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dst: no need to take reference on DST_NOCACHE dsts

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Since commit f886497212 ("ipv4: fix dst race in sk_dst_get()")
DST_NOCACHE dst_entries get freed by RCU. So there is no need to get a
reference on them when we are in rcu protected sections.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hannes Frederic Sowa
2014-12-06 19:19:42 +01:00
committed by David S. Miller
parent c19be735c9
commit dbfc4fb7d5
3 changed files with 4 additions and 47 deletions
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23
include/linux/skbuff.h
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@@ -717,9 +717,6 @@ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
skb->_skb_refdst = (unsigned long)dst;
}
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
@@ -732,24 +729,8 @@ void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst,
*/
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);
WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
}
/**