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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 CC079C3A5A3 for ; Thu, 29 Aug 2019 12:57:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8708233FF for ; Thu, 29 Aug 2019 12:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727315AbfH2M55 convert rfc822-to-8bit (ORCPT ); Thu, 29 Aug 2019 08:57:57 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:34438 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726637AbfH2M54 (ORCPT ); Thu, 29 Aug 2019 08:57:56 -0400 Received: by mail-qt1-f194.google.com with SMTP id a13so3547879qtj.1 for ; Thu, 29 Aug 2019 05:57:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=eBPBkBKyWo1gxv5n6v6wKh2d1Kik1L8vXbkWwc2K3bs=; b=UjE/x8ChOsxzteKI/pRBMu3LB7l20zkbHDbzysZAfaskhAQissgM5kKPEYDodLd8pf ahaLIO3F7W8GeUjaRXg6JkdYKkn2EY4bidCAJJi+LM3TaoFG0Vyv/j8+0t273dEX3ecH rrtjudrOnjjeJUGQ/oJQPByC/930c7KjlSudROiqnD+iABun7Cz1F6NFI87M+fw9oM28 m+FsdJN4Hap5LR0GlGviXh8YDLg0bK4JH9O/NzRHilabrsAr8Qn7zpnI7VQS03SLLLeg uxiUNXeUd9ecROeYn1rC6ARxHTLhBn5j0Amx363TMcLmUPFRqxGidgPOKtmz/OmD8C+9 kxlQ== X-Gm-Message-State: APjAAAXxMgXoqfXd3gqCKaVcqtusYe0W0t6klYINYMUcA5YWwGxejpVa AzDcG8RTH6HyH62txP+F74l1Q/LuLJI6V3d2968= X-Google-Smtp-Source: APXvYqwY3WgtxDzkiHef+9HQh/ay0Es1FEwtogifyQxitHWZN7yE+/+41B7zXg5JPfw7deyTXnwsCWcNTDVb6Yevmn4= X-Received: by 2002:ac8:239d:: with SMTP id q29mr9597999qtq.304.1567083475450; Thu, 29 Aug 2019 05:57:55 -0700 (PDT) MIME-Version: 1.0 References: <061a0de2042156669303f95526ec13476bf490c7.1567072270.git.msuchanek@suse.de> <20190829143716.6e41b10e@naga> In-Reply-To: <20190829143716.6e41b10e@naga> From: Arnd Bergmann Date: Thu, 29 Aug 2019 14:57:39 +0200 Message-ID: Subject: Re: [PATCH v4 1/4] powerpc: make llseek 32bit-only. To: =?UTF-8?Q?Michal_Such=C3=A1nek?= Cc: David Hildenbrand , Heiko Carstens , David Howells , Paul Mackerras , Breno Leitao , Michael Neuling , Geert Uytterhoeven , Allison Randal , Firoz Khan , Joel Stanley , Nicolai Stange , Nicholas Piggin , Thomas Gleixner , Christian Brauner , Greg Kroah-Hartman , Linux Kernel Mailing List , "Eric W. Biederman" , Andrew Donnellan , Hari Bathini , linuxppc-dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 29, 2019 at 2:37 PM Michal Suchánek wrote: > On Thu, 29 Aug 2019 14:19:46 +0200 Arnd Bergmann wrote: > > On Thu, Aug 29, 2019 at 12:23 PM Michal Suchanek wrote: > > In particular, I don't see why you single out llseek here, but leave other > > syscalls that are not needed on 64-bit machines such as pread64(). > > Because llseek is not built in fs/ when building 64bit only causing a > link error. > > I initially posted patch to build it always but it was pointed out it > is not needed, and the interface does not make sense on 64bit, and > that platforms that don't have it on 64bit now don't want that useless > code. Ok, please put that into the changeset description then. I looked at uses of __NR__llseek in debian code search and found this one: https://codesearch.debian.net/show?file=umview_0.8.2-1.2%2Fxmview%2Fum_mmap.c&line=328 It looks like this application will try to use llseek instead of lseek when built against kernel headers that define __NR_llseek. Changing the powerpc kernel not to provide that to user space may break it unless the program gets recompiled against the latest headers. Arnd