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Subject[PATCH v1 1/1] cpufreq: fix the target freq not in the range of policy->min & max
Date
    In cpufreq_frequency_table_target(), this function will try to find
an index for @target_freq in freq_table, and the frequency of selected
index should be in the range [policy->min, policy->max], which means:

policy->min <= policy->freq_table[idx].frequency <= policy->max

Though "clamp_val(target_freq, policy->min, policy->max);" would
have been called to check this condition, when policy->max or min is
not exactly one of the frequency in the frequency table,
policy->freq_table[idx].frequency may still go out of the range

For example, if our sorted freq_table is [3000, 2000, 1000], and
suppose we have:

@target_freq = 2500
@policy->min = 2000
@policy->max = 2200
@relation = CPUFREQ_RELATION_L

1. After clamp_val(target_freq, policy->min, policy->max); @target_freq
becomes 2200
2. Since we use CPUFREQ_REALTION_L, final selected freq will be 3000 which
beyonds policy->max

Signed-off-by: TungChen Shih <tung-chen.shih@mediatek.com>
---
include/linux/cpufreq.h | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 353969c7acd3..60cb15740fdf 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -975,21 +975,40 @@ static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
+ int idx = 0;
if (unlikely(policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED))
return cpufreq_table_index_unsorted(policy, target_freq,
relation);

switch (relation) {
case CPUFREQ_RELATION_L:
- return cpufreq_table_find_index_l(policy, target_freq);
+ idx = cpufreq_table_find_index_l(policy, target_freq);
+ break;
case CPUFREQ_RELATION_H:
- return cpufreq_table_find_index_h(policy, target_freq);
+ idx = cpufreq_table_find_index_h(policy, target_freq);
+ break;
case CPUFREQ_RELATION_C:
- return cpufreq_table_find_index_c(policy, target_freq);
+ idx = cpufreq_table_find_index_c(policy, target_freq);
+ break;
default:
WARN_ON_ONCE(1);
return 0;
}
+
+ /* target index verification */
+ if (policy->freq_table[idx].frequency > policy->max) {
+ if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
+ idx--;
+ else
+ idx++;
+ } else if (policy->freq_table[idx].frequency < policy->min) {
+ if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
+ idx++;
+ else
+ idx--;
+ }
+
+ return idx;
}

static inline int cpufreq_table_count_valid_entries(const struct cpufreq_policy *policy)
--
2.18.0
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