diff options
Diffstat (limited to 'net/core/dst.c')
-rw-r--r-- | net/core/dst.c | 300 |
1 files changed, 67 insertions, 233 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 960e503b5a52..00aa972ad1a1 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); @@ -151,13 +49,13 @@ int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb) } EXPORT_SYMBOL(dst_discard_out); -const u32 dst_default_metrics[RTAX_MAX + 1] = { +const struct dst_metrics dst_default_metrics = { /* This initializer is needed to force linker to place this variable * into const section. Otherwise it might end into bss section. * We really want to avoid false sharing on this variable, and catch * any writes on it. */ - [RTAX_MAX] = 0xdeadbeef, + .refcnt = ATOMIC_INIT(1), }; void dst_init(struct dst_entry *dst, struct dst_ops *ops, @@ -169,7 +67,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops, if (dev) dev_hold(dev); dst->ops = ops; - dst_init_metrics(dst, dst_default_metrics, true); + dst_init_metrics(dst, dst_default_metrics.metrics, true); dst->expires = 0UL; dst->path = dst; dst->from = NULL; @@ -216,41 +114,12 @@ 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; smp_rmb(); -again: child = dst->child; if (!(dst->flags & DST_NOCOUNT)) @@ -269,20 +138,8 @@ again: kmem_cache_free(dst->ops->kmem_cachep, dst); dst = child; - if (dst) { - int nohash = dst->flags & DST_NOHASH; - - if (atomic_dec_and_test(&dst->__refcnt)) { - /* We were real parent of this dst, so kill child. */ - if (nohash) - goto again; - } else { - /* Child is still referenced, return it for freeing. */ - if (nohash) - return dst; - /* Child is still in his hash table */ - } - } + if (dst) + dst_release_immediate(dst); return NULL; } EXPORT_SYMBOL(dst_destroy); @@ -292,47 +149,88 @@ static void dst_destroy_rcu(struct rcu_head *head) struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); dst = dst_destroy(dst); - if (dst) - __dst_free(dst); } +/* Operations to mark dst as DEAD and clean up the net device referenced + * by dst: + * 1. put the dst under loopback interface and discard all tx/rx packets + * on this route. + * 2. release the net_device + * This function should be called when removing routes from the fib tree + * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to + * make the next dst_ops->check() fail. + */ +void dst_dev_put(struct dst_entry *dst) +{ + struct net_device *dev = dst->dev; + + dst->obsolete = DST_OBSOLETE_DEAD; + if (dst->ops->ifdown) + dst->ops->ifdown(dst, dev, true); + dst->input = dst_discard; + dst->output = dst_discard_out; + dst->dev = dev_net(dst->dev)->loopback_dev; + dev_hold(dst->dev); + dev_put(dev); +} +EXPORT_SYMBOL(dst_dev_put); + void dst_release(struct dst_entry *dst) { if (dst) { int newrefcnt; - unsigned short nocache = dst->flags & DST_NOCACHE; newrefcnt = atomic_dec_return(&dst->__refcnt); if (unlikely(newrefcnt < 0)) net_warn_ratelimited("%s: dst:%p refcnt:%d\n", __func__, dst, newrefcnt); - if (!newrefcnt && unlikely(nocache)) + if (!newrefcnt) call_rcu(&dst->rcu_head, dst_destroy_rcu); } } EXPORT_SYMBOL(dst_release); +void dst_release_immediate(struct dst_entry *dst) +{ + if (dst) { + int newrefcnt; + + newrefcnt = atomic_dec_return(&dst->__refcnt); + if (unlikely(newrefcnt < 0)) + net_warn_ratelimited("%s: dst:%p refcnt:%d\n", + __func__, dst, newrefcnt); + if (!newrefcnt) + dst_destroy(dst); + } +} +EXPORT_SYMBOL(dst_release_immediate); + u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old) { - u32 *p = kmalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC); + struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC); if (p) { - u32 *old_p = __DST_METRICS_PTR(old); + struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old); unsigned long prev, new; - memcpy(p, old_p, sizeof(u32) * RTAX_MAX); + atomic_set(&p->refcnt, 1); + memcpy(p->metrics, old_p->metrics, sizeof(p->metrics)); new = (unsigned long) p; prev = cmpxchg(&dst->_metrics, old, new); if (prev != old) { kfree(p); - p = __DST_METRICS_PTR(prev); + p = (struct dst_metrics *)__DST_METRICS_PTR(prev); if (prev & DST_METRICS_READ_ONLY) p = NULL; + } else if (prev & DST_METRICS_REFCOUNTED) { + if (atomic_dec_and_test(&old_p->refcnt)) + kfree(old_p); } } - return p; + BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0); + return (u32 *)p; } EXPORT_SYMBOL(dst_cow_metrics_generic); @@ -341,7 +239,7 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old) { unsigned long prev, new; - new = ((unsigned long) dst_default_metrics) | DST_METRICS_READ_ONLY; + new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY; prev = cmpxchg(&dst->_metrics, old, new); if (prev == old) kfree(__DST_METRICS_PTR(old)); @@ -366,21 +264,25 @@ static int dst_md_discard(struct sk_buff *skb) return 0; } -static void __metadata_dst_init(struct metadata_dst *md_dst, u8 optslen) +static void __metadata_dst_init(struct metadata_dst *md_dst, + enum metadata_type type, u8 optslen) + { struct dst_entry *dst; dst = &md_dst->dst; dst_init(dst, &md_dst_ops, NULL, 1, DST_OBSOLETE_NONE, - DST_METADATA | DST_NOCACHE | DST_NOCOUNT); + DST_METADATA | DST_NOCOUNT); dst->input = dst_md_discard; dst->output = dst_md_discard_out; memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst)); + md_dst->type = type; } -struct metadata_dst *metadata_dst_alloc(u8 optslen, gfp_t flags) +struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type, + gfp_t flags) { struct metadata_dst *md_dst; @@ -388,7 +290,7 @@ struct metadata_dst *metadata_dst_alloc(u8 optslen, gfp_t flags) if (!md_dst) return NULL; - __metadata_dst_init(md_dst, optslen); + __metadata_dst_init(md_dst, type, optslen); return md_dst; } @@ -402,7 +304,8 @@ void metadata_dst_free(struct metadata_dst *md_dst) kfree(md_dst); } -struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, gfp_t flags) +struct metadata_dst __percpu * +metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags) { int cpu; struct metadata_dst __percpu *md_dst; @@ -413,77 +316,8 @@ struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, gfp_t flags) return NULL; for_each_possible_cpu(cpu) - __metadata_dst_init(per_cpu_ptr(md_dst, cpu), optslen); + __metadata_dst_init(per_cpu_ptr(md_dst, cpu), type, optslen); 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; - 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); -} |