Hi Pan,
On Tue, Jul 07, 2015 at 08:43:26PM +0800, Pan Xinhui wrote:
> @@ -364,19 +363,24 @@ static u32 get_cur_val(const struct cpumask *mask)
>
> static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
> + struct acpi_cpufreq_data *data;
> + struct cpufreq_policy *policy;
> unsigned int freq;
> unsigned int cached_freq;
>
> pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);
>
> - if (unlikely(data == NULL ||
> - data->acpi_data == NULL || data->freq_table == NULL)) {
> + policy = cpufreq_cpu_get(cpu);
> + if (unlikely(!policy))
> + return 0;
> +
> + data = policy->driver_data;
> + cpufreq_cpu_put(policy);
If we put policy here can we guarantee that memory pointed to by data
stays valid? Shoudln't we issue cpufreq_cpu_put(policy) after we done
assessing the pointer?
> + if (unlikely(!data || !data->acpi_data || !data->freq_table))
> return 0;
> - }
>
> cached_freq = data->freq_table[data->acpi_data->state].frequency;
> - freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
> + freq = extract_freq(get_cur_val(cpumask_of(cpu), data), data);
> if (freq != cached_freq) {
> /*
> * The dreaded BIOS frequency change behind our back.
Thanks.
--
Dmitry
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