From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754115AbYKHM61 (ORCPT ); Sat, 8 Nov 2008 07:58:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753240AbYKHM6T (ORCPT ); Sat, 8 Nov 2008 07:58:19 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:46801 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631AbYKHM6S (ORCPT ); Sat, 8 Nov 2008 07:58:18 -0500 Date: Sat, 8 Nov 2008 13:59:52 +0100 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andrew Morton , Linus Torvalds , LKML , pm list Subject: Re: [PATCH] Fix __pfn_to_page(pfn) for CONFIG_DISCONTIGMEM=y Message-ID: <20081108125952.GB21405@elf.ucw.cz> References: <200811081353.34442.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200811081353.34442.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > This would be good to have in .28 IMO. Actually, this makes sense even for .27-stable, AFAICT. > From: Rafael J. Wysocki > Subject: Fix __pfn_to_page(pfn) for CONFIG_DISCONTIGMEM=y > > Fix macro __pfn_to_page(pfn) so that it doesn't evaluate its > argument twice in the CONFIG_DISCONTIGMEM=y case, because 'pfn' may > be a result of a funtion call having side effects. function call? > For example, the hibernation code applies pfn_to_page(pfn) to the > result of a function returning the pfn corresponding to the next set > bit in a bitmap and the current bit position is modified on each > call. This leads to "interesting" failures for CONFIG_DISCONTIGMEM=y > due to the current behavior of __pfn_to_page(pfn). > > Signed-off-by: Rafael J. Wysocki > Cc: Pavel Machek Acked-by: Pavel Machek > include/asm-generic/memory_model.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6/include/asm-generic/memory_model.h > =================================================================== > --- linux-2.6.orig/include/asm-generic/memory_model.h > +++ linux-2.6/include/asm-generic/memory_model.h > @@ -34,7 +34,7 @@ > > #define __pfn_to_page(pfn) \ > ({ unsigned long __pfn = (pfn); \ > - unsigned long __nid = arch_pfn_to_nid(pfn); \ > + unsigned long __nid = arch_pfn_to_nid(__pfn); \ > NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\ > }) > -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html