From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C19AC43381 for ; Tue, 19 Feb 2019 16:35:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 44D0E20855 for ; Tue, 19 Feb 2019 16:35:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729373AbfBSQfi (ORCPT ); Tue, 19 Feb 2019 11:35:38 -0500 Received: from mail-qk1-f196.google.com ([209.85.222.196]:35665 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727061AbfBSQfi (ORCPT ); Tue, 19 Feb 2019 11:35:38 -0500 Received: by mail-qk1-f196.google.com with SMTP id w204so55301qka.2 for ; Tue, 19 Feb 2019 08:35:37 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=rNyb0phHO/kxef0nUEvEr2Ys4/Fmw8H9FxCGItCtvGA=; b=QuO08/xkcs+2Knu02zozca1NNqTj0n/e27BQf87Xlh3NDNnQxSHQ0JDq89Rs1Pbv6j qxrL7hWIafIPk43/Gpb0qWS1cqok4Tt3vHL86AROuZpWWzM2A9psdzm39jPdmvE9YQwV efp9bWLUOxXnQwoXjuLmHY3qp7AfjoLEXBdheuv6AoPVVlKcIzaqd3Tty2QlWcN91CJJ WmuV03/HuB/dUyvpi6tg3yK+HuMPdo3q2Od+bPfe9STIKe8x+jH/tx/uBFk8M0G2rLBv 3Bs/IOWfJaJuaM+hs5NxKsACE5iHXdCrC8ljkCvYV2xql+DleB6JvDklHsbQZ6GjGEDq Cq9g== X-Gm-Message-State: AHQUAub6DfALlN8G2nNQCbVifcjhBUsHvc0ODYX3jKI1L30hLCZ9zfss VlUJGkmEIkzoxJ+Ic3xP6hSgtQ== X-Google-Smtp-Source: AHgI3IbRMKTY5Xv4vJiPmdjUrnH8JrMhzWN2mYnXytiHTOpgz4V5XW95LLSa7CbThceTjXbJBBDlog== X-Received: by 2002:a37:bc04:: with SMTP id m4mr5711560qkf.41.1550594137204; Tue, 19 Feb 2019 08:35:37 -0800 (PST) Received: from redhat.com (pool-173-76-246-42.bstnma.fios.verizon.net. [173.76.246.42]) by smtp.gmail.com with ESMTPSA id n1sm9900350qti.36.2019.02.19.08.35.35 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 19 Feb 2019 08:35:36 -0800 (PST) Date: Tue, 19 Feb 2019 11:35:34 -0500 From: "Michael S. Tsirkin" To: Colin King Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed Message-ID: <20190219113510-mutt-send-email-mst@kernel.org> References: <20190219135713.10426-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190219135713.10426-1-colin.king@canonical.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 19, 2019 at 01:57:13PM +0000, Colin King wrote: > From: Colin Ian King > > Currently the loop that calls log_write_hva on each iovec is never > executed because of an incorrect error check on the return from the > call to translate_desc. The check should be checking for a -ve error > return and because it makes no sense to iterate over zero items, the > checks should also check for zero too. > > Detected by CoverityScan, CID#1476969 ("Logically dead code") > > Fixes: cc5e71075947 ("vhost: log dirty page correctly") > Signed-off-by: Colin Ian King Jason posted a similar patch recently. Are you happy with that one? > --- > drivers/vhost/vhost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 24a129fcdd61..a9a1709a859a 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len) > > ret = translate_desc(vq, (uintptr_t)vq->used + used_offset, > len, iov, 64, VHOST_ACCESS_WO); > - if (ret) > + if (ret <= 0) > return ret; > > for (i = 0; i < ret; i++) { > -- > 2.20.1