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Commit 01d6657b authored by Jason Wang's avatar Jason Wang Committed by Michael S. Tsirkin
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macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when skb is built successfully 



Current the SKBTX_DEV_ZEROCOPY is set unconditionally after
zerocopy_sg_from_iovec(), this would lead NULL pointer when macvtap
fails to build zerocopy skb because destructor_arg was not
initialized. Solve this by set this flag after the skb were built
successfully.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 02ce04bb

drivers/net/macvtap.c

+5 −4
Original line number Original line Diff line number Diff line
@@ -699,10 +699,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 
	if (!skb)

	if (!skb)

		goto err;

		goto err;





	if (zerocopy) {

	if (zerocopy)

		err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);

		err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);

		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;

	else

	} else

		err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,

		err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,

						   len);

						   len);

	if (err)

	if (err)
@@ -721,8 +720,10 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 
	rcu_read_lock_bh();

	rcu_read_lock_bh();

	vlan = rcu_dereference_bh(q->vlan);

	vlan = rcu_dereference_bh(q->vlan);

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

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

	if (zerocopy)

	if (zerocopy) {

		skb_shinfo(skb)->destructor_arg = m->msg_control;

		skb_shinfo(skb)->destructor_arg = m->msg_control;

		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;

	}

	if (vlan)

	if (vlan)

		macvlan_start_xmit(skb, vlan->dev);

		macvlan_start_xmit(skb, vlan->dev);

	else

	else