From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:51572) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UUbRv-0005tI-NM for qemu-devel@nongnu.org; Tue, 23 Apr 2013 07:31:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UUbRu-0003Pa-GZ for qemu-devel@nongnu.org; Tue, 23 Apr 2013 07:31:51 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44278 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UUbRu-0003PU-AY for qemu-devel@nongnu.org; Tue, 23 Apr 2013 07:31:50 -0400 Message-ID: <51767124.2060503@suse.de> Date: Tue, 23 Apr 2013 13:31:48 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1366658298-9275-1-git-send-email-agraf@suse.de> <1366716185-36913-1-git-send-email-borntraeger@de.ibm.com> <1366716185-36913-4-git-send-email-borntraeger@de.ibm.com> In-Reply-To: <1366716185-36913-4-git-send-email-borntraeger@de.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 3/4] s390-ccw.img: Fix compile warning in s390 ccw virtio code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger Cc: cornelia.huck@de.ibm.com, qemu-devel@nongnu.org, Dominik Dingel On 04/23/2013 01:23 PM, Christian Borntraeger wrote: > Lets fix this gcc warning: > > virtio.c: In function =E2=80=98vring_send_buf=E2=80=99: > virtio.c:125:35: error: operation on =E2=80=98vr->next_idx=E2=80=99 may= be undefined > [-Werror=3Dsequence-point] > > Signed-off-by: Christian Borntraeger > --- > pc-bios/s390-ccw/virtio.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c > index 79e2941..1968fc6 100644 > --- a/pc-bios/s390-ccw/virtio.c > +++ b/pc-bios/s390-ccw/virtio.c > @@ -122,7 +122,9 @@ static void vring_send_buf(struct vring *vr, void *= p, int len, int flags) > vr->desc[vr->next_idx].addr =3D (ulong)p; > vr->desc[vr->next_idx].len =3D len; > vr->desc[vr->next_idx].flags =3D flags& ~VRING_HIDDEN_IS_CHAIN; > - vr->desc[vr->next_idx].next =3D ++vr->next_idx; > + vr->desc[vr->next_idx].next =3D vr->next_idx; > + vr->desc[vr->next_idx].next++; > + vr->next_idx++; Hrm. This looks a lot more complicated than it needs to. Why is gcc=20 emitting a warning here? Maybe it only wants braces. Please try whether .next =3D ++(vr->next_id); works for you. Alex