From patchwork Sat Aug 19 06:41:29 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "K. Den" X-Patchwork-Id: 9910155 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 B81E0602A0 for ; Sat, 19 Aug 2017 06:41:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0C4F28DA6 for ; Sat, 19 Aug 2017 06:41:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9408A28DA8; Sat, 19 Aug 2017 06:41:54 +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 vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 27CB528DA6 for ; Sat, 19 Aug 2017 06:41:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751329AbdHSGls (ORCPT ); Sat, 19 Aug 2017 02:41:48 -0400 Received: from sender-of-o52.zoho.com ([135.84.80.217]:21434 "EHLO sender-of-o52.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751227AbdHSGlr (ORCPT ); Sat, 19 Aug 2017 02:41:47 -0400 Received: from localhost.localdomain (KD111107163154.au-net.ne.jp [111.107.163.154]) by mx.zohomail.com with SMTPS id 1503124903875454.3079709454738; Fri, 18 Aug 2017 23:41:43 -0700 (PDT) From: Koichiro Den To: mst@redhat.com, jasowang@redhat.com Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH 2/2] vhost-net: revert vhost_exceeds_maxpend logic to its original Date: Sat, 19 Aug 2017 15:41:29 +0900 Message-Id: <20170819064129.27272-1-den@klaipeden.com> X-Mailer: git-send-email 2.9.4 X-ZohoMailClient: External Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP To depend on vq.num and the usage of VHOST_MAX_PEND is not succinct and in some case unexpected, so revert its logic part only. Signed-off-by: Koichiro Den --- drivers/vhost/net.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 06d044862e58..99cf99b308a7 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -433,11 +433,15 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, static bool vhost_exceeds_maxpend(struct vhost_net *net) { + int num_pends; struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; struct vhost_virtqueue *vq = &nvq->vq; - return (nvq->upend_idx + vq->num - VHOST_MAX_PEND) % UIO_MAXIOV - == nvq->done_idx; + num_pends = likely(nvq->upend_idx >= nvq->done_idx) ? + (nvq->upend_idx - nvq->done_idx) : + (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx); + + return num_pends > VHOST_MAX_PEND; } /* Expects to be always run from workqueue - which acts as