linux-kernel - [tip:x86/urgent] x86/e820: Don't merge consecutive E820

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Date:   Sun, 16 Oct 2016 04:20:43 -0700
From:   tip-bot for Dan Williams <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     stable@...r.kernel.org, jpoimboe@...hat.com, yizhan@...hat.com,
        david@...morbit.com, bp@...en8.de, peterz@...radead.org,
        luto@...nel.org, jmoyer@...hat.com, dan.j.williams@...el.com,
        dvlasenk@...hat.com, hpa@...or.com, torvalds@...ux-foundation.org,
        linux-kernel@...r.kernel.org, mingo@...nel.org, brgerst@...il.com,
        tglx@...utronix.de
Subject: [tip:x86/urgent] x86/e820: Don't merge consecutive E820_PRAM ranges

Commit-ID:  23446cb66c073b827779e5eb3dec301623299b32
Gitweb:     http://git.kernel.org/tip/23446cb66c073b827779e5eb3dec301623299b32
Author:     Dan Williams <dan.j.williams@...el.com>
AuthorDate: Wed, 12 Oct 2016 11:01:48 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Sun, 16 Oct 2016 11:16:48 +0200

x86/e820: Don't merge consecutive E820_PRAM ranges

Commit:

  917db484dc6a ("x86/boot: Fix kdump, cleanup aborted E820_PRAM max_pfn manipulation")

... fixed up the broken manipulations of max_pfn in the presence of
E820_PRAM ranges.

However, it also broke the sanitize_e820_map() support for not merging
E820_PRAM ranges.

Re-introduce the enabling to keep resource boundaries between
consecutive defined ranges. Otherwise, for example, an environment that
boots with memmap=2G!8G,2G!10G will end up with a single 4G /dev/pmem0
device instead of a /dev/pmem0 and /dev/pmem1 device 2G in size.

Reported-by: Dave Chinner <david@...morbit.com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Cc: <stable@...r.kernel.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jeff Moyer <jmoyer@...hat.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Zhang Yi <yizhan@...hat.com>
Cc: linux-nvdimm@...ts.01.org
Fixes: 917db484dc6a ("x86/boot: Fix kdump, cleanup aborted E820_PRAM max_pfn manipulation")
Link: http://lkml.kernel.org/r/147629530854.10618.10383744751594021268.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/e820.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index b85fe5f..90e8dde 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -350,7 +350,7 @@ int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
 		 * continue building up new bios map based on this
 		 * information
 		 */
-		if (current_type != last_type) {
+		if (current_type != last_type || current_type == E820_PRAM) {
 			if (last_type != 0)	 {
 				new_bios[new_bios_entry].size =
 					change_point[chgidx]->addr - last_addr;