DECLARE_WAIT_QUEUE_HEAD_ONSTACK (unlink_wakeup);
DECLARE_WAITQUEUE (wait, current);
netif_stop_queue (net);
if (netif_msg_ifdown (dev))
devinfo (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
net->stats.rx_packets, net->stats.tx_packets,
net->stats.rx_errors, net->stats.tx_errors
);
// ensure there are no more active urbs
add_wait_queue (&unlink_wakeup, &wait);
dev->wait = &unlink_wakeup;
temp = unlink_urbs (dev, &dev->txq) + unlink_urbs (dev, &dev->rxq);
// maybe wait for deletions to finish.
while (!skb_queue_empty(&dev->rxq)
&& !skb_queue_empty(&dev->txq)
&& !skb_queue_empty(&dev->done)) {
msleep(UNLINK_TIMEOUT_MS);
if (netif_msg_ifdown (dev))
devdbg (dev, "waited for %d urb completions", temp);
}
dev->wait = NULL;
remove_wait_queue (&unlink_wakeup, &wait);
Can somebody explain to me why a waitqueue and the loop with msleep
is used? This makes no sense to me. Is there some deep reasoning going on?
Regards
Oliver
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