[PATCH] hrtimer: create generic sleeper

The removal of the data field in the hrtimer structure enforces the
embedding of the timer into another data structure.  nanosleep now uses a
private implementation of the most common used timer callback function
(simple task wakeup).

In order to avoid the reimplentation of such functionality all over the
place a generic hrtimer_sleeper functionality is created.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 93830158348e..b20939287613 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -58,6 +58,19 @@ struct hrtimer {
 };
 
 /**
+ * struct hrtimer_sleeper - simple sleeper structure
+ *
+ * @timer:      embedded timer structure
+ * @task:       task to wake up
+ *
+ * task is set to NULL, when the timer expires.
+ */
+struct hrtimer_sleeper {
+        struct hrtimer timer;
+        struct task_struct *task;
+};
+
+/**
  * struct hrtimer_base - the timer base for a specific clock
  *
  * @index:              clock type index for per_cpu support when moving a timer
@@ -127,6 +140,9 @@ extern long hrtimer_nanosleep(struct timespec *rqtp,
                               const enum hrtimer_mode mode,
                               const clockid_t clockid);
 
+extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
+                                 struct task_struct *tsk);
+
 /* Soft interrupt function to run the hrtimer queues: */
 extern void hrtimer_run_queues(void);
 
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 0237a556eb1f..877cdf9678bf 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -656,6 +656,25 @@ void hrtimer_run_queues(void)
  * Sleep related functions:
  */
 
+static int hrtimer_wakeup(struct hrtimer *timer)
+{
+        struct hrtimer_sleeper *t =
+                container_of(timer, struct hrtimer_sleeper, timer);
+        struct task_struct *task = t->task;
+
+        t->task = NULL;
+        if (task)
+                wake_up_process(task);
+
+        return HRTIMER_NORESTART;
+}
+
+void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, task_t *task)
+{
+        sl->timer.function = hrtimer_wakeup;
+        sl->task = task;
+}
+
 struct sleep_hrtimer {
         struct hrtimer timer;
         struct task_struct *task;