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 <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d460a4c..decce36 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 e508c1e..747263c 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))
+ if (!skb_unref(skb))
return;
- if (likely(atomic_read(&skb->users) == 1))
- smp_rmb();
- else if (likely(!atomic_dec_and_test(&skb->users)))
- 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))
+ if (!skb_unref(skb))
return;
- if (likely(atomic_read(&skb->users) == 1))
- smp_rmb();
- else if (likely(!atomic_dec_and_test(&skb->users)))
- return;
+
trace_consume_skb(skb);
__kfree_skb(skb);
}