diff options
| -rw-r--r-- | include/linux/skbuff.h | 14 | ||||
| -rw-r--r-- | net/core/dst.c | 29 | ||||
| -rw-r--r-- | net/ipv4/route.c | 9 |
3 files changed, 33 insertions, 19 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 05a358f1ba11..e6ba898de61c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -460,19 +460,7 @@ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) skb->_skb_refdst = (unsigned long)dst; } -/** - * skb_dst_set_noref - sets skb dst, without a reference - * @skb: buffer - * @dst: dst entry - * - * Sets skb dst, assuming a reference was not taken on dst - * skb_dst_drop() should not dst_release() this dst - */ -static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) -{ - WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); - skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; -} +extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst); /** * skb_dst_is_noref - Test if skb dst isnt refcounted diff --git a/net/core/dst.c b/net/core/dst.c index 32e542d7f472..8abe628b79f1 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -271,13 +271,40 @@ void dst_release(struct dst_entry *dst) if (dst) { int newrefcnt; - smp_mb__before_atomic_dec(); newrefcnt = atomic_dec_return(&dst->__refcnt); WARN_ON(newrefcnt < 0); + if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt) { + dst = dst_destroy(dst); + if (dst) + __dst_free(dst); + } } } EXPORT_SYMBOL(dst_release); +/** + * skb_dst_set_noref - sets skb dst, without a reference + * @skb: buffer + * @dst: dst entry + * + * Sets skb dst, assuming a reference was not taken on dst + * skb_dst_drop() should not dst_release() this dst + */ +void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) +{ + WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); + /* If dst not in cache, we must take a reference, because + * dst_release() will destroy dst as soon as its refcount becomes zero + */ + if (unlikely(dst->flags & DST_NOCACHE)) { + dst_hold(dst); + skb_dst_set(skb, dst); + } else { + skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; + } +} +EXPORT_SYMBOL(skb_dst_set_noref); + /* 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 diff --git a/net/ipv4/route.c b/net/ipv4/route.c index ff98983d2a45..d6cb2bfcd8e1 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1105,9 +1105,9 @@ restart: * Note that we do rt_free on this new route entry, so that * once its refcount hits zero, we are still able to reap it * (Thanks Alexey) - * Note also the rt_free uses call_rcu. We don't actually - * need rcu protection here, this is just our path to get - * on the route gc list. + * Note: To avoid expensive rcu stuff for this uncached dst, + * we set DST_NOCACHE so that dst_release() can free dst without + * waiting a grace period. */ rt->dst.flags |= DST_NOCACHE; @@ -1117,12 +1117,11 @@ restart: if (net_ratelimit()) printk(KERN_WARNING "Neighbour table failure & not caching routes.\n"); - rt_drop(rt); + ip_rt_put(rt); return err; } } - rt_free(rt); goto skip_hashing; } |