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* [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove()
@ 2022-02-25  8:24 Shawn Guo
  2022-02-25  8:30 ` Shawn Guo
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Shawn Guo @ 2022-02-25  8:24 UTC (permalink / raw)
  To: Daniel Lezcano, Rafael J . Wysocki
  Cc: Sudeep Holla, Ulf Hansson, linux-pm, linux-arm-kernel,
	linux-kernel, Shawn Guo

In case that psci_pd_init_topology() fails for some reason,
psci_pd_remove() will be responsible for deleting provider and removing
genpd from psci_pd_providers list.  There will be a failure when removing
the cluster PD, because the cpu (child) PDs haven't been removed.

[    0.050232] CPUidle PSCI: init PM domain cpu0
[    0.050278] CPUidle PSCI: init PM domain cpu1
[    0.050329] CPUidle PSCI: init PM domain cpu2
[    0.050370] CPUidle PSCI: init PM domain cpu3
[    0.050422] CPUidle PSCI: init PM domain cpu-cluster0
[    0.050475] PM: genpd_remove: unable to remove cpu-cluster0
[    0.051412] PM: genpd_remove: removed cpu3
[    0.051449] PM: genpd_remove: removed cpu2
[    0.051499] PM: genpd_remove: removed cpu1
[    0.051546] PM: genpd_remove: removed cpu0

Fix the problem by iterating the provider list in a reversely order, so
that parent PD gets removed before child's PDs.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---
 drivers/cpuidle/cpuidle-psci-domain.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index ff2c3f8e4668..ce5c415fb04d 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -182,7 +182,8 @@ static void psci_pd_remove(void)
 	struct psci_pd_provider *pd_provider, *it;
 	struct generic_pm_domain *genpd;
 
-	list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
+	list_for_each_entry_safe_reverse(pd_provider, it,
+					 &psci_pd_providers, link) {
 		of_genpd_del_provider(pd_provider->node);
 
 		genpd = of_genpd_remove_last(pd_provider->node);
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove()
  2022-02-25  8:24 [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove() Shawn Guo
@ 2022-02-25  8:30 ` Shawn Guo
  2022-02-25 14:14 ` Sudeep Holla
  2022-03-01 10:46 ` Ulf Hansson
  2 siblings, 0 replies; 4+ messages in thread
From: Shawn Guo @ 2022-02-25  8:30 UTC (permalink / raw)
  To: Daniel Lezcano, Rafael J . Wysocki
  Cc: Sudeep Holla, Ulf Hansson, linux-pm, linux-arm-kernel,
	linux-kernel

On Fri, Feb 25, 2022 at 04:24:20PM +0800, Shawn Guo wrote:
> In case that psci_pd_init_topology() fails for some reason,
> psci_pd_remove() will be responsible for deleting provider and removing
> genpd from psci_pd_providers list.  There will be a failure when removing
> the cluster PD, because the cpu (child) PDs haven't been removed.
> 
> [    0.050232] CPUidle PSCI: init PM domain cpu0
> [    0.050278] CPUidle PSCI: init PM domain cpu1
> [    0.050329] CPUidle PSCI: init PM domain cpu2
> [    0.050370] CPUidle PSCI: init PM domain cpu3
> [    0.050422] CPUidle PSCI: init PM domain cpu-cluster0
> [    0.050475] PM: genpd_remove: unable to remove cpu-cluster0
> [    0.051412] PM: genpd_remove: removed cpu3
> [    0.051449] PM: genpd_remove: removed cpu2
> [    0.051499] PM: genpd_remove: removed cpu1
> [    0.051546] PM: genpd_remove: removed cpu0
> 
> Fix the problem by iterating the provider list in a reversely order, so

s/reversely/reversed

> that parent PD gets removed before child's PDs.

s/before/after

Essentially, with this change, the PM domains will be removed in the same
order how they were added.

[    0.029052] CPUidle PSCI: init PM domain cpu0
[    0.029076] CPUidle PSCI: init PM domain cpu1
[    0.029103] CPUidle PSCI: init PM domain cpu2
[    0.029124] CPUidle PSCI: init PM domain cpu3
[    0.029151] CPUidle PSCI: init PM domain cpu-cluster0
[    0.029647] PM: genpd_remove: removed cpu0
[    0.029666] PM: genpd_remove: removed cpu1
[    0.029690] PM: genpd_remove: removed cpu2
[    0.029714] PM: genpd_remove: removed cpu3
[    0.029738] PM: genpd_remove: removed cpu-cluster0

Shawn

> 
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> ---
>  drivers/cpuidle/cpuidle-psci-domain.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
> index ff2c3f8e4668..ce5c415fb04d 100644
> --- a/drivers/cpuidle/cpuidle-psci-domain.c
> +++ b/drivers/cpuidle/cpuidle-psci-domain.c
> @@ -182,7 +182,8 @@ static void psci_pd_remove(void)
>  	struct psci_pd_provider *pd_provider, *it;
>  	struct generic_pm_domain *genpd;
>  
> -	list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
> +	list_for_each_entry_safe_reverse(pd_provider, it,
> +					 &psci_pd_providers, link) {
>  		of_genpd_del_provider(pd_provider->node);
>  
>  		genpd = of_genpd_remove_last(pd_provider->node);
> -- 
> 2.25.1
> 

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove()
  2022-02-25  8:24 [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove() Shawn Guo
  2022-02-25  8:30 ` Shawn Guo
@ 2022-02-25 14:14 ` Sudeep Holla
  2022-03-01 10:46 ` Ulf Hansson
  2 siblings, 0 replies; 4+ messages in thread
From: Sudeep Holla @ 2022-02-25 14:14 UTC (permalink / raw)
  To: Shawn Guo
  Cc: Daniel Lezcano, Rafael J . Wysocki, Sudeep Holla, Ulf Hansson,
	linux-pm, linux-arm-kernel, linux-kernel

On Fri, Feb 25, 2022 at 04:24:20PM +0800, Shawn Guo wrote:
> In case that psci_pd_init_topology() fails for some reason,
> psci_pd_remove() will be responsible for deleting provider and removing
> genpd from psci_pd_providers list.  There will be a failure when removing
> the cluster PD, because the cpu (child) PDs haven't been removed.
> 
> [    0.050232] CPUidle PSCI: init PM domain cpu0
> [    0.050278] CPUidle PSCI: init PM domain cpu1
> [    0.050329] CPUidle PSCI: init PM domain cpu2
> [    0.050370] CPUidle PSCI: init PM domain cpu3
> [    0.050422] CPUidle PSCI: init PM domain cpu-cluster0
> [    0.050475] PM: genpd_remove: unable to remove cpu-cluster0
> [    0.051412] PM: genpd_remove: removed cpu3
> [    0.051449] PM: genpd_remove: removed cpu2
> [    0.051499] PM: genpd_remove: removed cpu1
> [    0.051546] PM: genpd_remove: removed cpu0
> 
> Fix the problem by iterating the provider list in a reversely order, so
> that parent PD gets removed before child's PDs.
>

Makes sense.

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

-- 
Regards,
Sudeep

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove()
  2022-02-25  8:24 [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove() Shawn Guo
  2022-02-25  8:30 ` Shawn Guo
  2022-02-25 14:14 ` Sudeep Holla
@ 2022-03-01 10:46 ` Ulf Hansson
  2 siblings, 0 replies; 4+ messages in thread
From: Ulf Hansson @ 2022-03-01 10:46 UTC (permalink / raw)
  To: Shawn Guo
  Cc: Daniel Lezcano, Rafael J . Wysocki, Sudeep Holla, linux-pm,
	linux-arm-kernel, linux-kernel

On Fri, 25 Feb 2022 at 09:24, Shawn Guo <shawn.guo@linaro.org> wrote:
>
> In case that psci_pd_init_topology() fails for some reason,
> psci_pd_remove() will be responsible for deleting provider and removing
> genpd from psci_pd_providers list.  There will be a failure when removing
> the cluster PD, because the cpu (child) PDs haven't been removed.
>
> [    0.050232] CPUidle PSCI: init PM domain cpu0
> [    0.050278] CPUidle PSCI: init PM domain cpu1
> [    0.050329] CPUidle PSCI: init PM domain cpu2
> [    0.050370] CPUidle PSCI: init PM domain cpu3
> [    0.050422] CPUidle PSCI: init PM domain cpu-cluster0
> [    0.050475] PM: genpd_remove: unable to remove cpu-cluster0
> [    0.051412] PM: genpd_remove: removed cpu3
> [    0.051449] PM: genpd_remove: removed cpu2
> [    0.051499] PM: genpd_remove: removed cpu1
> [    0.051546] PM: genpd_remove: removed cpu0
>
> Fix the problem by iterating the provider list in a reversely order, so
> that parent PD gets removed before child's PDs.
>
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

Thanks for fixing this!

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

I think we should add a fixes tag, like below and also tag this for
stable kernels.

Fixes: a65a397f2451 ("cpuidle: psci: Add support for PM domains by using genpd")

Kind regards
Uffe

> ---
>  drivers/cpuidle/cpuidle-psci-domain.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
> index ff2c3f8e4668..ce5c415fb04d 100644
> --- a/drivers/cpuidle/cpuidle-psci-domain.c
> +++ b/drivers/cpuidle/cpuidle-psci-domain.c
> @@ -182,7 +182,8 @@ static void psci_pd_remove(void)
>         struct psci_pd_provider *pd_provider, *it;
>         struct generic_pm_domain *genpd;
>
> -       list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
> +       list_for_each_entry_safe_reverse(pd_provider, it,
> +                                        &psci_pd_providers, link) {
>                 of_genpd_del_provider(pd_provider->node);
>
>                 genpd = of_genpd_remove_last(pd_provider->node);
> --
> 2.25.1
>

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^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-03-01 10:48 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2022-02-25  8:24 [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd_remove() Shawn Guo
2022-02-25  8:30 ` Shawn Guo
2022-02-25 14:14 ` Sudeep Holla
2022-03-01 10:46 ` Ulf Hansson

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