Commit 5261ced4 authored by Waiman Long's avatar Waiman Long Committed by Ingo Molnar
Browse files

locking/ww_mutex: Remove DEFINE_WW_MUTEX() macro 



The current DEFINE_WW_MUTEX() macro fails to properly set up the lockdep
key of the ww_mutexes causing potential circular locking dependency
splat. Though it is possible to add more macro magic to make it work,
but the result is rather ugly.

Since locktorture was the only user of DEFINE_WW_MUTEX() and the
previous commit has just removed its use. It is easier to just remove
the macro to force future users of ww_mutexes to use ww_mutex_init()
for initialization.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210318172814.4400-4-longman@redhat.com
parent 2ea55bbb

include/linux/ww_mutex.h

+2 −15
Original line number Diff line number Diff line
@@ -48,39 +48,26 @@ struct ww_acquire_ctx { 
#endif

};



#ifdef CONFIG_DEBUG_LOCK_ALLOC

# define __WW_CLASS_MUTEX_INITIALIZER(lockname, class) \

		, .ww_class = class

#else

# define __WW_CLASS_MUTEX_INITIALIZER(lockname, class)

#endif



#define __WW_CLASS_INITIALIZER(ww_class, _is_wait_die)	    \

		{ .stamp = ATOMIC_LONG_INIT(0) \

		, .acquire_name = #ww_class "_acquire" \

		, .mutex_name = #ww_class "_mutex" \

		, .is_wait_die = _is_wait_die }



#define __WW_MUTEX_INITIALIZER(lockname, class) \

		{ .base =  __MUTEX_INITIALIZER(lockname.base) \

		__WW_CLASS_MUTEX_INITIALIZER(lockname, class) }



#define DEFINE_WD_CLASS(classname) \

	struct ww_class classname = __WW_CLASS_INITIALIZER(classname, 1)



#define DEFINE_WW_CLASS(classname) \

	struct ww_class classname = __WW_CLASS_INITIALIZER(classname, 0)



#define DEFINE_WW_MUTEX(mutexname, ww_class) \

	struct ww_mutex mutexname = __WW_MUTEX_INITIALIZER(mutexname, ww_class)



/**

 * ww_mutex_init - initialize the w/w mutex

 * @lock: the mutex to be initialized

 * @ww_class: the w/w class the mutex should belong to

 *

 * Initialize the w/w mutex to unlocked state and associate it with the given

 * class.

 * class. Static define macro for w/w mutex is not provided and this function

 * is the only way to properly initialize the w/w mutex.

 *

 * It is not allowed to initialize an already locked mutex.

 */