mirror of
https://github.com/joel16/android_kernel_sony_msm8994.git
synced 2024-12-11 22:34:20 +00:00
4b16bfbf8f
Chen, Kenneth W wrote: > The memory order semantics for include/asm-ia64/semaphore.h:down() > doesn't look right. It is using atomic_dec_return, which eventually > translate into ia64_fetch_and_add() that uses release semantics. > Shouldn't it use acquire semantics? Use ia64_fetchadd() instead of atomic_dec_return() Acked-by: Ken Chen <kenneth.w.chen@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
101 lines
2.1 KiB
C
101 lines
2.1 KiB
C
#ifndef _ASM_IA64_SEMAPHORE_H
|
|
#define _ASM_IA64_SEMAPHORE_H
|
|
|
|
/*
|
|
* Copyright (C) 1998-2000 Hewlett-Packard Co
|
|
* Copyright (C) 1998-2000 David Mosberger-Tang <davidm@hpl.hp.com>
|
|
*/
|
|
|
|
#include <linux/wait.h>
|
|
#include <linux/rwsem.h>
|
|
|
|
#include <asm/atomic.h>
|
|
|
|
struct semaphore {
|
|
atomic_t count;
|
|
int sleepers;
|
|
wait_queue_head_t wait;
|
|
};
|
|
|
|
#define __SEMAPHORE_INITIALIZER(name, n) \
|
|
{ \
|
|
.count = ATOMIC_INIT(n), \
|
|
.sleepers = 0, \
|
|
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
|
|
}
|
|
|
|
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
|
|
struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
|
|
|
|
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
|
|
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name, 0)
|
|
|
|
static inline void
|
|
sema_init (struct semaphore *sem, int val)
|
|
{
|
|
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
|
|
}
|
|
|
|
static inline void
|
|
init_MUTEX (struct semaphore *sem)
|
|
{
|
|
sema_init(sem, 1);
|
|
}
|
|
|
|
static inline void
|
|
init_MUTEX_LOCKED (struct semaphore *sem)
|
|
{
|
|
sema_init(sem, 0);
|
|
}
|
|
|
|
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);
|
|
|
|
/*
|
|
* Atomically decrement the semaphore's count. If it goes negative,
|
|
* block the calling thread in the TASK_UNINTERRUPTIBLE state.
|
|
*/
|
|
static inline void
|
|
down (struct semaphore *sem)
|
|
{
|
|
might_sleep();
|
|
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
|
|
__down(sem);
|
|
}
|
|
|
|
/*
|
|
* Atomically decrement the semaphore's count. If it goes negative,
|
|
* block the calling thread in the TASK_INTERRUPTIBLE state.
|
|
*/
|
|
static inline int
|
|
down_interruptible (struct semaphore * sem)
|
|
{
|
|
int ret = 0;
|
|
|
|
might_sleep();
|
|
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
|
|
ret = __down_interruptible(sem);
|
|
return ret;
|
|
}
|
|
|
|
static inline int
|
|
down_trylock (struct semaphore *sem)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
|
|
ret = __down_trylock(sem);
|
|
return ret;
|
|
}
|
|
|
|
static inline void
|
|
up (struct semaphore * sem)
|
|
{
|
|
if (ia64_fetchadd(1, &sem->count.counter, rel) <= -1)
|
|
__up(sem);
|
|
}
|
|
|
|
#endif /* _ASM_IA64_SEMAPHORE_H */
|