[deliverable/linux.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;

#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];
};

#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;
};

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

/*
 * 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)
/*
 * 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);

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)

#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)
/*
 * 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)

#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

#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
db0b0ead MT	15	#ifdef CONFIG_LOCKDEP
db0b0ead MT	16
fbb9ce95 IM	17	#include <linux/linkage.h>
	18	#include <linux/list.h>
	19	#include <linux/debug_locks.h>
	20	#include <linux/stacktrace.h>
	21
fbb9ce95	22	/*
9851673b PZ	23	* We'd rather not expose kernel/lockdep_states.h this wide, but we do need
9851673b PZ	24	* the total number of states... :-(
fbb9ce95	25	*/
9851673b	26	#define XXX_LOCK_USAGE_STATES (1+3*4)
fbb9ce95 IM	27
	28	#define MAX_LOCKDEP_SUBCLASSES 8UL
	29
	30	/*
	31	* Lock-classes are keyed via unique addresses, by embedding the
	32	* lockclass-key into the kernel (or module) .data section. (For
	33	* static locks we use the lock address itself as the key.)
	34	*/
	35	struct lockdep_subclass_key {
	36	char __one_byte;
	37	} __attribute__ ((__packed__));
	38
	39	struct lock_class_key {
	40	struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
	41	};
	42
c7e78cff PZ	43	#define LOCKSTAT_POINTS 4
c7e78cff PZ	44
fbb9ce95 IM	45	/*
	46	* The lock-class itself:
	47	*/
	48	struct lock_class {
	49	/*
	50	* class-hash:
	51	*/
	52	struct list_head hash_entry;
	53
	54	/*
	55	* global list of all lock-classes:
	56	*/
	57	struct list_head lock_entry;
	58
	59	struct lockdep_subclass_key *key;
	60	unsigned int subclass;
419ca3f1	61	unsigned int dep_gen_id;
fbb9ce95 IM	62
	63	/*
	64	* IRQ/softirq usage tracking bits:
	65	*/
	66	unsigned long usage_mask;
9851673b	67	struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
fbb9ce95 IM	68
	69	/*
	70	* These fields represent a directed graph of lock dependencies,
	71	* to every node we attach a list of "forward" and a list of
	72	* "backward" graph nodes.
	73	*/
	74	struct list_head locks_after, locks_before;
	75
	76	/*
	77	* Generation counter, when doing certain classes of graph walking,
	78	* to ensure that we check one node only once:
	79	*/
	80	unsigned int version;
	81
	82	/*
	83	* Statistics counter:
	84	*/
	85	unsigned long ops;
	86
	87	const char *name;
	88	int name_version;
f20786ff PZ	89
f20786ff PZ	90	#ifdef CONFIG_LOCK_STAT
c7e78cff PZ	91	unsigned long contention_point[LOCKSTAT_POINTS];
c7e78cff PZ	92	unsigned long contending_point[LOCKSTAT_POINTS];
f20786ff PZ	93	#endif
	94	};
	95
	96	#ifdef CONFIG_LOCK_STAT
	97	struct lock_time {
	98	s64 min;
	99	s64 max;
	100	s64 total;
	101	unsigned long nr;
fbb9ce95 IM	102	};
fbb9ce95 IM	103
96645678 PZ	104	enum bounce_type {
	105	bounce_acquired_write,
	106	bounce_acquired_read,
	107	bounce_contended_write,
	108	bounce_contended_read,
	109	nr_bounce_types,
	110
	111	bounce_acquired = bounce_acquired_write,
	112	bounce_contended = bounce_contended_write,
	113	};
	114
f20786ff PZ	115	struct lock_class_stats {
f20786ff PZ	116	unsigned long contention_point[4];
c7e78cff	117	unsigned long contending_point[4];
f20786ff PZ	118	struct lock_time read_waittime;
	119	struct lock_time write_waittime;
	120	struct lock_time read_holdtime;
	121	struct lock_time write_holdtime;
96645678	122	unsigned long bounces[nr_bounce_types];
f20786ff PZ	123	};
	124
	125	struct lock_class_stats lock_stats(struct lock_class *class);
	126	void clear_lock_stats(struct lock_class *class);
	127	#endif
	128
fbb9ce95 IM	129	/*
	130	* Map the lock object (the lock instance) to the lock-class object.
	131	* This is embedded into specific lock instances:
	132	*/
	133	struct lockdep_map {
	134	struct lock_class_key *key;
d6d897ce	135	struct lock_class *class_cache;
fbb9ce95	136	const char *name;
96645678 PZ	137	#ifdef CONFIG_LOCK_STAT
96645678 PZ	138	int cpu;
c7e78cff	139	unsigned long ip;
96645678	140	#endif
fbb9ce95 IM	141	};
	142
	143	/*
	144	* Every lock has a list of other locks that were taken after it.
	145	* We only grow the list, never remove from it:
	146	*/
	147	struct lock_list {
	148	struct list_head entry;
	149	struct lock_class *class;
	150	struct stack_trace trace;
068135e6	151	int distance;
fbb9ce95 IM	152	};
	153
	154	/*
	155	* We record lock dependency chains, so that we can cache them:
	156	*/
	157	struct lock_chain {
443cd507 HY	158	u8 irq_context;
	159	u8 depth;
	160	u16 base;
fbb9ce95 IM	161	struct list_head entry;
	162	u64 chain_key;
	163	};
	164
e5f363e3	165	#define MAX_LOCKDEP_KEYS_BITS 13
b42e737e PZ	166	/*
	167	* Subtract one because we offset hlock->class_idx by 1 in order
	168	* to make 0 mean no class. This avoids overflowing the class_idx
	169	* bitfield and hitting the BUG in hlock_class().
	170	*/
	171	#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
f82b217e	172
fbb9ce95 IM	173	struct held_lock {
	174	/*
	175	* One-way hash of the dependency chain up to this point. We
	176	* hash the hashes step by step as the dependency chain grows.
	177	*
	178	* We use it for dependency-caching and we skip detection
	179	* passes and dependency-updates if there is a cache-hit, so
	180	* it is absolutely critical for 100% coverage of the validator
	181	* to have a unique key value for every unique dependency path
	182	* that can occur in the system, to make a unique hash value
	183	* as likely as possible - hence the 64-bit width.
	184	*
	185	* The task struct holds the current hash value (initialized
	186	* with zero), here we store the previous hash value:
	187	*/
	188	u64 prev_chain_key;
fbb9ce95 IM	189	unsigned long acquire_ip;
fbb9ce95 IM	190	struct lockdep_map *instance;
7531e2f3	191	struct lockdep_map *nest_lock;
f20786ff PZ	192	#ifdef CONFIG_LOCK_STAT
	193	u64 waittime_stamp;
	194	u64 holdtime_stamp;
	195	#endif
f82b217e	196	unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
fbb9ce95 IM	197	/*
	198	* The lock-stack is unified in that the lock chains of interrupt
	199	* contexts nest ontop of process context chains, but we 'separate'
	200	* the hashes by starting with 0 if we cross into an interrupt
	201	* context, and we also keep do not add cross-context lock
	202	* dependencies - the lock usage graph walking covers that area
	203	* anyway, and we'd just unnecessarily increase the number of
	204	* dependencies otherwise. [Note: hardirq and softirq contexts
	205	* are separated from each other too.]
	206	*
	207	* The following field is used to detect when we cross into an
	208	* interrupt context:
	209	*/
f82b217e DJ	210	unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
	211	unsigned int trylock:1;
	212	unsigned int read:2; /* see lock_acquire() comment */
	213	unsigned int check:2; /* see lock_acquire() comment */
	214	unsigned int hardirqs_off:1;
fbb9ce95 IM	215	};
	216
	217	/*
	218	* Initialization, self-test and debugging-output methods:
	219	*/
	220	extern void lockdep_init(void);
	221	extern void lockdep_info(void);
	222	extern void lockdep_reset(void);
	223	extern void lockdep_reset_lock(struct lockdep_map *lock);
	224	extern void lockdep_free_key_range(void *start, unsigned long size);
b351d164	225	extern void lockdep_sys_exit(void);
fbb9ce95 IM	226
	227	extern void lockdep_off(void);
	228	extern void lockdep_on(void);
fbb9ce95 IM	229
	230	/*
	231	* These methods are used by specific locking variants (spinlocks,
	232	* rwlocks, mutexes and rwsems) to pass init/acquire/release events
	233	* to lockdep:
	234	*/
	235
	236	extern void lockdep_init_map(struct lockdep_map lock, const char name,
4dfbb9d8	237	struct lock_class_key *key, int subclass);
fbb9ce95	238
851a67b8 PZ	239	/*
	240	* To initialize a lockdep_map statically use this macro.
	241	* Note that _name must not be NULL.
	242	*/
	243	#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
	244	{ .name = (_name), .key = (void *)(_key), }
	245
fbb9ce95 IM	246	/*
	247	* Reinitialize a lock key - for cases where there is special locking or
	248	* special initialization of locks so that the validator gets the scope
	249	* of dependencies wrong: they are either too broad (they need a class-split)
	250	* or they are too narrow (they suffer from a false class-split):
	251	*/
	252	#define lockdep_set_class(lock, key) \
4dfbb9d8	253	lockdep_init_map(&(lock)->dep_map, #key, key, 0)
fbb9ce95	254	#define lockdep_set_class_and_name(lock, key, name) \
4dfbb9d8 PZ	255	lockdep_init_map(&(lock)->dep_map, name, key, 0)
	256	#define lockdep_set_class_and_subclass(lock, key, sub) \
	257	lockdep_init_map(&(lock)->dep_map, #key, key, sub)
	258	#define lockdep_set_subclass(lock, sub) \
	259	lockdep_init_map(&(lock)->dep_map, #lock, \
	260	(lock)->dep_map.key, sub)
9a7aa12f JK	261	/*
	262	* Compare locking classes
	263	*/
	264	#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
	265
	266	static inline int lockdep_match_key(struct lockdep_map *lock,
	267	struct lock_class_key *key)
	268	{
	269	return lock->key == key;
	270	}
fbb9ce95 IM	271
	272	/*
	273	* Acquire a lock.
	274	*
	275	* Values for "read":
	276	*
	277	* 0: exclusive (write) acquire
	278	* 1: read-acquire (no recursion allowed)
	279	* 2: read-acquire with same-instance recursion allowed
	280	*
	281	* Values for check:
	282	*
	283	* 0: disabled
	284	* 1: simple checks (freeing, held-at-exit-time, etc.)
	285	* 2: full validation
	286	*/
	287	extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
7531e2f3 PZ	288	int trylock, int read, int check,
7531e2f3 PZ	289	struct lockdep_map *nest_lock, unsigned long ip);
fbb9ce95 IM	290
	291	extern void lock_release(struct lockdep_map *lock, int nested,
	292	unsigned long ip);
	293
00ef9f73 PZ	294	extern void lock_set_class(struct lockdep_map lock, const char name,
	295	struct lock_class_key *key, unsigned int subclass,
	296	unsigned long ip);
	297
	298	static inline void lock_set_subclass(struct lockdep_map *lock,
	299	unsigned int subclass, unsigned long ip)
	300	{
	301	lock_set_class(lock, lock->name, lock->key, subclass, ip);
	302	}
64aa348e	303
cf40bd16 NP	304	extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
	305	extern void lockdep_clear_current_reclaim_state(void);
	306	extern void lockdep_trace_alloc(gfp_t mask);
	307
	308	# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
fbb9ce95	309
e3a55fd1	310	#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
d5abe669	311
fbb9ce95 IM	312	#else /* !LOCKDEP */
	313
	314	static inline void lockdep_off(void)
	315	{
	316	}
	317
	318	static inline void lockdep_on(void)
	319	{
	320	}
	321
7531e2f3	322	# define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
fbb9ce95	323	# define lock_release(l, n, i) do { } while (0)
00ef9f73	324	# define lock_set_class(l, n, k, s, i) do { } while (0)
64aa348e	325	# define lock_set_subclass(l, s, i) do { } while (0)
cf40bd16 NP	326	# define lockdep_set_current_reclaim_state(g) do { } while (0)
	327	# define lockdep_clear_current_reclaim_state() do { } while (0)
	328	# define lockdep_trace_alloc(g) do { } while (0)
fbb9ce95 IM	329	# define lockdep_init() do { } while (0)
fbb9ce95 IM	330	# define lockdep_info() do { } while (0)
e25cf3db IM	331	# define lockdep_init_map(lock, name, key, sub) \
e25cf3db IM	332	do { (void)(name); (void)(key); } while (0)
fbb9ce95 IM	333	# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
fbb9ce95 IM	334	# define lockdep_set_class_and_name(lock, key, name) \
e25cf3db	335	do { (void)(key); (void)(name); } while (0)
4dfbb9d8 PZ	336	#define lockdep_set_class_and_subclass(lock, key, sub) \
4dfbb9d8 PZ	337	do { (void)(key); } while (0)
07646e21	338	#define lockdep_set_subclass(lock, sub) do { } while (0)
9a7aa12f JK	339	/*
	340	* We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
	341	* case since the result is not well defined and the caller should rather
	342	* #ifdef the call himself.
	343	*/
07646e21	344
fbb9ce95 IM	345	# define INIT_LOCKDEP
	346	# define lockdep_reset() do { debug_locks = 1; } while (0)
	347	# define lockdep_free_key_range(start, size) do { } while (0)
b351d164	348	# define lockdep_sys_exit() do { } while (0)
fbb9ce95 IM	349	/*
	350	* The class key takes no space if lockdep is disabled:
	351	*/
	352	struct lock_class_key { };
d5abe669 PZ	353
	354	#define lockdep_depth(tsk) (0)
	355
fbb9ce95 IM	356	#endif /* !LOCKDEP */
fbb9ce95 IM	357
f20786ff PZ	358	#ifdef CONFIG_LOCK_STAT
	359
	360	extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
c7e78cff	361	extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
f20786ff PZ	362
	363	#define LOCK_CONTENDED(_lock, try, lock) \
	364	do { \
	365	if (!try(_lock)) { \
	366	lock_contended(&(_lock)->dep_map, _RET_IP_); \
	367	lock(_lock); \
f20786ff	368	} \
c7e78cff	369	lock_acquired(&(_lock)->dep_map, _RET_IP_); \
f20786ff PZ	370	} while (0)
	371
	372	#else /* CONFIG_LOCK_STAT */
	373
	374	#define lock_contended(lockdep_map, ip) do {} while (0)
c7e78cff	375	#define lock_acquired(lockdep_map, ip) do {} while (0)
f20786ff PZ	376
	377	#define LOCK_CONTENDED(_lock, try, lock) \
	378	lock(_lock)
	379
	380	#endif /* CONFIG_LOCK_STAT */
	381
e8c158bb RH	382	#ifdef CONFIG_LOCKDEP
	383
	384	/*
	385	* On lockdep we dont want the hand-coded irq-enable of
	386	* _raw_*_lock_flags() code, because lockdep assumes
	387	* that interrupts are not re-enabled during lock-acquire:
	388	*/
	389	#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	390	LOCK_CONTENDED((_lock), (try), (lock))
	391
	392	#else /* CONFIG_LOCKDEP */
	393
	394	#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
	395	lockfl((_lock), (flags))
	396
	397	#endif /* CONFIG_LOCKDEP */
	398
74c8a613	399	#ifdef CONFIG_GENERIC_HARDIRQS
243c7621 IM	400	extern void early_init_irq_lock_class(void);
243c7621 IM	401	#else
3117df04 IM	402	static inline void early_init_irq_lock_class(void)
	403	{
	404	}
243c7621 IM	405	#endif
243c7621 IM	406
fbb9ce95 IM	407	#ifdef CONFIG_TRACE_IRQFLAGS
	408	extern void early_boot_irqs_off(void);
	409	extern void early_boot_irqs_on(void);
3117df04	410	extern void print_irqtrace_events(struct task_struct *curr);
fbb9ce95	411	#else
3117df04 IM	412	static inline void early_boot_irqs_off(void)
	413	{
	414	}
	415	static inline void early_boot_irqs_on(void)
	416	{
	417	}
	418	static inline void print_irqtrace_events(struct task_struct *curr)
	419	{
	420	}
fbb9ce95 IM	421	#endif
	422
	423	/*
	424	* For trivial one-depth nesting of a lock-class, the following
	425	* global define can be used. (Subsystems with multiple levels
	426	* of nesting should define their own lock-nesting subclasses.)
	427	*/
	428	#define SINGLE_DEPTH_NESTING 1
	429
	430	/*
	431	* Map the dependency ops to NOP or to real lockdep ops, depending
	432	* on the per lock-class debug mode:
	433	*/
	434
	435	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	436	# ifdef CONFIG_PROVE_LOCKING
7531e2f3	437	# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
b7d39aff	438	# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i)
fbb9ce95	439	# else
7531e2f3	440	# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
b7d39aff	441	# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i)
fbb9ce95 IM	442	# endif
	443	# define spin_release(l, n, i) lock_release(l, n, i)
	444	#else
	445	# define spin_acquire(l, s, t, i) do { } while (0)
	446	# define spin_release(l, n, i) do { } while (0)
	447	#endif
	448
	449	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	450	# ifdef CONFIG_PROVE_LOCKING
7531e2f3 PZ	451	# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
7531e2f3 PZ	452	# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i)
fbb9ce95	453	# else
7531e2f3 PZ	454	# define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
7531e2f3 PZ	455	# define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i)
fbb9ce95 IM	456	# endif
	457	# define rwlock_release(l, n, i) lock_release(l, n, i)
	458	#else
	459	# define rwlock_acquire(l, s, t, i) do { } while (0)
	460	# define rwlock_acquire_read(l, s, t, i) do { } while (0)
	461	# define rwlock_release(l, n, i) do { } while (0)
	462	#endif
	463
	464	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	465	# ifdef CONFIG_PROVE_LOCKING
7531e2f3	466	# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
fbb9ce95	467	# else
7531e2f3	468	# define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
fbb9ce95 IM	469	# endif
	470	# define mutex_release(l, n, i) lock_release(l, n, i)
	471	#else
	472	# define mutex_acquire(l, s, t, i) do { } while (0)
	473	# define mutex_release(l, n, i) do { } while (0)
	474	#endif
	475
	476	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	477	# ifdef CONFIG_PROVE_LOCKING
7531e2f3 PZ	478	# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
7531e2f3 PZ	479	# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i)
fbb9ce95	480	# else
7531e2f3 PZ	481	# define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
7531e2f3 PZ	482	# define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i)
fbb9ce95 IM	483	# endif
	484	# define rwsem_release(l, n, i) lock_release(l, n, i)
	485	#else
	486	# define rwsem_acquire(l, s, t, i) do { } while (0)
	487	# define rwsem_acquire_read(l, s, t, i) do { } while (0)
	488	# define rwsem_release(l, n, i) do { } while (0)
	489	#endif
	490
4f3e7524 PZ	491	#ifdef CONFIG_DEBUG_LOCK_ALLOC
4f3e7524 PZ	492	# ifdef CONFIG_PROVE_LOCKING
3295f0ef	493	# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
4f3e7524	494	# else
3295f0ef	495	# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
4f3e7524	496	# endif
3295f0ef	497	# define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
4f3e7524	498	#else
3295f0ef IM	499	# define lock_map_acquire(l) do { } while (0)
3295f0ef IM	500	# define lock_map_release(l) do { } while (0)
4f3e7524 PZ	501	#endif
4f3e7524 PZ	502
76b189e9 PZ	503	#ifdef CONFIG_PROVE_LOCKING
	504	# define might_lock(lock) \
	505	do { \
	506	typecheck(struct lockdep_map *, &(lock)->dep_map); \
	507	lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
	508	lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
	509	} while (0)
	510	# define might_lock_read(lock) \
	511	do { \
	512	typecheck(struct lockdep_map *, &(lock)->dep_map); \
	513	lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
	514	lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
	515	} while (0)
	516	#else
	517	# define might_lock(lock) do { } while (0)
	518	# define might_lock_read(lock) do { } while (0)
	519	#endif
	520
fbb9ce95	521	#endif /* __LINUX_LOCKDEP_H */