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Commit ac4e4af1 authored by Vlad Yasevich's avatar Vlad Yasevich Committed by David S. Miller
Browse files

macvtap: Consistently use rcu functions 



Currently macvtap uses rcu_bh functions in its
user facing fuction macvtap_get_user() and macvtap_put_user().
However, its packet handlers use normal rcu as the rcu_read_lock()
is taken in netif_receive_skb().  We can safely discontinue
the usage or rcu with bh disabled.

Signed-off-by: default avatarVlad Yasevich <vyasevic@redhat.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 441ac0fc

drivers/net/macvtap.c

+9 −9
Original line number Diff line number Diff line
@@ -754,8 +754,8 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 


	skb_probe_transport_header(skb, ETH_HLEN);



	rcu_read_lock_bh();

	vlan = rcu_dereference_bh(q->vlan);

	rcu_read_lock();

	vlan = rcu_dereference(q->vlan);

	/* copy skb_ubuf_info for callback when skb has no error */

	if (zerocopy) {

		skb_shinfo(skb)->destructor_arg = m->msg_control;
@@ -766,7 +766,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 
		macvlan_start_xmit(skb, vlan->dev);

	else

		kfree_skb(skb);

	rcu_read_unlock_bh();

	rcu_read_unlock();



	return total_len;
@@ -774,11 +774,11 @@ err_kfree: 
	kfree_skb(skb);



err:

	rcu_read_lock_bh();

	vlan = rcu_dereference_bh(q->vlan);

	rcu_read_lock();

	vlan = rcu_dereference(q->vlan);

	if (vlan)

		vlan->dev->stats.tx_dropped++;

	rcu_read_unlock_bh();

	rcu_read_unlock();



	return err;

}
@@ -854,11 +854,11 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, 
	copied += len;



done:

	rcu_read_lock_bh();

	vlan = rcu_dereference_bh(q->vlan);

	rcu_read_lock();

	vlan = rcu_dereference(q->vlan);

	if (vlan)

		macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0);

	rcu_read_unlock_bh();

	rcu_read_unlock();



	return ret ? ret : copied;

}