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Commit 654d1f8a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

packet: less dev_put() calls 



- packet_sendmsg_spkt() can use dev_get_by_name_rcu() to avoid touching device refcount.

- packet_getname_spkt() & packet_getname() can use dev_get_by_index_rcu() to
  avoid touching device refcount too.

tpacket_snd() & packet_snd() can not use RCU yet because they can sleep when
allocating skb.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1178f66e

net/packet/af_packet.c

+12 −10
Original line number Diff line number Diff line
@@ -437,7 +437,8 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock, 
	 */



	saddr->spkt_device[13] = 0;

	dev = dev_get_by_name(sock_net(sk), saddr->spkt_device);

	rcu_read_lock();

	dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);

	err = -ENODEV;

	if (dev == NULL)

		goto out_unlock;
@@ -500,14 +501,13 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock, 
	 */



	dev_queue_xmit(skb);

	dev_put(dev);

	rcu_read_unlock();

	return len;



out_free:

	kfree_skb(skb);

out_unlock:

	if (dev)

		dev_put(dev);

	rcu_read_unlock();

	return err;

}
@@ -1518,12 +1518,13 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr, 
		return -EOPNOTSUPP;



	uaddr->sa_family = AF_PACKET;

	dev = dev_get_by_index(sock_net(sk), pkt_sk(sk)->ifindex);

	if (dev) {

	rcu_read_lock();

	dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);

	if (dev)

		strlcpy(uaddr->sa_data, dev->name, 15);

		dev_put(dev);

	} else

	else

		memset(uaddr->sa_data, 0, 14);

	rcu_read_unlock();

	*uaddr_len = sizeof(*uaddr);



	return 0;
@@ -1543,16 +1544,17 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr, 
	sll->sll_family = AF_PACKET;

	sll->sll_ifindex = po->ifindex;

	sll->sll_protocol = po->num;

	dev = dev_get_by_index(sock_net(sk), po->ifindex);

	rcu_read_lock();

	dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);

	if (dev) {

		sll->sll_hatype = dev->type;

		sll->sll_halen = dev->addr_len;

		memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);

		dev_put(dev);

	} else {

		sll->sll_hatype = 0;	/* Bad: we have no ARPHRD_UNSPEC */

		sll->sll_halen = 0;

	}

	rcu_read_unlock();

	*uaddr_len = offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;



	return 0;