--- /dev/null
+/*
+ * 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 "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 LIST_HEAD(wakelocks_lru_list);
+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(void)
+{
+ struct wakelock *wl, *aux;
+ ktime_t now;
+
+ if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
+ return;
+
+ 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;
+}
+#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;
+}
Code Review / kvmfornfv.git / blobdiff