Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754010AbZDFRnl (ORCPT ); Mon, 6 Apr 2009 13:43:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751993AbZDFRnd (ORCPT ); Mon, 6 Apr 2009 13:43:33 -0400 Received: from mx2.redhat.com ([66.187.237.31]:60103 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752048AbZDFRnc (ORCPT ); Mon, 6 Apr 2009 13:43:32 -0400 Message-ID: <49DA3F85.7050302@redhat.com> Date: Mon, 06 Apr 2009 13:44:37 -0400 From: Masami Hiramatsu User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Mathieu Desnoyers CC: Ingo Molnar , Ananth N Mavinakayanahalli , LKML , systemtap-ml Subject: Re: [BUGFIX][PATCH -tip] x86: fix text_poke to handle highmem pages References: <49D76FFF.6020202@redhat.com> <20090404154230.GB2451@Krystal> <49D7A6DF.8080804@redhat.com> <49D7AF26.5030808@redhat.com> <49D82987.5090003@redhat.com> <49DA37CB.4020901@redhat.com> <20090406173238.GA31867@Krystal> In-Reply-To: <20090406173238.GA31867@Krystal> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 43 Mathieu Desnoyers wrote: > * Masami Hiramatsu (mhiramat@redhat.com) wrote: >> Fix a bug in text_poke to handle highmem pages, because module >> text pages are possible to be highmem pages on x86-32. >> In that case, since fixmap can't handle those pages, text_poke >> uses kmap_atomic. >> > > Hrm, can you remind me what would be the downside of using kmap_atomic > in every scenarios (highmem and non-highmem) then ? kmap_atomic can handle only highmem pages. If you passes lowmem pages, it returns just original vaddr of it. (because kmap is only for highmem support) > > I would try to avoid "special cases" as much as possible, because they > just make problems harder to reproduce. Actually, this bug is a special case because it happens only on PAE kernel. > > The idea would be to either add fixmap highmem support, or to simply use > kmap_atomic() for all cases until we add fixmap highmem support. > Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: mhiramat@redhat.com -- 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/