From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752935Ab2GWBmT (ORCPT ); Sun, 22 Jul 2012 21:42:19 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53967 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862Ab2GWBmM (ORCPT ); Sun, 22 Jul 2012 21:42:12 -0400 Message-Id: <20120723010654.414283596@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 23 Jul 2012 02:07:10 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jason Wang , "Michael S. Tsirkin" Subject: [ 019/108] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when skb is built successfully In-Reply-To: <20120723010651.408577075@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang 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 Signed-off-by: Michael S. Tsirkin Signed-off-by: Ben Hutchings --- drivers/net/macvtap.c | 9 +++++---- 1 file 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