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SubjectRe: [PATCH 06/20] hwmon/via-cputemp: Convert to hotplug state machine
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On 11/17/2016 10:35 AM, Sebastian Andrzej Siewior wrote:
> Install the callbacks via the state machine and let the core invoke the
> callbacks on the already online CPUs. When the hotplug state is
> unregistered the cleanup function is called for each cpu. So both cpu loops
> in init() and exit() are not longer required.
>
> 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>

I would like to apply this patch, but I can not test it, and I want to make sure
it survives multiple removal/insertion sequences. Can someone give me a Tested-by: ?

Thanks,
Guenter

> ---
> drivers/hwmon/via-cputemp.c | 61 ++++++++++++---------------------------------
> 1 file changed, 16 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/hwmon/via-cputemp.c b/drivers/hwmon/via-cputemp.c
> index 5b9866b1b437..ee5377ecd7a9 100644
> --- a/drivers/hwmon/via-cputemp.c
> +++ b/drivers/hwmon/via-cputemp.c
> @@ -220,7 +220,7 @@ struct pdev_entry {
> static LIST_HEAD(pdev_list);
> static DEFINE_MUTEX(pdev_list_mutex);
>
> -static int via_cputemp_device_add(unsigned int cpu)
> +static int via_cputemp_online(unsigned int cpu)
> {
> int err;
> struct platform_device *pdev;
> @@ -261,7 +261,7 @@ static int via_cputemp_device_add(unsigned int cpu)
> return err;
> }
>
> -static void via_cputemp_device_remove(unsigned int cpu)
> +static int via_cputemp_down_prep(unsigned int cpu)
> {
> struct pdev_entry *p;
>
> @@ -272,33 +272,13 @@ static void via_cputemp_device_remove(unsigned int cpu)
> list_del(&p->list);
> mutex_unlock(&pdev_list_mutex);
> kfree(p);
> - return;
> + return 0;
> }
> }
> mutex_unlock(&pdev_list_mutex);
> + return 0;
> }
>
> -static int via_cputemp_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:
> - via_cputemp_device_add(cpu);
> - break;
> - case CPU_DOWN_PREPARE:
> - via_cputemp_device_remove(cpu);
> - break;
> - }
> - return NOTIFY_OK;
> -}
> -
> -static struct notifier_block via_cputemp_cpu_notifier __refdata = {
> - .notifier_call = via_cputemp_cpu_callback,
> -};
> -
> static const struct x86_cpu_id __initconst cputemp_ids[] = {
> { X86_VENDOR_CENTAUR, 6, 0xa, }, /* C7 A */
> { X86_VENDOR_CENTAUR, 6, 0xd, }, /* C7 D */
> @@ -307,6 +287,8 @@ static const struct x86_cpu_id __initconst cputemp_ids[] = {
> };
> MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);
>
> +static enum cpuhp_state via_temp_online;
> +
> static int __init via_cputemp_init(void)
> {
> int i, err;
> @@ -318,44 +300,33 @@ static int __init via_cputemp_init(void)
> if (err)
> goto exit;
>
> - cpu_notifier_register_begin();
> - for_each_online_cpu(i)
> - via_cputemp_device_add(i);
> + err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/via:online",
> + via_cputemp_online, via_cputemp_down_prep);
> + if (err < 0)
> + goto exit_driver_unreg;
> + via_temp_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(&via_cputemp_cpu_notifier);
> - cpu_notifier_register_done();
> return 0;
>
> #ifndef CONFIG_HOTPLUG_CPU
> +exit_hp_unreg:
> + cpuhp_remove_state_nocalls(via_temp_online);
> +#endif
> exit_driver_unreg:
> platform_driver_unregister(&via_cputemp_driver);
> -#endif
> exit:
> return err;
> }
>
> static void __exit via_cputemp_exit(void)
> {
> - struct pdev_entry *p, *n;
> -
> - cpu_notifier_register_begin();
> - __unregister_hotcpu_notifier(&via_cputemp_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(via_temp_online);
> platform_driver_unregister(&via_cputemp_driver);
> }
>
>

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