[PATCH net-next 1/3] net: factor out a helper to decrement the skb refcount
From: Paolo Abeni <pabeni@redhat.com>
Date: 2017-05-29 15:28:03
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The same code is replicated in 3 different places; move it to a common helper. Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- 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 45a59c1..3c25fca 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 bc46118..e5311a7 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 780b7c1..c81b828 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); }
--
2.9.4