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net/sock: factor out dequeue/peek with offset code 

And update __sk_queue_drop_skb() to work on the specified queue.
This will help the udp protocol to use an additional private
rx queue in a later patch.

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 2017-05-16 11:20:13 +02:00 committed by David S. Miller
parent 9dca599b7f
commit 65101aeca5
3 changed files with 60 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/skbuff.h
View File

@ -3056,6 +3056,13 @@ static inline void skb_frag_list_init(struct sk_buff *skb)
int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
const struct sk_buff *skb);
struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
struct sk_buff_head *queue,
unsigned int flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb),
int *peeked, int *off, int *err,
struct sk_buff **last);
struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb),

4
include/net/sock.h
View File

@ -2035,8 +2035,8 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer,
void sk_stop_timer(struct sock *sk, struct timer_list *timer);
int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
unsigned int flags,
int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
struct sk_buff *skb, unsigned int flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb));
int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);

90
net/core/datagram.c
View File

@ -161,6 +161,43 @@ static struct sk_buff *skb_set_peeked(struct sk_buff *skb)
return skb;
}
struct sk_buff *__skb_try_recv_from_queue(struct sock *sk,
struct sk_buff_head *queue,
unsigned int flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb),
int *peeked, int *off, int *err,
struct sk_buff **last)
{
struct sk_buff *skb;
*last = queue->prev;
skb_queue_walk(queue, skb) {
if (flags & MSG_PEEK) {
if (*off >= skb->len && (skb->len || *off ||
skb->peeked)) {
*off -= skb->len;
continue;
}
if (!skb->len) {
skb = skb_set_peeked(skb);
if (unlikely(IS_ERR(skb))) {
*err = PTR_ERR(skb);
return skb;
}
}
*peeked = 1;
atomic_inc(&skb->users);
} else {
__skb_unlink(skb, queue);
if (destructor)
destructor(sk, skb);
}
return skb;
}
return NULL;
}
/**
* __skb_try_recv_datagram - Receive a datagram skbuff
* @sk: socket
@ -216,46 +253,20 @@ 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.
*
* Look at current nfs client by the way...
* However, this function was correct in any case. 8)
*/
int _off = *off;
*last = (struct sk_buff *)queue;
spin_lock_irqsave(&queue->lock, cpu_flags);
skb_queue_walk(queue, skb) {
*last = skb;
if (flags & MSG_PEEK) {
if (_off >= skb->len && (skb->len || _off ||
skb->peeked)) {
_off -= skb->len;
continue;
}
if (!skb->len) {
skb = skb_set_peeked(skb);
if (IS_ERR(skb)) {
error = PTR_ERR(skb);
spin_unlock_irqrestore(&queue->lock,
cpu_flags);
goto no_packet;
}
}
*peeked = 1;
atomic_inc(&skb->users);
} else {
__skb_unlink(skb, queue);
if (destructor)
destructor(sk, skb);
}
spin_unlock_irqrestore(&queue->lock, cpu_flags);
*off = _off;
return skb;
}
skb = __skb_try_recv_from_queue(sk, queue, flags, destructor,
peeked, &_off, err, last);
spin_unlock_irqrestore(&queue->lock, cpu_flags);
if (skb)
return skb;
if (!sk_can_busy_loop(sk))
break;
@ -335,8 +346,8 @@ void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len)
}
EXPORT_SYMBOL(__skb_free_datagram_locked);
int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
unsigned int flags,
int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
struct sk_buff *skb, unsigned int flags,
void (*destructor)(struct sock *sk,
struct sk_buff *skb))
{
@ -344,15 +355,15 @@ int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
if (flags & MSG_PEEK) {
err = -ENOENT;
spin_lock_bh(&sk->sk_receive_queue.lock);
if (skb == skb_peek(&sk->sk_receive_queue)) {
__skb_unlink(skb, &sk->sk_receive_queue);
spin_lock_bh(&sk_queue->lock);
if (skb == skb_peek(sk_queue)) {
__skb_unlink(skb, sk_queue);
atomic_dec(&skb->users);
if (destructor)
destructor(sk, skb);
err = 0;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_unlock_bh(&sk_queue->lock);
}
atomic_inc(&sk->sk_drops);
@ -383,7 +394,8 @@ EXPORT_SYMBOL(__sk_queue_drop_skb);
int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
{
int err = __sk_queue_drop_skb(sk, skb, flags, NULL);
int err = __sk_queue_drop_skb(sk, &sk->sk_receive_queue, skb, flags,
NULL);
kfree_skb(skb);
sk_mem_reclaim_partial(sk);