lkml.org 
[lkml]   [2016]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH net 2/2] macvtap: handle ubuf refcount correctly when meet erros
Date
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>
---
The patch is needed for -stable.
---
drivers/net/macvtap.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index bceca28..7869b06 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -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);
--
2.7.4
\
 
 \ /
  Last update: 2016-11-30 06:19    [W:0.050 / U:0.704 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site