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Commit 4dfbb9d8 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Dmitry Torokhov
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Lockdep: add lockdep_set_class_and_subclass() and lockdep_set_subclass() 



This annotation makes it possible to assign a subclass on lock init. This
annotation is meant to reduce the _nested() annotations by assigning a
default subclass.

One could do without this annotation and rely on lockdep_set_class()
exclusively, but that would require a manual stack of struct lock_class_key
objects.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 86255d9d

include/linux/lockdep.h

+11 −4
Original line number Diff line number Diff line
@@ -202,7 +202,7 @@ extern int lockdep_internal(void); 
 */



extern void lockdep_init_map(struct lockdep_map *lock, const char *name,

			     struct lock_class_key *key);

			     struct lock_class_key *key, int subclass);



/*

 * Reinitialize a lock key - for cases where there is special locking or
@@ -211,9 +211,14 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 
 * or they are too narrow (they suffer from a false class-split):

 */

#define lockdep_set_class(lock, key) \

		lockdep_init_map(&(lock)->dep_map, #key, key)

		lockdep_init_map(&(lock)->dep_map, #key, key, 0)

#define lockdep_set_class_and_name(lock, key, name) \

		lockdep_init_map(&(lock)->dep_map, name, key)

		lockdep_init_map(&(lock)->dep_map, name, key, 0)

#define lockdep_set_class_and_subclass(lock, key, sub) \

		lockdep_init_map(&(lock)->dep_map, #key, key, sub)

#define lockdep_set_subclass(lock, sub)	\

		lockdep_init_map(&(lock)->dep_map, #lock, \

				 (lock)->dep_map.key, sub)



/*

 * Acquire a lock.
@@ -257,10 +262,12 @@ static inline int lockdep_internal(void) 
# define lock_release(l, n, i)			do { } while (0)

# define lockdep_init()				do { } while (0)

# define lockdep_info()				do { } while (0)

# define lockdep_init_map(lock, name, key)	do { (void)(key); } while (0)

# define lockdep_init_map(lock, name, key, sub)	do { (void)(key); } while (0)

# define lockdep_set_class(lock, key)		do { (void)(key); } while (0)

# define lockdep_set_class_and_name(lock, key, name) \

		do { (void)(key); } while (0)

#define lockdep_set_class_and_subclass(lock, key, sub) \

		do { (void)(key); } while (0)

# define INIT_LOCKDEP

# define lockdep_reset()		do { debug_locks = 1; } while (0)

# define lockdep_free_key_range(start, size)	do { } while (0)

kernel/lockdep.c

+6 −4
Original line number Diff line number Diff line
@@ -1177,7 +1177,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) 
 * itself, so actual lookup of the hash should be once per lock object.

 */

static inline struct lock_class *

register_lock_class(struct lockdep_map *lock, unsigned int subclass)

register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)

{

	struct lockdep_subclass_key *key;

	struct list_head *hash_head;
@@ -1249,7 +1249,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass) 
out_unlock_set:

	__raw_spin_unlock(&hash_lock);



	if (!subclass)

	if (!subclass || force)

		lock->class_cache = class;



	DEBUG_LOCKS_WARN_ON(class->subclass != subclass);
@@ -1937,7 +1937,7 @@ void trace_softirqs_off(unsigned long ip) 
 * Initialize a lock instance's lock-class mapping info:

 */

void lockdep_init_map(struct lockdep_map *lock, const char *name,

		      struct lock_class_key *key)

		      struct lock_class_key *key, int subclass)

{

	if (unlikely(!debug_locks))

		return;
@@ -1957,6 +1957,8 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, 
	lock->name = name;

	lock->key = key;

	lock->class_cache = NULL;

	if (subclass)

		register_lock_class(lock, subclass, 1);

}



EXPORT_SYMBOL_GPL(lockdep_init_map);
@@ -1995,7 +1997,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	 * Not cached yet or subclass?

	 */

	if (unlikely(!class)) {

		class = register_lock_class(lock, subclass);

		class = register_lock_class(lock, subclass, 0);

		if (!class)

			return 0;

	}

kernel/mutex-debug.c

+1 −1
Original line number Diff line number Diff line
@@ -91,7 +91,7 @@ void debug_mutex_init(struct mutex *lock, const char *name, 
	 * Make sure we are not reinitializing a held lock:

	 */

	debug_check_no_locks_freed((void *)lock, sizeof(*lock));

	lockdep_init_map(&lock->dep_map, name, key);

	lockdep_init_map(&lock->dep_map, name, key, 0);

#endif

	lock->owner = NULL;

	lock->magic = lock;

lib/rwsem-spinlock.c

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, 
	 * Make sure we are not reinitializing a held semaphore:

	 */

	debug_check_no_locks_freed((void *)sem, sizeof(*sem));

	lockdep_init_map(&sem->dep_map, name, key);

	lockdep_init_map(&sem->dep_map, name, key, 0);

#endif

	sem->activity = 0;

	spin_lock_init(&sem->wait_lock);

lib/rwsem.c

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, 
	 * Make sure we are not reinitializing a held semaphore:

	 */

	debug_check_no_locks_freed((void *)sem, sizeof(*sem));

	lockdep_init_map(&sem->dep_map, name, key);

	lockdep_init_map(&sem->dep_map, name, key, 0);

#endif

	sem->count = RWSEM_UNLOCKED_VALUE;

	spin_lock_init(&sem->wait_lock);