dc07e721a2
A little more detail here wouldn't hurt. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
358 lines
11 KiB
C
358 lines
11 KiB
C
#ifndef __LINUX_SPINLOCK_H
|
|
#define __LINUX_SPINLOCK_H
|
|
|
|
/*
|
|
* include/linux/spinlock.h - generic spinlock/rwlock declarations
|
|
*
|
|
* here's the role of the various spinlock/rwlock related include files:
|
|
*
|
|
* on SMP builds:
|
|
*
|
|
* asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
|
|
* initializers
|
|
*
|
|
* linux/spinlock_types.h:
|
|
* defines the generic type and initializers
|
|
*
|
|
* asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel
|
|
* implementations, mostly inline assembly code
|
|
*
|
|
* (also included on UP-debug builds:)
|
|
*
|
|
* linux/spinlock_api_smp.h:
|
|
* contains the prototypes for the _spin_*() APIs.
|
|
*
|
|
* linux/spinlock.h: builds the final spin_*() APIs.
|
|
*
|
|
* on UP builds:
|
|
*
|
|
* linux/spinlock_type_up.h:
|
|
* contains the generic, simplified UP spinlock type.
|
|
* (which is an empty structure on non-debug builds)
|
|
*
|
|
* linux/spinlock_types.h:
|
|
* defines the generic type and initializers
|
|
*
|
|
* linux/spinlock_up.h:
|
|
* contains the __raw_spin_*()/etc. version of UP
|
|
* builds. (which are NOPs on non-debug, non-preempt
|
|
* builds)
|
|
*
|
|
* (included on UP-non-debug builds:)
|
|
*
|
|
* linux/spinlock_api_up.h:
|
|
* builds the _spin_*() APIs.
|
|
*
|
|
* linux/spinlock.h: builds the final spin_*() APIs.
|
|
*/
|
|
|
|
#include <linux/preempt.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/compiler.h>
|
|
#include <linux/thread_info.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/stringify.h>
|
|
#include <linux/bottom_half.h>
|
|
|
|
#include <asm/system.h>
|
|
|
|
/*
|
|
* Must define these before including other files, inline functions need them
|
|
*/
|
|
#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME
|
|
|
|
#define LOCK_SECTION_START(extra) \
|
|
".subsection 1\n\t" \
|
|
extra \
|
|
".ifndef " LOCK_SECTION_NAME "\n\t" \
|
|
LOCK_SECTION_NAME ":\n\t" \
|
|
".endif\n"
|
|
|
|
#define LOCK_SECTION_END \
|
|
".previous\n\t"
|
|
|
|
#define __lockfunc __attribute__((section(".spinlock.text")))
|
|
|
|
/*
|
|
* Pull the raw_spinlock_t and raw_rwlock_t definitions:
|
|
*/
|
|
#include <linux/spinlock_types.h>
|
|
|
|
extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);
|
|
|
|
/*
|
|
* Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
|
|
*/
|
|
#ifdef CONFIG_SMP
|
|
# include <asm/spinlock.h>
|
|
#else
|
|
# include <linux/spinlock_up.h>
|
|
#endif
|
|
|
|
#ifdef CONFIG_DEBUG_SPINLOCK
|
|
extern void __spin_lock_init(spinlock_t *lock, const char *name,
|
|
struct lock_class_key *key);
|
|
# define spin_lock_init(lock) \
|
|
do { \
|
|
static struct lock_class_key __key; \
|
|
\
|
|
__spin_lock_init((lock), #lock, &__key); \
|
|
} while (0)
|
|
|
|
#else
|
|
# define spin_lock_init(lock) \
|
|
do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
|
|
#endif
|
|
|
|
#ifdef CONFIG_DEBUG_SPINLOCK
|
|
extern void __rwlock_init(rwlock_t *lock, const char *name,
|
|
struct lock_class_key *key);
|
|
# define rwlock_init(lock) \
|
|
do { \
|
|
static struct lock_class_key __key; \
|
|
\
|
|
__rwlock_init((lock), #lock, &__key); \
|
|
} while (0)
|
|
#else
|
|
# define rwlock_init(lock) \
|
|
do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
|
|
#endif
|
|
|
|
#define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock)
|
|
|
|
#ifdef CONFIG_GENERIC_LOCKBREAK
|
|
#define spin_is_contended(lock) ((lock)->break_lock)
|
|
#else
|
|
#define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock)
|
|
#endif
|
|
|
|
/**
|
|
* spin_unlock_wait - wait until the spinlock gets unlocked
|
|
* @lock: the spinlock in question.
|
|
*/
|
|
#define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock)
|
|
|
|
/*
|
|
* Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
|
|
*/
|
|
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
|
|
# include <linux/spinlock_api_smp.h>
|
|
#else
|
|
# include <linux/spinlock_api_up.h>
|
|
#endif
|
|
|
|
#ifdef CONFIG_DEBUG_SPINLOCK
|
|
extern void _raw_spin_lock(spinlock_t *lock);
|
|
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
|
|
extern int _raw_spin_trylock(spinlock_t *lock);
|
|
extern void _raw_spin_unlock(spinlock_t *lock);
|
|
extern void _raw_read_lock(rwlock_t *lock);
|
|
extern int _raw_read_trylock(rwlock_t *lock);
|
|
extern void _raw_read_unlock(rwlock_t *lock);
|
|
extern void _raw_write_lock(rwlock_t *lock);
|
|
extern int _raw_write_trylock(rwlock_t *lock);
|
|
extern void _raw_write_unlock(rwlock_t *lock);
|
|
#else
|
|
# define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock)
|
|
# define _raw_spin_lock_flags(lock, flags) \
|
|
__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
|
|
# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock)
|
|
# define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock)
|
|
# define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock)
|
|
# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock)
|
|
# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock)
|
|
# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock)
|
|
# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock)
|
|
# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock)
|
|
#endif
|
|
|
|
#define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock)
|
|
#define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock)
|
|
|
|
/*
|
|
* Define the various spin_lock and rw_lock methods. Note we define these
|
|
* regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
|
|
* methods are defined as nops in the case they are not required.
|
|
*/
|
|
#define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock))
|
|
#define read_trylock(lock) __cond_lock(lock, _read_trylock(lock))
|
|
#define write_trylock(lock) __cond_lock(lock, _write_trylock(lock))
|
|
|
|
#define spin_lock(lock) _spin_lock(lock)
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
|
|
#else
|
|
# define spin_lock_nested(lock, subclass) _spin_lock(lock)
|
|
#endif
|
|
|
|
#define write_lock(lock) _write_lock(lock)
|
|
#define read_lock(lock) _read_lock(lock)
|
|
|
|
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
|
|
|
|
#define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock)
|
|
#define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock)
|
|
#define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
#define spin_lock_irqsave_nested(lock, flags, subclass) \
|
|
flags = _spin_lock_irqsave_nested(lock, subclass)
|
|
#else
|
|
#define spin_lock_irqsave_nested(lock, flags, subclass) \
|
|
flags = _spin_lock_irqsave(lock)
|
|
#endif
|
|
|
|
#else
|
|
|
|
#define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags)
|
|
#define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags)
|
|
#define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
|
|
#define spin_lock_irqsave_nested(lock, flags, subclass) \
|
|
spin_lock_irqsave(lock, flags)
|
|
|
|
#endif
|
|
|
|
#define spin_lock_irq(lock) _spin_lock_irq(lock)
|
|
#define spin_lock_bh(lock) _spin_lock_bh(lock)
|
|
|
|
#define read_lock_irq(lock) _read_lock_irq(lock)
|
|
#define read_lock_bh(lock) _read_lock_bh(lock)
|
|
|
|
#define write_lock_irq(lock) _write_lock_irq(lock)
|
|
#define write_lock_bh(lock) _write_lock_bh(lock)
|
|
|
|
/*
|
|
* We inline the unlock functions in the nondebug case:
|
|
*/
|
|
#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
|
|
!defined(CONFIG_SMP)
|
|
# define spin_unlock(lock) _spin_unlock(lock)
|
|
# define read_unlock(lock) _read_unlock(lock)
|
|
# define write_unlock(lock) _write_unlock(lock)
|
|
# define spin_unlock_irq(lock) _spin_unlock_irq(lock)
|
|
# define read_unlock_irq(lock) _read_unlock_irq(lock)
|
|
# define write_unlock_irq(lock) _write_unlock_irq(lock)
|
|
#else
|
|
# define spin_unlock(lock) \
|
|
do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
|
|
# define read_unlock(lock) \
|
|
do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
|
|
# define write_unlock(lock) \
|
|
do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
|
|
# define spin_unlock_irq(lock) \
|
|
do { \
|
|
__raw_spin_unlock(&(lock)->raw_lock); \
|
|
__release(lock); \
|
|
local_irq_enable(); \
|
|
} while (0)
|
|
# define read_unlock_irq(lock) \
|
|
do { \
|
|
__raw_read_unlock(&(lock)->raw_lock); \
|
|
__release(lock); \
|
|
local_irq_enable(); \
|
|
} while (0)
|
|
# define write_unlock_irq(lock) \
|
|
do { \
|
|
__raw_write_unlock(&(lock)->raw_lock); \
|
|
__release(lock); \
|
|
local_irq_enable(); \
|
|
} while (0)
|
|
#endif
|
|
|
|
#define spin_unlock_irqrestore(lock, flags) \
|
|
_spin_unlock_irqrestore(lock, flags)
|
|
#define spin_unlock_bh(lock) _spin_unlock_bh(lock)
|
|
|
|
#define read_unlock_irqrestore(lock, flags) \
|
|
_read_unlock_irqrestore(lock, flags)
|
|
#define read_unlock_bh(lock) _read_unlock_bh(lock)
|
|
|
|
#define write_unlock_irqrestore(lock, flags) \
|
|
_write_unlock_irqrestore(lock, flags)
|
|
#define write_unlock_bh(lock) _write_unlock_bh(lock)
|
|
|
|
#define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))
|
|
|
|
#define spin_trylock_irq(lock) \
|
|
({ \
|
|
local_irq_disable(); \
|
|
spin_trylock(lock) ? \
|
|
1 : ({ local_irq_enable(); 0; }); \
|
|
})
|
|
|
|
#define spin_trylock_irqsave(lock, flags) \
|
|
({ \
|
|
local_irq_save(flags); \
|
|
spin_trylock(lock) ? \
|
|
1 : ({ local_irq_restore(flags); 0; }); \
|
|
})
|
|
|
|
#define write_trylock_irqsave(lock, flags) \
|
|
({ \
|
|
local_irq_save(flags); \
|
|
write_trylock(lock) ? \
|
|
1 : ({ local_irq_restore(flags); 0; }); \
|
|
})
|
|
|
|
/*
|
|
* Locks two spinlocks l1 and l2.
|
|
* l1_first indicates if spinlock l1 should be taken first.
|
|
*/
|
|
static inline void double_spin_lock(spinlock_t *l1, spinlock_t *l2,
|
|
bool l1_first)
|
|
__acquires(l1)
|
|
__acquires(l2)
|
|
{
|
|
if (l1_first) {
|
|
spin_lock(l1);
|
|
spin_lock(l2);
|
|
} else {
|
|
spin_lock(l2);
|
|
spin_lock(l1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Unlocks two spinlocks l1 and l2.
|
|
* l1_taken_first indicates if spinlock l1 was taken first and therefore
|
|
* should be released after spinlock l2.
|
|
*/
|
|
static inline void double_spin_unlock(spinlock_t *l1, spinlock_t *l2,
|
|
bool l1_taken_first)
|
|
__releases(l1)
|
|
__releases(l2)
|
|
{
|
|
if (l1_taken_first) {
|
|
spin_unlock(l2);
|
|
spin_unlock(l1);
|
|
} else {
|
|
spin_unlock(l1);
|
|
spin_unlock(l2);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Pull the atomic_t declaration:
|
|
* (asm-mips/atomic.h needs above definitions)
|
|
*/
|
|
#include <asm/atomic.h>
|
|
/**
|
|
* atomic_dec_and_lock - lock on reaching reference count zero
|
|
* @atomic: the atomic counter
|
|
* @lock: the spinlock in question
|
|
*
|
|
* Decrements @atomic by 1. If the result is 0, returns true and locks
|
|
* @lock. Returns false for all other cases.
|
|
*/
|
|
extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
|
|
#define atomic_dec_and_lock(atomic, lock) \
|
|
__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
|
|
|
|
/**
|
|
* spin_can_lock - would spin_trylock() succeed?
|
|
* @lock: the spinlock in question.
|
|
*/
|
|
#define spin_can_lock(lock) (!spin_is_locked(lock))
|
|
|
|
#endif /* __LINUX_SPINLOCK_H */
|