linux-kernel - Re: [PATCH] cpuidle: psci: Iterate backwards over list in psci_pd

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Date:   Fri, 25 Feb 2022 14:14:54 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     Shawn Guo <shawn.guo@...aro.org>
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Ulf Hansson <ulf.hansson@...aro.org>, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpuidle: psci: Iterate backwards over list in
 psci_pd_remove()

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@....com>

-- 
Regards,
Sudeep