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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D76CEC433EF for ; Tue, 15 Feb 2022 07:13:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6D2F86B0078; Tue, 15 Feb 2022 02:13:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 683496B007B; Tue, 15 Feb 2022 02:13:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 570B86B007D; Tue, 15 Feb 2022 02:13:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 4885F6B0078 for ; Tue, 15 Feb 2022 02:13:52 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 0A8AC8DA3A for ; Tue, 15 Feb 2022 07:13:52 +0000 (UTC) X-FDA: 79144149504.21.9428C5C Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [142.44.231.140]) by imf15.hostedemail.com (Postfix) with ESMTP id 88229A0004 for ; Tue, 15 Feb 2022 07:13:51 +0000 (UTC) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJs1u-001uPd-Et; Tue, 15 Feb 2022 07:13:42 +0000 Date: Tue, 15 Feb 2022 07:13:42 +0000 From: Al Viro To: Christoph Hellwig Cc: Arnd Bergmann , Linus Torvalds , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com, dalias@libc.org, davem@davemloft.net, richard@nod.at, x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com, akpm@linux-foundation.org, ardb@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org Subject: Re: [PATCH 09/14] m68k: drop custom __access_ok() Message-ID: References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-10-arnd@kernel.org> <20220215062942.GA12551@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220215062942.GA12551@lst.de> X-Rspamd-Queue-Id: 88229A0004 X-Rspam-User: Authentication-Results: imf15.hostedemail.com; dkim=none; dmarc=none; spf=none (imf15.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 142.44.231.140) smtp.mailfrom=viro@ftp.linux.org.uk X-Stat-Signature: u6rp1oosjon91kxd5jzy4i4b1hbg8yb6 X-Rspamd-Server: rspam11 X-HE-Tag: 1644909231-67498 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, Feb 15, 2022 at 07:29:42AM +0100, Christoph Hellwig wrote: > On Tue, Feb 15, 2022 at 12:37:41AM +0000, Al Viro wrote: > > Perhaps simply wrap that sucker into #ifdef CONFIG_CPU_HAS_ADDRESS_SPACES > > (and trim the comment down to "coldfire and 68000 will pick generic > > variant")? > > I wonder if we should invert CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE, > select the separate address space config for s390, sparc64, non-coldfire > m68k and mips with EVA and then just have one single access_ok for > overlapping address space (as added by Arnd) and non-overlapping ones > (always return true). parisc is also such... How about select ALTERNATE_SPACE_USERLAND for that bunch? While we are at it, how many unusual access_ok() instances are left after this series? arm64, itanic, um, anything else? FWIW, sparc32 has a slightly unusual instance (see uaccess_32.h there); it's obviously cheaper than generic and I wonder if the trick is legitimate (and applicable elsewhere, perhaps)...