diff options
Diffstat (limited to 'include/asm-arm/semaphore.h')
| -rw-r--r-- | include/asm-arm/semaphore.h | 219 |
1 files changed, 206 insertions, 13 deletions
diff --git a/include/asm-arm/semaphore.h b/include/asm-arm/semaphore.h index 5ba171be8..0ce171a3f 100644 --- a/include/asm-arm/semaphore.h +++ b/include/asm-arm/semaphore.h @@ -9,16 +9,28 @@ #include <linux/wait.h> #include <asm/atomic.h> +#include <asm/proc/locks.h> struct semaphore { atomic_t count; int sleepers; wait_queue_head_t wait; +#if WAITQUEUE_DEBUG + long __magic; +#endif }; +#if WAITQUEUE_DEBUG +# define __SEM_DEBUG_INIT(name) \ + , (long)&(name).__magic +#else +# define __SEM_DEBUG_INIT(name) +#endif + #define __SEMAPHORE_INIT(name,count) \ { ATOMIC_INIT(count), 0, \ - __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) } + __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ + __SEM_DEBUG_INIT(name) } #define __MUTEX_INITIALIZER(name) \ __SEMAPHORE_INIT(name,1) @@ -29,12 +41,15 @@ struct semaphore { #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) -#define sema_init(sem, val) \ -do { \ - atomic_set(&((sem)->count), (val)); \ - (sem)->sleepers = 0; \ - init_waitqueue_head(&(sem)->wait); \ -} while (0) +extern inline void sema_init(struct semaphore *sem, int val) +{ + atomic_set(&sem->count, val); + sem->sleepers = 0; + init_waitqueue_head(&sem->wait); +#if WAITQUEUE_DEBUG + sem->__magic = (long)&sem->__magic; +#endif +} static inline void init_MUTEX(struct semaphore *sem) { @@ -46,18 +61,196 @@ static inline void init_MUTEX_LOCKED(struct semaphore *sem) sema_init(sem, 0); } -asmlinkage void __down_failed (void /* special register calling convention */); -asmlinkage int __down_interruptible_failed (void /* special register calling convention */); -asmlinkage int __down_trylock_failed(void /* params in registers */); -asmlinkage void __up_wakeup (void /* special register calling convention */); +/* + * special register calling convention + */ +asmlinkage void __down_failed(void); +asmlinkage int __down_interruptible_failed(void); +asmlinkage int __down_trylock_failed(void); +asmlinkage void __up_wakeup(void); extern void __down(struct semaphore * sem); extern int __down_interruptible(struct semaphore * sem); extern int __down_trylock(struct semaphore * sem); extern void __up(struct semaphore * sem); -extern spinlock_t semaphore_wake_lock; +/* + * This is ugly, but we want the default case to fall through. + * "__down" is the actual routine that waits... + */ +extern inline void down(struct semaphore * sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + __down_op(sem, __down_failed); +} + +/* + * This is ugly, but we want the default case to fall through. + * "__down_interruptible" is the actual routine that waits... + */ +extern inline int down_interruptible (struct semaphore * sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + return __down_op_ret(sem, __down_interruptible_failed); +} + +extern inline int down_trylock(struct semaphore *sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + return __down_op_ret(sem, __down_trylock_failed); +} + +/* + * Note! This is subtle. We jump to wake people up only if + * the semaphore was negative (== somebody was waiting on it). + * The default case (no contention) will result in NO + * jumps for both down() and up(). + */ +extern inline void up(struct semaphore * sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + __up_op(sem, __up_wakeup); +} + +/* rw mutexes (should that be mutices? =) -- throw rw + * spinlocks and semaphores together, and this is what we + * end up with... + * + * The lock is initialized to BIAS. This way, a writer + * subtracts BIAS ands gets 0 for the case of an uncontended + * lock. Readers decrement by 1 and see a positive value + * when uncontended, negative if there are writers waiting + * (in which case it goes to sleep). + * + * In terms of fairness, this should result in the lock + * flopping back and forth between readers and writers + * under heavy use. + * + * -ben + */ +struct rw_semaphore { + atomic_t count; + volatile unsigned char write_bias_granted; + volatile unsigned char read_bias_granted; + volatile unsigned char pad1; + volatile unsigned char pad2; + wait_queue_head_t wait; + wait_queue_head_t write_bias_wait; +#if WAITQUEUE_DEBUG + long __magic; + atomic_t readers; + atomic_t writers; +#endif +}; + +#if WAITQUEUE_DEBUG +#define __RWSEM_DEBUG_INIT , ATOMIC_INIT(0), ATOMIC_INIT(0) +#else +#define __RWSEM_DEBUG_INIT /* */ +#endif + +#define __RWSEM_INITIALIZER(name,count) \ +{ ATOMIC_INIT(count), 0, 0, 0, 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ + __WAIT_QUEUE_HEAD_INITIALIZER((name).write_bias_wait) \ + __SEM_DEBUG_INIT(name) __RWSEM_DEBUG_INIT } + +#define __DECLARE_RWSEM_GENERIC(name,count) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) + +#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS) +#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1) +#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0) + +extern inline void init_rwsem(struct rw_semaphore *sem) +{ + atomic_set(&sem->count, RW_LOCK_BIAS); + sem->read_bias_granted = 0; + sem->write_bias_granted = 0; + init_waitqueue_head(&sem->wait); + init_waitqueue_head(&sem->write_bias_wait); +#if WAITQUEUE_DEBUG + sem->__magic = (long)&sem->__magic; + atomic_set(&sem->readers, 0); + atomic_set(&sem->writers, 0); +#endif +} + +extern struct rw_semaphore *__down_read_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *__down_write_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *__rwsem_wake(struct rw_semaphore *sem); + +extern inline void down_read(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + __down_op_read(sem, __down_read_failed); +#if WAITQUEUE_DEBUG + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->writers)) + BUG(); + atomic_inc(&sem->readers); +#endif +} + +extern inline void down_write(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + __down_op_write(sem, __down_write_failed); +#if WAITQUEUE_DEBUG + if (atomic_read(&sem->writers)) + BUG(); + if (atomic_read(&sem->readers)) + BUG(); + if (sem->read_bias_granted) + BUG(); + if (sem->write_bias_granted) + BUG(); + atomic_inc(&sem->writers); +#endif +} + +extern inline void up_read(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->writers)) + BUG(); + atomic_dec(&sem->readers); +#endif + __up_op_read(sem, __rwsem_wake); +} -#include <asm/proc/semaphore.h> +extern inline void up_write(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->read_bias_granted) + BUG(); + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->readers)) + BUG(); + if (atomic_read(&sem->writers) != 1) + BUG(); + atomic_dec(&sem->writers); +#endif + __up_op_write(sem, __rwsem_wake); +} #endif |