Re: [PATCH RT 2/2] rtmutex: Remove duplicate rt_mutex_init()

From: Steven Rostedt
Date: Fri May 02 2014 - 09:12:23 EST


On Fri, 2 May 2014 11:08:31 +0200
Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:

> * Steven Rostedt | 2014-04-08 22:47:02 [-0400]:
>
> >From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
> >
> >The rt_mutex_init() macro is the same whether or not
> >CONFIG_DEBUG_RT_MUTEX is set. Remove the duplicate.
> >
> >Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
>
> This does not apply cleanly on v3.14-rt

That's because I sent this out before 3.14-rt was released :-)

>
> >--- a/include/linux/rtmutex.h
> >+++ b/include/linux/rtmutex.h
> >@@ -62,25 +62,19 @@ struct hrtimer_sleeper;
> > # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
> > , .name = #mutexname, .file = __FILE__, .line = __LINE__
> >
> >-# define rt_mutex_init(mutex) \
> >- do { \
> >- raw_spin_lock_init(&(mutex)->wait_lock); \
> >- __rt_mutex_init(mutex, #mutex); \
> >- } while (0)
> >-
>
> The macro is the same in CONFIG_DEBUG_RT_MUTEXES and the else path.
> Shouldn't you remove both and define it before the ifdef?

That's exactly what the patch did! Except that it defined it *after* the ifdef.

Here's the patch again (as it was cut in the reply):

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -62,25 +62,19 @@ struct hrtimer_sleeper;
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
, .name = #mutexname, .file = __FILE__, .line = __LINE__

-# define rt_mutex_init(mutex) \
- do { \
- raw_spin_lock_init(&(mutex)->wait_lock); \
- __rt_mutex_init(mutex, #mutex); \
- } while (0)
-
extern void rt_mutex_debug_task_free(struct task_struct *tsk);
#else
# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)

+# define rt_mutex_debug_task_free(t) do { } while (0)
+#endif
+
# define rt_mutex_init(mutex) \
do { \
raw_spin_lock_init(&(mutex)->wait_lock); \
__rt_mutex_init(mutex, #mutex); \
} while (0)

-# define rt_mutex_debug_task_free(t) do { } while (0)
-#endif
-
#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
, .wait_list = PLIST_HEAD_INIT(mutexname.wait_list) \

Take special note of the movement of the "#endif".

-- Steve



> There are some
> users of this:
> |drivers/i2c/i2c-core.c: rt_mutex_init(&adap->bus_lock);
> |drivers/media/usb/em28xx/em28xx-cards.c: rt_mutex_init(&dev->i2c_bus_lock);
>
> Sebastian

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