timer: Remove redundant __setup_timer*() macros

With __init_timer*() now matching __setup_timer*(), remove the redundant
internal interface, clean up the resulting definitions and add more
documentation.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 20 insertions, 36 deletions

diff --git a/include/linux/timer.h b/include/linux/timer.h
index aff73b1c8f7b..b1ae64b112c2 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -78,6 +78,9 @@ struct timer_list {
         struct timer_list _name =                               \
                 __TIMER_INITIALIZER((TIMER_FUNC_TYPE)_function, 0)
 
+/*
+ * LOCKDEP and DEBUG timer interfaces.
+ */
 void init_timer_key(struct timer_list *timer,
                     void (*func)(struct timer_list *), unsigned int flags,
                     const char *name, struct lock_class_key *key);
@@ -87,9 +90,7 @@ extern void init_timer_on_stack_key(struct timer_list *timer,
                                     void (*func)(struct timer_list *),
                                     unsigned int flags, const char *name,
                                     struct lock_class_key *key);
-extern void destroy_timer_on_stack(struct timer_list *timer);
 #else
-static inline void destroy_timer_on_stack(struct timer_list *timer) { }
 static inline void init_timer_on_stack_key(struct timer_list *timer,
                                            void (*func)(struct timer_list *),
                                            unsigned int flags,
@@ -120,43 +121,26 @@ static inline void init_timer_on_stack_key(struct timer_list *timer,
         init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
 #endif
 
-#define __setup_timer(_timer, _fn, _flags)                              \
-        do {                                                            \
-                __init_timer((_timer), (_fn), (_flags));                \
-        } while (0)
-
-#define __setup_timer_on_stack(_timer, _fn, _flags)                     \
-        do {                                                            \
-                __init_timer_on_stack((_timer), (_fn), (_flags));       \
-        } while (0)
+/**
+ * timer_setup - prepare a timer for first use
+ * @timer: the timer in question
+ * @callback: the function to call when timer expires
+ * @flags: any TIMER_* flags
+ *
+ * Regular timer initialization should use either DEFINE_TIMER() above,
+ * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
+ * be used and must be balanced with a call to destroy_timer_on_stack().
+ */
+#define timer_setup(timer, callback, flags)                     \
+        __init_timer((timer), (callback), (flags))
 
-#ifndef CONFIG_LOCKDEP
-static inline void timer_setup(struct timer_list *timer,
-                               void (*callback)(struct timer_list *),
-                               unsigned int flags)
-{
-        __setup_timer(timer, (TIMER_FUNC_TYPE)callback, flags);
-}
+#define timer_setup_on_stack(timer, callback, flags)            \
+        __init_timer_on_stack((timer), (callback), (flags))
 
-static inline void timer_setup_on_stack(struct timer_list *timer,
-                               void (*callback)(struct timer_list *),
-                               unsigned int flags)
-{
-        __setup_timer_on_stack(timer, (TIMER_FUNC_TYPE)callback, flags);
-}
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+extern void destroy_timer_on_stack(struct timer_list *timer);
 #else
-/*
- * Under LOCKDEP, the timer lock_class_key (set up in __init_timer) needs
- * to be tied to the caller's context, so an inline (above) won't work. We
- * do want to keep the inline for argument type checking, though.
- */
-# define timer_setup(timer, callback, flags)                            \
-                __setup_timer((timer), (TIMER_FUNC_TYPE)(callback),     \
-                              (flags))
-# define timer_setup_on_stack(timer, callback, flags)                   \
-                __setup_timer_on_stack((timer),                         \
-                                       (TIMER_FUNC_TYPE)(callback),     \
-                                       (flags))
+static inline void destroy_timer_on_stack(struct timer_list *timer) { }
 #endif
 
 #define from_timer(var, callback_timer, timer_fieldname) \