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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A8026C47423 for ; Fri, 25 Sep 2020 13:34:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 20DE72067D for ; Fri, 25 Sep 2020 13:34:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20DE72067D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD39F6B005D; Fri, 25 Sep 2020 09:34:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A83326B0068; Fri, 25 Sep 2020 09:34:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9232B6B006E; Fri, 25 Sep 2020 09:34:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id 795A16B005D for ; Fri, 25 Sep 2020 09:34:01 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3FF121DFF for ; Fri, 25 Sep 2020 13:34:01 +0000 (UTC) X-FDA: 77301677082.20.gun93_410dd7127168 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 06B59180C07AB for ; Fri, 25 Sep 2020 13:34:01 +0000 (UTC) X-HE-Tag: gun93_410dd7127168 X-Filterd-Recvd-Size: 2887 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Fri, 25 Sep 2020 13:34:00 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B12AB11B3; Fri, 25 Sep 2020 06:33:59 -0700 (PDT) Received: from [10.37.12.53] (unknown [10.37.12.53]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EB5953F73B; Fri, 25 Sep 2020 06:33:56 -0700 (PDT) Subject: Re: [PATCH v3 24/39] arm64: mte: Add in-kernel MTE helpers To: Catalin Marinas Cc: Andrey Konovalov , Dmitry Vyukov , kasan-dev@googlegroups.com, Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20200925101558.GB4846@gaia> <20200925125059.GM4846@gaia> From: Vincenzo Frascino Message-ID: Date: Fri, 25 Sep 2020 14:36:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200925125059.GM4846@gaia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 9/25/20 1:50 PM, Catalin Marinas wrote: >>>> + */ >>>> +SYM_FUNC_START(mte_assign_mem_tag_range) >>>> + /* if (src == NULL) return; */ >>>> + cbz x0, 2f >>>> + /* if (size == 0) return; */ >>>> + cbz x1, 2f >>> I find these checks unnecessary, as I said a couple of times before, >>> just document the function pre-conditions. They are also incomplete >>> (i.e. you check for NULL but not alignment). >>> >> I thought we agreed to harden the code further, based on [1]. Maybe I >> misunderstood. I am going to remove them and extend the comment in the next version. >> >> [1] >> https://lore.kernel.org/linux-arm-kernel/921c4ed0-b5b5-bc01-5418-c52d80f1af59@arm.com/ > Well, you concluded that but I haven't confirmed ;). Since it's called > from a single place which does the checks already, I don't see the point > in duplicating them. Documenting should be sufficient. Have you ever heard about "tacit consent"? ;) Anw, fine by me, I will add a comment here. -- Regards, Vincenzo