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From c57df8c118c4c11ef6023034aa454636dd8780db Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Wed, 2 May 2012 11:42:06 +0800
Subject: [PATCH 019/109] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when
skb is built successfully
commit 01d6657b388438def19c8baaea28e742b6ed32ec upstream.
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: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/macvtap.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index f217247..7fecd66 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -698,10 +698,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
if (!skb)
goto err;
- if (zerocopy) {
+ if (zerocopy)
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,
len);
if (err)
@@ -720,8 +719,10 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
rcu_read_lock_bh();
vlan = rcu_dereference_bh(q->vlan);
/* 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)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+ }
if (vlan)
macvlan_start_xmit(skb, vlan->dev);
else
--
1.7.7.6
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