Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933081AbYFTUpF (ORCPT ); Fri, 20 Jun 2008 16:45:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764035AbYFTU24 (ORCPT ); Fri, 20 Jun 2008 16:28:56 -0400 Received: from smtp-outbound-1.vmware.com ([65.113.40.141]:34250 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764034AbYFTU2y (ORCPT ); Fri, 20 Jun 2008 16:28:54 -0400 Subject: Re: [PATCH 1/2] cleanup e820_setup_gap From: Alok Kataria Reply-To: akataria@vmware.com To: Yinghai Lu Cc: Ingo Molnar , "Brown, Len" , Andrew Morton , "linux-acpi@vger.kernel.org" , LKML In-Reply-To: <86802c440806201250g706bb062t2d472ee0637cac4e@mail.gmail.com> References: <1213916250.27983.35.camel@promb-2n-dhcp368.eng.vmware.com> <20080620153220.GD17373@elte.hu> <1213990711.31598.22.camel@promb-2n-dhcp368.eng.vmware.com> <86802c440806201250g706bb062t2d472ee0637cac4e@mail.gmail.com> Content-Type: text/plain Organization: VMware INC. Date: Fri, 20 Jun 2008 13:28:54 -0700 Message-Id: <1213993734.31598.27.camel@promb-2n-dhcp368.eng.vmware.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-40.el5) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4928 Lines: 152 On Fri, 2008-06-20 at 12:50 -0700, Yinghai Lu wrote: > On Fri, Jun 20, 2008 at 12:38 PM, Alok Kataria wrote: > > Here is the patch based on tip/master > > > > Please have a look > > > > -- > > > > This is a preparatory patch for the next patch in series. > > Moves some code from e820_setup_gap to a new function e820_search_gap. > > This patch is a part of a bug fix where we walk the ACPI table to calculate > > a gap for PCI optional devices. > > > > Signed-off-by: Alok N Kataria > > > > Index: linux-trees.git/arch/x86/kernel/e820.c > > =================================================================== > > --- linux-trees.git.orig/arch/x86/kernel/e820.c 2008-06-20 10:32:44.000000000 -0700 > > +++ linux-trees.git/arch/x86/kernel/e820.c 2008-06-20 12:27:58.000000000 -0700 > > @@ -442,26 +442,22 @@ > > } > > > > /* > > - * Search for the biggest gap in the low 32 bits of the e820 > > - * memory space. We pass this space to PCI to assign MMIO resources > > - * for hotplug or unconfigured devices in. > > - * Hopefully the BIOS let enough space left. > > + * Search for a gap in the e820 memory space from start_addr to 2^32. > > */ > > -__init void e820_setup_gap(void) > > +__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, > > + unsigned long start_addr) > > { > > - unsigned long gapstart, gapsize, round; > > - unsigned long long last; > > - int i; > > + unsigned long last = 0x100000000ull; > > why changing "unsigned long long" to "unsigned long" ? > it will overflow on 32bit > Oops...my bad, it was unsigned long in e820_64.c. Should be more careful with these cross ports. Thanks for catching it. -- This is a preparatory patch for the next patch in series. Moves some code from e820_setup_gap to a new function e820_search_gap. This patch is a part of a bug fix where we walk the ACPI table to calculate a gap for PCI optional devices. Signed-off-by: Alok N Kataria Index: linux-trees.git/arch/x86/kernel/e820.c =================================================================== --- linux-trees.git.orig/arch/x86/kernel/e820.c 2008-06-20 10:32:44.000000000 -0700 +++ linux-trees.git/arch/x86/kernel/e820.c 2008-06-20 13:23:32.000000000 -0700 @@ -442,26 +442,22 @@ } /* - * Search for the biggest gap in the low 32 bits of the e820 - * memory space. We pass this space to PCI to assign MMIO resources - * for hotplug or unconfigured devices in. - * Hopefully the BIOS let enough space left. + * Search for a gap in the e820 memory space from start_addr to 2^32. */ -__init void e820_setup_gap(void) +__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, + unsigned long start_addr) { - unsigned long gapstart, gapsize, round; - unsigned long long last; - int i; + unsigned long long last = 0x100000000ull; + int i = e820.nr_map; int found = 0; - last = 0x100000000ull; - gapstart = 0x10000000; - gapsize = 0x400000; - i = e820.nr_map; while (--i >= 0) { unsigned long long start = e820.map[i].addr; unsigned long long end = start + e820.map[i].size; + if (end < start_addr) + continue; + /* * Since "last" is at most 4GB, we know we'll * fit in 32 bits if this condition is true @@ -469,15 +465,32 @@ if (last > end) { unsigned long gap = last - end; - if (gap > gapsize) { - gapsize = gap; - gapstart = end; + if (gap >= *gapsize) { + *gapsize = gap; + *gapstart = end; found = 1; } } if (start < last) last = start; } + return found; +} + +/* + * Search for the biggest gap in the low 32 bits of the e820 + * memory space. We pass this space to PCI to assign MMIO resources + * for hotplug or unconfigured devices in. + * Hopefully the BIOS let enough space left. + */ +__init void e820_setup_gap(void) +{ + unsigned long gapstart, gapsize, round; + int found; + + gapstart = 0x10000000; + gapsize = 0x400000; + found = e820_search_gap(&gapstart, &gapsize, 0); #ifdef CONFIG_X86_64 if (!found) { Index: linux-trees.git/include/asm-x86/e820.h =================================================================== --- linux-trees.git.orig/include/asm-x86/e820.h 2008-06-20 10:32:44.000000000 -0700 +++ linux-trees.git/include/asm-x86/e820.h 2008-06-20 12:18:40.000000000 -0700 @@ -69,6 +69,8 @@ unsigned new_type); extern void update_e820(void); extern void e820_setup_gap(void); +extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, + unsigned long start_addr); struct setup_data; extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data); -- 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/