Commit 8c105683 authored May 09, 2006 by Herbert Xu Committed by David S. Miller May 09, 2006

[NET] linkwatch: Handle jiffies wrap-around



The test used in the linkwatch does not handle wrap-arounds correctly.
Since the intention of the code is to eliminate bursts of messages we
can afford to delay things up to a second.  Using that fact we can
easily handle wrap-arounds by making sure that we don't delay things
by more than one second.

This is based on diagnosis and a patch by Stefan Rompf.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stefan Rompf <stefan@loplof.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 788252e6

net/core/link_watch.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -170,13 +170,13 @@ void linkwatch_fire_event(struct net_device *dev)
		spin_unlock_irqrestore(&lweventlist_lock, flags);

		if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) {
		unsigned long thisevent = jiffies;
		unsigned long delay = linkwatch_nextevent - jiffies;

		if (thisevent >= linkwatch_nextevent) {
		/* If we wrap around we'll delay it by at most HZ. */
		if (!delay \|\| delay > HZ)
		schedule_work(&linkwatch_work);
		} else {
		schedule_delayed_work(&linkwatch_work, linkwatch_nextevent - thisevent);
		}
		else
		schedule_delayed_work(&linkwatch_work, delay);
		}
		}
		}

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