From 5b7c9a8ff828287af5aebe93e707271bf1a82cc3 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Sat, 17 Jun 2017 10:42:40 -0700 Subject: net: remove dst gc related code This patch removes all dst gc related code and all the dst free functions Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- net/core/dst.c | 213 --------------------------------------------------------- 1 file changed, 213 deletions(-) (limited to 'net/core/dst.c') diff --git a/net/core/dst.c b/net/core/dst.c index 64056ecca5b8..30bea01d2262 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -42,108 +42,6 @@ * 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); @@ -216,34 +114,6 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev, } 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; @@ -448,86 +318,3 @@ struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, gfp_t flags) 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); -} -- cgit