diff options
| -rw-r--r-- | include/linux/skbuff.h | 35 | ||||
| -rw-r--r-- | net/core/dst.c | 9 |
2 files changed, 39 insertions, 5 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 878e0ee..364e244 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -575,7 +575,40 @@ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) skb->_skb_refdst = (unsigned long)dst; } -extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst); +extern void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst, + bool force); + +/** + * skb_dst_set_noref - sets skb dst, hopefully, without taking reference + * @skb: buffer + * @dst: dst entry + * + * Sets skb dst, assuming a reference was not taken on dst. + * If dst entry is cached, we do not take reference and dst_release + * will be avoided by refdst_drop. If dst entry is not cached, we take + * reference, so that last dst_release can destroy the dst immediately. + */ +static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) +{ + __skb_dst_set_noref(skb, dst, false); +} + +/** + * skb_dst_set_noref_force - sets skb dst, without taking reference + * @skb: buffer + * @dst: dst entry + * + * Sets skb dst, assuming a reference was not taken on dst. + * No reference is taken and no dst_release will be called. While for + * cached dsts deferred reclaim is a basic feature, for entries that are + * not cached it is caller's job to guarantee that last dst_release for + * provided dst happens when nobody uses it, eg. after a RCU grace period. + */ +static inline void skb_dst_set_noref_force(struct sk_buff *skb, + struct dst_entry *dst) +{ + __skb_dst_set_noref(skb, dst, true); +} /** * skb_dst_is_noref - Test if skb dst isn't refcounted diff --git a/net/core/dst.c b/net/core/dst.c index 35fd12f..df9cc81 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -320,27 +320,28 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old) EXPORT_SYMBOL(__dst_destroy_metrics_generic); /** - * skb_dst_set_noref - sets skb dst, without a reference + * __skb_dst_set_noref - sets skb dst, without a reference * @skb: buffer * @dst: dst entry + * @force: if force is set, use noref version even for DST_NOCACHE entries * * 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) +void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst, bool force) { 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)) { + if (unlikely((dst->flags & DST_NOCACHE) && !force)) { dst_hold(dst); skb_dst_set(skb, dst); } else { skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; } } -EXPORT_SYMBOL(skb_dst_set_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 |
