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authorWillem de Bruijn <willemb@google.com>2014-08-31 21:30:27 -0400
committerDavid S. Miller <davem@davemloft.net>2014-09-01 21:49:08 -0700
commit364a9e93243d1785f310c0964af0e24bf1adac03 (patch)
treed94daf2c5c0cf6492708d28c56160f96d9917201 /net/core/skbuff.c
parent8fe2f761cae9da9f9031162f104164a812ce78ab (diff)
sock: deduplicate errqueue dequeue
sk->sk_error_queue is dequeued in four locations. All share the exact same logic. Deduplicate. Also collapse the two critical sections for dequeue (at the top of the recv handler) and signal (at the bottom). This moves signal generation for the next packet forward, which should be harmless. It also changes the behavior if the recv handler exits early with an error. Previously, a signal for follow-up packets on the errqueue would then not be scheduled. The new behavior, to always signal, is arguably a bug fix. For rxrpc, the change causes the same function to be called repeatedly for each queued packet (because the recv handler == sk_error_report). It is likely that all packets will fail for the same reason (e.g., memory exhaustion). This code runs without sk_lock held, so it is not safe to trust that sk->sk_err is immutable inbetween releasing q->lock and the subsequent test. Introduce int err just to avoid this potential race. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r--net/core/skbuff.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 163b673f9e62..53ce536e3d6e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3491,6 +3491,26 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(sock_queue_err_skb);
+struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
+{
+ struct sk_buff_head *q = &sk->sk_error_queue;
+ struct sk_buff *skb, *skb_next;
+ int err = 0;
+
+ spin_lock_bh(&q->lock);
+ skb = __skb_dequeue(q);
+ if (skb && (skb_next = skb_peek(q)))
+ err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
+ spin_unlock_bh(&q->lock);
+
+ sk->sk_err = err;
+ if (err)
+ sk->sk_error_report(sk);
+
+ return skb;
+}
+EXPORT_SYMBOL(sock_dequeue_err_skb);
+
void __skb_tstamp_tx(struct sk_buff *orig_skb,
struct skb_shared_hwtstamps *hwtstamps,
struct sock *sk, int tstype)