVICE_TABLE(x86cpu, coretemp_ids);
 
+static enum cpuhp_state coretemp_hp_online;
+
 static int __init coretemp_init(void)
 {
-	int i, err;
+	int err;
 
 	/*
 	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
@@ -809,44 +792,33 @@ static int __init coretemp_init(void)
 	if (err)
 		goto exit;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i)
-		get_core_online(i);
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/coretemp:online",
+				coretemp_cpu_online, coretemp_cpu_offline);
+	if (err < 0)
+		goto exit_driver_unreg;
+	coretemp_hp_online = err;
 
 #ifndef CONFIG_HOTPLUG_CPU
 	if (list_empty(&pdev_list)) {
-		cpu_notifier_register_done();
 		err = -ENODEV;
-		goto exit_driver_unreg;
+		goto exit_hp_unreg;
 	}
 #endif
-
-	__register_hotcpu_notifier(&coretemp_cpu_notifier);
-	cpu_notifier_register_done();
 	return 0;
 
 #ifndef CONFIG_HOTPLUG_CPU
+exit_hp_unreg:
+	cpuhp_remove_state(coretemp_hp_online);
+#endif
 exit_driver_unreg:
 	platform_driver_unregister(&coretemp_driver);
-#endif
 exit:
 	return err;
 }
 
 static void __exit coretemp_exit(void)
 {
-	struct pdev_entry *p, *n;
-
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&coretemp_cpu_notifier);
-	mutex_lock(&pdev_list_mutex);
-	list_for_each_entry_safe(p, n, &pdev_list, list) {
-		platform_device_unregister(p->pdev);
-		list_del(&p->list);
-		kfree(p);
-	}
-	mutex_unlock(&pdev_list_mutex);
-	cpu_notifier_register_done();
+	cpuhp_remove_state(coretemp_hp_online);
 	platform_driver_unregister(&coretemp_driver);
 }
 
-- 
2.10.2

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#1526313 — Re: [04/20] hwmon/coretemp: Convert to hotplug state machine

On Thu, Nov 17, 2016 at 07:35:25PM +0100, Sebastian Andrzej Siewior wrote:
> Install the callbacks via the state machine. Setup and teardown are handled
> by the hotplug core.
> 
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Jean Delvare <jdelvare@suse.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-hwmon@vger.kernel.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Install, modprobe, modprobe -r, modprobe,

[24078.179118] ------------[ cut here ]------------
[24078.179124] WARNING: CPU: 0 PID: 14 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x6e/0x80
[24078.179125] sysfs: cannot create duplicate filename
'/devices/platform/coretemp.0'

and many more of those.

I can not test the other hwmon drivers in this series, but I would assume
that they have the same problem.

Guenter

> ---
>  drivers/hwmon/coretemp.c | 74 +++++++++++++++---------------------------------
>  1 file changed, 23 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
> index 6a27eb2fed17..390038884f9e 100644
> --- a/drivers/hwmon/coretemp.c
> +++ b/drivers/hwmon/coretemp.c
> @@ -676,7 +676,7 @@ static bool is_any_core_online(struct platform_data *pdata)
>  	return false;
>  }
>  
> -static void get_core_online(unsigned int cpu)
> +static int coretemp_cpu_online(unsigned int cpu)
>  {
>  	struct cpuinfo_x86 *c = &cpu_data(cpu);
>  	struct platform_device *pdev = coretemp_get_pdev(cpu);
> @@ -688,12 +688,12 @@ static void get_core_online(unsigned int cpu)
>  	 * without thermal sensors will be filtered out.
>  	 */
>  	if (!cpu_has(c, X86_FEATURE_DTHERM))
> -		return;
> +		return 0;
>  
>  	if (!pdev) {
>  		/* Check the microcode version of the CPU */
>  		if (chk_ucode_version(cpu))
> -			return;
> +			return 0;
>  
>  		/*
>  		 * Alright, we have DTS support.
> @@ -703,7 +703,7 @@ static void get_core_online(unsigned int cpu)
>  		 */
>  		err = coretemp_device_add(cpu);
>  		if (err)
> -			return;
> +			return 0;
>  		/*
>  		 * Check whether pkgtemp support is available.
>  		 * If so, add interfaces for pkgtemp.
> @@ -716,9 +716,10 @@ static void get_core_online(unsigned int cpu)
>  	 * So, just add interfaces for this core.
>  	 */
>  	coretemp_add_core(cpu, 0);
> +	return 0;
>  }
>  
> -static void put_core_offline(unsigned int cpu)
> +static int coretemp_cpu_offline(unsigned int cpu)
>  {
>  	int i, indx;
>  	struct platform_data *pdata;
> @@ -726,7 +727,7 @@ static void put_core_offline(unsigned int cpu)
>  
>  	/* If the physical CPU device does not exist, just return */
>  	if (!pdev)
> -		return;
> +		return 0;
>  
>  	pdata = platform_get_drvdata(pdev);
>  
> @@ -734,7 +735,7 @@ static void put_core_offline(unsigned int cpu)
>  
>  	/* The core id is too big, just return */
>  	if (indx > MAX_CORE_DATA - 1)
> -		return;
> +		return 0;
>  
>  	if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu)
>  		coretemp_remove_core(pdata, indx);
> @@ -747,7 +748,7 @@ static void put_core_offline(unsigned int cpu)
>  	 */
>  	for_each_sibling(i, cpu) {
>  		if (i != cpu) {
> -			get_core_online(i);
> +			coretemp_cpu_online(i);
>  			/*
>  			 * Display temperature sensor data for one HT sibling
>  			 * per core only, so abort the loop after one such
> @@ -764,38 +765,20 @@ static void put_core_offline(unsigned int cpu)
>  	 */
>  	if (!is_any_core_online(pdata))
>  		coretemp_device_remove(cpu);
> +	return 0;
>  }
>  
> -static int coretemp_cpu_callback(struct notifier_block *nfb,
> -				 unsigned long action, void *hcpu)
> -{
> -	unsigned int cpu = (unsigned long) hcpu;
> -
> -	switch (action) {
> -	case CPU_ONLINE:
> -	case CPU_DOWN_FAILED:
> -		get_core_online(cpu);
> -		break;
> -	case CPU_DOWN_PREPARE:
> -		put_core_offline(cpu);
> -		break;
> -	}
> -	return NOTIFY_OK;
> -}
> -
> -static struct notifier_block coretemp_cpu_notifier __refdata = {
> -	.notifier_call = coretemp_cpu_callback,
> -};
> -
>  static const struct x86_cpu_id __initconst coretemp_ids[] = {
>  	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_DTHERM },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(x86cpu, coretemp_ids);
>  
> +static enum cpuhp_state coretemp_hp_online;
> +
>  static int __init coretemp_init(void)
>  {
> -	int i, err;
> +	int err;
>  
>  	/*
>  	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
> @@ -809,44 +792,33 @@ static int __init coretemp_init(void)
>  	if (err)
>  		goto exit;
>  
> -	cpu_notifier_register_begin();
> -	for_each_online_cpu(i)
> -		get_core_online(i);
> +	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/coretemp:online",
> +				coretemp_cpu_online, coretemp_cpu_offline);
> +	if (err < 0)
> +		goto exit_driver_unreg;
> +	coretemp_hp_online = err;
>  
>  #ifndef CONFIG_HOTPLUG_CPU
>  	if (list_empty(&pdev_list)) {
> -		cpu_notifier_register_done();
>  		err = -ENODEV;
> -		goto exit_driver_unreg;
> +		goto exit_hp_unreg;
>  	}
>  #endif
> -
> -	__register_hotcpu_notifier(&coretemp_cpu_notifier);
> -	cpu_notifier_register_done();
>  	return 0;
>  
>  #ifndef CONFIG_HOTPLUG_CPU
> +exit_hp_unreg:
> +	cpuhp_remove_state(coretemp_hp_online);
> +#endif
>  exit_driver_unreg:
>  	platform_driver_unregister(&coretemp_driver);
> -#endif
>  exit:
>  	return err;
>  }
>  
>  static void __exit coretemp_exit(void)
>  {
> -	struct pdev_entry *p, *n;
> -
> -	cpu_notifier_register_begin();
> -	__unregister_hotcpu_notifier(&coretemp_cpu_notifier);
> -	mutex_lock(&pdev_list_mutex);
> -	list_for_each_entry_safe(p, n, &pdev_list, list) {
> -		platform_device_unregister(p->pdev);
> -		list_del(&p->list);
> -		kfree(p);
> -	}
> -	mutex_unlock(&pdev_list_mutex);
> -	cpu_notifier_register_done();
> +	cpuhp_remove_state(coretemp_hp_online);
>  	platform_driver_unregister(&coretemp_driver);
>  }
>  

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#1527100 — Re: [04/20] hwmon/coretemp: Convert to hotplug state machine

On 2016-11-20 14:30:55 [-0800], Guenter Roeck wrote:
> Install, modprobe, modprobe -r, modprobe,
> 
> [24078.179118] ------------[ cut here ]------------
> [24078.179124] WARNING: CPU: 0 PID: 14 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x6e/0x80
> [24078.179125] sysfs: cannot create duplicate filename
> '/devices/platform/coretemp.0'
> 
> and many more of those.
> 
> I can not test the other hwmon drivers in this series, but I would assume
> that they have the same problem.

I managed to trigger this. I will take a look.

> Guenter

Sebastian

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#1526829 — [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state machine

Commit-ID:  73f4f6f5ab9a069037b8e98663193accaf18bd5c
Gitweb:     http://git.kernel.org/tip/73f4f6f5ab9a069037b8e98663193accaf18bd5c
Author:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Thu, 17 Nov 2016 19:35:25 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 21 Nov 2016 16:37:10 +0100

hwmon/coretemp: Convert to hotplug state machine

Install the callbacks via the state machine. Setup and teardown are handled
by the hotplug core.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-hwmon@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: rt@linuxtronix.de
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/20161117183541.8588-5-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 drivers/hwmon/coretemp.c | 74 +++++++++++++++---------------------------------
 1 file changed, 23 insertions(+), 51 deletions(-)

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 6a27eb2..3900388 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -676,7 +676,7 @@ static bool is_any_core_online(struct platform_data *pdata)
 	return false;
 }
 
-static void get_core_online(unsigned int cpu)
+static int coretemp_cpu_online(unsigned int cpu)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	struct platform_device *pdev = coretemp_get_pdev(cpu);
@@ -688,12 +688,12 @@ static void get_core_online(unsigned int cpu)
 	 * without thermal sensors will be filtered out.
 	 */
 	if (!cpu_has(c, X86_FEATURE_DTHERM))
-		return;
+		return 0;
 
 	if (!pdev) {
 		/* Check the microcode version of the CPU */
 		if (chk_ucode_version(cpu))
-			return;
+			return 0;
 
 		/*
 		 * Alright, we have DTS support.
@@ -703,7 +703,7 @@ static void get_core_online(unsigned int cpu)
 		 */
 		err = coretemp_device_add(cpu);
 		if (err)
-			return;
+			return 0;
 		/*
 		 * Check whether pkgtemp support is available.
 		 * If so, add interfaces for pkgtemp.
@@ -716,9 +716,10 @@ static void get_core_online(unsigned int cpu)
 	 * So, just add interfaces for this core.
 	 */
 	coretemp_add_core(cpu, 0);
+	return 0;
 }
 
-static void put_core_offline(unsigned int cpu)
+static int coretemp_cpu_offline(unsigned int cpu)
 {
 	int i, indx;
 	struct platform_data *pdata;
@@ -726,7 +727,7 @@ static void put_core_offline(unsigned int cpu)
 
 	/* If the physical CPU device does not exist, just return */
 	if (!pdev)
-		return;
+		return 0;
 
 	pdata = platform_get_drvdata(pdev);
 
@@ -734,7 +735,7 @@ static void put_core_offline(unsigned int cpu)
 
 	/* The core id is too big, just return */
 	if (indx > MAX_CORE_DATA - 1)
-		return;
+		return 0;
 
 	if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu)
 		coretemp_remove_core(pdata, indx);
@@ -747,7 +748,7 @@ static void put_core_offline(unsigned int cpu)
 	 */
 	for_each_sibling(i, cpu) {
 		if (i != cpu) {
-			get_core_online(i);
+			coretemp_cpu_online(i);
 			/*
 			 * Display temperature sensor data for one HT sibling
 			 * per core only, so abort the loop after one such
@@ -764,38 +765,20 @@ static void put_core_offline(unsigned int cpu)
 	 */
 	if (!is_any_core_online(pdata))
 		coretemp_device_remove(cpu);
+	return 0;
 }
 
-static int coretemp_cpu_callback(struct notifier_block *nfb,
-				 unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long) hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_DOWN_FAILED:
-		get_core_online(cpu);
-		break;
-	case CPU_DOWN_PREPARE:
-		put_core_offline(cpu);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block coretemp_cpu_notifier __refdata = {
-	.notifier_call = coretemp_cpu_callback,
-};
-
 static const struct x86_cpu_id __initconst coretemp_ids[] = {
 	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_DTHERM },
 	{}
 };
 MODULE_DEVICE_TABLE(x86cpu, coretemp_ids);
 
+static enum cpuhp_state coretemp_hp_online;
+
 static int __init coretemp_init(void)
 {
-	int i, err;
+	int err;
 
 	/*
 	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
@@ -809,44 +792,33 @@ static int __init coretemp_init(void)
 	if (err)
 		goto exit;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i)
-		get_core_online(i);
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/coretemp:online",
+				coretemp_cpu_online, coretemp_cpu_offline);
+	if (err < 0)
+		goto exit_driver_unreg;
+	coretemp_hp_online = err;
 
 #ifndef CONFIG_HOTPLUG_CPU
 	if (list_empty(&pdev_list)) {
-		cpu_notifier_register_done();
 		err = -ENODEV;
-		goto exit_driver_unreg;
+		goto exit_hp_unreg;
 	}
 #endif
-
-	__register_hotcpu_notifier(&coretemp_cpu_notifier);
-	cpu_notifier_register_done();
 	return 0;
 
 #ifndef CONFIG_HOTPLUG_CPU
+exit_hp_unreg:
+	cpuhp_remove_state(coretemp_hp_online);
+#endif
 exit_driver_unreg:
 	platform_driver_unregister(&coretemp_driver);
-#endif
 exit:
 	return err;
 }
 
 static void __exit coretemp_exit(void)
 {
-	struct pdev_entry *p, *n;
-
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&coretemp_cpu_notifier);
-	mutex_lock(&pdev_list_mutex);
-	list_for_each_entry_safe(p, n, &pdev_list, list) {
-		platform_device_unregister(p->pdev);
-		list_del(&p->list);
-		kfree(p);
-	}
-	mutex_unlock(&pdev_list_mutex);
-	cpu_notifier_register_done();
+	cpuhp_remove_state(coretemp_hp_online);
 	platform_driver_unregister(&coretemp_driver);
 }
 

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#1527071 — Re: [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state machine

On Mon, 21 Nov 2016, Guenter Roeck wrote:

> Just be aware that this patch is buggy.

Zapped it for now.

Thanks,

	tglx

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#1527085 — Re: [tip:smp/hotplug] hwmon/coretemp: Convert to hotplug state machine

Just be aware that this patch is buggy.

Guenter

On Mon, Nov 21, 2016 at 07:56:02AM -0800, tip-bot for Sebastian Andrzej Siewior wrote:
> Commit-ID:  73f4f6f5ab9a069037b8e98663193accaf18bd5c
> Gitweb:     http://git.kernel.org/tip/73f4f6f5ab9a069037b8e98663193accaf18bd5c
> Author:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> AuthorDate: Thu, 17 Nov 2016 19:35:25 +0100
> Committer:  Thomas Gleixner <tglx@linutronix.de>
> CommitDate: Mon, 21 Nov 2016 16:37:10 +0100
> 
> hwmon/coretemp: Convert to hotplug state machine
> 
> Install the callbacks via the state machine. Setup and teardown are handled
> by the hotplug core.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: linux-hwmon@vger.kernel.org
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Jean Delvare <jdelvare@suse.com>
> Cc: rt@linuxtronix.de
> Cc: Guenter Roeck <linux@roeck-us.net>
> Link: http://lkml.kernel.org/r/20161117183541.8588-5-bigeasy@linutronix.de
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> 
> ---
>  drivers/hwmon/coretemp.c | 74 +++++++++++++++---------------------------------
>  1 file changed, 23 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
> index 6a27eb2..3900388 100644
> --- a/drivers/hwmon/coretemp.c
> +++ b/drivers/hwmon/coretemp.c
> @@ -676,7 +676,7 @@ static bool is_any_core_online(struct platform_data *pdata)
>  	return false;
>  }
>  
> -static void get_core_online(unsigned int cpu)
> +static int coretemp_cpu_online(unsigned int cpu)
>  {
>  	struct cpuinfo_x86 *c = &cpu_data(cpu);
>  	struct platform_device *pdev = coretemp_get_pdev(cpu);
> @@ -688,12 +688,12 @@ static void get_core_online(unsigned int cpu)
>  	 * without thermal sensors will be filtered out.
>  	 */
>  	if (!cpu_has(c, X86_FEATURE_DTHERM))
> -		return;
> +		return 0;
>  
>  	if (!pdev) {
>  		/* Check the microcode version of the CPU */
>  		if (chk_ucode_version(cpu))
> -			return;
> +			return 0;
>  
>  		/*
>  		 * Alright, we have DTS support.
> @@ -703,7 +703,7 @@ static void get_core_online(unsigned int cpu)
>  		 */
>  		err = coretemp_device_add(cpu);
>  		if (err)
> -			return;
> +			return 0;
>  		/*
>  		 * Check whether pkgtemp support is available.
>  		 * If so, add interfaces for pkgtemp.
> @@ -716,9 +716,10 @@ static void get_core_online(unsigned int cpu)
>  	 * So, just add interfaces for this core.
>  	 */
>  	coretemp_add_core(cpu, 0);
> +	return 0;
>  }
>  
> -static void put_core_offline(unsigned int cpu)
> +static int coretemp_cpu_offline(unsigned int cpu)
>  {
>  	int i, indx;
>  	struct platform_data *pdata;
> @@ -726,7 +727,7 @@ static void put_core_offline(unsigned int cpu)
>  
>  	/* If the physical CPU device does not exist, just return */
>  	if (!pdev)
> -		return;
> +		return 0;
>  
>  	pdata = platform_get_drvdata(pdev);
>  
> @@ -734,7 +735,7 @@ static void put_core_offline(unsigned int cpu)
>  
>  	/* The core id is too big, just return */
>  	if (indx > MAX_CORE_DATA - 1)
> -		return;
> +		return 0;
>  
>  	if (pdata->core_data[indx] && pdata->core_data[indx]->cpu == cpu)
>  		coretemp_remove_core(pdata, indx);
> @@ -747,7 +748,7 @@ static void put_core_offline(unsigned int cpu)
>  	 */
>  	for_each_sibling(i, cpu) {
>  		if (i != cpu) {
> -			get_core_online(i);
> +			coretemp_cpu_online(i);
>  			/*
>  			 * Display temperature sensor data for one HT sibling
>  			 * per core only, so abort the loop after one such
> @@ -764,38 +765,20 @@ static void put_core_offline(unsigned int cpu)
>  	 */
>  	if (!is_any_core_online(pdata))
>  		coretemp_device_remove(cpu);
> +	return 0;
>  }
>  
> -static int coretemp_cpu_callback(struct notifier_block *nfb,
> -				 unsigned long action, void *hcpu)
> -{
> -	unsigned int cpu = (unsigned long) hcpu;
> -
> -	switch (action) {
> -	case CPU_ONLINE:
> -	case CPU_DOWN_FAILED:
> -		get_core_online(cpu);
> -		break;
> -	case CPU_DOWN_PREPARE:
> -		put_core_offline(cpu);
> -		break;
> -	}
> -	return NOTIFY_OK;
> -}
> -
> -static struct notifier_block coretemp_cpu_notifier __refdata = {
> -	.notifier_call = coretemp_cpu_callback,
> -};
> -
>  static const struct x86_cpu_id __initconst coretemp_ids[] = {
>  	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_DTHERM },
>  	{}
>  };
>  MODULE_DEVICE_TABLE(x86cpu, coretemp_ids);
>  
> +static enum cpuhp_state coretemp_hp_online;
> +
>  static int __init coretemp_init(void)
>  {
> -	int i, err;
> +	int err;
>  
>  	/*
>  	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
> @@ -809,44 +792,33 @@ static int __init coretemp_init(void)
>  	if (err)
>  		goto exit;
>  
> -	cpu_notifier_register_begin();
> -	for_each_online_cpu(i)
> -		get_core_online(i);
> +	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/coretemp:online",
> +				coretemp_cpu_online, coretemp_cpu_offline);
> +	if (err < 0)
> +		goto exit_driver_unreg;
> +	coretemp_hp_online = err;
>  
>  #ifndef CONFIG_HOTPLUG_CPU
>  	if (list_empty(&pdev_list)) {
> -		cpu_notifier_register_done();
>  		err = -ENODEV;
> -		goto exit_driver_unreg;
> +		goto exit_hp_unreg;
>  	}
>  #endif
> -
> -	__register_hotcpu_notifier(&coretemp_cpu_notifier);
> -	cpu_notifier_register_done();
>  	return 0;
>  
>  #ifndef CONFIG_HOTPLUG_CPU
> +exit_hp_unreg:
> +	cpuhp_remove_state(coretemp_hp_online);
> +#endif
>  exit_driver_unreg:
>  	platform_driver_unregister(&coretemp_driver);
> -#endif
>  exit:
>  	return err;
>  }
>  
>  static void __exit coretemp_exit(void)
>  {
> -	struct pdev_entry *p, *n;
> -
> -	cpu_notifier_register_begin();
> -	__unregister_hotcpu_notifier(&coretemp_cpu_notifier);
> -	mutex_lock(&pdev_list_mutex);
> -	list_for_each_entry_safe(p, n, &pdev_list, list) {
> -		platform_device_unregister(p->pdev);
> -		list_del(&p->list);
> -		kfree(p);
> -	}
> -	mutex_unlock(&pdev_list_mutex);
> -	cpu_notifier_register_done();
> +	cpuhp_remove_state(coretemp_hp_online);
>  	platform_driver_unregister(&coretemp_driver);
>  }
>  

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