From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753728AbYKQS2t (ORCPT ); Mon, 17 Nov 2008 13:28:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751524AbYKQS2l (ORCPT ); Mon, 17 Nov 2008 13:28:41 -0500 Received: from pasmtpb.tele.dk ([80.160.77.98]:43545 "EHLO pasmtpB.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751076AbYKQS2l (ORCPT ); Mon, 17 Nov 2008 13:28:41 -0500 Date: Mon, 17 Nov 2008 19:26:50 +0100 From: Jens Axboe To: Linus Torvalds Cc: Jeremy Fitzhardinge , Ingo Molnar , Tejun Heo , Arjan van de Ven , Hugh Dickins , linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH] Fix kunmap() argument in sg_miter_stop Message-ID: <20081117182650.GY26778@kernel.dk> References: <20081117093425.GG26778@kernel.dk> <20081117094147.GJ28786@elte.hu> <20081117094551.GI26778@kernel.dk> <20081117111350.GJ26778@kernel.dk> <4921A4F3.1030309@goop.org> <20081117171005.GA25729@elte.hu> <4921A6BE.7000206@goop.org> <20081117180738.GW26778@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 17 2008, Linus Torvalds wrote: > > > On Mon, 17 Nov 2008, Jens Axboe wrote: > > > > Any opinions on the kunmap/kunmap_atomic pointer checking? It's a bit > > ugly that we have to enforce a void * rule for kunmap_atomic(), > > I don't think that's a "bit ugly". I think it's unacceptable. > > Making sure we pass in "struct page" to kunmap() sounds good, but the > kunmap_atomic() part just sounds insane. It's been the primary source of bugs that I have seen. The xen and sg iter bug were kunmap() variants though, but otherwise I've mostly seen the opposite. But it is ugly, no doubt about it. I can't think of a better way to attempt to warn about it though, so if you really dislike it I'll just drop the _atomic() bits. -- Jens Axboe