Re: [PATCH] cpufreq/amd-pstate: Remove unnecessary driver_lock in set_boost

[Mario Limonciello]

On 2/3/2025 04:48, Viresh Kumar wrote:
> On 30-01-25, 08:52, Dhananjay Ugwekar wrote:
> > set_boost is a per-policy function call, hence a driver wide lock is
> > unnecessary. Also this mutex_acquire can collide with the mutex_acquire
> > from the mode-switch path in status_store(), which can lead to a
> > deadlock. So, remove it.
> >
> > Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@xxxxxxx>
> > ---
> > PS: This patch should ideally go before [1], as that patch uncovers this
> > bug and actually leads to a deadlock when switching the amd_pstate driver
> > mode.
> > [1] https://lore.kernel.org/linux-pm/e16c06d4b8ffdb20e802ffe648f14dc515e60426.1737707712.git.viresh.kumar@xxxxxxxxxx/
> > ---
> >   drivers/cpufreq/amd-pstate.c | 1 -
> >   1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> > index d5be51bf8692..93788bce7e6a 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -740,7 +740,6 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
> >   		pr_err("Boost mode is not supported by this processor or SBIOS\n");
> >   		return -EOPNOTSUPP;
> >   	}
> > -	guard(mutex)(&amd_pstate_driver_lock);
> >   
> >   	ret = amd_pstate_cpu_boost_update(policy, state);
> >   	refresh_frequency_limits(policy);
>
> Applied. Thanks.

Sorry for my delay with the recent holiday.
I have no concerns with this going to the start of the series.

Acked-by: Mario Limonciello <mario.limonciello@xxxxxxx>