From patchwork Mon Jun 27 22:12:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 9201509 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 91A53607D3 for ; Mon, 27 Jun 2016 22:12:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 67D31285C2 for ; Mon, 27 Jun 2016 22:12:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4723E285C9; Mon, 27 Jun 2016 22:12:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DC165285C2 for ; Mon, 27 Jun 2016 22:12:28 +0000 (UTC) Received: from localhost ([::1]:33127 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHelX-00014H-Ea for patchwork-qemu-devel@patchwork.kernel.org; Mon, 27 Jun 2016 18:12:27 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47182) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHelH-00010G-9o for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bHelD-0000vD-JJ for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56722) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bHelD-0000v9-DT for qemu-devel@nongnu.org; Mon, 27 Jun 2016 18:12:07 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9CF2D1176C5; Mon, 27 Jun 2016 22:12:06 +0000 (UTC) Received: from thh440s.redhat.com (ovpn-116-29.ams2.redhat.com [10.36.116.29]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u5RMC4Su031275; Mon, 27 Jun 2016 18:12:05 -0400 From: Thomas Huth To: "Michael S. Tsirkin" , qemu-devel@nongnu.org Date: Tue, 28 Jun 2016 00:12:03 +0200 Message-Id: <1467065523-13881-1-git-send-email-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 27 Jun 2016 22:12:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] virtio: Tell the user what went wrong when event_notifier_init failed 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: , Cc: Cornelia Huck , armbru@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP event_notifier_init() can fail in real life, for example when there are not enough open file handles available (EMFILE) when using a lot of devices. So instead of leaving the average user with a cryptic error number only, print out a proper error message with strerror() instead, so that the user has a better way to figure out what is going on and that using "ulimit -n" might help here for example. Signed-off-by: Thomas Huth Reviewed-by: Eric Blake Reviewed-by: Cornelia Huck --- hw/virtio/virtio-bus.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c index 1313760..08e38fb 100644 --- a/hw/virtio/virtio-bus.c +++ b/hw/virtio/virtio-bus.c @@ -164,7 +164,8 @@ static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus, if (assign) { r = event_notifier_init(notifier, 1); if (r < 0) { - error_report("%s: unable to init event notifier: %d", __func__, r); + error_report("%s: unable to init event notifier: %s (%d)", + __func__, strerror(-r), r); return r; } virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);