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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 6D55EC433DB for ; Mon, 1 Feb 2021 12:41:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E30764EA2 for ; Mon, 1 Feb 2021 12:41:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231201AbhBAMkv (ORCPT ); Mon, 1 Feb 2021 07:40:51 -0500 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:38531 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229524AbhBAMks (ORCPT ); Mon, 1 Feb 2021 07:40:48 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0UNbCbFm_1612183069; Received: from B-455UMD6M-2027.local(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0UNbCbFm_1612183069) by smtp.aliyun-inc.com(127.0.0.1); Mon, 01 Feb 2021 20:37:50 +0800 Subject: Re: [PATCH v3 5/5] x86/sgx: Remove redundant if conditions in sgx_encl_create To: Jarkko Sakkinen Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Sean Christopherson , Shuah Khan , x86@kernel.org, linux-sgx@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Jia Zhang References: <20210124062907.88229-1-tianjia.zhang@linux.alibaba.com> <20210124062907.88229-6-tianjia.zhang@linux.alibaba.com> From: Tianjia Zhang Message-ID: <96dad409-e00e-6b2f-ab4d-cef80921c1f4@linux.alibaba.com> Date: Mon, 1 Feb 2021 20:37:49 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On 1/30/21 10:33 PM, Jarkko Sakkinen wrote: > On Sun, Jan 24, 2021 at 02:29:07PM +0800, 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. >> >> Signed-off-by: Tianjia Zhang >> --- >> arch/x86/kernel/cpu/sgx/ioctl.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c >> index 1c6ecf9fbeff..b0b829f1b761 100644 >> --- a/arch/x86/kernel/cpu/sgx/ioctl.c >> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c >> @@ -66,9 +66,11 @@ 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. */ > > This is fine. The check does not make sense. > >> + >> + if (WARN_ONCE(!va_page, "non-empty VA page list before ECREATE")) >> + return -EIO; > > No need for this WARN_ONCE(). > >> + >> + list_add(&va_page->list, &encl->va_pages); > > This is fine. > >> >> /* The extra page goes to SECS. */ >> encl_size = secs->size + PAGE_SIZE; >> -- >> 2.19.1.3.ge56e4f7 >> >> > > /Jarkko > Will be improved in the next version. Thanks, Tianjia