On 3/15/25 1:46 AM, Avri Altman wrote:
Shouldn't you now call for reinit_completion now?
before wait_for_dev? Or at ufshcd_dev_cmd_completion ?
complete() increments the counter in struct completion and
wait_for_complete() decrements it, isn't it? From
kernel/sched/completion.c:
void complete(struct completion *x)
{
complete_with_flags(x, 0);
}
EXPORT_SYMBOL(complete);
static void complete_with_flags(struct completion *x, int wake_flags)
{
unsigned long flags;
raw_spin_lock_irqsave(&x->wait.lock, flags);
if (x->done != UINT_MAX)
x->done++;
swake_up_locked(&x->wait, wake_flags);
raw_spin_unlock_irqrestore(&x->wait.lock, flags);
}
As one can see complete() increments x->done if it is less than
UINT_MAX, which should be the case in the UFS driver.
From the same file:
void __sched wait_for_completion(struct completion *x)
{
wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion);
static long __sched
wait_for_common(struct completion *x, long timeout, int state)
{
return __wait_for_common(x, schedule_timeout, timeout, state);
}
static inline long __sched
__wait_for_common(struct completion *x,
long (*action)(long), long timeout, int state)
{
might_sleep();
complete_acquire(x);
raw_spin_lock_irq(&x->wait.lock);
timeout = do_wait_for_common(x, action, timeout, state);
raw_spin_unlock_irq(&x->wait.lock);
complete_release(x);
return timeout;
}
static inline long __sched
do_wait_for_common(struct completion *x,
long (*action)(long), long timeout, int state)
{
if (!x->done) {
DECLARE_SWAITQUEUE(wait);
do {
if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;
break;
}
__prepare_to_swait(&x->wait, &wait);
__set_current_state(state);
raw_spin_unlock_irq(&x->wait.lock);
timeout = action(timeout);
raw_spin_lock_irq(&x->wait.lock);
} while (!x->done && timeout);
__finish_swait(&x->wait, &wait);
if (!x->done)
return timeout;
}
if (x->done != UINT_MAX)
x->done--;
return timeout ?: 1;
}
If I read the above code correctly, it waits until x->done != 0 or the
timeout has been reached. x->done is decremented if a strictly positive
value is returned. do_wait_for_common() ignores pending signals because
state == TASK_UNINTERRUPTIBLE.
Bart.
