Commit d9568ba9 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[NET] link_watch: Always schedule urgent events 



Urgent events may be delayed if we already have a non-urgent event
queued for that device.  This patch changes this by making sure that
an urgent event is always looked at immediately.

I've replaced the LW_RUNNING flag by LW_URGENT since whether work
is scheduled is already kept track by the work queue system.

The only complication is that we have to provide some exclusion for
the setting linkwatch_nextevent which is available in the actual
work function.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db0ccffe

net/core/link_watch.c

+41 −19
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ 




enum lw_bits {

	LW_RUNNING = 0,

	LW_URGENT = 0,

};



static unsigned long linkwatch_flags;
@@ -95,18 +95,41 @@ static void linkwatch_add_event(struct net_device *dev) 
}





static void linkwatch_schedule_work(unsigned long delay)

static void linkwatch_schedule_work(int urgent)

{

	if (test_and_set_bit(LW_RUNNING, &linkwatch_flags))

	unsigned long delay = linkwatch_nextevent - jiffies;



	if (test_bit(LW_URGENT, &linkwatch_flags))

		return;



	/* If we wrap around we'll delay it by at most HZ. */

	if (delay > HZ) {

		linkwatch_nextevent = jiffies;

	/* Minimise down-time: drop delay for up event. */

	if (urgent) {

		if (test_and_set_bit(LW_URGENT, &linkwatch_flags))

			return;

		delay = 0;

	}



	schedule_delayed_work(&linkwatch_work, delay);

	/* If we wrap around we'll delay it by at most HZ. */

	if (delay > HZ)

		delay = 0;



	/*

	 * This is true if we've scheduled it immeditately or if we don't

	 * need an immediate execution and it's already pending.

	 */

	if (schedule_delayed_work(&linkwatch_work, delay) == !delay)

		return;



	/* Don't bother if there is nothing urgent. */

	if (!test_bit(LW_URGENT, &linkwatch_flags))

		return;



	/* It's already running which is good enough. */

	if (!cancel_delayed_work(&linkwatch_work))

		return;



	/* Otherwise we reschedule it again for immediate exection. */

	schedule_delayed_work(&linkwatch_work, 0);

}
@@ -123,7 +146,11 @@ static void __linkwatch_run_queue(int urgent_only) 
	 */

	if (!urgent_only)

		linkwatch_nextevent = jiffies + HZ;

	clear_bit(LW_RUNNING, &linkwatch_flags);

	/* Limit wrap-around effect on delay. */

	else if (time_after(linkwatch_nextevent, jiffies + HZ))

		linkwatch_nextevent = jiffies;



	clear_bit(LW_URGENT, &linkwatch_flags);



	spin_lock_irq(&lweventlist_lock);

	next = lweventlist;
@@ -166,7 +193,7 @@ static void __linkwatch_run_queue(int urgent_only) 
	}



	if (lweventlist)

		linkwatch_schedule_work(linkwatch_nextevent - jiffies);

		linkwatch_schedule_work(0);

}
@@ -187,21 +214,16 @@ static void linkwatch_event(struct work_struct *dummy) 


void linkwatch_fire_event(struct net_device *dev)

{

	if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {

		unsigned long delay;

	int urgent = linkwatch_urgent_event(dev);



	if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {

		dev_hold(dev);



		linkwatch_add_event(dev);

	} else if (!urgent)

		return;



		delay = linkwatch_nextevent - jiffies;



		/* Minimise down-time: drop delay for up event. */

		if (linkwatch_urgent_event(dev))

			delay = 0;



		linkwatch_schedule_work(delay);

	}

	linkwatch_schedule_work(urgent);

}



EXPORT_SYMBOL(linkwatch_fire_event);

CRA Git | Maintained and supported by SUSTech CRA and CCSE