From 3889a803e1da9bd7cd10d6504bf281ee7e55dfd6 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 12 Jun 2017 11:23:41 +0200 Subject: [PATCH] net: factor out a helper to decrement the skb refcount The same code is replicated in 3 different places; move it to a common helper. Signed-off-by: Paolo Abeni Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/skbuff.h | 13 +++++++++++++ net/core/datagram.c | 4 +--- net/core/skbuff.c | 14 ++++---------- 3 files changed, 18 insertions(+), 13 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index d460a4cbda1c..decce3655a48 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -867,6 +867,19 @@ static inline unsigned int skb_napi_id(const struct sk_buff *skb) #endif } +/* decrement the reference count and return true if we can free the skb */ +static inline bool skb_unref(struct sk_buff *skb) +{ + if (unlikely(!skb)) + return false; + if (likely(atomic_read(&skb->users) == 1)) + smp_rmb(); + else if (likely(!atomic_dec_and_test(&skb->users))) + return false; + + return true; +} + void kfree_skb(struct sk_buff *skb); void kfree_skb_list(struct sk_buff *segs); void skb_tx_error(struct sk_buff *skb); diff --git a/net/core/datagram.c b/net/core/datagram.c index bc46118486fe..e5311a7c70da 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -330,9 +330,7 @@ void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len) { bool slow; - if (likely(atomic_read(&skb->users) == 1)) - smp_rmb(); - else if (likely(!atomic_dec_and_test(&skb->users))) { + if (!skb_unref(skb)) { sk_peek_offset_bwd(sk, len); return; } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e508c1eae67f..747263c49838 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -694,12 +694,9 @@ EXPORT_SYMBOL(__kfree_skb); */ void kfree_skb(struct sk_buff *skb) { - if (unlikely(!skb)) - return; - if (likely(atomic_read(&skb->users) == 1)) - smp_rmb(); - else if (likely(!atomic_dec_and_test(&skb->users))) + if (!skb_unref(skb)) return; + trace_kfree_skb(skb, __builtin_return_address(0)); __kfree_skb(skb); } @@ -746,12 +743,9 @@ EXPORT_SYMBOL(skb_tx_error); */ void consume_skb(struct sk_buff *skb) { - if (unlikely(!skb)) - return; - if (likely(atomic_read(&skb->users) == 1)) - smp_rmb(); - else if (likely(!atomic_dec_and_test(&skb->users))) + if (!skb_unref(skb)) return; + trace_consume_skb(skb); __kfree_skb(skb); } -- 2.45.2