[linux-2.6-block.git] / kernel / power / wakelock.c

// SPDX-License-Identifier: GPL-2.0
/*
 * kernel/power/wakelock.c
 *
 * User space wakeup sources support.
 *
 * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
 *
 * This code is based on the analogous interface allowing user space to
 * manipulate wakelocks on Android.
 */

#include <linux/capability.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "power.h"

static DEFINE_MUTEX(wakelocks_lock);

struct wakelock {
	char			*name;
	struct rb_node		node;
	struct wakeup_source	*ws;
#ifdef CONFIG_PM_WAKELOCKS_GC
	struct list_head	lru;
#endif
};

static struct rb_root wakelocks_tree = RB_ROOT;

ssize_t pm_show_wakelocks(char *buf, bool show_active)
{
	struct rb_node *node;
	struct wakelock *wl;
	int len = 0;

	mutex_lock(&wakelocks_lock);

	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
		wl = rb_entry(node, struct wakelock, node);
		if (wl->ws->active == show_active)
			len += sysfs_emit_at(buf, len, "%s ", wl->name);
	}

	len += sysfs_emit_at(buf, len, "\n");

	mutex_unlock(&wakelocks_lock);
	return len;
}

#if CONFIG_PM_WAKELOCKS_LIMIT > 0
static unsigned int number_of_wakelocks;

static inline bool wakelocks_limit_exceeded(void)
{
	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
}

static inline void increment_wakelocks_number(void)
{
	number_of_wakelocks++;
}

static inline void decrement_wakelocks_number(void)
{
	number_of_wakelocks--;
}
#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
static inline bool wakelocks_limit_exceeded(void) { return false; }
static inline void increment_wakelocks_number(void) {}
static inline void decrement_wakelocks_number(void) {}
#endif /* CONFIG_PM_WAKELOCKS_LIMIT */

#ifdef CONFIG_PM_WAKELOCKS_GC
#define WL_GC_COUNT_MAX	100
#define WL_GC_TIME_SEC	300

static void __wakelocks_gc(struct work_struct *work);
static LIST_HEAD(wakelocks_lru_list);
static DECLARE_WORK(wakelock_work, __wakelocks_gc);
static unsigned int wakelocks_gc_count;

static inline void wakelocks_lru_add(struct wakelock *wl)
{
	list_add(&wl->lru, &wakelocks_lru_list);
}

static inline void wakelocks_lru_most_recent(struct wakelock *wl)
{
	list_move(&wl->lru, &wakelocks_lru_list);
}

static void __wakelocks_gc(struct work_struct *work)
{
	struct wakelock *wl, *aux;
	ktime_t now;

	mutex_lock(&wakelocks_lock);

	now = ktime_get();
	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
		u64 idle_time_ns;
		bool active;

		spin_lock_irq(&wl->ws->lock);
		idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
		active = wl->ws->active;
		spin_unlock_irq(&wl->ws->lock);

		if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
			break;

		if (!active) {
			wakeup_source_unregister(wl->ws);
			rb_erase(&wl->node, &wakelocks_tree);
			list_del(&wl->lru);
			kfree(wl->name);
			kfree(wl);
			decrement_wakelocks_number();
		}
	}
	wakelocks_gc_count = 0;

	mutex_unlock(&wakelocks_lock);
}

static void wakelocks_gc(void)
{
	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
		return;

	schedule_work(&wakelock_work);
}
#else /* !CONFIG_PM_WAKELOCKS_GC */
static inline void wakelocks_lru_add(struct wakelock *wl) {}
static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
static inline void wakelocks_gc(void) {}
#endif /* !CONFIG_PM_WAKELOCKS_GC */

static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
					    bool add_if_not_found)
{
	struct rb_node **node = &wakelocks_tree.rb_node;
	struct rb_node *parent = *node;
	struct wakelock *wl;

	while (*node) {
		int diff;

		parent = *node;
		wl = rb_entry(*node, struct wakelock, node);
		diff = strncmp(name, wl->name, len);
		if (diff == 0) {
			if (wl->name[len])
				diff = -1;
			else
				return wl;
		}
		if (diff < 0)
			node = &(*node)->rb_left;
		else
			node = &(*node)->rb_right;
	}
	if (!add_if_not_found)
		return ERR_PTR(-EINVAL);

	if (wakelocks_limit_exceeded())
		return ERR_PTR(-ENOSPC);

	/* Not found, we have to add a new one. */
	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	if (!wl)
		return ERR_PTR(-ENOMEM);

	wl->name = kstrndup(name, len, GFP_KERNEL);
	if (!wl->name) {
		kfree(wl);
		return ERR_PTR(-ENOMEM);
	}

	wl->ws = wakeup_source_register(NULL, wl->name);
	if (!wl->ws) {
		kfree(wl->name);
		kfree(wl);
		return ERR_PTR(-ENOMEM);
	}
	wl->ws->last_time = ktime_get();

	rb_link_node(&wl->node, parent, node);
	rb_insert_color(&wl->node, &wakelocks_tree);
	wakelocks_lru_add(wl);
	increment_wakelocks_number();
	return wl;
}

int pm_wake_lock(const char *buf)
{
	const char *str = buf;
	struct wakelock *wl;
	u64 timeout_ns = 0;
	size_t len;
	int ret = 0;

	if (!capable(CAP_BLOCK_SUSPEND))
		return -EPERM;

	while (*str && !isspace(*str))
		str++;

	len = str - buf;
	if (!len)
		return -EINVAL;

	if (*str && *str != '\n') {
		/* Find out if there's a valid timeout string appended. */
		ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
		if (ret)
			return -EINVAL;
	}

	mutex_lock(&wakelocks_lock);

	wl = wakelock_lookup_add(buf, len, true);
	if (IS_ERR(wl)) {
		ret = PTR_ERR(wl);
		goto out;
	}
	if (timeout_ns) {
		u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;

		do_div(timeout_ms, NSEC_PER_MSEC);
		__pm_wakeup_event(wl->ws, timeout_ms);
	} else {
		__pm_stay_awake(wl->ws);
	}

	wakelocks_lru_most_recent(wl);

 out:
	mutex_unlock(&wakelocks_lock);
	return ret;
}

int pm_wake_unlock(const char *buf)
{
	struct wakelock *wl;
	size_t len;
	int ret = 0;

	if (!capable(CAP_BLOCK_SUSPEND))
		return -EPERM;

	len = strlen(buf);
	if (!len)
		return -EINVAL;

	if (buf[len-1] == '\n')
		len--;

	if (!len)
		return -EINVAL;

	mutex_lock(&wakelocks_lock);

	wl = wakelock_lookup_add(buf, len, false);
	if (IS_ERR(wl)) {
		ret = PTR_ERR(wl);
		goto out;
	}
	__pm_relax(wl->ws);

	wakelocks_lru_most_recent(wl);
	wakelocks_gc();

 out:
	mutex_unlock(&wakelocks_lock);
	return ret;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
b86ff982 RW	2	/*
	3	* kernel/power/wakelock.c
	4	*
	5	* User space wakeup sources support.
	6	*
	7	* Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
	8	*
	9	* This code is based on the analogous interface allowing user space to
	10	* manipulate wakelocks on Android.
	11	*/
	12
11388c87	13	#include <linux/capability.h>
b86ff982 RW	14	#include <linux/ctype.h>
	15	#include <linux/device.h>
	16	#include <linux/err.h>
	17	#include <linux/hrtimer.h>
	18	#include <linux/list.h>
	19	#include <linux/rbtree.h>
	20	#include <linux/slab.h>
6ce12a97	21	#include <linux/workqueue.h>
b86ff982	22
6c5be291 RK	23	#include "power.h"
6c5be291 RK	24
b86ff982 RW	25	static DEFINE_MUTEX(wakelocks_lock);
	26
	27	struct wakelock {
	28	char *name;
	29	struct rb_node node;
2434aea5	30	struct wakeup_source *ws;
4e585d25	31	#ifdef CONFIG_PM_WAKELOCKS_GC
b86ff982	32	struct list_head lru;
4e585d25	33	#endif
b86ff982 RW	34	};
	35
	36	static struct rb_root wakelocks_tree = RB_ROOT;
b86ff982 RW	37
	38	ssize_t pm_show_wakelocks(char *buf, bool show_active)
	39	{
	40	struct rb_node *node;
	41	struct wakelock *wl;
c9d967b2	42	int len = 0;
b86ff982 RW	43
	44	mutex_lock(&wakelocks_lock);
	45
	46	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
	47	wl = rb_entry(node, struct wakelock, node);
2434aea5	48	if (wl->ws->active == show_active)
c9d967b2	49	len += sysfs_emit_at(buf, len, "%s ", wl->name);
b86ff982	50	}
b86ff982	51
c9d967b2	52	len += sysfs_emit_at(buf, len, "\n");
b86ff982 RW	53
b86ff982 RW	54	mutex_unlock(&wakelocks_lock);
c9d967b2	55	return len;
b86ff982 RW	56	}
b86ff982 RW	57
c73893e2 RW	58	#if CONFIG_PM_WAKELOCKS_LIMIT > 0
	59	static unsigned int number_of_wakelocks;
	60
	61	static inline bool wakelocks_limit_exceeded(void)
	62	{
	63	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
	64	}
	65
	66	static inline void increment_wakelocks_number(void)
	67	{
	68	number_of_wakelocks++;
	69	}
	70
	71	static inline void decrement_wakelocks_number(void)
	72	{
	73	number_of_wakelocks--;
	74	}
	75	#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
	76	static inline bool wakelocks_limit_exceeded(void) { return false; }
	77	static inline void increment_wakelocks_number(void) {}
	78	static inline void decrement_wakelocks_number(void) {}
	79	#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
	80
4e585d25 RW	81	#ifdef CONFIG_PM_WAKELOCKS_GC
	82	#define WL_GC_COUNT_MAX 100
	83	#define WL_GC_TIME_SEC 300
	84
6ce12a97	85	static void __wakelocks_gc(struct work_struct *work);
4e585d25	86	static LIST_HEAD(wakelocks_lru_list);
6ce12a97	87	static DECLARE_WORK(wakelock_work, __wakelocks_gc);
4e585d25 RW	88	static unsigned int wakelocks_gc_count;
	89
	90	static inline void wakelocks_lru_add(struct wakelock *wl)
	91	{
	92	list_add(&wl->lru, &wakelocks_lru_list);
	93	}
	94
	95	static inline void wakelocks_lru_most_recent(struct wakelock *wl)
	96	{
	97	list_move(&wl->lru, &wakelocks_lru_list);
	98	}
	99
6ce12a97	100	static void __wakelocks_gc(struct work_struct *work)
4e585d25 RW	101	{
	102	struct wakelock wl, aux;
	103	ktime_t now;
	104
6ce12a97	105	mutex_lock(&wakelocks_lock);
4e585d25 RW	106
	107	now = ktime_get();
	108	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
	109	u64 idle_time_ns;
	110	bool active;
	111
2434aea5 TV	112	spin_lock_irq(&wl->ws->lock);
	113	idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
	114	active = wl->ws->active;
	115	spin_unlock_irq(&wl->ws->lock);
4e585d25 RW	116
	117	if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
	118	break;
	119
	120	if (!active) {
2434aea5	121	wakeup_source_unregister(wl->ws);
4e585d25 RW	122	rb_erase(&wl->node, &wakelocks_tree);
	123	list_del(&wl->lru);
	124	kfree(wl->name);
	125	kfree(wl);
	126	decrement_wakelocks_number();
	127	}
	128	}
	129	wakelocks_gc_count = 0;
6ce12a97 SK	130
	131	mutex_unlock(&wakelocks_lock);
	132	}
	133
	134	static void wakelocks_gc(void)
	135	{
	136	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
	137	return;
	138
	139	schedule_work(&wakelock_work);
4e585d25 RW	140	}
	141	#else /* !CONFIG_PM_WAKELOCKS_GC */
	142	static inline void wakelocks_lru_add(struct wakelock *wl) {}
	143	static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
	144	static inline void wakelocks_gc(void) {}
	145	#endif /* !CONFIG_PM_WAKELOCKS_GC */
	146
b86ff982 RW	147	static struct wakelock wakelock_lookup_add(const char name, size_t len,
	148	bool add_if_not_found)
	149	{
	150	struct rb_node **node = &wakelocks_tree.rb_node;
	151	struct rb_node parent = node;
	152	struct wakelock *wl;
	153
	154	while (*node) {
	155	int diff;
	156
	157	parent = *node;
	158	wl = rb_entry(*node, struct wakelock, node);
	159	diff = strncmp(name, wl->name, len);
	160	if (diff == 0) {
	161	if (wl->name[len])
	162	diff = -1;
	163	else
	164	return wl;
	165	}
	166	if (diff < 0)
	167	node = &(*node)->rb_left;
	168	else
	169	node = &(*node)->rb_right;
	170	}
	171	if (!add_if_not_found)
	172	return ERR_PTR(-EINVAL);
	173
c73893e2	174	if (wakelocks_limit_exceeded())
b86ff982 RW	175	return ERR_PTR(-ENOSPC);
	176
	177	/* Not found, we have to add a new one. */
	178	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	179	if (!wl)
	180	return ERR_PTR(-ENOMEM);
	181
	182	wl->name = kstrndup(name, len, GFP_KERNEL);
	183	if (!wl->name) {
	184	kfree(wl);
	185	return ERR_PTR(-ENOMEM);
	186	}
2434aea5	187
c8377adf	188	wl->ws = wakeup_source_register(NULL, wl->name);
2434aea5 TV	189	if (!wl->ws) {
	190	kfree(wl->name);
	191	kfree(wl);
	192	return ERR_PTR(-ENOMEM);
	193	}
	194	wl->ws->last_time = ktime_get();
	195
b86ff982 RW	196	rb_link_node(&wl->node, parent, node);
b86ff982 RW	197	rb_insert_color(&wl->node, &wakelocks_tree);
4e585d25	198	wakelocks_lru_add(wl);
c73893e2	199	increment_wakelocks_number();
b86ff982 RW	200	return wl;
	201	}
	202
	203	int pm_wake_lock(const char *buf)
	204	{
	205	const char *str = buf;
	206	struct wakelock *wl;
	207	u64 timeout_ns = 0;
	208	size_t len;
	209	int ret = 0;
	210
11388c87 RW	211	if (!capable(CAP_BLOCK_SUSPEND))
	212	return -EPERM;
	213
b86ff982 RW	214	while (str && !isspace(str))
	215	str++;
	216
	217	len = str - buf;
	218	if (!len)
	219	return -EINVAL;
	220
	221	if (str && str != '\n') {
	222	/* Find out if there's a valid timeout string appended. */
	223	ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
	224	if (ret)
	225	return -EINVAL;
	226	}
	227
	228	mutex_lock(&wakelocks_lock);
	229
	230	wl = wakelock_lookup_add(buf, len, true);
	231	if (IS_ERR(wl)) {
	232	ret = PTR_ERR(wl);
	233	goto out;
	234	}
	235	if (timeout_ns) {
	236	u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
	237
	238	do_div(timeout_ms, NSEC_PER_MSEC);
2434aea5	239	__pm_wakeup_event(wl->ws, timeout_ms);
b86ff982	240	} else {
2434aea5	241	__pm_stay_awake(wl->ws);
b86ff982 RW	242	}
b86ff982 RW	243
4e585d25	244	wakelocks_lru_most_recent(wl);
b86ff982 RW	245
	246	out:
	247	mutex_unlock(&wakelocks_lock);
	248	return ret;
	249	}
	250
b86ff982 RW	251	int pm_wake_unlock(const char *buf)
	252	{
	253	struct wakelock *wl;
	254	size_t len;
	255	int ret = 0;
	256
11388c87 RW	257	if (!capable(CAP_BLOCK_SUSPEND))
	258	return -EPERM;
	259
b86ff982 RW	260	len = strlen(buf);
	261	if (!len)
	262	return -EINVAL;
	263
	264	if (buf[len-1] == '\n')
	265	len--;
	266
	267	if (!len)
	268	return -EINVAL;
	269
	270	mutex_lock(&wakelocks_lock);
	271
	272	wl = wakelock_lookup_add(buf, len, false);
	273	if (IS_ERR(wl)) {
	274	ret = PTR_ERR(wl);
	275	goto out;
	276	}
2434aea5	277	__pm_relax(wl->ws);
4e585d25 RW	278
	279	wakelocks_lru_most_recent(wl);
	280	wakelocks_gc();
b86ff982 RW	281
	282	out:
	283	mutex_unlock(&wakelocks_lock);
	284	return ret;
	285	}