* to dirty as few cache lines as possible in __dst_free().
* As this is not a very strong hint, we dont force an alignment on SMP.
*/
-static struct {
- spinlock_t lock;
- struct dst_entry *list;
- unsigned long timer_inc;
- unsigned long timer_expires;
-} dst_garbage = {
- .lock = __SPIN_LOCK_UNLOCKED(dst_garbage.lock),
- .timer_inc = DST_GC_MAX,
-};
-static void dst_gc_task(struct work_struct *work);
-static void ___dst_free(struct dst_entry *dst);
-
-static DECLARE_DELAYED_WORK(dst_gc_work, dst_gc_task);
-
-static DEFINE_MUTEX(dst_gc_mutex);
-/*
- * long lived entries are maintained in this list, guarded by dst_gc_mutex
- */
-static struct dst_entry *dst_busy_list;
-
-static void dst_gc_task(struct work_struct *work)
-{
- int delayed = 0;
- int work_performed = 0;
- unsigned long expires = ~0L;
- struct dst_entry *dst, *next, head;
- struct dst_entry *last = &head;
-
- mutex_lock(&dst_gc_mutex);
- next = dst_busy_list;
-
-loop:
- while ((dst = next) != NULL) {
- next = dst->next;
- prefetch(&next->next);
- cond_resched();
- if (likely(atomic_read(&dst->__refcnt))) {
- last->next = dst;
- last = dst;
- delayed++;
- continue;
- }
- work_performed++;
-
- dst = dst_destroy(dst);
- if (dst) {
- /* NOHASH and still referenced. Unless it is already
- * on gc list, invalidate it and add to gc list.
- *
- * Note: this is temporary. Actually, NOHASH dst's
- * must be obsoleted when parent is obsoleted.
- * But we do not have state "obsoleted, but
- * referenced by parent", so it is right.
- */
- if (dst->obsolete > 0)
- continue;
-
- ___dst_free(dst);
- dst->next = next;
- next = dst;
- }
- }
-
- spin_lock_bh(&dst_garbage.lock);
- next = dst_garbage.list;
- if (next) {
- dst_garbage.list = NULL;
- spin_unlock_bh(&dst_garbage.lock);
- goto loop;
- }
- last->next = NULL;
- dst_busy_list = head.next;
- if (!dst_busy_list)
- dst_garbage.timer_inc = DST_GC_MAX;
- else {
- /*
- * if we freed less than 1/10 of delayed entries,
- * we can sleep longer.
- */
- if (work_performed <= delayed/10) {
- dst_garbage.timer_expires += dst_garbage.timer_inc;
- if (dst_garbage.timer_expires > DST_GC_MAX)
- dst_garbage.timer_expires = DST_GC_MAX;
- dst_garbage.timer_inc += DST_GC_INC;
- } else {
- dst_garbage.timer_inc = DST_GC_INC;
- dst_garbage.timer_expires = DST_GC_MIN;
- }
- expires = dst_garbage.timer_expires;
- /*
- * if the next desired timer is more than 4 seconds in the
- * future then round the timer to whole seconds
- */
- if (expires > 4*HZ)
- expires = round_jiffies_relative(expires);
- schedule_delayed_work(&dst_gc_work, expires);
- }
-
- spin_unlock_bh(&dst_garbage.lock);
- mutex_unlock(&dst_gc_mutex);
-}
-
int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
}
EXPORT_SYMBOL(dst_alloc);
-static void ___dst_free(struct dst_entry *dst)
-{
- /* The first case (dev==NULL) is required, when
- protocol module is unloaded.
- */
- if (dst->dev == NULL || !(dst->dev->flags&IFF_UP)) {
- dst->input = dst_discard;
- dst->output = dst_discard_out;
- }
- dst->obsolete = DST_OBSOLETE_DEAD;
-}
-
-void __dst_free(struct dst_entry *dst)
-{
- spin_lock_bh(&dst_garbage.lock);
- ___dst_free(dst);
- dst->next = dst_garbage.list;
- dst_garbage.list = dst;
- if (dst_garbage.timer_inc > DST_GC_INC) {
- dst_garbage.timer_inc = DST_GC_INC;
- dst_garbage.timer_expires = DST_GC_MIN;
- mod_delayed_work(system_wq, &dst_gc_work,
- dst_garbage.timer_expires);
- }
- spin_unlock_bh(&dst_garbage.lock);
-}
-EXPORT_SYMBOL(__dst_free);
-
struct dst_entry *dst_destroy(struct dst_entry * dst)
{
struct dst_entry *child;
return md_dst;
}
EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
-
-/* Dirty hack. We did it in 2.2 (in __dst_free),
- * we have _very_ good reasons not to repeat
- * this mistake in 2.3, but we have no choice
- * now. _It_ _is_ _explicit_ _deliberate_
- * _race_ _condition_.
- *
- * Commented and originally written by Alexey.
- */
-static void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
- int unregister)
-{
- if (dst->ops->ifdown)
- dst->ops->ifdown(dst, dev, unregister);
-
- if (dev != dst->dev)
- return;
-
- if (!unregister) {
- dst->input = dst_discard;
- dst->output = dst_discard_out;
- } else {
- dst->dev = dev_net(dst->dev)->loopback_dev;
- dev_hold(dst->dev);
- dev_put(dev);
- }
-}
-
-static int dst_dev_event(struct notifier_block *this, unsigned long event,
- void *ptr)
-{
- struct net_device *dev = netdev_notifier_info_to_dev(ptr);
- struct dst_entry *dst, *last = NULL;
-
- switch (event) {
- case NETDEV_UNREGISTER_FINAL:
- case NETDEV_DOWN:
- mutex_lock(&dst_gc_mutex);
- for (dst = dst_busy_list; dst; dst = dst->next) {
- last = dst;
- dst_ifdown(dst, dev, event != NETDEV_DOWN);
- }
-
- spin_lock_bh(&dst_garbage.lock);
- dst = dst_garbage.list;
- dst_garbage.list = NULL;
- /* The code in dst_ifdown places a hold on the loopback device.
- * If the gc entry processing is set to expire after a lengthy
- * interval, this hold can cause netdev_wait_allrefs() to hang
- * out and wait for a long time -- until the the loopback
- * interface is released. If we're really unlucky, it'll emit
- * pr_emerg messages to console too. Reset the interval here,
- * so dst cleanups occur in a more timely fashion.
- */
- if (dst_garbage.timer_inc > DST_GC_INC) {
- dst_garbage.timer_inc = DST_GC_INC;
- dst_garbage.timer_expires = DST_GC_MIN;
- mod_delayed_work(system_wq, &dst_gc_work,
- dst_garbage.timer_expires);
- }
- spin_unlock_bh(&dst_garbage.lock);
-
- if (last)
- last->next = dst;
- else
- dst_busy_list = dst;
- for (; dst; dst = dst->next)
- dst_ifdown(dst, dev, event != NETDEV_DOWN);
- mutex_unlock(&dst_gc_mutex);
- break;
- }
- return NOTIFY_DONE;
-}
-
-static struct notifier_block dst_dev_notifier = {
- .notifier_call = dst_dev_event,
- .priority = -10, /* must be called after other network notifiers */
-};
-
-void __init dst_subsys_init(void)
-{
- register_netdevice_notifier(&dst_dev_notifier);
-}
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff