PM / Sleep: Make the limit of user space wakeup sources configurable

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@sisk.pl>
Acked-by: Arve Hjønnevåg <arve@android.com>

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

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, bool show_active)
 	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_add(const char *name, size_t len,
 	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_add(const char *name, size_t len,
 	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;