static ssize_t my_read(struct file *filp, char __user *buf, size_t count,
loff_t *off)
{
ssize_t ret;
mutex_lock(&my_lock);
int len = strlen(str);
mutex_unlock(&my_lock);
if (*off < len || len == 0) {
// ret = wait_event_interruptible_exclusive(my_wait, condition() > 5);
if (!(condition())) {
do {
DEFINE_WAIT(__wait);
\
for (;;) {
prepare_to_wait_exclusive(&my_wait, &__wait,
TASK_INTERRUPTIBLE);
if (condition()) {
finish_wait(&my_wait, &__wait);
break;
}
if (!signal_pending(current)) {
schedule();
continue;
}
ret = -ERESTARTSYS;
abort_exclusive_wait(&my_wait, &__wait,
TASK_INTERRUPTIBLE, NULL);
break;
}
} while (0);
}
if (ret < 0) {
return ret;
}
}
mutex_lock(&my_lock);
ret = simple_read_from_buffer(buf, count, off, str, strlen(str));
mutex_unlock(&my_lock);
return ret;
}
int __sched
__wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
int (*action)(void *), unsigned mode)
{
do {
int ret;
prepare_to_wait_exclusive(wq, &q->wait, mode);
if (!test_bit(q->key.bit_nr, q->key.flags))
continue;
ret = action(q->key.flags);
if (!ret)
continue;
abort_exclusive_wait(wq, &q->wait, mode, &q->key);
return ret;
} while (test_and_set_bit(q->key.bit_nr, q->key.flags));
finish_wait(wq, &q->wait);
return 0;
}
