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#ifndef __ASM_SPINLOCK_LOCK1_H
#define __ASM_SPINLOCK_LOCK1_H
#include <asm/bug.h>
#include <asm/global_lock.h>
static inline int arch_spin_is_locked(arch_spinlock_t *lock)
{
int ret;
barrier();
ret = lock->lock;
WARN_ON(ret != 0 && ret != 1);
return ret;
}
static inline void arch_spin_lock(arch_spinlock_t *lock)
{
unsigned int we_won = 0;
unsigned long flags;
again:
__global_lock1(flags);
if (lock->lock == 0) {
fence();
lock->lock = 1;
we_won = 1;
}
__global_unlock1(flags);
if (we_won == 0)
goto again;
WARN_ON(lock->lock != 1);
}
/* Returns 0 if failed to acquire lock */
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
unsigned long flags;
unsigned int ret;
__global_lock1(flags);
ret = lock->lock;
if (ret == 0) {
fence();
lock->lock = 1;
}
__global_unlock1(flags);
return (ret == 0);
}
static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
barrier();
WARN_ON(!lock->lock);
lock->lock = 0;
}
/*
* RWLOCKS
*
*
* Write locks are easy - we just set bit 31. When unlocking, we can
* just write zero since the lock is exclusively held.
*/
static inline void arch_write_lock(arch_rwlock_t *rw)
{
unsigned long flags;
unsigned int we_won = 0;
again:
__global_lock1(flags);
if (rw->lock == 0) {
fence();
rw->lock = 0x80000000;
we_won = 1;
}
__global_unlock1(flags);
if (we_won == 0)
goto again;
WARN_ON(rw->lock != 0x80000000);
}
static inline int arch_write_trylock(arch_rwlock_t *rw)
{
unsigned long flags;
unsigned int ret;
__global_lock1(flags);
ret = rw->lock;
if (ret == 0) {
fence();
rw->lock = 0x80000000;
}
__global_unlock1(flags);
return (ret == 0);
}
static inline void arch_write_unlock(arch_rwlock_t *rw)
{
barrier();
WARN_ON(rw->lock != 0x80000000);
rw->lock = 0;
}
/* write_can_lock - would write_trylock() succeed? */
static inline int arch_write_can_lock(arch_rwlock_t *rw)
{
unsigned int ret;
barrier();
ret = rw->lock;
return (ret == 0);
}
/*
* Read locks are a bit more hairy:
* - Exclusively load the lock value.
* - Increment it.
* - Store new lock value if positive, and we still own this location.
* If the value is negative, we've already failed.
* - If we failed to store the value, we want a negative result.
* - If we failed, try again.
* Unlocking is similarly hairy. We may have multiple read locks
* currently active. However, we know we won't have any write
* locks.
*/
static inline void arch_read_lock(arch_rwlock_t *rw)
{
unsigned long flags;
unsigned int we_won = 0, ret;
again:
__global_lock1(flags);
ret = rw->lock;
if (ret < 0x80000000) {
fence();
rw->lock = ret + 1;
we_won = 1;
}
__global_unlock1(flags);
if (!we_won)
goto again;
}
static inline void arch_read_unlock(arch_rwlock_t *rw)
{
unsigned long flags;
unsigned int ret;
__global_lock1(flags);
fence();
ret = rw->lock--;
__global_unlock1(flags);
WARN_ON(ret == 0);
}
static inline int arch_read_trylock(arch_rwlock_t *rw)
{
unsigned long flags;
unsigned int ret;
__global_lock1(flags);
ret = rw->lock;
if (ret < 0x80000000) {
fence();
rw->lock = ret + 1;
}
__global_unlock1(flags);
return (ret < 0x80000000);
}
/* read_can_lock - would read_trylock() succeed? */
static inline int arch_read_can_lock(arch_rwlock_t *rw)
{
unsigned int ret;
barrier();
ret = rw->lock;
return (ret < 0x80000000);
}
#endif /* __ASM_SPINLOCK_LOCK1_H */
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