Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759862AbXE2TLI (ORCPT ); Tue, 29 May 2007 15:11:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751252AbXE2TK4 (ORCPT ); Tue, 29 May 2007 15:10:56 -0400 Received: from mu-out-0910.google.com ([209.85.134.188]:52869 "EHLO mu-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750828AbXE2TKz (ORCPT ); Tue, 29 May 2007 15:10:55 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ANbWZIItaolRU13IvWbklCwTwCsydhuG0PH9v1Fc0Fqra18a7yWg1g6VVqcdVU7InJ8LvZGzmhRHuauI6HduvJ51wDmg/Qq6AgTSJUngK29tlddQdbUkSHZpEUwHiB1v45uM3vhoLIBn2z9/6e/molT/ixd66mciXj/xjjUsvng= Message-ID: <625fc13d0705291144u1aef3b6dx4b00873f3d05b652@mail.gmail.com> Date: Tue, 29 May 2007 13:44:42 -0500 From: "Josh Boyer" To: "Randy Dunlap" Subject: Re: [PATCH] FILESYSTEMS: Delete unused "int dummy[5]" from inodes_stat_t. Cc: "Robert P. J. Day" , "Andrew Morton" , "Linux Kernel Mailing List" , "Alexander Viro" In-Reply-To: <465C71EA.5040706@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070529110041.49bf57f1.akpm@linux-foundation.org> <20070529111902.27055fd0.randy.dunlap@oracle.com> <465C71EA.5040706@oracle.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2076 Lines: 49 On 5/29/07, Randy Dunlap wrote: > Robert P. J. Day wrote: > > On Tue, 29 May 2007, Randy Dunlap wrote: > > > >> On Tue, 29 May 2007 14:07:01 -0400 (EDT) Robert P. J. Day wrote: > >> > >>> On Tue, 29 May 2007, Andrew Morton wrote: > >>> > >>>> kernel/sysctl.c: > >>>> > >>>> { > >>>> .ctl_name = FS_STATINODE, > >>>> .procname = "inode-state", > >>>> .data = &inodes_stat, > >>>> .maxlen = 7*sizeof(int), <----- > >>>> .mode = 0444, > >>>> .proc_handler = &proc_dointvec, > >>>> }, > >>>> > >>>> akpm:/home/akpm> cat /proc/sys/fs/inode-state > >>>> 608039 178454 0 0 0 0 0 > >>>> > >>>> So it _is_ used: to present those five zeroes. I think this is > >>>> for back-compatibility with some cretaceous-era kernel. > >>> ah, gotcha. well, i'll leave this up to someone else to do > >>> anything with if they are so inclined. > >> There's little to be done, except possibly put a /* comment */ on > >> the struct's dummy line so that we don't go thru this again in N > >> years. > > > > so, just to clarify, what *is* the value of those trailing five > > zeroes? andrew suggests it's to be backward-compatible with an old > > kernel, which doesn't make much sense to me. it would make more sense > > to say that that's backward-compatible with some old userspace app > > that always wants to see seven values and just ignores the last five. > > Agreed, it's for compat with some (unknown) userspace app that reads > /proc/sys/fs/inode-state and scans for 7 (or more than 2) numbers there. > The mantra is "don't break userspace," so we leave the numbers there... Couldn't you remove the dummy member and just have the proc entry print out 5 dummy zeros? josh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/