From dbfc4fb7d578d4f224faa6b60deb40804dfdc1b1 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Sat, 6 Dec 2014 19:19:42 +0100 Subject: dst: no need to take reference on DST_NOCACHE dsts Since commit f8864972126899 ("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 Cc: Julian Anastasov Signed-off-by: Hannes Frederic Sowa Reviewed-by: Julian Anastasov Signed-off-by: David S. Miller --- include/linux/skbuff.h | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) (limited to 'include/linux') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index e9281b5b7f59..ef64cec42804 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -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; } /** -- cgit v1.2.3