linux-kernel - [PATCH 1/2] PM / Sleep: Make the limit of user space wakeup sources configurable

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Message-Id: <201205032130.41519.rjw@sisk.pl>
Date:	Thu, 3 May 2012 21:30:41 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Arve Hjønnevåg <arve@...roid.com>
Cc:	NeilBrown <neilb@...e.de>, John Stultz <johnstul@...ibm.com>,
	Linux PM list <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Magnus Damm <magnus.damm@...il.com>, markgross@...gnar.org,
	Matthew Garrett <mjg@...hat.com>,
	Greg KH <gregkh@...uxfoundation.org>,
	John Stultz <john.stultz@...aro.org>,
	Brian Swetland <swetland@...gle.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
Subject: [PATCH 1/2] PM / Sleep: Make the limit of user space wakeup sources configurable

From: Rafael J. Wysocki <rjw@...k.pl>

Make it possible to configure out the check against the limit of
user space wakeup sources for debugging and default Android builds.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 kernel/power/Kconfig    |    6 ++++++
 kernel/power/wakelock.c |   31 ++++++++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 5 deletions(-)

Index: linux/kernel/power/Kconfig
===================================================================
--- linux.orig/kernel/power/Kconfig
+++ linux/kernel/power/Kconfig
@@ -119,6 +119,12 @@ config PM_WAKELOCKS
 	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_RUNTIME
 	bool "Run-time PM core functionality"
 	depends on !IA64_HP_SIM
Index: linux/kernel/power/wakelock.c
===================================================================
--- linux.orig/kernel/power/wakelock.c
+++ linux/kernel/power/wakelock.c
@@ -17,7 +17,6 @@
 #include <linux/rbtree.h>
 #include <linux/slab.h>
 
-#define WL_NUMBER_LIMIT	100
 #define WL_GC_COUNT_MAX	100
 #define WL_GC_TIME_SEC	300
 
@@ -32,7 +31,6 @@ struct wakelock {
 
 static struct rb_root wakelocks_tree = RB_ROOT;
 static LIST_HEAD(wakelocks_lru_list);
-static unsigned int number_of_wakelocks;
 static unsigned int wakelocks_gc_count;
 
 ssize_t pm_show_wakelocks(char *buf, bool show_active)
@@ -58,6 +56,29 @@ ssize_t pm_show_wakelocks(char *buf, boo
 	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 */
+
 static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
 					    bool add_if_not_found)
 {
@@ -85,7 +106,7 @@ static struct wakelock *wakelock_lookup_
 	if (!add_if_not_found)
 		return ERR_PTR(-EINVAL);
 
-	if (number_of_wakelocks > WL_NUMBER_LIMIT)
+	if (wakelocks_limit_exceeded())
 		return ERR_PTR(-ENOSPC);
 
 	/* Not found, we have to add a new one. */
@@ -103,7 +124,7 @@ static struct wakelock *wakelock_lookup_
 	rb_link_node(&wl->node, parent, node);
 	rb_insert_color(&wl->node, &wakelocks_tree);
 	list_add(&wl->lru, &wakelocks_lru_list);
-	number_of_wakelocks++;
+	increment_wakelocks_number();
 	return wl;
 }
 
@@ -175,7 +196,7 @@ static void wakelocks_gc(void)
 			list_del(&wl->lru);
 			kfree(wl->name);
 			kfree(wl);
-			number_of_wakelocks--;
+			decrement_wakelocks_number();
 		}
 	}
 	wakelocks_gc_count = 0;

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