net: add skb_dst_set_noref_force
Rename skb_dst_set_noref to __skb_dst_set_noref and add force flag as suggested by David Miller. The new wrapper skb_dst_set_noref_force will force dst entries that are not cached to be attached as skb dst without taking reference as long as provided dst is reclaimed after RCU grace period. Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off by: Hans Schillstrom <hans@schillstrom.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Simon Horman <horms@verge.net.au>
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committed by
Pablo Neira Ayuso

parent
e5c5d22e8d
commit
932bc4d7a5
@@ -320,27 +320,28 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
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EXPORT_SYMBOL(__dst_destroy_metrics_generic);
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/**
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* skb_dst_set_noref - sets skb dst, without a reference
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* __skb_dst_set_noref - sets skb dst, without a reference
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* @skb: buffer
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* @dst: dst entry
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* @force: if force is set, use noref version even for DST_NOCACHE entries
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*
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* Sets skb dst, assuming a reference was not taken on dst
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* skb_dst_drop() should not dst_release() this dst
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*/
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void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
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void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst, bool force)
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{
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WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
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/* If dst not in cache, we must take a reference, because
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* dst_release() will destroy dst as soon as its refcount becomes zero
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*/
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if (unlikely(dst->flags & DST_NOCACHE)) {
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if (unlikely((dst->flags & DST_NOCACHE) && !force)) {
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dst_hold(dst);
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skb_dst_set(skb, dst);
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} else {
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skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
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}
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}
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EXPORT_SYMBOL(skb_dst_set_noref);
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EXPORT_SYMBOL(__skb_dst_set_noref);
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/* Dirty hack. We did it in 2.2 (in __dst_free),
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* we have _very_ good reasons not to repeat
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