X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=net%2Fcore%2Flink_watch.c;h=a5e372b9ec4df3a866ff4a26b44c4fed96021b8b;hb=a6baf3af89a266a3d745117de570788b956396e7;hp=8b45c9d3b2490ce22bfdffd522dd5530439e8ca3;hpb=4935361766cc73949fe032cd157d314f288922ba;p=linux-2.6-omap-h63xx.git diff --git a/net/core/link_watch.c b/net/core/link_watch.c index 8b45c9d3b24..a5e372b9ec4 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -19,7 +19,6 @@ #include #include #include -#include #include #include #include @@ -27,8 +26,7 @@ enum lw_bits { - LW_RUNNING = 0, - LW_SE_USED + LW_URGENT = 0, }; static unsigned long linkwatch_flags; @@ -37,17 +35,9 @@ static unsigned long linkwatch_nextevent; static void linkwatch_event(struct work_struct *dummy); static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event); -static LIST_HEAD(lweventlist); +static struct net_device *lweventlist; static DEFINE_SPINLOCK(lweventlist_lock); -struct lw_event { - struct list_head list; - struct net_device *dev; -}; - -/* Avoid kmalloc() for most systems */ -static struct lw_event singleevent; - static unsigned char default_operstate(const struct net_device *dev) { if (!netif_carrier_ok(dev)) @@ -79,7 +69,7 @@ static void rfc2863_policy(struct net_device *dev) case IF_LINK_MODE_DEFAULT: default: break; - }; + } dev->operstate = operstate; @@ -87,25 +77,102 @@ static void rfc2863_policy(struct net_device *dev) } -/* Must be called with the rtnl semaphore held */ -void linkwatch_run_queue(void) +static int linkwatch_urgent_event(struct net_device *dev) +{ + return netif_running(dev) && netif_carrier_ok(dev) && + dev->qdisc != dev->qdisc_sleeping; +} + + +static void linkwatch_add_event(struct net_device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&lweventlist_lock, flags); + dev->link_watch_next = lweventlist; + lweventlist = dev; + spin_unlock_irqrestore(&lweventlist_lock, flags); +} + + +static void linkwatch_schedule_work(int urgent) +{ + unsigned long delay = linkwatch_nextevent - jiffies; + + if (test_bit(LW_URGENT, &linkwatch_flags)) + return; + + /* Minimise down-time: drop delay for up event. */ + if (urgent) { + if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) + return; + delay = 0; + } + + /* 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); +} + + +static void __linkwatch_run_queue(int urgent_only) { - struct list_head head, *n, *next; + struct net_device *next; + + /* + * Limit the number of linkwatch events to one + * per second so that a runaway driver does not + * cause a storm of messages on the netlink + * socket. This limit does not apply to up events + * while the device qdisc is down. + */ + if (!urgent_only) + linkwatch_nextevent = jiffies + HZ; + /* 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); - list_replace_init(&lweventlist, &head); + next = lweventlist; + lweventlist = NULL; spin_unlock_irq(&lweventlist_lock); - list_for_each_safe(n, next, &head) { - struct lw_event *event = list_entry(n, struct lw_event, list); - struct net_device *dev = event->dev; + while (next) { + struct net_device *dev = next; - if (event == &singleevent) { - clear_bit(LW_SE_USED, &linkwatch_flags); - } else { - kfree(event); + next = dev->link_watch_next; + + if (urgent_only && !linkwatch_urgent_event(dev)) { + linkwatch_add_event(dev); + continue; } + /* + * Make sure the above read is complete since it can be + * rewritten as soon as we clear the bit below. + */ + smp_mb__before_clear_bit(); + /* We are about to handle this device, * so new events can be accepted */ @@ -124,58 +191,39 @@ void linkwatch_run_queue(void) dev_put(dev); } + + if (lweventlist) + linkwatch_schedule_work(0); } -static void linkwatch_event(struct work_struct *dummy) +/* Must be called with the rtnl semaphore held */ +void linkwatch_run_queue(void) { - /* Limit the number of linkwatch events to one - * per second so that a runaway driver does not - * cause a storm of messages on the netlink - * socket - */ - linkwatch_nextevent = jiffies + HZ; - clear_bit(LW_RUNNING, &linkwatch_flags); + __linkwatch_run_queue(0); +} + +static void linkwatch_event(struct work_struct *dummy) +{ rtnl_lock(); - linkwatch_run_queue(); + __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); rtnl_unlock(); } void linkwatch_fire_event(struct net_device *dev) { - if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { - unsigned long flags; - struct lw_event *event; - - if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) { - event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC); - - if (unlikely(event == NULL)) { - clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); - return; - } - } else { - event = &singleevent; - } + int urgent = linkwatch_urgent_event(dev); + if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { dev_hold(dev); - event->dev = dev; - - spin_lock_irqsave(&lweventlist_lock, flags); - list_add_tail(&event->list, &lweventlist); - spin_unlock_irqrestore(&lweventlist_lock, flags); - if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) { - unsigned long delay = linkwatch_nextevent - jiffies; + linkwatch_add_event(dev); + } else if (!urgent) + return; - /* If we wrap around we'll delay it by at most HZ. */ - if (delay > HZ) - delay = 0; - schedule_delayed_work(&linkwatch_work, delay); - } - } + linkwatch_schedule_work(urgent); } EXPORT_SYMBOL(linkwatch_fire_event);