PM / sleep: Simplify sleep states sysfs interface code

Simplify the sleep states sysfs interface /sys/power/state code by
redefining pm_states[] as an array of pointers to constant strings
such that only the entries corresponding to valid states are set.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

4 files changed, 31 insertions, 41 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 8e90f330f139..d57f66a367dc 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -296,8 +296,8 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
         suspend_state_t i;
 
         for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
-                if (pm_states[i].state)
-                        s += sprintf(s,"%s ", pm_states[i].label);
+                if (pm_states[i])
+                        s += sprintf(s,"%s ", pm_states[i]);
 
 #endif
         if (hibernation_available())
@@ -311,8 +311,7 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 static suspend_state_t decode_state(const char *buf, size_t n)
 {
 #ifdef CONFIG_SUSPEND
-        suspend_state_t state = PM_SUSPEND_MIN;
-        struct pm_sleep_state *s;
+        suspend_state_t state;
 #endif
         char *p;
         int len;
@@ -325,10 +324,12 @@ static suspend_state_t decode_state(const char *buf, size_t n)
                 return PM_SUSPEND_MAX;
 
 #ifdef CONFIG_SUSPEND
-        for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
-                if (s->state && len == strlen(s->label)
-                    && !strncmp(buf, s->label, len))
-                        return s->state;
+        for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
+                const char *label = pm_states[state];
+
+                if (label && len == strlen(label) && !strncmp(buf, label, len))
+                        return state;
+        }
 #endif
 
         return PM_SUSPEND_ON;
@@ -446,8 +447,8 @@ static ssize_t autosleep_show(struct kobject *kobj,
 
 #ifdef CONFIG_SUSPEND
         if (state < PM_SUSPEND_MAX)
-                return sprintf(buf, "%s\n", pm_states[state].state ?
-                                        pm_states[state].label : "error");
+                return sprintf(buf, "%s\n", pm_states[state] ?
+                                        pm_states[state] : "error");
 #endif
 #ifdef CONFIG_HIBERNATION
         return sprintf(buf, "disk\n");
diff --git a/kernel/power/power.h b/kernel/power/power.h
index c60f13b5270a..5d49dcac2537 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -178,13 +178,8 @@ extern void swsusp_show_speed(struct timeval *, struct timeval *,
                                 unsigned int, char *);
 
 #ifdef CONFIG_SUSPEND
-struct pm_sleep_state {
-        const char *label;
-        suspend_state_t state;
-};
-
 /* kernel/power/suspend.c */
-extern struct pm_sleep_state pm_states[];
+extern const char *pm_states[];
 
 extern int suspend_devices_and_enter(suspend_state_t state);
 #else /* !CONFIG_SUSPEND */
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ed35a4790afe..83f5b3e70d95 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -31,11 +31,8 @@
 
 #include "power.h"
 
-struct pm_sleep_state pm_states[PM_SUSPEND_MAX] = {
-        [PM_SUSPEND_FREEZE] = { .label = "freeze", .state = PM_SUSPEND_FREEZE },
-        [PM_SUSPEND_STANDBY] = { .label = "standby", },
-        [PM_SUSPEND_MEM] = { .label = "mem", },
-};
+static const char *pm_labels[] = { "mem", "standby", "freeze", };
+const char *pm_states[PM_SUSPEND_MAX];
 
 static const struct platform_suspend_ops *suspend_ops;
 static const struct platform_freeze_ops *freeze_ops;
@@ -97,10 +94,7 @@ static bool relative_states;
 static int __init sleep_states_setup(char *str)
 {
         relative_states = !strncmp(str, "1", 1);
-        if (relative_states) {
-                pm_states[PM_SUSPEND_MEM].state = PM_SUSPEND_FREEZE;
-                pm_states[PM_SUSPEND_FREEZE].state = 0;
-        }
+        pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
         return 1;
 }
 
@@ -113,20 +107,20 @@ __setup("relative_sleep_states=", sleep_states_setup);
 void suspend_set_ops(const struct platform_suspend_ops *ops)
 {
         suspend_state_t i;
-        int j = PM_SUSPEND_MAX - 1;
+        int j = 0;
 
         lock_system_sleep();
 
         suspend_ops = ops;
         for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
-                if (valid_state(i))
-                        pm_states[j--].state = i;
-                else if (!relative_states)
-                        pm_states[j--].state = 0;
+                if (valid_state(i)) {
+                        pm_states[i] = pm_labels[j++];
+                } else if (!relative_states) {
+                        pm_states[i] = NULL;
+                        j++;
+                }
 
-        pm_states[j--].state = PM_SUSPEND_FREEZE;
-        while (j >= PM_SUSPEND_MIN)
-                pm_states[j--].state = 0;
+        pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
 
         unlock_system_sleep();
 }
@@ -395,7 +389,7 @@ static int enter_state(suspend_state_t state)
         printk("done.\n");
         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 
-        pr_debug("PM: Preparing system for %s sleep\n", pm_states[state].label);
+        pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
         error = suspend_prepare(state);
         if (error)
                 goto Unlock;
@@ -404,7 +398,7 @@ static int enter_state(suspend_state_t state)
                 goto Finish;
 
         trace_suspend_resume(TPS("suspend_enter"), state, false);
-        pr_debug("PM: Entering %s sleep\n", pm_states[state].label);
+        pr_debug("PM: Entering %s sleep\n", pm_states[state]);
         pm_restrict_gfp_mask();
         error = suspend_devices_and_enter(state);
         pm_restore_gfp_mask();
diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c
index 269b097e78ea..2f524928b6aa 100644
--- a/kernel/power/suspend_test.c
+++ b/kernel/power/suspend_test.c
@@ -92,13 +92,13 @@ static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
         }
 
         if (state == PM_SUSPEND_MEM) {
-                printk(info_test, pm_states[state].label);
+                printk(info_test, pm_states[state]);
                 status = pm_suspend(state);
                 if (status == -ENODEV)
                         state = PM_SUSPEND_STANDBY;
         }
         if (state == PM_SUSPEND_STANDBY) {
-                printk(info_test, pm_states[state].label);
+                printk(info_test, pm_states[state]);
                 status = pm_suspend(state);
         }
         if (status < 0)
@@ -141,8 +141,8 @@ static int __init setup_test_suspend(char *value)
         /* "=mem" ==> "mem" */
         value++;
         for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
-                if (!strcmp(pm_states[i].label, value)) {
-                        test_state = pm_states[i].state;
+                if (!strcmp(pm_states[i], value)) {
+                        test_state = i;
                         return 0;
                 }
 
@@ -162,8 +162,8 @@ static int __init test_suspend(void)
         /* PM is initialized by now; is that state testable? */
         if (test_state == PM_SUSPEND_ON)
                 goto done;
-        if (!pm_states[test_state].state) {
-                printk(warn_bad_state, pm_states[test_state].label);
+        if (!pm_states[test_state]) {
+                printk(warn_bad_state, pm_states[test_state]);
                 goto done;
         }