PM / sleep: Add support for read-only sysfs attributes

Some sysfs attributes in /sys/power/ should really be read-only,
so add support for that, convert those attributes to read-only
and drop the stub .show() routines from them.

Original-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 11 insertions, 15 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index b2dd4d999900..27946975eff0 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -280,13 +280,7 @@ static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
         return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
 }
 
-static ssize_t pm_wakeup_irq_store(struct kobject *kobj,
-                                        struct kobj_attribute *attr,
-                                        const char *buf, size_t n)
-{
-        return -EINVAL;
-}
-power_attr(pm_wakeup_irq);
+power_attr_ro(pm_wakeup_irq);
 
 #else /* !CONFIG_PM_SLEEP_DEBUG */
 static inline void pm_print_times_init(void) {}
@@ -564,14 +558,7 @@ static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
         return show_trace_dev_match(buf, PAGE_SIZE);
 }
 
-static ssize_t
-pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
-                         const char *buf, size_t n)
-{
-        return -EINVAL;
-}
-
-power_attr(pm_trace_dev_match);
+power_attr_ro(pm_trace_dev_match);
 
 #endif /* CONFIG_PM_TRACE */
 
diff --git a/kernel/power/power.h b/kernel/power/power.h
index caadb566e82b..efe1b3b17c88 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -77,6 +77,15 @@ static struct kobj_attribute _name##_attr = {	\
         .store  = _name##_store,                \
 }
 
+#define power_attr_ro(_name) \
+static struct kobj_attribute _name##_attr = {   \
+        .attr   = {                             \
+                .name = __stringify(_name),     \
+                .mode = S_IRUGO,                \
+        },                                      \
+        .show   = _name##_show,                 \
+}
+
 /* Preferred image size in bytes (default 500 MB) */
 extern unsigned long image_size;
 /* Size of memory reserved for drivers (default SPARE_PAGES x PAGE_SIZE) */