[PATCH 08/13] PM: Add user-space wake lock api.

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This adds /sys/power/wake_lock and /sys/power/wake_unlock.Writing a string to wake_lock creates a wake lock thefirst time is sees a string and locks it. Optionally, thestring can be followed by a timeout.To unlock the wake lock, write the same string to wake_unlock.
Signed-off-by: Arve Hjønnevåg <arve@xxxxxxxxxxx>--- kernel/power/Kconfig        |   10 ++ kernel/power/Makefile       |    1 + kernel/power/main.c         |    9 ++ kernel/power/power.h        |   11 ++ kernel/power/userwakelock.c |  218 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 249 insertions(+), 0 deletions(-) create mode 100644 kernel/power/userwakelock.c
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfigindex 689abfe..aedea7e 100644--- a/kernel/power/Kconfig+++ b/kernel/power/Kconfig@@ -147,6 +147,16 @@ config DISABLE_SYS_POWER_STATE 	  want to run user-space code that does not support wakelocks, do not 	  enable this option since it removes the interface. +config USER_WAKELOCK+	bool "Userspace wake locks"+	depends on WAKELOCK+	default y+	---help---+	  User-space wake lock api. Write "lockname" or "lockname timeout"+	  to /sys/power/wake_lock lock and if needed create a wake lock.+	  Write "lockname" to /sys/power/wake_unlock to unlock a user wake+	  lock.+ config EARLYSUSPEND 	bool "Early suspend" 	depends on WAKELOCKdiff --git a/kernel/power/Makefile b/kernel/power/Makefileindex 2f17e1d..d3467b3 100644--- a/kernel/power/Makefile+++ b/kernel/power/Makefile@@ -7,6 +7,7 @@ obj-y				:= main.o obj-$(CONFIG_PM_SLEEP)		+= console.o obj-$(CONFIG_FREEZER)		+= process.o obj-$(CONFIG_WAKELOCK)		+= wakelock.o+obj-$(CONFIG_USER_WAKELOCK)	+= userwakelock.o obj-$(CONFIG_EARLYSUSPEND)	+= earlysuspend.o obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o diff --git a/kernel/power/main.c b/kernel/power/main.cindex 676a8b0..a4065f3 100644--- a/kernel/power/main.c+++ b/kernel/power/main.c@@ -641,6 +641,11 @@ pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr, power_attr(pm_trace); #endif /* CONFIG_PM_TRACE */ +#ifdef CONFIG_USER_WAKELOCK+power_attr(wake_lock);+power_attr(wake_unlock);+#endif+ static struct attribute * g[] = { #ifndef CONFIG_DISABLE_SYS_POWER_STATE 	&state_attr.attr,@@ -654,6 +659,10 @@ static struct attribute * g[] = { #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG) 	&pm_test_attr.attr, #endif+#ifdef CONFIG_USER_WAKELOCK+	&wake_lock_attr.attr,+	&wake_unlock_attr.attr,+#endif 	NULL, }; diff --git a/kernel/power/power.h b/kernel/power/power.hindex acbb13a..1b01327 100644--- a/kernel/power/power.h+++ b/kernel/power/power.h@@ -232,6 +232,17 @@ extern suspend_state_t requested_suspend_state; extern bool ignore_suspend_wakelocks; #endif +#ifdef CONFIG_USER_WAKELOCK+ssize_t wake_lock_show(struct kobject *kobj, struct kobj_attribute *attr,+			char *buf);+ssize_t wake_lock_store(struct kobject *kobj, struct kobj_attribute *attr,+			const char *buf, size_t n);+ssize_t wake_unlock_show(struct kobject *kobj, struct kobj_attribute *attr,+			char *buf);+ssize_t  wake_unlock_store(struct kobject *kobj, struct kobj_attribute *attr,+			const char *buf, size_t n);+#endif+ #ifdef CONFIG_EARLYSUSPEND /* kernel/power/earlysuspend.c */ void request_suspend_state(suspend_state_t state);diff --git a/kernel/power/userwakelock.c b/kernel/power/userwakelock.cnew file mode 100644index 0000000..d7242d9--- /dev/null+++ b/kernel/power/userwakelock.c@@ -0,0 +1,218 @@+/* kernel/power/userwakelock.c+ *+ * Copyright (C) 2005-2008 Google, Inc.+ *+ * This software is licensed under the terms of the GNU General Public+ * License version 2, as published by the Free Software Foundation, and+ * may be copied, distributed, and modified under those terms.+ *+ * This program is distributed in the hope that it will be useful,+ * but WITHOUT ANY WARRANTY; without even the implied warranty of+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the+ * GNU General Public License for more details.+ *+ */++#include <linux/ctype.h>+#include <linux/module.h>+#include <linux/wakelock.h>++#include "power.h"++enum {+	DEBUG_FAILURE	= BIT(0),+	DEBUG_ERROR	= BIT(1),+	DEBUG_NEW	= BIT(2),+	DEBUG_ACCESS	= BIT(3),+	DEBUG_LOOKUP	= BIT(4),+};+static int debug_mask = DEBUG_FAILURE;+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);++static DEFINE_MUTEX(tree_lock);++struct user_wake_lock {+	struct rb_node		node;+	struct wake_lock	wake_lock;+	char			name[0];+};+struct rb_root user_wake_locks;++static struct user_wake_lock *lookup_wake_lock_name(+	const char *buf, int allocate, long *timeoutptr)+{+	struct rb_node **p = &user_wake_locks.rb_node;+	struct rb_node *parent = NULL;+	struct user_wake_lock *l;+	int diff;+	u64 timeout;+	int name_len;+	const char *arg;++	/* Find length of lock name and start of optional timeout string */+	arg = buf;+	while (*arg && !isspace(*arg))+		arg++;+	name_len = arg - buf;+	if (!name_len)+		goto bad_arg;+	while (isspace(*arg))+		arg++;++	/* Process timeout string */+	if (timeoutptr && *arg) {+		timeout = simple_strtoull(arg, (char **)&arg, 0);+		while (isspace(*arg))+			arg++;+		if (*arg)+			goto bad_arg;+		/* convert timeout from nanoseconds to jiffies > 0 */+		timeout += (NSEC_PER_SEC / HZ) - 1;+		do_div(timeout, (NSEC_PER_SEC / HZ));+		if (timeout <= 0)+			timeout = 1;+		*timeoutptr = timeout;+	} else if (*arg)+		goto bad_arg;+	else if (timeoutptr)+		*timeoutptr = 0;++	/* Lookup wake lock in rbtree */+	while (*p) {+		parent = *p;+		l = rb_entry(parent, struct user_wake_lock, node);+		diff = strncmp(buf, l->name, name_len);+		if (!diff && l->name[name_len])+			diff = -1;+		if (debug_mask & DEBUG_ERROR)+			pr_info("lookup_wake_lock_name: compare %.*s %s %d\n",+				name_len, buf, l->name, diff);++		if (diff < 0)+			p = &(*p)->rb_left;+		else if (diff > 0)+			p = &(*p)->rb_right;+		else+			return l;+	}++	/* Allocate and add new wakelock to rbtree */+	if (!allocate) {+		if (debug_mask & DEBUG_ERROR)+			pr_info("lookup_wake_lock_name: %.*s not found\n",+				name_len, buf);+		return ERR_PTR(-EINVAL);+	}+	l = kzalloc(sizeof(*l) + name_len + 1, GFP_KERNEL);+	if (l == NULL) {+		if (debug_mask & DEBUG_FAILURE)+			pr_err("lookup_wake_lock_name: failed to allocate "+				"memory for %.*s\n", name_len, buf);+		return ERR_PTR(-ENOMEM);+	}+	memcpy(l->name, buf, name_len);+	if (debug_mask & DEBUG_NEW)+		pr_info("lookup_wake_lock_name: new wake lock %s\n", l->name);+	wake_lock_init(&l->wake_lock, WAKE_LOCK_SUSPEND, l->name);+	rb_link_node(&l->node, parent, p);+	rb_insert_color(&l->node, &user_wake_locks);+	return l;++bad_arg:+	if (debug_mask & DEBUG_ERROR)+		pr_info("lookup_wake_lock_name: wake lock, %.*s, bad arg, %s\n",+			name_len, buf, arg);+	return ERR_PTR(-EINVAL);+}++ssize_t wake_lock_show(+	struct kobject *kobj, struct kobj_attribute *attr, char *buf)+{+	char *s = buf;+	char *end = buf + PAGE_SIZE;+	struct rb_node *n;+	struct user_wake_lock *l;++	mutex_lock(&tree_lock);++	for (n = rb_first(&user_wake_locks); n != NULL; n = rb_next(n)) {+		l = rb_entry(n, struct user_wake_lock, node);+		if (wake_lock_active(&l->wake_lock))+			s += scnprintf(s, end - s, "%s ", l->name);+	}+	s += scnprintf(s, end - s, "\n");++	mutex_unlock(&tree_lock);+	return (s - buf);+}++ssize_t wake_lock_store(+	struct kobject *kobj, struct kobj_attribute *attr,+	const char *buf, size_t n)+{+	long timeout;+	struct user_wake_lock *l;++	mutex_lock(&tree_lock);+	l = lookup_wake_lock_name(buf, 1, &timeout);+	if (IS_ERR(l)) {+		n = PTR_ERR(l);+		goto bad_name;+	}++	if (debug_mask & DEBUG_ACCESS)+		pr_info("wake_lock_store: %s, timeout %ld\n", l->name, timeout);++	if (timeout)+		wake_lock_timeout(&l->wake_lock, timeout);+	else+		wake_lock(&l->wake_lock);+bad_name:+	mutex_unlock(&tree_lock);+	return n;+}+++ssize_t wake_unlock_show(+	struct kobject *kobj, struct kobj_attribute *attr, char *buf)+{+	char *s = buf;+	char *end = buf + PAGE_SIZE;+	struct rb_node *n;+	struct user_wake_lock *l;++	mutex_lock(&tree_lock);++	for (n = rb_first(&user_wake_locks); n != NULL; n = rb_next(n)) {+		l = rb_entry(n, struct user_wake_lock, node);+		if (!wake_lock_active(&l->wake_lock))+			s += scnprintf(s, end - s, "%s ", l->name);+	}+	s += scnprintf(s, end - s, "\n");++	mutex_unlock(&tree_lock);+	return (s - buf);+}++ssize_t wake_unlock_store(+	struct kobject *kobj, struct kobj_attribute *attr,+	const char *buf, size_t n)+{+	struct user_wake_lock *l;++	mutex_lock(&tree_lock);+	l = lookup_wake_lock_name(buf, 0, NULL);+	if (IS_ERR(l)) {+		n = PTR_ERR(l);+		goto not_found;+	}++	if (debug_mask & DEBUG_ACCESS)+		pr_info("wake_unlock_store: %s\n", l->name);++	wake_unlock(&l->wake_lock);+not_found:+	mutex_unlock(&tree_lock);+	return n;+}+-- 1.6.1
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