diff options
Diffstat (limited to 'include/linux/spinlock.h')
| -rw-r--r-- | include/linux/spinlock.h | 627 |
1 files changed, 125 insertions, 502 deletions
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index d6ba068719b..cdc99a27840 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -2,7 +2,48 @@ #define __LINUX_SPINLOCK_H /* - * include/linux/spinlock.h - generic locking declarations + * 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/config.h> @@ -13,7 +54,6 @@ #include <linux/kernel.h> #include <linux/stringify.h> -#include <asm/processor.h> /* for cpu relax */ #include <asm/system.h> /* @@ -35,423 +75,84 @@ #define __lockfunc fastcall __attribute__((section(".spinlock.text"))) /* - * If CONFIG_SMP is set, pull in the _raw_* definitions + * Pull the raw_spinlock_t and raw_rwlock_t definitions: */ -#ifdef CONFIG_SMP - -#define assert_spin_locked(x) BUG_ON(!spin_is_locked(x)) -#include <asm/spinlock.h> - -int __lockfunc _spin_trylock(spinlock_t *lock); -int __lockfunc _read_trylock(rwlock_t *lock); -int __lockfunc _write_trylock(rwlock_t *lock); - -void __lockfunc _spin_lock(spinlock_t *lock) __acquires(spinlock_t); -void __lockfunc _read_lock(rwlock_t *lock) __acquires(rwlock_t); -void __lockfunc _write_lock(rwlock_t *lock) __acquires(rwlock_t); - -void __lockfunc _spin_unlock(spinlock_t *lock) __releases(spinlock_t); -void __lockfunc _read_unlock(rwlock_t *lock) __releases(rwlock_t); -void __lockfunc _write_unlock(rwlock_t *lock) __releases(rwlock_t); - -unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) __acquires(spinlock_t); -unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) __acquires(rwlock_t); -unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) __acquires(rwlock_t); - -void __lockfunc _spin_lock_irq(spinlock_t *lock) __acquires(spinlock_t); -void __lockfunc _spin_lock_bh(spinlock_t *lock) __acquires(spinlock_t); -void __lockfunc _read_lock_irq(rwlock_t *lock) __acquires(rwlock_t); -void __lockfunc _read_lock_bh(rwlock_t *lock) __acquires(rwlock_t); -void __lockfunc _write_lock_irq(rwlock_t *lock) __acquires(rwlock_t); -void __lockfunc _write_lock_bh(rwlock_t *lock) __acquires(rwlock_t); - -void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) __releases(spinlock_t); -void __lockfunc _spin_unlock_irq(spinlock_t *lock) __releases(spinlock_t); -void __lockfunc _spin_unlock_bh(spinlock_t *lock) __releases(spinlock_t); -void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) __releases(rwlock_t); -void __lockfunc _read_unlock_irq(rwlock_t *lock) __releases(rwlock_t); -void __lockfunc _read_unlock_bh(rwlock_t *lock) __releases(rwlock_t); -void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) __releases(rwlock_t); -void __lockfunc _write_unlock_irq(rwlock_t *lock) __releases(rwlock_t); -void __lockfunc _write_unlock_bh(rwlock_t *lock) __releases(rwlock_t); - -int __lockfunc _spin_trylock_bh(spinlock_t *lock); -int __lockfunc generic_raw_read_trylock(rwlock_t *lock); -int in_lock_functions(unsigned long addr); - -#else +#include <linux/spinlock_types.h> -#define in_lock_functions(ADDR) 0 +extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock); -#if !defined(CONFIG_PREEMPT) && !defined(CONFIG_DEBUG_SPINLOCK) -# define _atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic) -# define ATOMIC_DEC_AND_LOCK -#endif - -#ifdef CONFIG_DEBUG_SPINLOCK - -#define SPINLOCK_MAGIC 0x1D244B3C -typedef struct { - unsigned long magic; - volatile unsigned long lock; - volatile unsigned int babble; - const char *module; - char *owner; - int oline; -} spinlock_t; -#define SPIN_LOCK_UNLOCKED (spinlock_t) { SPINLOCK_MAGIC, 0, 10, __FILE__ , NULL, 0} - -#define spin_lock_init(x) \ - do { \ - (x)->magic = SPINLOCK_MAGIC; \ - (x)->lock = 0; \ - (x)->babble = 5; \ - (x)->module = __FILE__; \ - (x)->owner = NULL; \ - (x)->oline = 0; \ - } while (0) - -#define CHECK_LOCK(x) \ - do { \ - if ((x)->magic != SPINLOCK_MAGIC) { \ - printk(KERN_ERR "%s:%d: spin_is_locked on uninitialized spinlock %p.\n", \ - __FILE__, __LINE__, (x)); \ - } \ - } while(0) - -#define _raw_spin_lock(x) \ - do { \ - CHECK_LOCK(x); \ - if ((x)->lock&&(x)->babble) { \ - (x)->babble--; \ - printk("%s:%d: spin_lock(%s:%p) already locked by %s/%d\n", \ - __FILE__,__LINE__, (x)->module, \ - (x), (x)->owner, (x)->oline); \ - } \ - (x)->lock = 1; \ - (x)->owner = __FILE__; \ - (x)->oline = __LINE__; \ - } while (0) - -/* without debugging, spin_is_locked on UP always says - * FALSE. --> printk if already locked. */ -#define spin_is_locked(x) \ - ({ \ - CHECK_LOCK(x); \ - if ((x)->lock&&(x)->babble) { \ - (x)->babble--; \ - printk("%s:%d: spin_is_locked(%s:%p) already locked by %s/%d\n", \ - __FILE__,__LINE__, (x)->module, \ - (x), (x)->owner, (x)->oline); \ - } \ - 0; \ - }) - -/* with debugging, assert_spin_locked() on UP does check - * the lock value properly */ -#define assert_spin_locked(x) \ - ({ \ - CHECK_LOCK(x); \ - BUG_ON(!(x)->lock); \ - }) - -/* without debugging, spin_trylock on UP always says - * TRUE. --> printk if already locked. */ -#define _raw_spin_trylock(x) \ - ({ \ - CHECK_LOCK(x); \ - if ((x)->lock&&(x)->babble) { \ - (x)->babble--; \ - printk("%s:%d: spin_trylock(%s:%p) already locked by %s/%d\n", \ - __FILE__,__LINE__, (x)->module, \ - (x), (x)->owner, (x)->oline); \ - } \ - (x)->lock = 1; \ - (x)->owner = __FILE__; \ - (x)->oline = __LINE__; \ - 1; \ - }) - -#define spin_unlock_wait(x) \ - do { \ - CHECK_LOCK(x); \ - if ((x)->lock&&(x)->babble) { \ - (x)->babble--; \ - printk("%s:%d: spin_unlock_wait(%s:%p) owned by %s/%d\n", \ - __FILE__,__LINE__, (x)->module, (x), \ - (x)->owner, (x)->oline); \ - }\ - } while (0) - -#define _raw_spin_unlock(x) \ - do { \ - CHECK_LOCK(x); \ - if (!(x)->lock&&(x)->babble) { \ - (x)->babble--; \ - printk("%s:%d: spin_unlock(%s:%p) not locked\n", \ - __FILE__,__LINE__, (x)->module, (x));\ - } \ - (x)->lock = 0; \ - } while (0) -#else /* - * gcc versions before ~2.95 have a nasty bug with empty initializers. + * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them): */ -#if (__GNUC__ > 2) - typedef struct { } spinlock_t; - #define SPIN_LOCK_UNLOCKED (spinlock_t) { } +#if defined(CONFIG_SMP) +# include <asm/spinlock.h> #else - typedef struct { int gcc_is_buggy; } spinlock_t; - #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } +# include <linux/spinlock_up.h> #endif +#define spin_lock_init(lock) do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0) +#define rwlock_init(lock) do { *(lock) = RW_LOCK_UNLOCKED; } while (0) + +#define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock) + +/** + * 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) + /* - * If CONFIG_SMP is unset, declare the _raw_* definitions as nops + * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: */ -#define spin_lock_init(lock) do { (void)(lock); } while(0) -#define _raw_spin_lock(lock) do { (void)(lock); } while(0) -#define spin_is_locked(lock) ((void)(lock), 0) -#define assert_spin_locked(lock) do { (void)(lock); } while(0) -#define _raw_spin_trylock(lock) (((void)(lock), 1)) -#define spin_unlock_wait(lock) (void)(lock) -#define _raw_spin_unlock(lock) do { (void)(lock); } while(0) -#endif /* CONFIG_DEBUG_SPINLOCK */ - -/* RW spinlocks: No debug version */ - -#if (__GNUC__ > 2) - typedef struct { } rwlock_t; - #define RW_LOCK_UNLOCKED (rwlock_t) { } +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) +# include <linux/spinlock_api_smp.h> #else - typedef struct { int gcc_is_buggy; } rwlock_t; - #define RW_LOCK_UNLOCKED (rwlock_t) { 0 } +# include <linux/spinlock_api_up.h> #endif -#define rwlock_init(lock) do { (void)(lock); } while(0) -#define _raw_read_lock(lock) do { (void)(lock); } while(0) -#define _raw_read_unlock(lock) do { (void)(lock); } while(0) -#define _raw_write_lock(lock) do { (void)(lock); } while(0) -#define _raw_write_unlock(lock) do { (void)(lock); } while(0) -#define read_can_lock(lock) (((void)(lock), 1)) -#define write_can_lock(lock) (((void)(lock), 1)) -#define _raw_read_trylock(lock) ({ (void)(lock); (1); }) -#define _raw_write_trylock(lock) ({ (void)(lock); (1); }) - -#define _spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \ - 1 : ({preempt_enable(); 0;});}) - -#define _read_trylock(lock) ({preempt_disable();_raw_read_trylock(lock) ? \ - 1 : ({preempt_enable(); 0;});}) - -#define _write_trylock(lock) ({preempt_disable(); _raw_write_trylock(lock) ? \ - 1 : ({preempt_enable(); 0;});}) - -#define _spin_trylock_bh(lock) ({preempt_disable(); local_bh_disable(); \ - _raw_spin_trylock(lock) ? \ - 1 : ({preempt_enable_no_resched(); local_bh_enable(); 0;});}) - -#define _spin_lock(lock) \ -do { \ - preempt_disable(); \ - _raw_spin_lock(lock); \ - __acquire(lock); \ -} while(0) - -#define _write_lock(lock) \ -do { \ - preempt_disable(); \ - _raw_write_lock(lock); \ - __acquire(lock); \ -} while(0) - -#define _read_lock(lock) \ -do { \ - preempt_disable(); \ - _raw_read_lock(lock); \ - __acquire(lock); \ -} while(0) - -#define _spin_unlock(lock) \ -do { \ - _raw_spin_unlock(lock); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _write_unlock(lock) \ -do { \ - _raw_write_unlock(lock); \ - preempt_enable(); \ - __release(lock); \ -} while(0) - -#define _read_unlock(lock) \ -do { \ - _raw_read_unlock(lock); \ - preempt_enable(); \ - __release(lock); \ -} while(0) - -#define _spin_lock_irqsave(lock, flags) \ -do { \ - local_irq_save(flags); \ - preempt_disable(); \ - _raw_spin_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _spin_lock_irq(lock) \ -do { \ - local_irq_disable(); \ - preempt_disable(); \ - _raw_spin_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _spin_lock_bh(lock) \ -do { \ - local_bh_disable(); \ - preempt_disable(); \ - _raw_spin_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _read_lock_irqsave(lock, flags) \ -do { \ - local_irq_save(flags); \ - preempt_disable(); \ - _raw_read_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _read_lock_irq(lock) \ -do { \ - local_irq_disable(); \ - preempt_disable(); \ - _raw_read_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _read_lock_bh(lock) \ -do { \ - local_bh_disable(); \ - preempt_disable(); \ - _raw_read_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _write_lock_irqsave(lock, flags) \ -do { \ - local_irq_save(flags); \ - preempt_disable(); \ - _raw_write_lock(lock); \ - __acquire(lock); \ -} while (0) +#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_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) +# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock) +# 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_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock) +# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock) +# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock) +# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock) +# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock) +# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock) +#endif -#define _write_lock_irq(lock) \ -do { \ - local_irq_disable(); \ - preempt_disable(); \ - _raw_write_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _write_lock_bh(lock) \ -do { \ - local_bh_disable(); \ - preempt_disable(); \ - _raw_write_lock(lock); \ - __acquire(lock); \ -} while (0) - -#define _spin_unlock_irqrestore(lock, flags) \ -do { \ - _raw_spin_unlock(lock); \ - local_irq_restore(flags); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _spin_unlock_irq(lock) \ -do { \ - _raw_spin_unlock(lock); \ - local_irq_enable(); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _spin_unlock_bh(lock) \ -do { \ - _raw_spin_unlock(lock); \ - preempt_enable_no_resched(); \ - local_bh_enable(); \ - __release(lock); \ -} while (0) - -#define _write_unlock_bh(lock) \ -do { \ - _raw_write_unlock(lock); \ - preempt_enable_no_resched(); \ - local_bh_enable(); \ - __release(lock); \ -} while (0) - -#define _read_unlock_irqrestore(lock, flags) \ -do { \ - _raw_read_unlock(lock); \ - local_irq_restore(flags); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _write_unlock_irqrestore(lock, flags) \ -do { \ - _raw_write_unlock(lock); \ - local_irq_restore(flags); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _read_unlock_irq(lock) \ -do { \ - _raw_read_unlock(lock); \ - local_irq_enable(); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#define _read_unlock_bh(lock) \ -do { \ - _raw_read_unlock(lock); \ - preempt_enable_no_resched(); \ - local_bh_enable(); \ - __release(lock); \ -} while (0) - -#define _write_unlock_irq(lock) \ -do { \ - _raw_write_unlock(lock); \ - local_irq_enable(); \ - preempt_enable(); \ - __release(lock); \ -} while (0) - -#endif /* !SMP */ +#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(_spin_trylock(lock)) -#define read_trylock(lock) __cond_lock(_read_trylock(lock)) -#define write_trylock(lock) __cond_lock(_write_trylock(lock)) +#define spin_trylock(lock) __cond_lock(_spin_trylock(lock)) +#define read_trylock(lock) __cond_lock(_read_trylock(lock)) +#define write_trylock(lock) __cond_lock(_write_trylock(lock)) -#define spin_lock(lock) _spin_lock(lock) -#define write_lock(lock) _write_lock(lock) -#define read_lock(lock) _read_lock(lock) +#define spin_lock(lock) _spin_lock(lock) +#define write_lock(lock) _write_lock(lock) +#define read_lock(lock) _read_lock(lock) -#ifdef CONFIG_SMP +#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) @@ -470,137 +171,59 @@ do { \ #define write_lock_irq(lock) _write_lock_irq(lock) #define write_lock_bh(lock) _write_lock_bh(lock) -#define spin_unlock(lock) _spin_unlock(lock) -#define write_unlock(lock) _write_unlock(lock) -#define read_unlock(lock) _read_unlock(lock) +#define spin_unlock(lock) _spin_unlock(lock) +#define write_unlock(lock) _write_unlock(lock) +#define read_unlock(lock) _read_unlock(lock) -#define spin_unlock_irqrestore(lock, flags) _spin_unlock_irqrestore(lock, flags) +#define spin_unlock_irqrestore(lock, flags) \ + _spin_unlock_irqrestore(lock, flags) #define spin_unlock_irq(lock) _spin_unlock_irq(lock) #define spin_unlock_bh(lock) _spin_unlock_bh(lock) -#define read_unlock_irqrestore(lock, flags) _read_unlock_irqrestore(lock, flags) -#define read_unlock_irq(lock) _read_unlock_irq(lock) -#define read_unlock_bh(lock) _read_unlock_bh(lock) +#define read_unlock_irqrestore(lock, flags) \ + _read_unlock_irqrestore(lock, flags) +#define read_unlock_irq(lock) _read_unlock_irq(lock) +#define read_unlock_bh(lock) _read_unlock_bh(lock) -#define write_unlock_irqrestore(lock, flags) _write_unlock_irqrestore(lock, flags) -#define write_unlock_irq(lock) _write_unlock_irq(lock) -#define write_unlock_bh(lock) _write_unlock_bh(lock) +#define write_unlock_irqrestore(lock, flags) \ + _write_unlock_irqrestore(lock, flags) +#define write_unlock_irq(lock) _write_unlock_irq(lock) +#define write_unlock_bh(lock) _write_unlock_bh(lock) -#define spin_trylock_bh(lock) __cond_lock(_spin_trylock_bh(lock)) +#define spin_trylock_bh(lock) __cond_lock(_spin_trylock_bh(lock)) #define spin_trylock_irq(lock) \ ({ \ local_irq_disable(); \ _spin_trylock(lock) ? \ - 1 : ({local_irq_enable(); 0; }); \ + 1 : ({ local_irq_enable(); 0; }); \ }) #define spin_trylock_irqsave(lock, flags) \ ({ \ local_irq_save(flags); \ _spin_trylock(lock) ? \ - 1 : ({local_irq_restore(flags); 0;}); \ + 1 : ({ local_irq_restore(flags); 0; }); \ }) -#ifdef CONFIG_LOCKMETER -extern void _metered_spin_lock (spinlock_t *lock); -extern void _metered_spin_unlock (spinlock_t *lock); -extern int _metered_spin_trylock(spinlock_t *lock); -extern void _metered_read_lock (rwlock_t *lock); -extern void _metered_read_unlock (rwlock_t *lock); -extern void _metered_write_lock (rwlock_t *lock); -extern void _metered_write_unlock (rwlock_t *lock); -extern int _metered_read_trylock (rwlock_t *lock); -extern int _metered_write_trylock(rwlock_t *lock); -#endif - -/* "lock on reference count zero" */ -#ifndef ATOMIC_DEC_AND_LOCK -#include <asm/atomic.h> -extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); -#endif - -#define atomic_dec_and_lock(atomic,lock) __cond_lock(_atomic_dec_and_lock(atomic,lock)) - -/* - * bit-based spin_lock() - * - * Don't use this unless you really need to: spin_lock() and spin_unlock() - * are significantly faster. - */ -static inline void bit_spin_lock(int bitnum, unsigned long *addr) -{ - /* - * Assuming the lock is uncontended, this never enters - * the body of the outer loop. If it is contended, then - * within the inner loop a non-atomic test is used to - * busywait with less bus contention for a good time to - * attempt to acquire the lock bit. - */ - preempt_disable(); -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) - while (test_and_set_bit(bitnum, addr)) { - while (test_bit(bitnum, addr)) { - preempt_enable(); - cpu_relax(); - preempt_disable(); - } - } -#endif - __acquire(bitlock); -} - /* - * Return true if it was acquired + * Pull the atomic_t declaration: + * (asm-mips/atomic.h needs above definitions) */ -static inline int bit_spin_trylock(int bitnum, unsigned long *addr) -{ - preempt_disable(); -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) - if (test_and_set_bit(bitnum, addr)) { - preempt_enable(); - return 0; - } -#endif - __acquire(bitlock); - return 1; -} - -/* - * bit-based spin_unlock() - */ -static inline void bit_spin_unlock(int bitnum, unsigned long *addr) -{ -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) - BUG_ON(!test_bit(bitnum, addr)); - smp_mb__before_clear_bit(); - clear_bit(bitnum, addr); -#endif - preempt_enable(); - __release(bitlock); -} - -/* - * Return true if the lock is held. +#include <asm/atomic.h> +/** + * atomic_dec_and_lock - lock on reaching reference count zero + * @atomic: the atomic counter + * @lock: the spinlock in question */ -static inline int bit_spin_is_locked(int bitnum, unsigned long *addr) -{ -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) - return test_bit(bitnum, addr); -#elif defined CONFIG_PREEMPT - return preempt_count(); -#else - return 1; -#endif -} - -#define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED -#define DEFINE_RWLOCK(x) rwlock_t x = RW_LOCK_UNLOCKED +extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); +#define atomic_dec_and_lock(atomic, lock) \ + __cond_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)) +#define spin_can_lock(lock) (!spin_is_locked(lock)) #endif /* __LINUX_SPINLOCK_H */ |