[PATCH] sadump: Support more than 16TB physical memory space.

This patch makes sadump format support more than 16TB physical memory
space.

The limitation is caused by several members of dump_header structure:
max_mapnr and the others. They have 4 byte length only. In particular,
max_mapnr member gets overflow if more than 16TB physical memory space
is given.

To support more than 16TB physical memory space, this patch adds new 4
64-bit length members in dump_header structure:

- max_mapnr_64
- total_ram_blocks_64
- device_blocks_64
- written_blocks_64

Next table shows correspondence between the 32-bit version and the
64-bit version members:

    | 32-bit version         | 64-bit version            |
    |------------------------+---------------------------|
    | max_mapnr              | max_mapnr_64              |
    | total_ram_blocks       | total_ram_blocks_64       |
    | device_blocks          | device_blocks_64          |
    | written_blocks         | written_blocks_64         |

In addition, header_version member of dump_header structure is
increased to 1 in this extended new format.

Old makedumpfile can access the new sadump format under 16TB
correctly.

Current implementation treats vmcore with kernel version 2 or later as
kernel version 1, assuming backward compatibility.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/sadump_mod.h b/sadump_mod.h
index afeead8..0dd5bb5 100644
--- a/sadump_mod.h
+++ b/sadump_mod.h
@@ -106,6 +106,14 @@ struct sadump_header {
 	uint32_t written_blocks;	/* Number of written blocks */
 	uint32_t current_cpu;	/* CPU# which handles dump */
 	uint32_t nr_cpus;	/* Number of CPUs */
+	/*
+	 * The members from below are supported in header version 1
+	 * and later.
+	 */
+	uint64_t max_mapnr_64;
+	uint64_t total_ram_blocks_64;
+	uint64_t device_blocks_64;
+	uint64_t written_blocks_64;
 };
 
 struct sadump_apic_state {