[net-next-2.6.git] / include / linux / lockdep.h

/*
 * Runtime locking correctness validator
 *
 *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
 *
 * see Documentation/lockdep-design.txt for more details.
 */
#ifndef __LINUX_LOCKDEP_H
#define __LINUX_LOCKDEP_H

struct task_struct;
struct lockdep_map;

/* for sysctl */
extern int prove_locking;
extern int lock_stat;

#ifdef CONFIG_LOCKDEP

#include <linux/linkage.h>
#include <linux/list.h>
#include <linux/debug_locks.h>
#include <linux/stacktrace.h>

/*
 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
 * the total number of states... :-(
 */
#define XXX_LOCK_USAGE_STATES		(1+3*4)

#define MAX_LOCKDEP_SUBCLASSES		8UL

/*
 * Lock-classes are keyed via unique addresses, by embedding the
 * lockclass-key into the kernel (or module) .data section. (For
 * static locks we use the lock address itself as the key.)
 */
struct lockdep_subclass_key {
	char __one_byte;
} __attribute__ ((__packed__));

struct lock_class_key {
	struct lockdep_subclass_key	subkeys[MAX_LOCKDEP_SUBCLASSES];
};

extern struct lock_class_key __lockdep_no_validate__;

#define LOCKSTAT_POINTS		4

/*
 * The lock-class itself:
 */
struct lock_class {
	/*
	 * class-hash:
	 */
	struct list_head		hash_entry;

	/*
	 * global list of all lock-classes:
	 */
	struct list_head		lock_entry;

	struct lockdep_subclass_key	*key;
	unsigned int			subclass;
	unsigned int			dep_gen_id;

	/*
	 * IRQ/softirq usage tracking bits:
	 */
	unsigned long			usage_mask;
	struct stack_trace		usage_traces[XXX_LOCK_USAGE_STATES];

	/*
	 * These fields represent a directed graph of lock dependencies,
	 * to every node we attach a list of "forward" and a list of
	 * "backward" graph nodes.
	 */
	struct list_head		locks_after, locks_before;

	/*
	 * Generation counter, when doing certain classes of graph walking,
	 * to ensure that we check one node only once:
	 */
	unsigned int			version;

	/*
	 * Statistics counter:
	 */
	unsigned long			ops;

	const char			*name;
	int				name_version;

#ifdef CONFIG_LOCK_STAT
	unsigned long			contention_point[LOCKSTAT_POINTS];
	unsigned long			contending_point[LOCKSTAT_POINTS];
#endif
};

#ifdef CONFIG_LOCK_STAT
struct lock_time {
	s64				min;
	s64				max;
	s64				total;
	unsigned long			nr;
};

enum bounce_type {
	bounce_acquired_write,
	bounce_acquired_read,
	bounce_contended_write,
	bounce_contended_read,
	nr_bounce_types,

	bounce_acquired = bounce_acquired_write,
	bounce_contended = bounce_contended_write,
};

struct lock_class_stats {
	unsigned long			contention_point[4];
	unsigned long			contending_point[4];
	struct lock_time		read_waittime;
	struct lock_time		write_waittime;
	struct lock_time		read_holdtime;
	struct lock_time		write_holdtime;
	unsigned long			bounces[nr_bounce_types];
};

struct lock_class_stats lock_stats(struct lock_class *class);
void clear_lock_stats(struct lock_class *class);
#endif

/*
 * Map the lock object (the lock instance) to the lock-class object.
 * This is embedded into specific lock instances:
 */
struct lockdep_map {
	struct lock_class_key		*key;
	struct lock_class		*class_cache;
	const char			*name;
#ifdef CONFIG_LOCK_STAT
	int				cpu;
	unsigned long			ip;
#endif
};

/*
 * Every lock has a list of other locks that were taken after it.
 * We only grow the list, never remove from it:
 */
struct lock_list {
	struct list_head		entry;
	struct lock_class		*class;
	struct stack_trace		trace;
	int				distance;

	/*
	 * The parent field is used to implement breadth-first search, and the
	 * bit 0 is reused to indicate if the lock has been accessed in BFS.
	 */
	struct lock_list		*parent;
};

/*
 * We record lock dependency chains, so that we can cache them:
 */
struct lock_chain {
	u8				irq_context;
	u8				depth;
	u16				base;
	struct list_head		entry;
	u64				chain_key;
};

#define MAX_LOCKDEP_KEYS_BITS		13
/*
 * Subtract one because we offset hlock->class_idx by 1 in order
 * to make 0 mean no class. This avoids overflowing the class_idx
 * bitfield and hitting the BUG in hlock_class().
 */
#define MAX_LOCKDEP_KEYS		((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)

struct held_lock {
	/*
	 * One-way hash of the dependency chain up to this point. We
	 * hash the hashes step by step as the dependency chain grows.
	 *
	 * We use it for dependency-caching and we skip detection
	 * passes and dependency-updates if there is a cache-hit, so
	 * it is absolutely critical for 100% coverage of the validator
	 * to have a unique key value for every unique dependency path
	 * that can occur in the system, to make a unique hash value
	 * as likely as possible - hence the 64-bit width.
	 *
	 * The task struct holds the current hash value (initialized
	 * with zero), here we store the previous hash value:
	 */
	u64				prev_chain_key;
	unsigned long			acquire_ip;
	struct lockdep_map		*instance;
	struct lockdep_map		*nest_lock;
#ifdef CONFIG_LOCK_STAT
	u64 				waittime_stamp;
	u64				holdtime_stamp;
#endif
	unsigned int			class_idx:MAX_LOCKDEP_KEYS_BITS;
	/*
	 * The lock-stack is unified in that the lock chains of interrupt
	 * contexts nest ontop of process context chains, but we 'separate'
	 * the hashes by starting with 0 if we cross into an interrupt
	 * context, and we also keep do not add cross-context lock
	 * dependencies - the lock usage graph walking covers that area
	 * anyway, and we'd just unnecessarily increase the number of
	 * dependencies otherwise. [Note: hardirq and softirq contexts
	 * are separated from each other too.]
	 *
	 * The following field is used to detect when we cross into an
	 * interrupt context:
	 */
	unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
	unsigned int trylock:1;						/* 16 bits */

	unsigned int read:2;        /* see lock_acquire() comment */
	unsigned int check:2;       /* see lock_acquire() comment */
	unsigned int hardirqs_off:1;
	unsigned int references:11;					/* 32 bits */
};

/*
 * Initialization, self-test and debugging-output methods:
 */
extern void lockdep_init(void);
extern void lockdep_info(void);
extern void lockdep_reset(void);
extern void lockdep_reset_lock(struct lockdep_map *lock);
extern void lockdep_free_key_range(void *start, unsigned long size);
extern void lockdep_sys_exit(void);

extern void lockdep_off(void);
extern void lockdep_on(void);

/*
 * These methods are used by specific locking variants (spinlocks,
 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
 * to lockdep:
 */

extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
			     struct lock_class_key *key, int subclass);

/*
 * To initialize a lockdep_map statically use this macro.
 * Note that _name must not be NULL.
 */
#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
	{ .name = (_name), .key = (void *)(_key), }

/*
 * Reinitialize a lock key - for cases where there is special locking or
 * special initialization of locks so that the validator gets the scope
 * of dependencies wrong: they are either too broad (they need a class-split)
 * 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, 0)
#define lockdep_set_class_and_name(lock, key, name) \
		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)

#define lockdep_set_novalidate_class(lock) \
	lockdep_set_class(lock, &__lockdep_no_validate__)
/*
 * Compare locking classes
 */
#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)

static inline int lockdep_match_key(struct lockdep_map *lock,
				    struct lock_class_key *key)
{
	return lock->key == key;
}

/*
 * Acquire a lock.
 *
 * Values for "read":
 *
 *   0: exclusive (write) acquire
 *   1: read-acquire (no recursion allowed)
 *   2: read-acquire with same-instance recursion allowed
 *
 * Values for check:
 *
 *   0: disabled
 *   1: simple checks (freeing, held-at-exit-time, etc.)
 *   2: full validation
 */
extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
			 int trylock, int read, int check,
			 struct lockdep_map *nest_lock, unsigned long ip);

extern void lock_release(struct lockdep_map *lock, int nested,
			 unsigned long ip);

#define lockdep_is_held(lock)	lock_is_held(&(lock)->dep_map)

extern int lock_is_held(struct lockdep_map *lock);

extern void lock_set_class(struct lockdep_map *lock, const char *name,
			   struct lock_class_key *key, unsigned int subclass,
			   unsigned long ip);

static inline void lock_set_subclass(struct lockdep_map *lock,
		unsigned int subclass, unsigned long ip)
{
	lock_set_class(lock, lock->name, lock->key, subclass, ip);
}

extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
extern void lockdep_clear_current_reclaim_state(void);
extern void lockdep_trace_alloc(gfp_t mask);

# define INIT_LOCKDEP				.lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,

#define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)

#define lockdep_assert_held(l)	WARN_ON(debug_locks && !lockdep_is_held(l))

#else /* !LOCKDEP */

static inline void lockdep_off(void)
{
}

static inline void lockdep_on(void)
{
}

# define lock_acquire(l, s, t, r, c, n, i)	do { } while (0)
# define lock_release(l, n, i)			do { } while (0)
# define lock_set_class(l, n, k, s, i)		do { } while (0)
# define lock_set_subclass(l, s, i)		do { } while (0)
# define lockdep_set_current_reclaim_state(g)	do { } while (0)
# define lockdep_clear_current_reclaim_state()	do { } while (0)
# define lockdep_trace_alloc(g)			do { } while (0)
# define lockdep_init()				do { } while (0)
# define lockdep_info()				do { } while (0)
# define lockdep_init_map(lock, name, key, sub) \
		do { (void)(name); (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); (void)(name); } while (0)
#define lockdep_set_class_and_subclass(lock, key, sub) \
		do { (void)(key); } while (0)
#define lockdep_set_subclass(lock, sub)		do { } while (0)

#define lockdep_set_novalidate_class(lock) do { } while (0)

/*
 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
 * case since the result is not well defined and the caller should rather
 * #ifdef the call himself.
 */

# define INIT_LOCKDEP
# define lockdep_reset()		do { debug_locks = 1; } while (0)
# define lockdep_free_key_range(start, size)	do { } while (0)
# define lockdep_sys_exit() 			do { } while (0)
/*
 * The class key takes no space if lockdep is disabled:
 */
struct lock_class_key { };

#define lockdep_depth(tsk)	(0)

#define lockdep_assert_held(l)			do { } while (0)

#endif /* !LOCKDEP */

#ifdef CONFIG_LOCK_STAT

extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);

#define LOCK_CONTENDED(_lock, try, lock)			\
do {								\
	if (!try(_lock)) {					\
		lock_contended(&(_lock)->dep_map, _RET_IP_);	\
		lock(_lock);					\
	}							\
	lock_acquired(&(_lock)->dep_map, _RET_IP_);			\
} while (0)

#else /* CONFIG_LOCK_STAT */

#define lock_contended(lockdep_map, ip) do {} while (0)
#define lock_acquired(lockdep_map, ip) do {} while (0)

#define LOCK_CONTENDED(_lock, try, lock) \
	lock(_lock)

#endif /* CONFIG_LOCK_STAT */

#ifdef CONFIG_LOCKDEP

/*
 * On lockdep we dont want the hand-coded irq-enable of
 * _raw_*_lock_flags() code, because lockdep assumes
 * that interrupts are not re-enabled during lock-acquire:
 */
#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	LOCK_CONTENDED((_lock), (try), (lock))

#else /* CONFIG_LOCKDEP */

#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	lockfl((_lock), (flags))

#endif /* CONFIG_LOCKDEP */

#ifdef CONFIG_GENERIC_HARDIRQS
extern void early_init_irq_lock_class(void);
#else
static inline void early_init_irq_lock_class(void)
{
}
#endif

#ifdef CONFIG_TRACE_IRQFLAGS
extern void early_boot_irqs_off(void);
extern void early_boot_irqs_on(void);
extern void print_irqtrace_events(struct task_struct *curr);
#else
static inline void early_boot_irqs_off(void)
{
}
static inline void early_boot_irqs_on(void)
{
}
static inline void print_irqtrace_events(struct task_struct *curr)
{
}
#endif

/*
 * For trivial one-depth nesting of a lock-class, the following
 * global define can be used. (Subsystems with multiple levels
 * of nesting should define their own lock-nesting subclasses.)
 */
#define SINGLE_DEPTH_NESTING			1

/*
 * Map the dependency ops to NOP or to real lockdep ops, depending
 * on the per lock-class debug mode:
 */

#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
# define spin_acquire(l, s, t, i)		do { } while (0)
# define spin_release(l, n, i)			do { } while (0)
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
#  define rwlock_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
#  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 2, NULL, i)
# else
#  define rwlock_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
#  define rwlock_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 2, 1, NULL, i)
# endif
# define rwlock_release(l, n, i)		lock_release(l, n, i)
#else
# define rwlock_acquire(l, s, t, i)		do { } while (0)
# define rwlock_acquire_read(l, s, t, i)	do { } while (0)
# define rwlock_release(l, n, i)		do { } while (0)
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
#  define mutex_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
# else
#  define mutex_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
# endif
# define mutex_release(l, n, i)			lock_release(l, n, i)
#else
# define mutex_acquire(l, s, t, i)		do { } while (0)
# define mutex_release(l, n, i)			do { } while (0)
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
#  define rwsem_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 2, NULL, i)
#  define rwsem_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 1, 2, NULL, i)
# else
#  define rwsem_acquire(l, s, t, i)		lock_acquire(l, s, t, 0, 1, NULL, i)
#  define rwsem_acquire_read(l, s, t, i)	lock_acquire(l, s, t, 1, 1, NULL, i)
# endif
# define rwsem_release(l, n, i)			lock_release(l, n, i)
#else
# define rwsem_acquire(l, s, t, i)		do { } while (0)
# define rwsem_acquire_read(l, s, t, i)		do { } while (0)
# define rwsem_release(l, n, i)			do { } while (0)
#endif

#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
#  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
# else
#  define lock_map_acquire(l)		lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
# endif
# define lock_map_release(l)			lock_release(l, 1, _THIS_IP_)
#else
# define lock_map_acquire(l)			do { } while (0)
# define lock_map_release(l)			do { } while (0)
#endif

#ifdef CONFIG_PROVE_LOCKING
# 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_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_release(&(lock)->dep_map, 0, _THIS_IP_);			\
} while (0)
#else
# define might_lock(lock) do { } while (0)
# define might_lock_read(lock) do { } while (0)
#endif

#ifdef CONFIG_PROVE_RCU
extern void lockdep_rcu_dereference(const char *file, const int line);
#endif

#endif /* __LINUX_LOCKDEP_H */
Commit	Line	Data
fbb9ce95 IM	1	/*
	2	* Runtime locking correctness validator
	3	*
4b32d0a4 PZ	4	* Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
4b32d0a4 PZ	5	* Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
fbb9ce95 IM	6	*
	7	* see Documentation/lockdep-design.txt for more details.
	8	*/
	9	#ifndef __LINUX_LOCKDEP_H
	10	#define __LINUX_LOCKDEP_H
	11
a1e96b03	12	struct task_struct;
f20786ff	13	struct lockdep_map;
a1e96b03	14
2edf5e49 DY	15	/* for sysctl */
	16	extern int prove_locking;
	17	extern int lock_stat;
	18
db0b0ead MT	19	#ifdef CONFIG_LOCKDEP
db0b0ead MT	20
fbb9ce95 IM	21	#include <linux/linkage.h>
	22	#include <linux/list.h>
	23	#include <linux/debug_locks.h>
	24	#include <linux/stacktrace.h>
	25
fbb9ce95	26	/*
9851673b PZ	27	* We'd rather not expose kernel/lockdep_states.h this wide, but we do need
9851673b PZ	28	* the total number of states... :-(
fbb9ce95	29	*/
9851673b	30	#define XXX_LOCK_USAGE_STATES (1+3*4)
fbb9ce95 IM	31
	32	#define MAX_LOCKDEP_SUBCLASSES 8UL
	33
	34	/*
	35	* Lock-classes are keyed via unique addresses, by embedding the
	36	* lockclass-key into the kernel (or module) .data section. (For
	37	* static locks we use the lock address itself as the key.)
	38	*/
	39	struct lockdep_subclass_key {
	40	char __one_byte;
	41	} __attribute__ ((__packed__));
	42
	43	struct lock_class_key {
	44	struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
	45	};
	46
1704f47b PZ	47	extern struct lock_class_key __lockdep_no_validate__;
1704f47b PZ	48
c7e78cff PZ	49	#define LOCKSTAT_POINTS 4
c7e78cff PZ	50
fbb9ce95 IM	51	/*
	52	* The lock-class itself:
	53	*/
	54	struct lock_class {
	55	/*
	56	* class-hash:
	57	*/
	58	struct list_head hash_entry;
	59
	60	/*
	61	* global list of all lock-classes:
	62	*/
	63	struct list_head lock_entry;
	64
	65	struct lockdep_subclass_key *key;
	66	unsigned int subclass;
e351b660	67	unsigned int dep_gen_id;
fbb9ce95 IM	68
	69	/*
	70	* IRQ/softirq usage tracking bits:
	71	*/
	72	unsigned long usage_mask;
9851673b	73	struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
fbb9ce95 IM	74
	75	/*
	76	* These fields represent a directed graph of lock dependencies,
	77	* to every node we attach a list of "forward" and a list of
	78	* "backward" graph nodes.
	79	*/
	80	struct list_head locks_after, locks_before;
	81
	82	/*
	83	* Generation counter, when doing certain classes of graph walking,
	84	* to ensure that we check one node only once:
	85	*/
	86	unsigned int version;
	87
	88	/*
	89	* Statistics counter:
	90	*/
	91	unsigned long ops;
	92
	93	const char *name;
	94	int name_version;
f20786ff PZ	95
f20786ff PZ	96	#ifdef CONFIG_LOCK_STAT
c7e78cff PZ	97	unsigned long contention_point[LOCKSTAT_POINTS];
c7e78cff PZ	98	unsigned long contending_point[LOCKSTAT_POINTS];
f20786ff PZ	99	#endif
	100	};
	101
	102	#ifdef CONFIG_LOCK_STAT
	103	struct lock_time {
	104	s64 min;
	105	s64 max;
	106	s64 total;
	107	unsigned long nr;
fbb9ce95 IM	108	};
fbb9ce95 IM	109
96645678 PZ	110	enum bounce_type {
	111	bounce_acquired_write,
	112	bounce_acquired_read,
	113	bounce_contended_write,
	114	bounce_contended_read,
	115	nr_bounce_types,
	116
	117	bounce_acquired = bounce_acquired_write,
	118	bounce_contended = bounce_contended_write,
	119	};
	120
f20786ff PZ	121	struct lock_class_stats {
f20786ff PZ	122	unsigned long contention_point[4];
c7e78cff	123	unsigned long contending_point[4];
f20786ff PZ	124	struct lock_time read_waittime;
	125	struct lock_time write_waittime;
	126	struct lock_time read_holdtime;
	127	struct lock_time write_holdtime;
96645678	128	unsigned long bounces[nr_bounce_types];
f20786ff PZ	129	};
	130
	131	struct lock_class_stats lock_stats(struct lock_class *class);
	132	void clear_lock_stats(struct lock_class *class);
	133	#endif
	134
fbb9ce95 IM	135	/*
	136	* Map the lock object (the lock instance) to the lock-class object.
	137	* This is embedded into specific lock instances:
	138	*/
	139	struct lockdep_map {
	140	struct lock_class_key *key;
d6d897ce	141	struct lock_class *class_cache;
fbb9ce95	142	const char *name;
96645678 PZ	143	#ifdef CONFIG_LOCK_STAT
96645678 PZ	144	int cpu;
c7e78cff	145	unsigned long ip;
96645678	146	#endif
fbb9ce95 IM	147	};
	148
	149	/*
	150	* Every lock has a list of other locks that were taken after it.
	151	* We only grow the list, never remove from it:
	152	*/
	153	struct lock_list {
	154	struct list_head entry;
	155	struct lock_class *class;
	156	struct stack_trace trace;
068135e6	157	int distance;
c94aa5ca	158
af012961 PZ	159	/*
	160	* The parent field is used to implement breadth-first search, and the
	161	* bit 0 is reused to indicate if the lock has been accessed in BFS.
c94aa5ca ML	162	*/
c94aa5ca ML	163	struct lock_list *parent;
fbb9ce95 IM	164	};
	165
	166	/*
	167	* We record lock dependency chains, so that we can cache them:
	168	*/
	169	struct lock_chain {
443cd507 HY	170	u8 irq_context;
	171	u8 depth;
	172	u16 base;
fbb9ce95 IM	173	struct list_head entry;
	174	u64 chain_key;
	175	};
	176
e5f363e3	177	#define MAX_LOCKDEP_KEYS_BITS 13
b42e737e PZ	178	/*
	179	* Subtract one because we offset hlock->class_idx by 1 in order
	180	* to make 0 mean no class. This avoids overflowing the class_idx
	181	* bitfield and hitting the BUG in hlock_class().
	182	*/
	183	#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
f82b217e	184
fbb9ce95 IM	185	struct held_lock {
	186	/*
	187	* One-way hash of the dependency chain up to this point. We
	188	* hash the hashes step by step as the dependency chain grows.
	189	*
	190	* We use it for dependency-caching and we skip detection
	191	* passes and dependency-updates if there is a cache-hit, so
	192	* it is absolutely critical for 100% coverage of the validator
	193	* to have a unique key value for every unique dependency path
	194	* that can occur in the system, to make a unique hash value
	195	* as likely as possible - hence the 64-bit width.
	196	*
	197	* The task struct holds the current hash value (initialized
	198	* with zero), here we store the previous hash value:
	199	*/
	200	u64 prev_chain_key;
fbb9ce95 IM	201	unsigned long acquire_ip;
fbb9ce95 IM	202	struct lockdep_map *instance;
7531e2f3	203	struct lockdep_map *nest_lock;
f20786ff PZ	204	#ifdef CONFIG_LOCK_STAT
	205	u64 waittime_stamp;
	206	u64 holdtime_stamp;
	207	#endif
f82b217e	208	unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
fbb9ce95 IM	209	/*
	210	* The lock-stack is unified in that the lock chains of interrupt
	211	* contexts nest ontop of process context chains, but we 'separate'
	212	* the hashes by starting with 0 if we cross into an interrupt
	213	* context, and we also keep do not add cross-context lock
	214	* dependencies - the lock usage graph walking covers that area
	215	* anyway, and we'd just unnecessarily increase the number of
	216	* dependencies otherwise. [Note: hardirq and softirq contexts
	217	* are separated from each other too.]
	218	*
	219	* The following field is used to detect when we cross into an
	220	* interrupt context:
	221	*/
f82b217e	222	unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
bb97a91e PZ	223	unsigned int trylock:1; /* 16 bits */
bb97a91e PZ	224
f82b217e DJ	225	unsigned int read:2; /* see lock_acquire() comment */
	226	unsigned int check:2; /* see lock_acquire() comment */
	227	unsigned int hardirqs_off:1;
bb97a91e	228	unsigned int references:11; /* 32 bits */
fbb9ce95 IM	229	};
	230
	231	/*
	232	* Initialization, self-test and debugging-output methods:
	233	*/
	234	extern void lockdep_init(void);
	235	extern void lockdep_info(void);
	236	extern void lockdep_reset(void);
	237	extern void lockdep_reset_lock(struct lockdep_map *lock);
	238	extern void lockdep_free_key_range(void *start, unsigned long size);
b351d164	239	extern void lockdep_sys_exit(void);
fbb9ce95 IM	240
	241	extern void lockdep_off(void);
	242	extern void lockdep_on(void);
fbb9ce95 IM	243
	244	/*
	245	* These methods are used by specific locking variants (spinlocks,
	246	* rwlocks, mutexes and rwsems) to pass init/acquire/release events
	247	* to lockdep:
	248	*/
	249
	250	extern void lockdep_init_map(struct lockdep_map lock, const char name,
4dfbb9d8	251	struct lock_class_key *key, int subclass);
fbb9ce95	252
851a67b8 PZ	253	/*
	254	* To initialize a lockdep_map statically use this macro.
	255	* Note that _name must not be NULL.
	256	*/
	257	#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
	258	{ .name = (_name), .key = (void *)(_key), }
	259
fbb9ce95 IM	260	/*
	261	* Reinitialize a lock key - for cases where there is special locking or
	262	* special initialization of locks so that the validator gets the scope
	263	* of dependencies wrong: they are either too broad (they need a class-split)
	264	* or they are too narrow (they suffer from a false class-split):
	265	*/
	266	#define lockdep_set_class(lock, key) \
4dfbb9d8	267	lockdep_init_map(&(lock)->dep_map, #key, key, 0)
fbb9ce95	268	#define lockdep_set_class_and_name(lock, key, name) \
4dfbb9d8 PZ	269	lockdep_init_map(&(lock)->dep_map, name, key, 0)
	270	#define lockdep_set_class_and_subclass(lock, key, sub) \
	271	lockdep_init_map(&(lock)->dep_map, #key, key, sub)
	272	#define lockdep_set_subclass(lock, sub) \
	273	lockdep_init_map(&(lock)->dep_map, #lock, \
	274	(lock)->dep_map.key, sub)
1704f47b PZ	275
	276	#define lockdep_set_novalidate_class(lock) \
	277	lockdep_set_class(lock, &__lockdep_no_validate__)
9a7aa12f JK	278	/*
	279	* Compare locking classes
	280	*/
	281	#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
	282
	283	static inline int lockdep_match_key(struct lockdep_map *lock,
	284	struct lock_class_key *key)
	285	{
	286	return lock->key == key;
	287	}
fbb9ce95 IM	288
	289	/*
	290	* Acquire a lock.
	291	*
	292	* Values for "read":
	293	*
	294	* 0: exclusive (write) acquire
	295	* 1: read-acquire (no recursion allowed)
	296	* 2: read-acquire with same-instance recursion allowed
	297	*
	298	* Values for check:
	299	*
	300	* 0: disabled
	301	* 1: simple checks (freeing, held-at-exit-time, etc.)
	302	* 2: full validation
	303	*/
	304	extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
7531e2f3 PZ	305	int trylock, int read, int check,
7531e2f3 PZ	306	struct lockdep_map *nest_lock, unsigned long ip);
fbb9ce95 IM	307
	308	extern void lock_release(struct lockdep_map *lock, int nested,
	309	unsigned long ip);
	310
f607c668 PZ	311	#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
	312
	313	extern int lock_is_held(struct lockdep_map *lock);
	314
00ef9f73 PZ	315	extern void lock_set_class(struct lockdep_map lock, const char name,
	316	struct lock_class_key *key, unsigned int subclass,
	317	unsigned long ip);
	318
	319	static inline void lock_set_subclass(struct lockdep_map *lock,
	320	unsigned int subclass, unsigned long ip)
	321	{
	322	lock_set_class(lock, lock->name, lock->key, subclass, ip);
	323	}
64aa348e	324
cf40bd16 NP	325	extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
	326	extern void lockdep_clear_current_reclaim_state(void);
	327	extern void lockdep_trace_alloc(gfp_t mask);
	328
	329	# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
fbb9ce95	330
e3a55fd1	331	#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
d5abe669	332
f607c668 PZ	333	#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l))
f607c668 PZ	334
fbb9ce95 IM	335	#else /* !LOCKDEP */
	336
	337	static inline void lockdep_off(void)
	338	{
	339	}
	340
	341	static inline void lockdep_on(void)
	342	{
	343	}
	344
7531e2f3	345	# define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
fbb9ce95	346	# define lock_release(l, n, i) do { } while (0)
00ef9f73	347	# define lock_set_class(l, n, k, s, i) do { } while (0)
64aa348e	348	# define lock_set_subclass(l, s, i) do { } while (0)
cf40bd16 NP	349	# define lockdep_set_current_reclaim_state(g) do { } while (0)
	350	# define lockdep_clear_current_reclaim_state() do { } while (0)
	351	# define lockdep_trace_alloc(g) do { } while (0)
fbb9ce95 IM	352	# define lockdep_init() do { } while (0)
fbb9ce95 IM	353	# define lockdep_info() do { } while (0)
e25cf3db IM	354	# define lockdep_init_map(lock, name, key, sub) \
e25cf3db IM	355	do { (void)(name); (void)(key); } while (0)
fbb9ce95 IM	356	# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
fbb9ce95 IM	357	# define lockdep_set_class_and_name(lock, key, name) \
e25cf3db	358	do { (void)(key); (void)(name); } while (0)
4dfbb9d8 PZ	359	#define lockdep_set_class_and_subclass(lock, key, sub) \
4dfbb9d8 PZ	360	do { (void)(key); } while (0)
07646e21	361	#define lockdep_set_subclass(lock, sub) do { } while (0)
1704f47b PZ	362
	363	#define lockdep_set_novalidate_class(lock) do { } while (0)
	364
9a7aa12f JK	365	/*
	366	* We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
	367	* case since the result is not well defined and the caller should rather
	368	* #ifdef the call himself.
	369	*/
07646e21	370
fbb9ce95 IM	371	# define INIT_LOCKDEP
	372	# define lockdep_reset() do { debug_locks = 1; } while (0)
	373	# define lockdep_free_key_range(start, size) do { } while (0)
b351d164	374	# define lockdep_sys_exit() do { } while (0)
fbb9ce95 IM	375	/*
	376	* The class key takes no space if lockdep is disabled:
	377	*/
	378	struct lock_class_key { };
d5abe669 PZ	379
	380	#define lockdep_depth(tsk) (0)
	381
f607c668 PZ	382	#define lockdep_assert_held(l) do { } while (0)
f607c668 PZ	383
fbb9ce95 IM	384	#endif /* !LOCKDEP */
fbb9ce95 IM	385
f20786ff PZ	386	#ifdef CONFIG_LOCK_STAT
	387
	388	extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
c7e78cff	389	extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
f20786ff PZ	390
	391	#define LOCK_CONTENDED(_lock, try, lock) \
	392	do { \
	393	if (!try(_lock)) { \
	394	lock_contended(&(_lock)->dep_map, _RET_IP_); \
	395	lock(_lock); \
f20786ff	396	} \
c7e78cff	397	lock_acquired(&(_lock)->dep_map, _RET_IP_); \
f20786ff PZ	398	} while (0)
	399
	400	#else /* CONFIG_LOCK_STAT */
	401
	402	#define lock_contended(lockdep_map, ip) do {} while (0)
c7e78cff	403	#define lock_acquired(lockdep_map, ip) do {} while (0)
f20786ff PZ	404
	405	#define LOCK_CONTENDED(_lock, try, lock) \
	406	lock(_lock)
	407
	408	#endif /* CONFIG_LOCK_STAT */
	409
e8c158bb RH	410	#ifdef CONFIG_LOCKDEP
	411
	412	/*
	413	* On lockdep we dont want the hand-coded irq-enable of
	414	* _raw_*_lock_flags() code, because lockdep assumes
	415	* that interrupts are not re-enabled during lock-acquire:
	416	*/
	417	#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	418	LOCK_CONTENDED((_lock), (try), (lock))
	419
	420	#else /* CONFIG_LOCKDEP */
	421
	422	#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	423	lockfl((_lock), (flags))
	424
	425	#endif /* CONFIG_LOCKDEP */
	426
74c8a613	427	#ifdef CONFIG_GENERIC_HARDIRQS
243c7621 IM	428	extern void early_init_irq_lock_class(void);
243c7621 IM	429	#else
3117df04 IM	430	static inline void early_init_irq_lock_class(void)
	431	{
	432	}
243c7621 IM	433	#endif
243c7621 IM	434
fbb9ce95 IM	435	#ifdef CONFIG_TRACE_IRQFLAGS
	436	extern void early_boot_irqs_off(void);
	437	extern void early_boot_irqs_on(void);
3117df04	438	extern void print_irqtrace_events(struct task_struct *curr);
fbb9ce95	439	#else
3117df04 IM	440	static inline void early_boot_irqs_off(void)
	441	{
	442	}
	443	static inline void early_boot_irqs_on(void)
	444	{
	445	}
	446	static inline void print_irqtrace_events(struct task_struct *curr)
	447	{
	448	}
fbb9ce95 IM	449	#endif
	450
	451	/*
	452	* For trivial one-depth nesting of a lock-class, the following
	453	* global define can be used. (Subsystems with multiple levels
	454	* of nesting should define their own lock-nesting subclasses.)
	455	*/
	456	#define SINGLE_DEPTH_NESTING 1
	457
	458	/*
	459	* Map the dependency ops to NOP or to real lockdep ops, depending
	460	* on the per lock-class debug mode:
	461	*/
	462
	463	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	464	# ifdef CONFIG_PROVE_LOCKING
7531e2f3	465	# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
b7d39aff	466	# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i)
fbb9ce95	467	# else
7531e2f3	468	# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
b7d39aff	469	# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i)
fbb9ce95 IM	470	# endif
	471	# define spin_release(l, n, i) lock_release(l, n, i)
	472	#else
	473	# define spin_acquire(l, s, t, i) do { } while (0)
	474	# define spin_release(l, n, i) do { } while (0)
	475	#endif
	476
	477	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	478	# ifdef CONFIG_PROVE_LOCKING
7531e2f3 PZ	479	# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
7531e2f3 PZ	480	# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i)
fbb9ce95	481	# else
7531e2f3 PZ	482	# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
7531e2f3 PZ	483	# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i)
fbb9ce95 IM	484	# endif
	485	# define rwlock_release(l, n, i) lock_release(l, n, i)
	486	#else
	487	# define rwlock_acquire(l, s, t, i) do { } while (0)
	488	# define rwlock_acquire_read(l, s, t, i) do { } while (0)
	489	# define rwlock_release(l, n, i) do { } while (0)
	490	#endif
	491
	492	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	493	# ifdef CONFIG_PROVE_LOCKING
7531e2f3	494	# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
fbb9ce95	495	# else
7531e2f3	496	# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
fbb9ce95 IM	497	# endif
	498	# define mutex_release(l, n, i) lock_release(l, n, i)
	499	#else
	500	# define mutex_acquire(l, s, t, i) do { } while (0)
	501	# define mutex_release(l, n, i) do { } while (0)
	502	#endif
	503
	504	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	505	# ifdef CONFIG_PROVE_LOCKING
7531e2f3 PZ	506	# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
7531e2f3 PZ	507	# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i)
fbb9ce95	508	# else
7531e2f3 PZ	509	# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
7531e2f3 PZ	510	# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i)
fbb9ce95 IM	511	# endif
	512	# define rwsem_release(l, n, i) lock_release(l, n, i)
	513	#else
	514	# define rwsem_acquire(l, s, t, i) do { } while (0)
	515	# define rwsem_acquire_read(l, s, t, i) do { } while (0)
	516	# define rwsem_release(l, n, i) do { } while (0)
	517	#endif
	518
4f3e7524 PZ	519	#ifdef CONFIG_DEBUG_LOCK_ALLOC
4f3e7524 PZ	520	# ifdef CONFIG_PROVE_LOCKING
3295f0ef	521	# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
4f3e7524	522	# else
3295f0ef	523	# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
4f3e7524	524	# endif
3295f0ef	525	# define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
4f3e7524	526	#else
3295f0ef IM	527	# define lock_map_acquire(l) do { } while (0)
3295f0ef IM	528	# define lock_map_release(l) do { } while (0)
4f3e7524 PZ	529	#endif
4f3e7524 PZ	530
76b189e9 PZ	531	#ifdef CONFIG_PROVE_LOCKING
	532	# define might_lock(lock) \
	533	do { \
	534	typecheck(struct lockdep_map *, &(lock)->dep_map); \
	535	lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
	536	lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
	537	} while (0)
	538	# define might_lock_read(lock) \
	539	do { \
	540	typecheck(struct lockdep_map *, &(lock)->dep_map); \
	541	lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
	542	lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
	543	} while (0)
	544	#else
	545	# define might_lock(lock) do { } while (0)
	546	# define might_lock_read(lock) do { } while (0)
	547	#endif
	548
0632eb3d PM	549	#ifdef CONFIG_PROVE_RCU
	550	extern void lockdep_rcu_dereference(const char *file, const int line);
	551	#endif
	552
fbb9ce95	553	#endif /* __LINUX_LOCKDEP_H */