BugLink: http://bugs.launchpad.net/bugs/601057

In some cases (for instance with kernel threads) it may be desireable to
use on-stack deferrable timers to get their power saving benefits. Add
interfaces to support this for the IPS driver.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
(cherry picked from commit 8cadd2831bf3abc94f4530e7fdbab7bb39b6b27d)

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
---
include/linux/timer.h | 15 +++++++++++++++
kernel/timer.c | 13 +++++++++++++
2 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/include/linux/timer.h b/include/linux/timer.h
index ea965b8..38cf093 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -100,6 +100,13 @@ void init_timer_deferrable_key(struct timer_list *timer,
setup_timer_on_stack_key((timer), #timer, &__key,
(fn), (data));
} while (0)
+#define setup_deferrable_timer_on_stack(timer, fn, data)
+ do {
+ static struct lock_class_key __key;
+ setup_deferrable_timer_on_stack_key((timer), #timer,
+ &__key, (fn),
+ (data));
+ } while (0)
#else
#define init_timer(timer)
init_timer_key((timer), NULL, NULL)
@@ -111,6 +118,8 @@ void init_timer_deferrable_key(struct timer_list *timer,
setup_timer_key((timer), NULL, NULL, (fn), (data))
#define setup_timer_on_stack(timer, fn, data)
setup_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
+#define setup_deferrable_timer_on_stack(timer, fn, data)
+ setup_deferrable_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
#endif

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
@@ -150,6 +159,12 @@ static inline void setup_timer_on_stack_key(struct timer_list *timer,
init_timer_on_stack_key(timer, name, key);
}

+extern void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
+ const char *name,
+ struct lock_class_key *key,
+ void (*function)(unsigned long),
+ unsigned long data);
+
/**
* timer_pending - is a timer pending?
* @timer: the timer in question
diff --git a/kernel/timer.c b/kernel/timer.c
index ee305c8..efde11e 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -577,6 +577,19 @@ static void __init_timer(struct timer_list *timer,
lockdep_init_map(&timer->lockdep_map, name, key, 0);
}

+void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
+ const char *name,
+ struct lock_class_key *key,
+ void (*function)(unsigned long),
+ unsigned long data)
+{
+ timer->function = function;
+ timer->data = data;
+ init_timer_on_stack_key(timer, name, key);
+ timer_set_deferrable(timer);
+}
+EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack _key);
+
/**
* init_timer_key - initialize a timer
* @timer: the timer to be initialized
--
1.7.0.4


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