#include <linux/rtnetlink.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
-#include <linux/list.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
enum lw_bits {
- LW_RUNNING = 0,
- LW_SE_USED
+ LW_URGENT = 0,
};
static unsigned long linkwatch_flags;
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))
case IF_LINK_MODE_DEFAULT:
default:
break;
- };
+ }
dev->operstate = operstate;
}
-/* 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
*/
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);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff