From nobody Wed Oct 29 17:11:31 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 152542769740513.284079870474898; Fri, 4 May 2018 02:54:57 -0700 (PDT) Received: from localhost ([::1]:33356 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fEXQT-0000x5-8o for importer@patchew.org; Fri, 04 May 2018 05:54:53 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fEXPb-0000Ol-QC for qemu-devel@nongnu.org; Fri, 04 May 2018 05:54:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fEXPW-0003p3-VV for qemu-devel@nongnu.org; Fri, 04 May 2018 05:53:59 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34930 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fEXPW-0003oB-RB for qemu-devel@nongnu.org; Fri, 04 May 2018 05:53:54 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CE25240858CD for ; Fri, 4 May 2018 09:53:50 +0000 (UTC) Received: from dgilbert-t530.redhat.com (unknown [10.36.117.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 22DD3215CDA7; Fri, 4 May 2018 09:53:47 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, mst@redhat.com, marcandre.lureau@redhat.com Date: Fri, 4 May 2018 10:53:46 +0100 Message-Id: <20180504095346.14159-1-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 04 May 2018 09:53:50 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 04 May 2018 09:53:50 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dgilbert@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] libvhost-user: Send messages with no data X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" The response to a VHOST_USER_POSTCOPY_ADVISE contains a fd but doesn't actually contain any data. FIx vu_message_write so that it doesn't do a 0-byte write() call, since this was ending up with rc=3D0 that was confusing the error handling code. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Marc-Andr=C3=A9 Lureau --- contrib/libvhost-user/libvhost-user.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/= libvhost-user.c index beeed0c43f..54e643d871 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -323,13 +323,15 @@ vu_message_write(VuDev *dev, int conn_fd, VhostUserMs= g *vmsg) rc =3D sendmsg(conn_fd, &msg, 0); } while (rc < 0 && (errno =3D=3D EINTR || errno =3D=3D EAGAIN)); =20 - do { - if (vmsg->data) { - rc =3D write(conn_fd, vmsg->data, vmsg->size); - } else { - rc =3D write(conn_fd, p + VHOST_USER_HDR_SIZE, vmsg->size); - } - } while (rc < 0 && (errno =3D=3D EINTR || errno =3D=3D EAGAIN)); + if (vmsg->size) { + do { + if (vmsg->data) { + rc =3D write(conn_fd, vmsg->data, vmsg->size); + } else { + rc =3D write(conn_fd, p + VHOST_USER_HDR_SIZE, vmsg->size); + } + } while (rc < 0 && (errno =3D=3D EINTR || errno =3D=3D EAGAIN)); + } =20 if (rc <=3D 0) { vu_panic(dev, "Error while writing: %s", strerror(errno)); --=20 2.17.0