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Revert "cpufreq: Avoid using inconsistent policy->min and policy->max"

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This reverts commit 681400579b which is
commit 7491cdf46b5cbdf123fc84fbe0a07e9e3d7b7620 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I8c729ffa77816414bc3ae3f4db045116e4b04569
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman
2025-05-11 05:36:49 +00:00
parent 9840922a87
commit 4894546596
1 changed files with 6 additions and 25 deletions
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31
drivers/cpufreq/cpufreq.c
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@@ -538,6 +538,7 @@ static unsigned int __resolve_freq(struct cpufreq_policy *policy,
unsigned int idx;
unsigned int old_target_freq = target_freq;
target_freq = clamp_val(target_freq, policy->min, policy->max);
trace_android_vh_cpufreq_resolve_freq(policy, &target_freq, old_target_freq);
if (!policy->freq_table)
@@ -563,22 +564,7 @@ static unsigned int __resolve_freq(struct cpufreq_policy *policy,
unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
unsigned int target_freq)
{
unsigned int min = READ_ONCE(policy->min);
unsigned int max = READ_ONCE(policy->max);
/*
* If this function runs in parallel with cpufreq_set_policy(), it may
* read policy->min before the update and policy->max after the update
* or the other way around, so there is no ordering guarantee.
*
* Resolve this by always honoring the max (in case it comes from
* thermal throttling or similar).
*/
if (unlikely(min > max))
min = max;
return __resolve_freq(policy, clamp_val(target_freq, min, max),
CPUFREQ_RELATION_LE);
return __resolve_freq(policy, target_freq, CPUFREQ_RELATION_LE);
}
EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
@@ -2320,7 +2306,6 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
if (cpufreq_disabled())
return -ENODEV;
target_freq = clamp_val(target_freq, policy->min, policy->max);
target_freq = __resolve_freq(policy, target_freq, relation);
trace_android_vh_cpufreq_target(policy, &target_freq, old_target_freq);
@@ -2613,15 +2598,11 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
* Resolve policy min/max to available frequencies. It ensures
* no frequency resolution will neither overshoot the requested maximum
* nor undershoot the requested minimum.
*
* Avoid storing intermediate values in policy->max or policy->min and
* compiler optimizations around them because they may be accessed
* concurrently by cpufreq_driver_resolve_freq() during the update.
*/
WRITE_ONCE(policy->max, __resolve_freq(policy, new_data.max, CPUFREQ_RELATION_H));
new_data.min = __resolve_freq(policy, new_data.min, CPUFREQ_RELATION_L);
WRITE_ONCE(policy->min, new_data.min > policy->max ? policy->max : new_data.min);
policy->min = new_data.min;
policy->max = new_data.max;
policy->min = __resolve_freq(policy, policy->min, CPUFREQ_RELATION_L);
policy->max = __resolve_freq(policy, policy->max, CPUFREQ_RELATION_H);
trace_cpu_frequency_limits(policy);
policy->cached_target_freq = UINT_MAX;