From: Russell King Subject: Re: [RFC][PATCH] sys_fallocate() system call Date: Sat, 17 Mar 2007 14:53:48 +0000 Message-ID: <20070317145348.GA32278@flint.arm.linux.org.uk> References: <20070117094658.GA17390@amitarora.in.ibm.com> <20070225022326.137b4875.akpm@linux-foundation.org> <20070301183445.GA7911@amitarora.in.ibm.com> <20070316143101.GA10152@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, Andrew Morton , suparna@in.ibm.com, cmm@us.ibm.com, alex@clusterfs.com, suzuki@in.ibm.com To: "Amit K. Arora" Return-path: Received: from caramon.arm.linux.org.uk ([217.147.92.249]:2327 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750719AbXCQOyH (ORCPT ); Sat, 17 Mar 2007 10:54:07 -0400 Content-Disposition: inline In-Reply-To: <20070316143101.GA10152@amitarora.in.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, Mar 16, 2007 at 08:01:01PM +0530, Amit K. Arora wrote: > Attached below is the patch which implements this system call. It has > been currently implemented and tested on i386, ppc64 and x86_64 > architectures. I am facing some problems while trying to implement this > on s390, and thus the delay. While I try to get it right on s390(x), we > thought of posting this patch, so that we can save some time. Parallely > we will work on getting the patch work on s390, and probably it will > come as a separate patch. I suggest reading the very end of arch/arm/kernel/sys_arm.c; I'd rather avoid adding more and more hacks like that to the kernel if at all possible. One solution (already mentioned elsewhere) is that we start avoiding passing 64-bit arguments and instead pass two 32-bit instead. This nicely avoids the alignment restrictions for 64-bit args in ABIs. (The issue for ARM is that with anything other than the "fd, mode, offset, len" layout we will have to deal with different ABI argument layouts, or implement our own wrapper function as done for sys_arm_sync_file_range.) I think the problem comes down to "what is the argument layout which causes the least amount of problems for the complete set of architectures." For ARM, that's the "fd, mode, offset, len" layout. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: