From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751460Ab1H0CuM (ORCPT ); Fri, 26 Aug 2011 22:50:12 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:61918 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750828Ab1H0CuH (ORCPT ); Fri, 26 Aug 2011 22:50:07 -0400 Subject: Re: [PATCH] virtio: fix size computation according to the definition of struct vring_used in vring_size From: Wanlong Gao Reply-To: wanlong.gao@gmail.com To: Wang Sheng-Hui Cc: rusty@rustcorp.com.au, mst@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <4E584365.1010806@gmail.com> References: <4E584365.1010806@gmail.com> Content-Type: text/plain; charset="UTF-8" Organization: FNST Date: Sat, 27 Aug 2011 10:49:59 +0800 Message-ID: <1314413399.1913.1.camel@Allen> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2011-08-27 at 09:07 +0800, Wang Sheng-Hui wrote: > The patch is against 3.1-rc3. > > struct vring_used has two __u16 fields plus array of struct vring_used_elem. > Current vring_size counts the __u16 fields to 3. Fix it to 2 in the patch. > > Signed-off-by: Wang Sheng-Hui > --- > include/linux/virtio_ring.h | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h > index 4a32cb6..fcda152 100644 > --- a/include/linux/virtio_ring.h > +++ b/include/linux/virtio_ring.h > @@ -143,7 +143,7 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) > { > return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (2 + num) > + align - 1) & ~(align - 1)) > - + sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; > + + sizeof(__u16) * 2 + sizeof(struct vring_used_elem) * num; > } > > /* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ Hi: I'm not deep into it, but I think you can see this: http://marc.info/?l=git-commits-head&m=130687915816130&w=2 Thanks -Wanlong Gao