From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
The cpb sysfs attribute is only exposed by the ACPI cpufreq driver
after a runtime check. For this purpose, the driver keeps a NULL
placeholder in its table of sysfs attributes and replaces the NULL
with a pointer to an attribute structure if it decides to expose
cpb.
That is confusing, so make the driver set a pointer to the cpb
attribute structure upfront and replace it with NULL if the
attribute should not be exposed instead.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/cpufreq/acpi-cpufreq.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
Index: linux-pm/drivers/cpufreq/acpi-cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/acpi-cpufreq.c
+++ linux-pm/drivers/cpufreq/acpi-cpufreq.c
@@ -886,7 +886,9 @@ static int acpi_cpufreq_resume(struct cp
static struct freq_attr *acpi_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
&freqdomain_cpus,
- NULL, /* this is a placeholder for cpb, do not remove */
+#ifdef CONFIG_X86_ACPI_CPUFREQ_CPB
+ &cpb,
+#endif
NULL,
};
@@ -959,17 +961,16 @@ static int __init acpi_cpufreq_init(void
* only if configured. This is considered legacy code, which
* will probably be removed at some point in the future.
*/
- if (check_amd_hwpstate_cpu(0)) {
- struct freq_attr **iter;
-
- pr_debug("adding sysfs entry for cpb\n");
+ if (!check_amd_hwpstate_cpu(0)) {
+ struct freq_attr **attr;
- for (iter = acpi_cpufreq_attr; *iter != NULL; iter++)
- ;
+ pr_debug("CPB unsupported, do not expose it\n");
- /* make sure there is a terminator behind it */
- if (iter[1] == NULL)
- *iter = &cpb;
+ for (attr = acpi_cpufreq_attr; *attr; attr++)
+ if (*attr == &cpb) {
+ *attr = NULL;
+ break;
+ }
}
#endif
acpi_cpufreq_boost_init();
--
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