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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 AAFCBC433ED for ; Wed, 19 May 2021 12:07:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 400A461363 for ; Wed, 19 May 2021 12:07:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 400A461363 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 87D276B0073; Wed, 19 May 2021 08:07:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 861636B0074; Wed, 19 May 2021 08:07:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 71D876B0075; Wed, 19 May 2021 08:07:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id 3FDD46B0073 for ; Wed, 19 May 2021 08:07:21 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B8CED815F for ; Wed, 19 May 2021 12:07:20 +0000 (UTC) X-FDA: 78157855440.24.0413086 Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by imf24.hostedemail.com (Postfix) with ESMTP id 2AD74A0003AA for ; Wed, 19 May 2021 12:07:17 +0000 (UTC) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 14JC39Wa013687; Wed, 19 May 2021 07:03:09 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 14JC36gU013684; Wed, 19 May 2021 07:03:06 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Wed, 19 May 2021 07:03:06 -0500 From: Segher Boessenkool To: Michael Ellerman Cc: "Aneesh Kumar K.V" , npiggin@gmail.com, linux-mm@kvack.org, kaleshsingh@google.com, joel@joelfernandes.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, Guenter Roeck Subject: Re: [PATCH v5 5/9] powerpc/mm/book3s64: Update tlb flush routines to take a page walk cache flush argument Message-ID: <20210519120306.GD10366@gate.crashing.org> References: <20210422054323.150993-1-aneesh.kumar@linux.ibm.com> <20210422054323.150993-6-aneesh.kumar@linux.ibm.com> <20210515163525.GA1106462@roeck-us.net> <87pmxpqxb1.fsf@linux.ibm.com> <87a6ork1qp.fsf@mpe.ellerman.id.au> <20210519004514.GC10366@gate.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210519004514.GC10366@gate.crashing.org> User-Agent: Mutt/1.4.2.3i Authentication-Results: imf24.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf24.hostedemail.com: domain of segher@kernel.crashing.org designates 63.228.1.57 as permitted sender) smtp.mailfrom=segher@kernel.crashing.org X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 2AD74A0003AA X-Stat-Signature: e4jhnygarxpegwesy7d4ctsrziodf1jt X-HE-Tag: 1621426037-169474 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 Tue, May 18, 2021 at 07:45:14PM -0500, Segher Boessenkool wrote: > On Wed, May 19, 2021 at 10:26:22AM +1000, Michael Ellerman wrote: > > Guenter Roeck writes: > > > Ah, sorry. I wasn't aware that the following is valid C code > > > > > > void f1() > > > { > > > return f2(); > > > ^^^^^^ > > > } > > > > > > as long as f2() is void as well. Confusing, but we live and learn. > > > > It might be valid, but it's still bad IMHO. > > > > It's confusing to readers, and serves no useful purpose. > > And it actually explicitly is undefined behaviour in C90 already > (3.6.6.4 in C90, 6.8.6.4 in C99 and later). ... but there is a GCC extension that allows this by default: For C only, warn about a 'return' statement with an expression in a function whose return type is 'void', unless the expression type is also 'void'. As a GNU extension, the latter case is accepted without a warning unless '-Wpedantic' is used. Segher