From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758014Ab2GKOzR (ORCPT ); Wed, 11 Jul 2012 10:55:17 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:34288 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755442Ab2GKOzP (ORCPT ); Wed, 11 Jul 2012 10:55:15 -0400 Date: Wed, 11 Jul 2012 22:54:12 +0800 From: Ram Pai To: "Purdila, Octavian" Cc: Ram Pai , Andrew Morton , "H. Peter Anvin" , linux-kernel@vger.kernel.org, Jesse Barnes Subject: Re: [PATCH] resource: make sure requested range intersects root range Message-ID: <20120711145412.GA2430@ram-ThinkPad-T61> Reply-To: Ram Pai References: <1341057657-7823-1-git-send-email-octavian.purdila@intel.com> <20120710143348.d977da44.akpm@linux-foundation.org> <20120711020902.GC13885@ram-ThinkPad-T61> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12071114-2398-0000-0000-00000865A5C4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 11, 2012 at 02:06:10PM +0300, Purdila, Octavian wrote: > On Wed, Jul 11, 2012 at 5:09 AM, Ram Pai wrote: > > > > > Wait.. I am not sure this will fix the problem entirely. The above check > > will handle the case where the range requested is entirey out of the > > root's range. But if the requested range overlapps that of the root > > range, we will still call __reserve_region_with_split() and end up with > > a recursion if there is a overflow. Wont we? > > > > Good catch. I will fix this as well as address Andrew's and Joe's > comments in a new patch. The only question is how to handle the > overlap case: > > (a) abort the whole request or > > (b) try to reserve the part that overlaps (and adjust the request to > avoid the overflow) > > I think (b) is more in line with the current implementation for reservations. I prefer (b). following patch should handle that. diff --git a/kernel/resource.c b/kernel/resource.c index e1d2b8e..dd87fde 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -780,6 +780,10 @@ static void __init __reserve_region_with_split(struct resource *root, if (conflict->start > start) __reserve_region_with_split(root, start, conflict->start-1, name); + + if (conflict->end == parent->end ) + return; + if (conflict->end < end) __reserve_region_with_split(root, conflict->end+1, end, name); } RP