Subversion Repositories HelenOS

/** Interrupt sleeping thread.

 *

 * This routine attempts to interrupt a thread from its sleep in a waitqueue.

 * If the thread is not found sleeping, no action is taken.

 *

 * @param t Thread to be interrupted.

 */

void waitq_interrupt_sleep(thread_t *t)

{

    waitq_t *wq;

    bool do_wakeup = false;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&threads_lock);

    if (!thread_exists(t))

        goto out;

grab_locks:

    spinlock_lock(&t->lock);

    if ((wq = t->sleep_queue)) {        /* assignment */

        if (!(t->sleep_interruptible)) {

            /*

             * The sleep cannot be interrupted.

             */

            spinlock_unlock(&t->lock);

            goto out;

        }

        if (!spinlock_trylock(&wq->lock)) {

            spinlock_unlock(&t->lock);

            goto grab_locks;    /* avoid deadlock */

        }

        if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))

            t->timeout_pending = false;

        list_remove(&t->wq_link);

        t->saved_context = t->sleep_interruption_context;

        do_wakeup = true;

        t->sleep_queue = NULL;

        spinlock_unlock(&wq->lock);

    }

    spinlock_unlock(&t->lock);

    if (do_wakeup)

        thread_ready(t);

out:

    spinlock_unlock(&threads_lock);

    interrupts_restore(ipl);

}