From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752954Ab2GWBmV (ORCPT ); Sun, 22 Jul 2012 21:42:21 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53963 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752859Ab2GWBmL (ORCPT ); Sun, 22 Jul 2012 21:42:11 -0400 Message-Id: <20120723010653.983024423@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 23 Jul 2012 02:07:07 +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: [ 016/108] macvtap: zerocopy: fix offset calculation when building skb 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 3afc9621f15701c557e60f61eba9242bac2771dd upstream. This patch fixes the offset calculation when building skb: - offset1 were used as skb data offset not vector offset - reset offset to zero only when we advance to next vector Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin Signed-off-by: Ben Hutchings --- drivers/net/macvtap.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 0427c65..bd4a70d 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -505,10 +505,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, if (copy > size) { ++from; --count; - } + offset = 0; + } else + offset += size; copy -= size; offset1 += size; - offset = 0; } if (len == offset1) @@ -519,13 +520,13 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, int num_pages; unsigned long base; - len = from->iov_len - offset1; + len = from->iov_len - offset; if (!len) { - offset1 = 0; + offset = 0; ++from; continue; } - base = (unsigned long)from->iov_base + offset1; + base = (unsigned long)from->iov_base + offset; size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; num_pages = get_user_pages_fast(base, size, 0, &page[i]); if ((num_pages != size) || @@ -546,7 +547,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, len -= size; i++; } - offset1 = 0; + offset = 0; ++from; } return 0;