From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [V2 PATCH 4/9] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when skb is built successfully Date: Wed, 02 May 2012 11:42:06 +0800 Message-ID: <20120502034206.11782.91643.stgit@amd-6168-8-1.englab.nay.redhat.com> References: <20120502033901.11782.13157.stgit@amd-6168-8-1.englab.nay.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: eric.dumazet@gmail.com, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ebiederm@xmission.com, davem@davemloft.net Return-path: In-Reply-To: <20120502033901.11782.13157.stgit@amd-6168-8-1.englab.nay.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- 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 9ab182a..a4ff694 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -699,10 +699,9 @@ 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) @@ -721,8 +720,10 @@ 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