Commit de321ed3 authored by Andrey Vagin's avatar Andrey Vagin Committed by David S. Miller
Browse files

net: fix __skb_try_recv_from_queue to return the old behavior 



This function has to return NULL on a error case, because there is a
separate error variable.

The offset has to be changed only if skb is returned

v2: fix udp code to not use an extra variable

Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Fixes: 65101aec ("net/sock: factor out dequeue/peek with offset cod")
Signed-off-by: default avatarAndrei Vagin <avagin@openvz.org>
Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 66727145

net/core/datagram.c

+8 −6
Original line number Diff line number Diff line
@@ -170,20 +170,21 @@ struct sk_buff *__skb_try_recv_from_queue(struct sock *sk, 
					  struct sk_buff **last)

{

	struct sk_buff *skb;

	int _off = *off;



	*last = queue->prev;

	skb_queue_walk(queue, skb) {

		if (flags & MSG_PEEK) {

			if (*off >= skb->len && (skb->len || *off ||

			if (_off >= skb->len && (skb->len || _off ||

						 skb->peeked)) {

				*off -= skb->len;

				_off -= skb->len;

				continue;

			}

			if (!skb->len) {

				skb = skb_set_peeked(skb);

				if (unlikely(IS_ERR(skb))) {

					*err = PTR_ERR(skb);

					return skb;

					return NULL;

				}

			}

			*peeked = 1;
@@ -193,6 +194,7 @@ struct sk_buff *__skb_try_recv_from_queue(struct sock *sk, 
			if (destructor)

				destructor(sk, skb);

		}

		*off = _off;

		return skb;

	}

	return NULL;
@@ -253,8 +255,6 @@ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned int flags, 


	*peeked = 0;

	do {

		int _off = *off;



		/* Again only user level code calls this function, so nothing

		 * interrupt level will suddenly eat the receive_queue.

		 *
@@ -263,8 +263,10 @@ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned int flags, 
		 */

		spin_lock_irqsave(&queue->lock, cpu_flags);

		skb = __skb_try_recv_from_queue(sk, queue, flags, destructor,

						peeked, &_off, err, last);

						peeked, off, &error, last);

		spin_unlock_irqrestore(&queue->lock, cpu_flags);

		if (error)

			goto no_packet;

		if (skb)

			return skb;

net/ipv4/udp.c

+3 −9
Original line number Diff line number Diff line
@@ -1465,16 +1465,13 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 
		error = -EAGAIN;

		*peeked = 0;

		do {

			int _off = *off;



			spin_lock_bh(&queue->lock);

			skb = __skb_try_recv_from_queue(sk, queue, flags,

							udp_skb_destructor,

							peeked, &_off, err,

							peeked, off, err,

							&last);

			if (skb) {

				spin_unlock_bh(&queue->lock);

				*off = _off;

				return skb;

			}
@@ -1488,20 +1485,17 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, 
			 * the sk_receive_queue lock if fwd memory scheduling

			 * is needed.

			 */

			_off = *off;

			spin_lock(&sk_queue->lock);

			skb_queue_splice_tail_init(sk_queue, queue);



			skb = __skb_try_recv_from_queue(sk, queue, flags,

							udp_skb_dtor_locked,

							peeked, &_off, err,

							peeked, off, err,

							&last);

			spin_unlock(&sk_queue->lock);

			spin_unlock_bh(&queue->lock);

			if (skb) {

				*off = _off;

			if (skb)

				return skb;

			}



busy_check:

			if (!sk_can_busy_loop(sk))