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authorEric Dumazet <eric.dumazet@gmail.com>2010-05-03 23:18:14 -0700
committerDavid S. Miller <davem@davemloft.net>2010-05-03 23:18:14 -0700
commit93bb64eac10aad3dae6178d7da94765f207d121f (patch)
tree5f0990ed1a0a9fa9483d828a16235085d5d84215 /net/core
parentf5460618405eec8c3300947a499011528a115acd (diff)
net: skb_free_datagram_locked() fix
Commit 4b0b72f7dd617b ( net: speedup udp receive path ) introduced a bug in skb_free_datagram_locked(). We should not skb_orphan() skb if we dont have the guarantee we are the last skb user, this might happen with MSG_PEEK concurrent users. To keep socket locked for the smallest period of time, we split consume_skb() logic, inlined in skb_free_datagram_locked() Reported-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/datagram.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 95b851f3d713..e0097531417a 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -229,13 +229,18 @@ EXPORT_SYMBOL(skb_free_datagram);
void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb)
{
+ if (likely(atomic_read(&skb->users) == 1))
+ smp_rmb();
+ else if (likely(!atomic_dec_and_test(&skb->users)))
+ return;
+
lock_sock_bh(sk);
skb_orphan(skb);
sk_mem_reclaim_partial(sk);
unlock_sock_bh(sk);
- /* skb is now orphaned, might be freed outside of locked section */
- consume_skb(skb);
+ /* skb is now orphaned, can be freed outside of locked section */
+ __kfree_skb(skb);
}
EXPORT_SYMBOL(skb_free_datagram_locked);