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macvtap: handle ubuf refcount correctly when meet errors 

We trigger uarg->callback() immediately after we decide do datacopy
even if caller want to do zerocopy. This will cause the callback
(vhost_net_zerocopy_callback) decrease the refcount. But when we meet
an error afterwards, the error handling in vhost handle_tx() will try
to decrease it again. This is wrong and fix this by delay the
uarg->callback() until we're sure there's no errors.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Jason Wang 2016-11-30 13:17:52 +08:00 committed by David S. Miller
parent af1cc7a2b8
commit aa196eed3d
1 changed files with 5 additions and 6 deletions
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11
drivers/net/macvtap.c
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@ -742,13 +742,8 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
if (zerocopy)
err = zerocopy_sg_from_iter(skb, from);
else {
else
err = skb_copy_datagram_from_iter(skb, 0, from, len);
if (!err && m && m->msg_control) {
struct ubuf_info *uarg = m->msg_control;
uarg->callback(uarg, false);
}
}
if (err)
goto err_kfree;
@ -779,7 +774,11 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
skb_shinfo(skb)->destructor_arg = m->msg_control;
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
} else if (m && m->msg_control) {
struct ubuf_info *uarg = m->msg_control;
uarg->callback(uarg, false);
}
if (vlan) {
skb->dev = vlan->dev;
dev_queue_xmit(skb);