Commit fb9edbe9 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

lockdep: Make held_lock->check and "int check" argument bool 



The "int check" argument of lock_acquire() and held_lock->check are
misleading. This is actually a boolean: 2 means "true", everything
else is "false".

And there is no need to pass 1 or 0 to lock_acquire() depending on
CONFIG_PROVE_LOCKING, __lock_acquire() checks prove_locking at the
start and clears "check" if !CONFIG_PROVE_LOCKING.

Note: probably we can simply kill this member/arg. The only explicit
user of check => 0 is rcu_lock_acquire(), perhaps we can change it to
use lock_acquire(trylock =>, read => 2). __lockdep_no_validate means
check => 0 implicitly, but we can change validate_chain() to check
hlock->instance->key instead. Not to mention it would be nice to get
rid of lockdep_set_novalidate_class().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140120182006.GA26495@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ddf1d169

drivers/tty/tty_ldsem.c

+4 −11
Original line number Diff line number Diff line
@@ -39,17 +39,10 @@ 
				lock_acquire(&(l)->dep_map, s, t, r, c, n, i)

# define __rel(l, n, i)				\

				lock_release(&(l)->dep_map, n, i)

# ifdef CONFIG_PROVE_LOCKING

#  define lockdep_acquire(l, s, t, i)		__acq(l, s, t, 0, 2, NULL, i)

#  define lockdep_acquire_nest(l, s, t, n, i)	__acq(l, s, t, 0, 2, n, i)

#  define lockdep_acquire_read(l, s, t, i)	__acq(l, s, t, 1, 2, NULL, i)

#  define lockdep_release(l, n, i)		__rel(l, n, i)

# else

#define lockdep_acquire(l, s, t, i)		__acq(l, s, t, 0, 1, NULL, i)

#define lockdep_acquire_nest(l, s, t, n, i)	__acq(l, s, t, 0, 1, n, i)

#define lockdep_acquire_read(l, s, t, i)	__acq(l, s, t, 1, 1, NULL, i)

#define lockdep_release(l, n, i)		__rel(l, n, i)

# endif

#else

# define lockdep_acquire(l, s, t, i)		do { } while (0)

# define lockdep_acquire_nest(l, s, t, n, i)	do { } while (0)

include/linux/lockdep.h

+9 −16
Original line number Diff line number Diff line
@@ -252,9 +252,9 @@ struct held_lock { 
	unsigned int trylock:1;						/* 16 bits */



	unsigned int read:2;        /* see lock_acquire() comment */

	unsigned int check:2;       /* see lock_acquire() comment */

	unsigned int check:1;       /* see lock_acquire() comment */

	unsigned int hardirqs_off:1;

	unsigned int references:11;					/* 32 bits */

	unsigned int references:12;					/* 32 bits */

};



/*
@@ -326,9 +326,8 @@ static inline int lockdep_match_key(struct lockdep_map *lock, 
 *

 * Values for check:

 *

 *   0: disabled

 *   1: simple checks (freeing, held-at-exit-time, etc.)

 *   2: full validation

 *   0: simple checks (freeing, held-at-exit-time, etc.)

 *   1: full validation

 */

extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,

			 int trylock, int read, int check,
@@ -479,15 +478,9 @@ static inline void print_irqtrace_events(struct task_struct *curr) 
 * on the per lock-class debug mode:

 */



#ifdef CONFIG_PROVE_LOCKING

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

 #define lock_acquire_shared(l, s, t, n, i)		lock_acquire(l, s, t, 1, 2, n, i)

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

#else

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

#define lock_acquire_shared(l, s, t, n, i)		lock_acquire(l, s, t, 1, 1, n, i)

#define lock_acquire_shared_recursive(l, s, t, n, i)	lock_acquire(l, s, t, 2, 1, n, i)

#endif



#define spin_acquire(l, s, t, i)		lock_acquire_exclusive(l, s, t, NULL, i)

#define spin_acquire_nest(l, s, t, n, i)	lock_acquire_exclusive(l, s, t, n, i)
@@ -518,13 +511,13 @@ static inline void print_irqtrace_events(struct task_struct *curr) 
# define might_lock(lock) 						\

do {									\

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

	lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_);	\

	lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_);	\

	lock_release(&(lock)->dep_map, 0, _THIS_IP_);			\

} while (0)

# define might_lock_read(lock) 						\

do {									\

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

	lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_);	\

	lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_);	\

	lock_release(&(lock)->dep_map, 0, _THIS_IP_);			\

} while (0)

#else

include/linux/rcupdate.h

+1 −1
Original line number Diff line number Diff line
@@ -314,7 +314,7 @@ static inline bool rcu_lockdep_current_cpu_online(void) 


static inline void rcu_lock_acquire(struct lockdep_map *map)

{

	lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);

	lock_acquire(map, 0, 0, 2, 0, NULL, _THIS_IP_);

}



static inline void rcu_lock_release(struct lockdep_map *map)

kernel/locking/lockdep.c

+4 −7
Original line number Diff line number Diff line
@@ -2098,7 +2098,7 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, 
	 * (If lookup_chain_cache() returns with 1 it acquires

	 * graph_lock for us)

	 */

	if (!hlock->trylock && (hlock->check == 2) &&

	if (!hlock->trylock && hlock->check &&

	    lookup_chain_cache(curr, hlock, chain_key)) {

		/*

		 * Check whether last held lock:
@@ -3055,9 +3055,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	int class_idx;

	u64 chain_key;



	if (!prove_locking)

		check = 1;



	if (unlikely(!debug_locks))

		return 0;
@@ -3069,8 +3066,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))

		return 0;



	if (lock->key == &__lockdep_no_validate__)

		check = 1;

	if (!prove_locking || lock->key == &__lockdep_no_validate__)

		check = 0;



	if (subclass < NR_LOCKDEP_CACHING_CLASSES)

		class = lock->class_cache[subclass];
@@ -3138,7 +3135,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	hlock->holdtime_stamp = lockstat_clock();

#endif



	if (check == 2 && !mark_irqflags(curr, hlock))

	if (check && !mark_irqflags(curr, hlock))

		return 0;



	/* mark it as used: */

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