From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266365AbUHSOu6 (ORCPT ); Thu, 19 Aug 2004 10:50:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266349AbUHSOud (ORCPT ); Thu, 19 Aug 2004 10:50:33 -0400 Received: from mx1.redhat.com ([66.187.233.31]:22419 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S266344AbUHSOqo (ORCPT ); Thu, 19 Aug 2004 10:46:44 -0400 Date: Thu, 19 Aug 2004 07:42:55 -0700 From: "David S. Miller" To: Andrew Morton Cc: paulus@samba.org, viro@parcelfarce.linux.theplanet.co.uk, olof@austin.ibm.com, linux-kernel@vger.kernel.org Subject: Re: Alignment of bitmaps for ext2_set_bit et al. Message-Id: <20040819074255.00e27060.davem@redhat.com> In-Reply-To: <20040819042234.75020cbc.akpm@osdl.org> References: <16676.35837.215958.814591@cargo.ozlabs.ibm.com> <20040819042234.75020cbc.akpm@osdl.org> X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; sparc-unknown-linux-gnu) X-Face: "_;p5u5aPsO,_Vsx"^v-pEq09'CU4&Dc1$fQExov$62l60cgCc%FnIwD=.UF^a>?5'9Kn[;433QFVV9M..2eN.@4ZWPGbdi<=?[:T>y?SD(R*-3It"Vj:)"dP Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Aug 2004 04:22:34 -0700 Andrew Morton wrote: > Paul Mackerras wrote: > > > > What can we assume about the alignment of the bitmap pointer passed to > > the ext2_{set,clear}_bit_atomic functions? Can we assume that they > > will be aligned to an long boundary (8 bytes on 64-bit)? > > For ext2 and ext3 it's safe to assume that they are 1024-byte aligned. > > But it's possible that other filesystems are using these (awfully named) > functions. FWIW, I've been using 4-byte word atomics for those routines on sparc64 and have never gotten an unaligned trap for it yet.