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net: fix __skb_try_recv_from_queue to return the old behavior

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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: 65101aeca5 ("net/sock: factor out dequeue/peek with offset cod")
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andrey Vagin 2017-05-17 11:39:05 -07:00 committed by David S. Miller
parent 667271455f
commit de321ed384
2 changed files with 11 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
net/core/datagram.c
View file

@ -170,20 +170,21 @@ struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
struct sk_buff **last) struct sk_buff **last)
{ {
struct sk_buff *skb; struct sk_buff *skb;
int _off = *off;
*last = queue->prev; *last = queue->prev;
skb_queue_walk(queue, skb) { skb_queue_walk(queue, skb) {
if (flags & MSG_PEEK) { if (flags & MSG_PEEK) {
if (*off >= skb->len && (skb->len || *off || if (_off >= skb->len && (skb->len || _off ||
skb->peeked)) { skb->peeked)) {
*off -= skb->len; _off -= skb->len;
continue; continue;
} }
if (!skb->len) { if (!skb->len) {
skb = skb_set_peeked(skb); skb = skb_set_peeked(skb);
if (unlikely(IS_ERR(skb))) { if (unlikely(IS_ERR(skb))) {
*err = PTR_ERR(skb); *err = PTR_ERR(skb);
return skb; return NULL;
} }
} }
*peeked = 1; *peeked = 1;
@ -193,6 +194,7 @@ struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
if (destructor) if (destructor)
destructor(sk, skb); destructor(sk, skb);
} }
*off = _off;
return skb; return skb;
} }
return NULL; return NULL;
@ -253,8 +255,6 @@ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned int flags,
*peeked = 0; *peeked = 0;
do { do {
int _off = *off;
/* Again only user level code calls this function, so nothing /* Again only user level code calls this function, so nothing
* interrupt level will suddenly eat the receive_queue. * 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); spin_lock_irqsave(&queue->lock, cpu_flags);
skb = __skb_try_recv_from_queue(sk, queue, flags, destructor, 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); spin_unlock_irqrestore(&queue->lock, cpu_flags);
if (error)
goto no_packet;
if (skb) if (skb)
return skb; return skb;

12
net/ipv4/udp.c
View file

@ -1465,16 +1465,13 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
error = -EAGAIN; error = -EAGAIN;
*peeked = 0; *peeked = 0;
do { do {
int _off = *off;
spin_lock_bh(&queue->lock); spin_lock_bh(&queue->lock);
skb = __skb_try_recv_from_queue(sk, queue, flags, skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_destructor, udp_skb_destructor,
peeked, &_off, err, peeked, off, err,
&last); &last);
if (skb) { if (skb) {
spin_unlock_bh(&queue->lock); spin_unlock_bh(&queue->lock);
*off = _off;
return skb; 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 * the sk_receive_queue lock if fwd memory scheduling
* is needed. * is needed.
*/ */
_off = *off;
spin_lock(&sk_queue->lock); spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, queue); skb_queue_splice_tail_init(sk_queue, queue);
skb = __skb_try_recv_from_queue(sk, queue, flags, skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_dtor_locked, udp_skb_dtor_locked,
peeked, &_off, err, peeked, off, err,
&last); &last);
spin_unlock(&sk_queue->lock); spin_unlock(&sk_queue->lock);
spin_unlock_bh(&queue->lock); spin_unlock_bh(&queue->lock);
if (skb) { if (skb)
*off = _off;
return skb; return skb;
}
busy_check: busy_check:
if (!sk_can_busy_loop(sk)) if (!sk_can_busy_loop(sk))