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 B5A30C433B4 for ; Wed, 19 May 2021 00:49:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 271596112F for ; Wed, 19 May 2021 00:49:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 271596112F 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 8E3946B00A5; Tue, 18 May 2021 20:49:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 895E36B00A7; Tue, 18 May 2021 20:49:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 75AFC8E002F; Tue, 18 May 2021 20:49:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0026.hostedemail.com [216.40.44.26]) by kanga.kvack.org (Postfix) with ESMTP id 43AE66B00A5 for ; Tue, 18 May 2021 20:49:29 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id DEE27180AD830 for ; Wed, 19 May 2021 00:49:28 +0000 (UTC) X-FDA: 78156147216.29.34F608A Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by imf30.hostedemail.com (Postfix) with ESMTP id CDB14E0001AF for ; Wed, 19 May 2021 00:49:27 +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 14J0jGKJ029726; Tue, 18 May 2021 19:45:16 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 14J0jFLQ029725; Tue, 18 May 2021 19:45:15 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 18 May 2021 19:45:14 -0500 From: Segher Boessenkool To: Michael Ellerman Cc: Guenter Roeck , "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 Subject: Re: [PATCH v5 5/9] powerpc/mm/book3s64: Update tlb flush routines to take a page walk cache flush argument Message-ID: <20210519004514.GC10366@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a6ork1qp.fsf@mpe.ellerman.id.au> User-Agent: Mutt/1.4.2.3i X-Rspamd-Queue-Id: CDB14E0001AF Authentication-Results: imf30.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf30.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: rspam04 X-Stat-Signature: y391szik9ye6era5zc936i1nbfx9p139 X-HE-Tag: 1621385367-409682 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 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). Segher 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 16BACC433B4 for ; Wed, 19 May 2021 00:52:01 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 42EF860FE3 for ; Wed, 19 May 2021 00:52:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42EF860FE3 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=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FlDpk4MXNz309G for ; Wed, 19 May 2021 10:51:58 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4FlDpH66d4z2xvP for ; Wed, 19 May 2021 10:51:34 +1000 (AEST) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 14J0jGKJ029726; Tue, 18 May 2021 19:45:16 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 14J0jFLQ029725; Tue, 18 May 2021 19:45:15 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 18 May 2021 19:45:14 -0500 From: Segher Boessenkool To: Michael Ellerman Subject: Re: [PATCH v5 5/9] powerpc/mm/book3s64: Update tlb flush routines to take a page walk cache flush argument Message-ID: <20210519004514.GC10366@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a6ork1qp.fsf@mpe.ellerman.id.au> User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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). Segher