Merge tag 'pm-for-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:

 - Implementation of opportunistic suspend (autosleep) and user space
   interface for manipulating wakeup sources.

 - Hibernate updates from Bojan Smojver and Minho Ban.

 - Updates of the runtime PM core and generic PM domains framework
   related to PM QoS.

 - Assorted fixes.

* tag 'pm-for-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (25 commits)
  epoll: Fix user space breakage related to EPOLLWAKEUP
  PM / Domains: Make it possible to add devices to inactive domains
  PM / Hibernate: Use get_gendisk to verify partition if resume_file is integer format
  PM / Domains: Fix computation of maximum domain off time
  PM / Domains: Fix link checking when add subdomain
  PM / Sleep: User space wakeup sources garbage collector Kconfig option
  PM / Sleep: Make the limit of user space wakeup sources configurable
  PM / Documentation: suspend-and-cpuhotplug.txt: Fix typo
  PM / Domains: Cache device stop and domain power off governor results, v3
  PM / Domains: Make device removal more straightforward
  PM / Sleep: Fix a mistake in a conditional in autosleep_store()
  epoll: Add a flag, EPOLLWAKEUP, to prevent suspend while epoll events are ready
  PM / QoS: Create device constraints objects on notifier registration
  PM / Runtime: Remove device fields related to suspend time, v2
  PM / Domains: Rework default domain power off governor function, v2
  PM / Domains: Rework default device stop governor function, v2
  PM / Sleep: Add user space interface for manipulating wakeup sources, v3
  PM / Sleep: Add "prevent autosleep time" statistics to wakeup sources
  PM / Sleep: Implement opportunistic sleep, v2
  PM / Sleep: Add wakeup_source_activate and wakeup_source_deactivate tracepoints
  ...

8 files changed, 635 insertions, 42 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index deb5461e3216..8f9b4eb974e0 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -103,6 +103,33 @@ config PM_SLEEP_SMP
         select HOTPLUG
         select HOTPLUG_CPU
 
+config PM_AUTOSLEEP
+        bool "Opportunistic sleep"
+        depends on PM_SLEEP
+        default n
+        ---help---
+        Allow the kernel to trigger a system transition into a global sleep
+        state automatically whenever there are no active wakeup sources.
+
+config PM_WAKELOCKS
+        bool "User space wakeup sources interface"
+        depends on PM_SLEEP
+        default n
+        ---help---
+        Allow user space to create, activate and deactivate wakeup source
+        objects with the help of a sysfs-based interface.
+
+config PM_WAKELOCKS_LIMIT
+        int "Maximum number of user space wakeup sources (0 = no limit)"
+        range 0 100000
+        default 100
+        depends on PM_WAKELOCKS
+
+config PM_WAKELOCKS_GC
+        bool "Garbage collector for user space wakeup sources"
+        depends on PM_WAKELOCKS
+        default y
+
 config PM_RUNTIME
         bool "Run-time PM core functionality"
         depends on !IA64_HP_SIM
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 66d808ec5252..29472bff11ef 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -9,5 +9,7 @@ obj-$(CONFIG_SUSPEND)		+= suspend.o
 obj-$(CONFIG_PM_TEST_SUSPEND)   += suspend_test.o
 obj-$(CONFIG_HIBERNATION)       += hibernate.o snapshot.o swap.o user.o \
                                    block_io.o
+obj-$(CONFIG_PM_AUTOSLEEP)      += autosleep.o
+obj-$(CONFIG_PM_WAKELOCKS)      += wakelock.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)       += poweroff.o
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
new file mode 100644
index 000000000000..ca304046d9e2
--- /dev/null
+++ b/kernel/power/autosleep.c
@@ -0,0 +1,127 @@
+/*
+ * kernel/power/autosleep.c
+ *
+ * Opportunistic sleep support.
+ *
+ * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm_wakeup.h>
+
+#include "power.h"
+
+static suspend_state_t autosleep_state;
+static struct workqueue_struct *autosleep_wq;
+/*
+ * Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
+ * is active, otherwise a deadlock with try_to_suspend() is possible.
+ * Alternatively mutex_lock_interruptible() can be used.  This will then fail
+ * if an auto_sleep cycle tries to freeze processes.
+ */
+static DEFINE_MUTEX(autosleep_lock);
+static struct wakeup_source *autosleep_ws;
+
+static void try_to_suspend(struct work_struct *work)
+{
+        unsigned int initial_count, final_count;
+
+        if (!pm_get_wakeup_count(&initial_count, true))
+                goto out;
+
+        mutex_lock(&autosleep_lock);
+
+        if (!pm_save_wakeup_count(initial_count)) {
+                mutex_unlock(&autosleep_lock);
+                goto out;
+        }
+
+        if (autosleep_state == PM_SUSPEND_ON) {
+                mutex_unlock(&autosleep_lock);
+                return;
+        }
+        if (autosleep_state >= PM_SUSPEND_MAX)
+                hibernate();
+        else
+                pm_suspend(autosleep_state);
+
+        mutex_unlock(&autosleep_lock);
+
+        if (!pm_get_wakeup_count(&final_count, false))
+                goto out;
+
+        /*
+         * If the wakeup occured for an unknown reason, wait to prevent the
+         * system from trying to suspend and waking up in a tight loop.
+         */
+        if (final_count == initial_count)
+                schedule_timeout_uninterruptible(HZ / 2);
+
+ out:
+        queue_up_suspend_work();
+}
+
+static DECLARE_WORK(suspend_work, try_to_suspend);
+
+void queue_up_suspend_work(void)
+{
+        if (!work_pending(&suspend_work) && autosleep_state > PM_SUSPEND_ON)
+                queue_work(autosleep_wq, &suspend_work);
+}
+
+suspend_state_t pm_autosleep_state(void)
+{
+        return autosleep_state;
+}
+
+int pm_autosleep_lock(void)
+{
+        return mutex_lock_interruptible(&autosleep_lock);
+}
+
+void pm_autosleep_unlock(void)
+{
+        mutex_unlock(&autosleep_lock);
+}
+
+int pm_autosleep_set_state(suspend_state_t state)
+{
+
+#ifndef CONFIG_HIBERNATION
+        if (state >= PM_SUSPEND_MAX)
+                return -EINVAL;
+#endif
+
+        __pm_stay_awake(autosleep_ws);
+
+        mutex_lock(&autosleep_lock);
+
+        autosleep_state = state;
+
+        __pm_relax(autosleep_ws);
+
+        if (state > PM_SUSPEND_ON) {
+                pm_wakep_autosleep_enabled(true);
+                queue_up_suspend_work();
+        } else {
+                pm_wakep_autosleep_enabled(false);
+        }
+
+        mutex_unlock(&autosleep_lock);
+        return 0;
+}
+
+int __init pm_autosleep_init(void)
+{
+        autosleep_ws = wakeup_source_register("autosleep");
+        if (!autosleep_ws)
+                return -ENOMEM;
+
+        autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
+        if (autosleep_wq)
+                return 0;
+
+        wakeup_source_unregister(autosleep_ws);
+        return -ENOMEM;
+}
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e09dfbfeecee..8b53db38a279 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -25,6 +25,8 @@
 #include <linux/freezer.h>
 #include <linux/gfp.h>
 #include <linux/syscore_ops.h>
+#include <linux/ctype.h>
+#include <linux/genhd.h>
 #include <scsi/scsi_scan.h>
 
 #include "power.h"
@@ -722,6 +724,17 @@ static int software_resume(void)
 
         /* Check if the device is there */
         swsusp_resume_device = name_to_dev_t(resume_file);
+
+        /*
+         * name_to_dev_t is ineffective to verify parition if resume_file is in
+         * integer format. (e.g. major:minor)
+         */
+        if (isdigit(resume_file[0]) && resume_wait) {
+                int partno;
+                while (!get_gendisk(swsusp_resume_device, &partno))
+                        msleep(10);
+        }
+
         if (!swsusp_resume_device) {
                 /*
                  * Some device discovery might still be in progress; we need
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 1c12581f1c62..428f8a034e96 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -269,8 +269,7 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
         return (s - buf);
 }
 
-static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
-                           const char *buf, size_t n)
+static suspend_state_t decode_state(const char *buf, size_t n)
 {
 #ifdef CONFIG_SUSPEND
         suspend_state_t state = PM_SUSPEND_STANDBY;
@@ -278,27 +277,48 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 #endif
         char *p;
         int len;
-        int error = -EINVAL;
 
         p = memchr(buf, '\n', n);
         len = p ? p - buf : n;
 
-        /* First, check if we are requested to hibernate */
-        if (len == 4 && !strncmp(buf, "disk", len)) {
-                error = hibernate();
-                goto Exit;
-        }
+        /* Check hibernation first. */
+        if (len == 4 && !strncmp(buf, "disk", len))
+                return PM_SUSPEND_MAX;
 
 #ifdef CONFIG_SUSPEND
-        for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
-                if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
-                        error = pm_suspend(state);
-                        break;
-                }
-        }
+        for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
+                if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
+                        return state;
 #endif
 
- Exit:
+        return PM_SUSPEND_ON;
+}
+
+static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
+                           const char *buf, size_t n)
+{
+        suspend_state_t state;
+        int error;
+
+        error = pm_autosleep_lock();
+        if (error)
+                return error;
+
+        if (pm_autosleep_state() > PM_SUSPEND_ON) {
+                error = -EBUSY;
+                goto out;
+        }
+
+        state = decode_state(buf, n);
+        if (state < PM_SUSPEND_MAX)
+                error = pm_suspend(state);
+        else if (state == PM_SUSPEND_MAX)
+                error = hibernate();
+        else
+                error = -EINVAL;
+
+ out:
+        pm_autosleep_unlock();
         return error ? error : n;
 }
 
@@ -339,7 +359,8 @@ static ssize_t wakeup_count_show(struct kobject *kobj,
 {
         unsigned int val;
 
-        return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
+        return pm_get_wakeup_count(&val, true) ?
+                sprintf(buf, "%u\n", val) : -EINTR;
 }
 
 static ssize_t wakeup_count_store(struct kobject *kobj,
@@ -347,15 +368,106 @@ static ssize_t wakeup_count_store(struct kobject *kobj,
                                 const char *buf, size_t n)
 {
         unsigned int val;
+        int error;
+
+        error = pm_autosleep_lock();
+        if (error)
+                return error;
+
+        if (pm_autosleep_state() > PM_SUSPEND_ON) {
+                error = -EBUSY;
+                goto out;
+        }
 
+        error = -EINVAL;
         if (sscanf(buf, "%u", &val) == 1) {
                 if (pm_save_wakeup_count(val))
-                        return n;
+                        error = n;
         }
-        return -EINVAL;
+
+ out:
+        pm_autosleep_unlock();
+        return error;
 }
 
 power_attr(wakeup_count);
+
+#ifdef CONFIG_PM_AUTOSLEEP
+static ssize_t autosleep_show(struct kobject *kobj,
+                              struct kobj_attribute *attr,
+                              char *buf)
+{
+        suspend_state_t state = pm_autosleep_state();
+
+        if (state == PM_SUSPEND_ON)
+                return sprintf(buf, "off\n");
+
+#ifdef CONFIG_SUSPEND
+        if (state < PM_SUSPEND_MAX)
+                return sprintf(buf, "%s\n", valid_state(state) ?
+                                                pm_states[state] : "error");
+#endif
+#ifdef CONFIG_HIBERNATION
+        return sprintf(buf, "disk\n");
+#else
+        return sprintf(buf, "error");
+#endif
+}
+
+static ssize_t autosleep_store(struct kobject *kobj,
+                               struct kobj_attribute *attr,
+                               const char *buf, size_t n)
+{
+        suspend_state_t state = decode_state(buf, n);
+        int error;
+
+        if (state == PM_SUSPEND_ON
+            && strcmp(buf, "off") && strcmp(buf, "off\n"))
+                return -EINVAL;
+
+        error = pm_autosleep_set_state(state);
+        return error ? error : n;
+}
+
+power_attr(autosleep);
+#endif /* CONFIG_PM_AUTOSLEEP */
+
+#ifdef CONFIG_PM_WAKELOCKS
+static ssize_t wake_lock_show(struct kobject *kobj,
+                              struct kobj_attribute *attr,
+                              char *buf)
+{
+        return pm_show_wakelocks(buf, true);
+}
+
+static ssize_t wake_lock_store(struct kobject *kobj,
+                               struct kobj_attribute *attr,
+                               const char *buf, size_t n)
+{
+        int error = pm_wake_lock(buf);
+        return error ? error : n;
+}
+
+power_attr(wake_lock);
+
+static ssize_t wake_unlock_show(struct kobject *kobj,
+                                struct kobj_attribute *attr,
+                                char *buf)
+{
+        return pm_show_wakelocks(buf, false);
+}
+
+static ssize_t wake_unlock_store(struct kobject *kobj,
+                                 struct kobj_attribute *attr,
+                                 const char *buf, size_t n)
+{
+        int error = pm_wake_unlock(buf);
+        return error ? error : n;
+}
+
+power_attr(wake_unlock);
+
+#endif /* CONFIG_PM_WAKELOCKS */
 #endif /* CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_PM_TRACE
@@ -409,6 +521,13 @@ static struct attribute * g[] = {
 #ifdef CONFIG_PM_SLEEP
         &pm_async_attr.attr,
         &wakeup_count_attr.attr,
+#ifdef CONFIG_PM_AUTOSLEEP
+        &autosleep_attr.attr,
+#endif
+#ifdef CONFIG_PM_WAKELOCKS
+        &wake_lock_attr.attr,
+        &wake_unlock_attr.attr,
+#endif
 #ifdef CONFIG_PM_DEBUG
         &pm_test_attr.attr,
 #endif
@@ -444,7 +563,10 @@ static int __init pm_init(void)
         power_kobj = kobject_create_and_add("power", NULL);
         if (!power_kobj)
                 return -ENOMEM;
-        return sysfs_create_group(power_kobj, &attr_group);
+        error = sysfs_create_group(power_kobj, &attr_group);
+        if (error)
+                return error;
+        return pm_autosleep_init();
 }
 
 core_initcall(pm_init);
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 98f3622d7407..b0bd4beaebfe 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -264,3 +264,30 @@ static inline void suspend_thaw_processes(void)
 {
 }
 #endif
+
+#ifdef CONFIG_PM_AUTOSLEEP
+
+/* kernel/power/autosleep.c */
+extern int pm_autosleep_init(void);
+extern int pm_autosleep_lock(void);
+extern void pm_autosleep_unlock(void);
+extern suspend_state_t pm_autosleep_state(void);
+extern int pm_autosleep_set_state(suspend_state_t state);
+
+#else /* !CONFIG_PM_AUTOSLEEP */
+
+static inline int pm_autosleep_init(void) { return 0; }
+static inline int pm_autosleep_lock(void) { return 0; }
+static inline void pm_autosleep_unlock(void) {}
+static inline suspend_state_t pm_autosleep_state(void) { return PM_SUSPEND_ON; }
+
+#endif /* !CONFIG_PM_AUTOSLEEP */
+
+#ifdef CONFIG_PM_WAKELOCKS
+
+/* kernel/power/wakelock.c */
+extern ssize_t pm_show_wakelocks(char *buf, bool show_active);
+extern int pm_wake_lock(const char *buf);
+extern int pm_wake_unlock(const char *buf);
+
+#endif /* !CONFIG_PM_WAKELOCKS */
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index eef311a58a64..11e22c068e8b 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -6,7 +6,7 @@
  *
  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
- * Copyright (C) 2010 Bojan Smojver <bojan@rexursive.com>
+ * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
  *
  * This file is released under the GPLv2.
  *
@@ -282,14 +282,17 @@ static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
                 return -ENOSPC;
 
         if (bio_chain) {
-                src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+                src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
+                                              __GFP_NORETRY);
                 if (src) {
                         copy_page(src, buf);
                 } else {
                         ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
                         if (ret)
                                 return ret;
-                        src = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+                        src = (void *)__get_free_page(__GFP_WAIT |
+                                                      __GFP_NOWARN |
+                                                      __GFP_NORETRY);
                         if (src) {
                                 copy_page(src, buf);
                         } else {
@@ -367,12 +370,17 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
                 clear_page(handle->cur);
                 handle->cur_swap = offset;
                 handle->k = 0;
-        }
-        if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
-                error = hib_wait_on_bio_chain(bio_chain);
-                if (error)
-                        goto out;
-                handle->reqd_free_pages = reqd_free_pages();
+
+                if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
+                        error = hib_wait_on_bio_chain(bio_chain);
+                        if (error)
+                                goto out;
+                        /*
+                         * Recalculate the number of required free pages, to
+                         * make sure we never take more than half.
+                         */
+                        handle->reqd_free_pages = reqd_free_pages();
+                }
         }
  out:
         return error;
@@ -419,8 +427,9 @@ static int swap_writer_finish(struct swap_map_handle *handle,
 /* Maximum number of threads for compression/decompression. */
 #define LZO_THREADS     3
 
-/* Maximum number of pages for read buffering. */
-#define LZO_READ_PAGES  (MAP_PAGE_ENTRIES * 8)
+/* Minimum/maximum number of pages for read buffering. */
+#define LZO_MIN_RD_PAGES        1024
+#define LZO_MAX_RD_PAGES        8192
 
 
 /**
@@ -631,12 +640,6 @@ static int save_image_lzo(struct swap_map_handle *handle,
         }
 
         /*
-         * Adjust number of free pages after all allocations have been done.
-         * We don't want to run out of pages when writing.
-         */
-        handle->reqd_free_pages = reqd_free_pages();
-
-        /*
          * Start the CRC32 thread.
          */
         init_waitqueue_head(&crc->go);
@@ -657,6 +660,12 @@ static int save_image_lzo(struct swap_map_handle *handle,
                 goto out_clean;
         }
 
+        /*
+         * Adjust the number of required free pages after all allocations have
+         * been done. We don't want to run out of pages when writing.
+         */
+        handle->reqd_free_pages = reqd_free_pages();
+
         printk(KERN_INFO
                 "PM: Using %u thread(s) for compression.\n"
                 "PM: Compressing and saving image data (%u pages) ...     ",
@@ -1067,7 +1076,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
         unsigned i, thr, run_threads, nr_threads;
         unsigned ring = 0, pg = 0, ring_size = 0,
                  have = 0, want, need, asked = 0;
-        unsigned long read_pages;
+        unsigned long read_pages = 0;
         unsigned char **page = NULL;
         struct dec_data *data = NULL;
         struct crc_data *crc = NULL;
@@ -1079,7 +1088,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
         nr_threads = num_online_cpus() - 1;
         nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
 
-        page = vmalloc(sizeof(*page) * LZO_READ_PAGES);
+        page = vmalloc(sizeof(*page) * LZO_MAX_RD_PAGES);
         if (!page) {
                 printk(KERN_ERR "PM: Failed to allocate LZO page\n");
                 ret = -ENOMEM;
@@ -1144,15 +1153,22 @@ static int load_image_lzo(struct swap_map_handle *handle,
         }
 
         /*
-         * Adjust number of pages for read buffering, in case we are short.
+         * Set the number of pages for read buffering.
+         * This is complete guesswork, because we'll only know the real
+         * picture once prepare_image() is called, which is much later on
+         * during the image load phase. We'll assume the worst case and
+         * say that none of the image pages are from high memory.
          */
-        read_pages = (nr_free_pages() - snapshot_get_image_size()) >> 1;
-        read_pages = clamp_val(read_pages, LZO_CMP_PAGES, LZO_READ_PAGES);
+        if (low_free_pages() > snapshot_get_image_size())
+                read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
+        read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
 
         for (i = 0; i < read_pages; i++) {
                 page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
                                                   __GFP_WAIT | __GFP_HIGH :
-                                                  __GFP_WAIT);
+                                                  __GFP_WAIT | __GFP_NOWARN |
+                                                  __GFP_NORETRY);
+
                 if (!page[i]) {
                         if (i < LZO_CMP_PAGES) {
                                 ring_size = i;
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
new file mode 100644
index 000000000000..c8fba3380076
--- /dev/null
+++ b/kernel/power/wakelock.c
@@ -0,0 +1,259 @@
+/*
+ * 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/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>
+
+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;
+
+        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;
+
+        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;
+}