[PATCH] x86/e820: don't merge consecutive E820_PRAM ranges

From: Dan Williams
Date: Wed Oct 12 2016 - 14:05:13 EST

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.

Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Zhang Yi <yizhan@xxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reported-by: Dave Chinner <david@xxxxxxxxxxxxx>
Fixes: 917db484dc6a ("x86/boot: Fix kdump, cleanup aborted E820_PRAM max_pfn manipulation")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
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 b85fe5f91c3f..90e8dde3ec26 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;