Commit 6f0b13f1 authored by Mario Limonciello's avatar Mario Limonciello
Browse files

cpufreq/amd-pstate: Overhaul locking 



amd_pstate_cpu_boost_update() and refresh_frequency_limits() both
update the policy state and have nothing to do with the amd-pstate
driver itself.

A global "limits" lock doesn't make sense because each CPU can have
policies changed independently.  Each time a CPU changes values they
will atomically be written to the per-CPU perf member. Drop per CPU
locking cases.

The remaining "global" driver lock is used to ensure that only one
entity can change driver modes at a given time.

Reviewed-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: default avatarDhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
parent 009d1c29

drivers/cpufreq/amd-pstate.c

+3 −10
Original line number Diff line number Diff line
@@ -196,7 +196,6 @@ static inline int get_mode_idx_from_str(const char *str, size_t size) 
	return -EINVAL;

}



static DEFINE_MUTEX(amd_pstate_limits_lock);

static DEFINE_MUTEX(amd_pstate_driver_lock);



static u8 msr_get_epp(struct amd_cpudata *cpudata)
@@ -752,7 +751,6 @@ 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);
@@ -1170,8 +1168,6 @@ static ssize_t store_energy_performance_preference( 
	if (ret < 0)

		return -EINVAL;



	guard(mutex)(&amd_pstate_limits_lock);



	ret = amd_pstate_set_energy_pref_index(policy, ret);



	return ret ? ret : count;
@@ -1344,8 +1340,10 @@ int amd_pstate_update_status(const char *buf, size_t size) 
	if (mode_idx < 0 || mode_idx >= AMD_PSTATE_MAX)

		return -EINVAL;



	if (mode_state_machine[cppc_state][mode_idx])

	if (mode_state_machine[cppc_state][mode_idx]) {

		guard(mutex)(&amd_pstate_driver_lock);

		return mode_state_machine[cppc_state][mode_idx](mode_idx);

	}



	return 0;

}
@@ -1366,7 +1364,6 @@ static ssize_t status_store(struct device *a, struct device_attribute *b, 
	char *p = memchr(buf, '\n', count);

	int ret;



	guard(mutex)(&amd_pstate_driver_lock);

	ret = amd_pstate_update_status(buf, p ? p - buf : count);



	return ret < 0 ? ret : count;
@@ -1638,8 +1635,6 @@ static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy) 
	if (cpudata->suspended)

		return 0;



	guard(mutex)(&amd_pstate_limits_lock);



	if (trace_amd_pstate_epp_perf_enabled()) {

		trace_amd_pstate_epp_perf(cpudata->cpu, perf.highest_perf,

					  AMD_CPPC_EPP_BALANCE_POWERSAVE,
@@ -1679,8 +1674,6 @@ static int amd_pstate_epp_resume(struct cpufreq_policy *policy) 
	struct amd_cpudata *cpudata = policy->driver_data;



	if (cpudata->suspended) {

		guard(mutex)(&amd_pstate_limits_lock);



		/* enable amd pstate from suspend state*/

		amd_pstate_epp_reenable(policy);