Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755648AbYJXDWP (ORCPT ); Thu, 23 Oct 2008 23:22:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751703AbYJXDV7 (ORCPT ); Thu, 23 Oct 2008 23:21:59 -0400 Received: from gate.crashing.org ([63.228.1.57]:40894 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751474AbYJXDV6 (ORCPT ); Thu, 23 Oct 2008 23:21:58 -0400 Subject: Re: Adding kmap_atomic_prot_pfn (was: [git pull] drm patches for 2.6.27-rc1) From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Linus Torvalds Cc: Andrew Morton , Keith Packard , mingo@elte.hu, nickpiggin@yahoo.com.au, airlied@linux.ie, linux-kernel@vger.kernel.org, jbarnes@virtuousgeek.org, dri-devel@lists.sf.net, yinghai@kernel.org In-Reply-To: References: <20081018203741.GA23396@elte.hu> <1224366690.4384.89.camel@koto.keithp.com> <20081018223214.GA5093@elte.hu> <1224389697.4384.118.camel@koto.keithp.com> <1224398496.5303.7.camel@koto.keithp.com> <20081019175320.GA6442@elte.hu> <1224450291.5303.23.camel@koto.keithp.com> <20081020115810.GC10594@elte.hu> <1224517744.5195.1.camel@koto.keithp.com> <20081022093615.GF12453@elte.hu> <1224793332.22877.8.camel@koto.keithp.com> <20081023133840.d4eef579.akpm@linux-foundation.org> Content-Type: text/plain Date: Fri, 24 Oct 2008 14:21:14 +1100 Message-Id: <1224818474.7654.429.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1154 Lines: 28 On Thu, 2008-10-23 at 14:24 -0700, Linus Torvalds wrote: > The whole point of that function has absolutely nothing to do with > highmem, and it *must* be useful on non-highmem configurations to be > appropriate. > > So I'd much rather create a new or something. Or just > expose this from to or something. Let's not confuse > this > with highmem, even if the implementation _historically_ was due to > that. Well, on powerpc, we just went (or rather, Kumar just went) through the oops of implementing fixmap and then kmap on top of it... just because we wanted kmap_atomic functionality on non-highmem platforms :-) (and the fixmap approach has some other interesting features). So yes, I agree. Typically very useful for any 32-bit processor with a memory mapped PCI Express config space since it's something like 256M of virtual space to map it all iirc. Cheers, Ben. -- 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/