[PATCH 6/6] typesafe: TIMER_INITIALIZER and setup_timer

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From: Rusty Russell
Date: Sunday, April 20, 2008 - 4:10 pm

This patch lets timer callback functions have their natural type
(ie. exactly match the data pointer type); it allows the old "unsigned
long data" type as well.

Downside: if you use the old "unsigned long" callback type, you won't
get a warning if your data is not an unsigned long, due to the cast.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/timer.h |   24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff -r 1a72bd2d9ea6 include/linux/timer.h
--- a/include/linux/timer.h	Mon Apr 21 07:04:32 2008 +1000
+++ b/include/linux/timer.h	Mon Apr 21 07:28:46 2008 +1000
@@ -24,11 +24,21 @@ struct timer_list {
 
 extern struct tvec_base boot_tvec_bases;
 
-#define TIMER_INITIALIZER(_function, _expires, _data) {		\
-		.function = (_function),			\
-		.expires = (_expires),				\
-		.data = (_data),				\
-		.base = &boot_tvec_bases,			\
+/*
+ * For historic reasons the timer function takes an unsigned long, so
+ * we use this variant of typesafe_cb.  data is converted to an unsigned long
+ * if it is another integer type, by adding 0UL.
+ */
+#define typesafe_timerfn(fn, data)				\
+	__typesafe_cb(void (*)(unsigned long), (fn),		\
+		      void (*)(const typeof((data)+0UL)),	\
+		      void (*)(typeof((data)+0UL)))
+
+#define TIMER_INITIALIZER(_function, _expires, _data) {			\
+		.function = typesafe_timerfn((_function), (_data)),	\
+		.expires = (_expires),					\
+		.data = (unsigned long)(_data),				\
+		.base = &boot_tvec_bases,				\
 	}
 
 #define DEFINE_TIMER(_name, _function, _expires, _data)		\
@@ -38,9 +48,13 @@ void init_timer(struct timer_list *timer
 void init_timer(struct timer_list *timer);
 void init_timer_deferrable(struct timer_list *timer);
 
-static inline void setup_timer(struct timer_list * timer,
-				void (*function)(unsigned long),
-				unsigned long data)
+#define setup_timer(timer, function, data)				\
+	__setup_timer((timer), typesafe_timerfn((function), (data)),	\
+		      (unsigned long)(data))
+
+static inline void __setup_timer(struct timer_list * timer,
+				 void (*function)(unsigned long),
+				 unsigned long data)
 {
 	timer->function = function;
 	timer->data = data;
--
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Messages in current thread:
[PATCH 0/6] typesafe callbacks, Rusty Russell, (Sun Apr 20, 3:58 pm)
[PATCH 2/6] typesafe_cb: wrappers for typesafe callbacks., Rusty Russell, (Sun Apr 20, 4:01 pm)
[PATCH 3/6] typesafe: Convert stop_machine, Rusty Russell, (Sun Apr 20, 4:05 pm)
[PATCH 4/6] typesafe: kthread_create and kthread_run, Rusty Russell, (Sun Apr 20, 4:07 pm)
[PATCH 5/6] typesafe: request_irq and devm_request_irq, Rusty Russell, (Sun Apr 20, 4:09 pm)
[PATCH 6/6] typesafe: TIMER_INITIALIZER and setup_timer, Rusty Russell, (Sun Apr 20, 4:10 pm)