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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 B12EEC433E6 for ; Thu, 21 Jan 2021 00:52:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AC8F23730 for ; Thu, 21 Jan 2021 00:52:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728191AbhAUAvq (ORCPT ); Wed, 20 Jan 2021 19:51:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:33986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732789AbhAUAbf (ORCPT ); Wed, 20 Jan 2021 19:31:35 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 032102376F; Thu, 21 Jan 2021 00:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611189054; bh=4yI1tHsy7IU5ZtsfF68rC47orrOygZ+JpaM2hnsfqGo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iWnwvweNrT/zWAAr1o94ACIxD2d52gIZHO+DTKnrAoZA6C/8yHZEvXA/g9pK8Q1bD exhyyXx7mFrbBgemBuOtJDjF8KSqWe2y/0bG+MN0XtDIcgVCK8NeSbhDVVbpcwjuOs obGchRMqgE35o0yO2ZtUCAID2uGxaJfjgXVblXfW0Ygvg+gCZMc7ruWWHENwAZDHeF lHBh6RGuTkKmGx6hjor4lDKUyTFQRfBW2MKkcd7n/+FAj85XZlMvcWif/s7nmpY/cl HEXPj57fK1zqZUo27sHESK4p7msj1Xpx+zlGAtmLzZytkJuvtiogf8DxfAa6bXy5U4 th4s3WlGBNfgQ== Date: Thu, 21 Jan 2021 02:30:49 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: Tianjia Zhang , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, Jia Zhang Subject: Re: [PATCH v2] x86/sgx: Remove redundant if conditions in sgx_encl_create Message-ID: References: <20210120035328.19868-1-tianjia.zhang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Wed, Jan 20, 2021 at 09:47:53AM -0800, Sean Christopherson wrote: > On Wed, Jan 20, 2021, Tianjia Zhang wrote: > > In this scenario, there is no case where va_page is NULL, and > > the error has been checked. The if condition statement here is > > redundant, so remove the condition detection. > > > > Reported-by: Jia Zhang > > Suggested-by: Sean Christopherson > > Signed-off-by: Tianjia Zhang > > --- > > arch/x86/kernel/cpu/sgx/ioctl.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c > > index 1c6ecf9fbeff..efad2fb61c76 100644 > > --- a/arch/x86/kernel/cpu/sgx/ioctl.c > > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c > > @@ -66,9 +66,12 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs) > > va_page = sgx_encl_grow(encl); > > if (IS_ERR(va_page)) > > return PTR_ERR(va_page); > > - else if (va_page) > > - list_add(&va_page->list, &encl->va_pages); > > - /* else the tail page of the VA page list had free slots. */ > > + > > + if (WARN_ONCE(!va_page, > > + "the tail page of the VA page list had free slots\n")) > > IMO it's worth trimming down the message to keep this on a single line. The > newline isn't necessary, and this code expects a completely empty list, e.g. it > can be reworded to something like: > > if (WARN_ONCE(!va_page, "non-empty VA page list before ECREATE")) Agreed. If I recall correctly, these days you can have at least 100 characters per line (if not more, cannot recall the exact number). /Jarkko > > > + return -EIO; > > + > > + list_add(&va_page->list, &encl->va_pages); > > > > /* The extra page goes to SECS. */ > > encl_size = secs->size + PAGE_SIZE; > > -- > > 2.19.1.3.ge56e4f7 > > >