mirror of https://gitee.com/openkylin/linux.git
[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: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -26,7 +26,7 @@
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enum lw_bits {
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LW_RUNNING = 0,
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LW_URGENT = 0,
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};
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static unsigned long linkwatch_flags;
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@ -95,18 +95,41 @@ static void linkwatch_add_event(struct net_device *dev)
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}
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static void linkwatch_schedule_work(unsigned long delay)
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static void linkwatch_schedule_work(int urgent)
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{
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if (test_and_set_bit(LW_RUNNING, &linkwatch_flags))
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unsigned long delay = linkwatch_nextevent - jiffies;
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if (test_bit(LW_URGENT, &linkwatch_flags))
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return;
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/* If we wrap around we'll delay it by at most HZ. */
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if (delay > HZ) {
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linkwatch_nextevent = jiffies;
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/* Minimise down-time: drop delay for up event. */
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if (urgent) {
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if (test_and_set_bit(LW_URGENT, &linkwatch_flags))
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return;
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delay = 0;
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}
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schedule_delayed_work(&linkwatch_work, delay);
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/* If we wrap around we'll delay it by at most HZ. */
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if (delay > HZ)
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delay = 0;
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/*
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* This is true if we've scheduled it immeditately or if we don't
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* need an immediate execution and it's already pending.
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*/
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if (schedule_delayed_work(&linkwatch_work, delay) == !delay)
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return;
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/* Don't bother if there is nothing urgent. */
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if (!test_bit(LW_URGENT, &linkwatch_flags))
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return;
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/* It's already running which is good enough. */
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if (!cancel_delayed_work(&linkwatch_work))
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return;
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/* Otherwise we reschedule it again for immediate exection. */
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schedule_delayed_work(&linkwatch_work, 0);
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}
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@ -123,7 +146,11 @@ static void __linkwatch_run_queue(int urgent_only)
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*/
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if (!urgent_only)
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linkwatch_nextevent = jiffies + HZ;
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clear_bit(LW_RUNNING, &linkwatch_flags);
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/* Limit wrap-around effect on delay. */
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else if (time_after(linkwatch_nextevent, jiffies + HZ))
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linkwatch_nextevent = jiffies;
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clear_bit(LW_URGENT, &linkwatch_flags);
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spin_lock_irq(&lweventlist_lock);
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next = lweventlist;
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@ -166,7 +193,7 @@ static void __linkwatch_run_queue(int urgent_only)
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}
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if (lweventlist)
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linkwatch_schedule_work(linkwatch_nextevent - jiffies);
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linkwatch_schedule_work(0);
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}
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@ -187,21 +214,16 @@ static void linkwatch_event(struct work_struct *dummy)
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void linkwatch_fire_event(struct net_device *dev)
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{
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if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
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unsigned long delay;
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int urgent = linkwatch_urgent_event(dev);
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if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
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dev_hold(dev);
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linkwatch_add_event(dev);
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} else if (!urgent)
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return;
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delay = linkwatch_nextevent - jiffies;
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/* Minimise down-time: drop delay for up event. */
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if (linkwatch_urgent_event(dev))
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delay = 0;
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linkwatch_schedule_work(delay);
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}
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linkwatch_schedule_work(urgent);
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}
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EXPORT_SYMBOL(linkwatch_fire_event);
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