Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964915AbWCPX4J (ORCPT ); Thu, 16 Mar 2006 18:56:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964916AbWCPX4I (ORCPT ); Thu, 16 Mar 2006 18:56:08 -0500 Received: from mx.pathscale.com ([64.160.42.68]:22506 "EHLO mx.pathscale.com") by vger.kernel.org with ESMTP id S964909AbWCPX4G (ORCPT ); Thu, 16 Mar 2006 18:56:06 -0500 Subject: Re: Remapping pages mapped to userspace (was: [PATCH 10 of 20] ipath - support for userspace apps using core driver) From: "Bryan O'Sullivan" To: Roland Dreier Cc: Hugh Dickins , Andrew Morton , torvalds@osdl.org, hch@infradead.org, linux-kernel@vger.kernel.org In-Reply-To: References: <71644dd19420ddb07a75.1141922823@localhost.localdomain> <1141948516.10693.55.camel@serpentine.pathscale.com> <1141949262.10693.69.camel@serpentine.pathscale.com> <20060309163740.0b589ea4.akpm@osdl.org> <1142470579.6994.78.camel@localhost.localdomain> <1142475069.6994.114.camel@localhost.localdomain> <1142477579.6994.124.camel@localhost.localdomain> <20060315192813.71a5d31a.akpm@osdl.org> <1142485103.25297.13.camel@camp4.serpentine.com> <20060315213813.747b5967.akpm@osdl.org> Content-Type: text/plain Organization: PathScale, Inc. Date: Thu, 16 Mar 2006 15:56:01 -0800 Message-Id: <1142553361.15045.19.camel@serpentine.pathscale.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 703 Lines: 18 On Thu, 2006-03-16 at 15:51 -0800, Roland Dreier wrote: > However, on a hot unplug event, when the underlying PCI device is > going away, I would like to replace that mapping with a mapping (with > a mapping to the zero page?), so that userspace accesses after the > device is gone don't explode. Why would you not want accesses to explode? Exploding seems like the right behaviour to me, since there's no hardware for userspace to talk to any more.