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net: factor out a helper to decrement the skb refcount

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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>
This commit is contained in:
Paolo Abeni 2017-06-12 11:23:41 +02:00 committed by David S. Miller
parent 78d6102256
commit 3889a803e1
3 changed files with 18 additions and 13 deletions
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13
include/linux/skbuff.h
View File

@ -867,6 +867,19 @@ static inline unsigned int skb_napi_id(const struct sk_buff *skb)
#endif #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(struct sk_buff *skb);
void kfree_skb_list(struct sk_buff *segs); void kfree_skb_list(struct sk_buff *segs);
void skb_tx_error(struct sk_buff *skb); void skb_tx_error(struct sk_buff *skb);

4
net/core/datagram.c
View File

@ -330,9 +330,7 @@ void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len)
{ {
bool slow; bool slow;
if (likely(atomic_read(&skb->users) == 1)) if (!skb_unref(skb)) {
smp_rmb();
else if (likely(!atomic_dec_and_test(&skb->users))) {
sk_peek_offset_bwd(sk, len); sk_peek_offset_bwd(sk, len);
return; return;
} }

14
net/core/skbuff.c
View File

@ -694,12 +694,9 @@ EXPORT_SYMBOL(__kfree_skb);
*/ */
void kfree_skb(struct sk_buff *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; return;
trace_kfree_skb(skb, __builtin_return_address(0)); trace_kfree_skb(skb, __builtin_return_address(0));
__kfree_skb(skb); __kfree_skb(skb);
} }
@ -746,12 +743,9 @@ EXPORT_SYMBOL(skb_tx_error);
*/ */
void consume_skb(struct sk_buff *skb) 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; return;
trace_consume_skb(skb); trace_consume_skb(skb);
__kfree_skb(skb); __kfree_skb(skb);
} }