[mirror_ubuntu-bionic-kernel.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;
	char *str = buf;
	char *end = buf + PAGE_SIZE;

	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)
			str += scnprintf(str, end - str, "%s ", wl->name);
	}
	if (str > buf)
		str--;

	str += scnprintf(str, end - str, "\n");

	mutex_unlock(&wakelocks_lock);
	return (str - buf);
}

#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_remove(&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.name = wl->name;
	wakeup_source_add(&wl->ws);
	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;
	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;
	42	char *str = buf;
	43	char *end = buf + PAGE_SIZE;
	44
	45	mutex_lock(&wakelocks_lock);
	46
	47	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
	48	wl = rb_entry(node, struct wakelock, node);
	49	if (wl->ws.active == show_active)
	50	str += scnprintf(str, end - str, "%s ", wl->name);
	51	}
	52	if (str > buf)
	53	str--;
	54
	55	str += scnprintf(str, end - str, "\n");
	56
	57	mutex_unlock(&wakelocks_lock);
	58	return (str - buf);
	59	}
	60
c73893e2 RW	61	#if CONFIG_PM_WAKELOCKS_LIMIT > 0
	62	static unsigned int number_of_wakelocks;
	63
	64	static inline bool wakelocks_limit_exceeded(void)
	65	{
	66	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
	67	}
	68
	69	static inline void increment_wakelocks_number(void)
	70	{
	71	number_of_wakelocks++;
	72	}
	73
	74	static inline void decrement_wakelocks_number(void)
	75	{
	76	number_of_wakelocks--;
	77	}
	78	#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
	79	static inline bool wakelocks_limit_exceeded(void) { return false; }
	80	static inline void increment_wakelocks_number(void) {}
	81	static inline void decrement_wakelocks_number(void) {}
	82	#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
	83
4e585d25 RW	84	#ifdef CONFIG_PM_WAKELOCKS_GC
	85	#define WL_GC_COUNT_MAX 100
	86	#define WL_GC_TIME_SEC 300
	87
6ce12a97	88	static void __wakelocks_gc(struct work_struct *work);
4e585d25	89	static LIST_HEAD(wakelocks_lru_list);
6ce12a97	90	static DECLARE_WORK(wakelock_work, __wakelocks_gc);
4e585d25 RW	91	static unsigned int wakelocks_gc_count;
	92
	93	static inline void wakelocks_lru_add(struct wakelock *wl)
	94	{
	95	list_add(&wl->lru, &wakelocks_lru_list);
	96	}
	97
	98	static inline void wakelocks_lru_most_recent(struct wakelock *wl)
	99	{
	100	list_move(&wl->lru, &wakelocks_lru_list);
	101	}
	102
6ce12a97	103	static void __wakelocks_gc(struct work_struct *work)
4e585d25 RW	104	{
	105	struct wakelock wl, aux;
	106	ktime_t now;
	107
6ce12a97	108	mutex_lock(&wakelocks_lock);
4e585d25 RW	109
	110	now = ktime_get();
	111	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
	112	u64 idle_time_ns;
	113	bool active;
	114
	115	spin_lock_irq(&wl->ws.lock);
	116	idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
	117	active = wl->ws.active;
	118	spin_unlock_irq(&wl->ws.lock);
	119
	120	if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
	121	break;
	122
	123	if (!active) {
	124	wakeup_source_remove(&wl->ws);
	125	rb_erase(&wl->node, &wakelocks_tree);
	126	list_del(&wl->lru);
	127	kfree(wl->name);
	128	kfree(wl);
	129	decrement_wakelocks_number();
	130	}
	131	}
	132	wakelocks_gc_count = 0;
6ce12a97 SK	133
	134	mutex_unlock(&wakelocks_lock);
	135	}
	136
	137	static void wakelocks_gc(void)
	138	{
	139	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
	140	return;
	141
	142	schedule_work(&wakelock_work);
4e585d25 RW	143	}
	144	#else /* !CONFIG_PM_WAKELOCKS_GC */
	145	static inline void wakelocks_lru_add(struct wakelock *wl) {}
	146	static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
	147	static inline void wakelocks_gc(void) {}
	148	#endif /* !CONFIG_PM_WAKELOCKS_GC */
	149
b86ff982 RW	150	static struct wakelock wakelock_lookup_add(const char name, size_t len,
	151	bool add_if_not_found)
	152	{
	153	struct rb_node **node = &wakelocks_tree.rb_node;
	154	struct rb_node parent = node;
	155	struct wakelock *wl;
	156
	157	while (*node) {
	158	int diff;
	159
	160	parent = *node;
	161	wl = rb_entry(*node, struct wakelock, node);
	162	diff = strncmp(name, wl->name, len);
	163	if (diff == 0) {
	164	if (wl->name[len])
	165	diff = -1;
	166	else
	167	return wl;
	168	}
	169	if (diff < 0)
	170	node = &(*node)->rb_left;
	171	else
	172	node = &(*node)->rb_right;
	173	}
	174	if (!add_if_not_found)
	175	return ERR_PTR(-EINVAL);
	176
c73893e2	177	if (wakelocks_limit_exceeded())
b86ff982 RW	178	return ERR_PTR(-ENOSPC);
	179
	180	/* Not found, we have to add a new one. */
	181	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
	182	if (!wl)
	183	return ERR_PTR(-ENOMEM);
	184
	185	wl->name = kstrndup(name, len, GFP_KERNEL);
	186	if (!wl->name) {
	187	kfree(wl);
	188	return ERR_PTR(-ENOMEM);
	189	}
	190	wl->ws.name = wl->name;
	191	wakeup_source_add(&wl->ws);
	192	rb_link_node(&wl->node, parent, node);
	193	rb_insert_color(&wl->node, &wakelocks_tree);
4e585d25	194	wakelocks_lru_add(wl);
c73893e2	195	increment_wakelocks_number();
b86ff982 RW	196	return wl;
	197	}
	198
	199	int pm_wake_lock(const char *buf)
	200	{
	201	const char *str = buf;
	202	struct wakelock *wl;
	203	u64 timeout_ns = 0;
	204	size_t len;
	205	int ret = 0;
	206
11388c87 RW	207	if (!capable(CAP_BLOCK_SUSPEND))
	208	return -EPERM;
	209
b86ff982 RW	210	while (str && !isspace(str))
	211	str++;
	212
	213	len = str - buf;
	214	if (!len)
	215	return -EINVAL;
	216
	217	if (str && str != '\n') {
	218	/* Find out if there's a valid timeout string appended. */
	219	ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
	220	if (ret)
	221	return -EINVAL;
	222	}
	223
	224	mutex_lock(&wakelocks_lock);
	225
	226	wl = wakelock_lookup_add(buf, len, true);
	227	if (IS_ERR(wl)) {
	228	ret = PTR_ERR(wl);
	229	goto out;
	230	}
	231	if (timeout_ns) {
	232	u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
	233
	234	do_div(timeout_ms, NSEC_PER_MSEC);
	235	__pm_wakeup_event(&wl->ws, timeout_ms);
	236	} else {
	237	__pm_stay_awake(&wl->ws);
	238	}
	239
4e585d25	240	wakelocks_lru_most_recent(wl);
b86ff982 RW	241
	242	out:
	243	mutex_unlock(&wakelocks_lock);
	244	return ret;
	245	}
	246
b86ff982 RW	247	int pm_wake_unlock(const char *buf)
	248	{
	249	struct wakelock *wl;
	250	size_t len;
	251	int ret = 0;
	252
11388c87 RW	253	if (!capable(CAP_BLOCK_SUSPEND))
	254	return -EPERM;
	255
b86ff982 RW	256	len = strlen(buf);
	257	if (!len)
	258	return -EINVAL;
	259
	260	if (buf[len-1] == '\n')
	261	len--;
	262
	263	if (!len)
	264	return -EINVAL;
	265
	266	mutex_lock(&wakelocks_lock);
	267
	268	wl = wakelock_lookup_add(buf, len, false);
	269	if (IS_ERR(wl)) {
	270	ret = PTR_ERR(wl);
	271	goto out;
	272	}
	273	__pm_relax(&wl->ws);
4e585d25 RW	274
	275	wakelocks_lru_most_recent(wl);
	276	wakelocks_gc();
b86ff982 RW	277
	278	out:
	279	mutex_unlock(&wakelocks_lock);
	280	return ret;
	281	}