Commit b7d39aff authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

lockdep: spin_lock_nest_lock() 



Expose the new lock protection lock.

This can be used to annotate places where we take multiple locks of the
same class and avoid deadlocks by always taking another (top-level) lock
first.

NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7531e2f3

include/linux/lockdep.h

+2 −0
Original line number Diff line number Diff line
@@ -410,8 +410,10 @@ static inline void print_irqtrace_events(struct task_struct *curr) 
#ifdef CONFIG_DEBUG_LOCK_ALLOC

# ifdef CONFIG_PROVE_LOCKING

#  define spin_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)

#  define spin_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 2, n, i)

# else

#  define spin_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)

#  define spin_acquire_nest(l, s, t, n, i)	lock_acquire(l, s, t, 0, 1, NULL, i)

# endif

# define spin_release(l, n, i)			lock_release(l, n, i)

#else

include/linux/spinlock.h

+6 −0
Original line number Diff line number Diff line
@@ -183,8 +183,14 @@ do { \ 


#ifdef CONFIG_DEBUG_LOCK_ALLOC

# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)

# define spin_lock_nest_lock(lock, nest_lock)				\

	 do {								\

		 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\

		 _spin_lock_nest_lock(lock, &(nest_lock)->dep_map);	\

	 } while (0)

#else

# define spin_lock_nested(lock, subclass) _spin_lock(lock)

# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)

#endif



#define write_lock(lock)		_write_lock(lock)

include/linux/spinlock_api_smp.h

+2 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ int in_lock_functions(unsigned long addr); 
void __lockfunc _spin_lock(spinlock_t *lock)		__acquires(lock);

void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)

							__acquires(lock);

void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *map)

							__acquires(lock);

void __lockfunc _read_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _write_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _spin_lock_bh(spinlock_t *lock)		__acquires(lock);

kernel/spinlock.c

+11 −0
Original line number Diff line number Diff line
@@ -292,6 +292,7 @@ void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) 
}



EXPORT_SYMBOL(_spin_lock_nested);



unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)

{

	unsigned long flags;
@@ -314,6 +315,16 @@ unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclas 


EXPORT_SYMBOL(_spin_lock_irqsave_nested);



void __lockfunc _spin_lock_nest_lock(spinlock_t *lock,

				     struct lockdep_map *nest_lock)

{

	preempt_disable();

	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);

	LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);

}



EXPORT_SYMBOL(_spin_lock_nest_lock);



#endif



void __lockfunc _spin_unlock(spinlock_t *lock)

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