[PATCH] cpufreq: acpi-cpufreq: Using cpufreq_for_each_entry() to iterate in extract_io()

[lirongqing <lirongqing@baidu.com>]

From: Li RongQing <lirongqing@baidu.com>

In extract_io(), the loop iterates up to perf->state_count. However,
when building policy->freq_table in acpi_cpufreq_cpu_init(), duplicate
frequency entries are skipped, making freq_table smaller than
perf->state_count.

Iterating perf->state_count times directly over policy->freq_table[i] can
result in out-of-bounds array reads. Furthermore, policy->freq_table[i]
does not necessarily correspond to perf->states[i], as the original P-state
index is stored in freq_table[entry].driver_data.

Fix this by using cpufreq_for_each_entry() to iterate over
policy->freq_table, similar to extract_msr().

Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 drivers/cpufreq/acpi-cpufreq.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 21639d9..87e4923 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -196,15 +196,14 @@ static int check_amd_hwpstate_cpu(unsigned int cpuid)
 static unsigned extract_io(struct cpufreq_policy *policy, u32 value)
 {
 	struct acpi_cpufreq_data *data = policy->driver_data;
+	struct cpufreq_frequency_table *pos;
 	struct acpi_processor_performance *perf;
-	int i;
 
 	perf = to_perf_data(data);
 
-	for (i = 0; i < perf->state_count; i++) {
-		if (value == perf->states[i].status)
-			return policy->freq_table[i].frequency;
-	}
+	cpufreq_for_each_entry(pos, policy->freq_table)
+		if (value == perf->states[pos->driver_data].status)
+			return pos->frequency;
 	return 0;
 }
 
-- 
2.9.4