[PATCH v2 01/10] PM: sleep: stats: Use array of suspend step names

From: Rafael J. Wysocki
Date: Mon Jan 29 2024 - 11:35:58 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Replace suspend_step_name() in the suspend statistics code with an array
of suspend step names which has fewer lines of code and less overhead.

While at it, remove two unnecessary line breaks in suspend_stats_show()
and adjust some white space in there to the kernel coding style for a
more consistent code layout.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
---

v1 -> v2: Added R-by from Stanislaw.

---
include/linux/suspend.h | 3 +-
kernel/power/main.c | 50 +++++++++++++++++-------------------------------
2 files changed, 20 insertions(+), 33 deletions(-)

Index: linux-pm/include/linux/suspend.h
===================================================================
--- linux-pm.orig/include/linux/suspend.h
+++ linux-pm/include/linux/suspend.h
@@ -41,7 +41,8 @@ typedef int __bitwise suspend_state_t;
#define PM_SUSPEND_MAX ((__force suspend_state_t) 4)

enum suspend_stat_step {
- SUSPEND_FREEZE = 1,
+ SUSPEND_NONE = 0,
+ SUSPEND_FREEZE,
SUSPEND_PREPARE,
SUSPEND_SUSPEND,
SUSPEND_SUSPEND_LATE,
Index: linux-pm/kernel/power/main.c
===================================================================
--- linux-pm.orig/kernel/power/main.c
+++ linux-pm/kernel/power/main.c
@@ -319,25 +319,17 @@ static ssize_t pm_test_store(struct kobj
power_attr(pm_test);
#endif /* CONFIG_PM_SLEEP_DEBUG */

-static char *suspend_step_name(enum suspend_stat_step step)
-{
- switch (step) {
- case SUSPEND_FREEZE:
- return "freeze";
- case SUSPEND_PREPARE:
- return "prepare";
- case SUSPEND_SUSPEND:
- return "suspend";
- case SUSPEND_SUSPEND_NOIRQ:
- return "suspend_noirq";
- case SUSPEND_RESUME_NOIRQ:
- return "resume_noirq";
- case SUSPEND_RESUME:
- return "resume";
- default:
- return "";
- }
-}
+static const char * const suspend_step_names[] = {
+ [SUSPEND_NONE] = "",
+ [SUSPEND_FREEZE] = "freeze",
+ [SUSPEND_PREPARE] = "prepare",
+ [SUSPEND_SUSPEND] = "suspend",
+ [SUSPEND_SUSPEND_LATE] = "suspend_late",
+ [SUSPEND_SUSPEND_NOIRQ] = "suspend_noirq",
+ [SUSPEND_RESUME_NOIRQ] = "resume_noirq",
+ [SUSPEND_RESUME_EARLY] = "resume_early",
+ [SUSPEND_RESUME] = "resume",
+};

#define suspend_attr(_name, format_str) \
static ssize_t _name##_show(struct kobject *kobj, \
@@ -392,16 +384,14 @@ static struct kobj_attribute last_failed
static ssize_t last_failed_step_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
- int index;
enum suspend_stat_step step;
- char *last_failed_step = NULL;
+ int index;

index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
index %= REC_FAILED_NUM;
step = suspend_stats.failed_steps[index];
- last_failed_step = suspend_step_name(step);

- return sprintf(buf, "%s\n", last_failed_step);
+ return sprintf(buf, "%s\n", suspend_step_names[step]);
}
static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);

@@ -473,30 +463,26 @@ static int suspend_stats_show(struct seq
"failed_resume_noirq",
suspend_stats.failed_resume_noirq);
seq_printf(s, "failures:\n last_failed_dev:\t%-s\n",
- suspend_stats.failed_devs[last_dev]);
+ suspend_stats.failed_devs[last_dev]);
for (i = 1; i < REC_FAILED_NUM; i++) {
index = last_dev + REC_FAILED_NUM - i;
index %= REC_FAILED_NUM;
- seq_printf(s, "\t\t\t%-s\n",
- suspend_stats.failed_devs[index]);
+ seq_printf(s, "\t\t\t%-s\n", suspend_stats.failed_devs[index]);
}
seq_printf(s, " last_failed_errno:\t%-d\n",
suspend_stats.errno[last_errno]);
for (i = 1; i < REC_FAILED_NUM; i++) {
index = last_errno + REC_FAILED_NUM - i;
index %= REC_FAILED_NUM;
- seq_printf(s, "\t\t\t%-d\n",
- suspend_stats.errno[index]);
+ seq_printf(s, "\t\t\t%-d\n", suspend_stats.errno[index]);
}
seq_printf(s, " last_failed_step:\t%-s\n",
- suspend_step_name(
- suspend_stats.failed_steps[last_step]));
+ suspend_step_names[suspend_stats.failed_steps[last_step]]);
for (i = 1; i < REC_FAILED_NUM; i++) {
index = last_step + REC_FAILED_NUM - i;
index %= REC_FAILED_NUM;
seq_printf(s, "\t\t\t%-s\n",
- suspend_step_name(
- suspend_stats.failed_steps[index]));
+ suspend_step_names[suspend_stats.failed_steps[index]]);
}

return 0;