/*
* release a write lock on the semaphore
*/
void __up_write(struct rw_semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 0;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 1);
spin_unlock_irqrestore(&sem->wait_lock, flags);
}
/*
* downgrade a write lock into a read lock
* - just wake up any readers at the front of the queue
*/
void __downgrade_write(struct rw_anon_semaphore *sem)
{
unsigned long flags;
raw_spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 1;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 0);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
}
/*
* release a write lock on the semaphore
*/
void fastcall __up_write(struct rw_semaphore *sem)
{
rwsemtrace(sem,"Entering __up_write");
spin_lock(&sem->wait_lock);
sem->activity = 0;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem);
spin_unlock(&sem->wait_lock);
rwsemtrace(sem,"Leaving __up_write");
}
/*
* release a write lock on the semaphore
*/
void __up_write(struct rw_semaphore *sem)
{
unsigned long flags;
raw_spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 0;
#ifdef CONFIG_BRCM_DEBUG_RWSEM
sem->wr_owner = NULL;
#endif
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 1);
raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
}
/*
* downgrade a write lock into a read lock
* - caller incremented waiting part of count and discovered it still negative
* - just wake up any readers at the front of the queue
*/
struct rw_semaphore fastcall *rwsem_downgrade_wake(struct rw_semaphore *sem)
{
rwsemtrace(sem, "Entering rwsem_downgrade_wake");
spin_lock(&sem->wait_lock);
/* do nothing if list empty */
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 1);
spin_unlock(&sem->wait_lock);
rwsemtrace(sem, "Leaving rwsem_downgrade_wake");
return sem;
}
/*
* downgrade a write lock into a read lock
* - just wake up any readers at the front of the queue
*/
void fastcall __downgrade_write(struct rw_semaphore *sem)
{
unsigned long flags;
rwsemtrace(sem, "Entering __downgrade_write");
spin_lock_irqsave(&sem->wait_lock, flags);
sem->activity = 1;
if (!list_empty(&sem->wait_list))
sem = __rwsem_do_wake(sem, 0);
spin_unlock_irqrestore(&sem->wait_lock, flags);
rwsemtrace(sem, "Leaving __downgrade_write");
}
/*
* wait for a lock to be granted
*/
static inline struct rw_semaphore *rwsem_down_failed_common(struct rw_semaphore *sem,
struct rwsem_waiter *waiter,
signed long adjustment)
{
struct task_struct *tsk = current;
signed long count;
set_task_state(tsk,TASK_UNINTERRUPTIBLE);
/* set up my own style of waitqueue */
spin_lock(&sem->wait_lock);
waiter->task = tsk;
list_add_tail(&waiter->list,&sem->wait_list);
/* note that we're now waiting on the lock, but no longer actively read-locking */
count = rwsem_atomic_update(adjustment,sem);
/* if there are no longer active locks, wake the front queued process(es) up
* - it might even be this process, since the waker takes a more active part
*/
if (!(count & RWSEM_ACTIVE_MASK))
sem = __rwsem_do_wake(sem,1);
spin_unlock(&sem->wait_lock);
/* wait to be given the lock */
for (;;) {
if (!waiter->flags)
break;
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}
tsk->state = TASK_RUNNING;
return sem;
}
