x86-64, NUMA: Fix distance table handling

NUMA distance table handling has the following problems.

* numa_reset_distance() uses numa_distance * sizeof(numa_distance[0])
  as the table size when it should be using the square of
  numa_distance.

* The same size miscalculation when allocation space for phys_dist in
  numa_emulation().

* In numa_emulation(), phys_dist must be reserved; otherwise, the new
  emulated distance table may overlap it.

Fix them and, while at it, take numa_distance_cnt resetting in
numa_reset_distance() out of the if block to simplify the code a bit.

David Rientjes reported incorrect handling of distance table during
emulation.

-tj: Edited out numa_alloc_distance() related changes which weren't
     necessary and rewrote patch description.

-v2: Ingo was unhappy with 80-column limit induced linebreaks.  Let
     lines run over 80-column.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: David Rientjes <rientjes@google.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 7757d2214fa..541746fdeb4 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -390,14 +390,12 @@ static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
  */
 void __init numa_reset_distance(void)
 {
-	size_t size;
+	size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]);
 
-	if (numa_distance_cnt) {
-		size = numa_distance_cnt * sizeof(numa_distance[0]);
+	if (numa_distance_cnt)
 		memblock_x86_free_range(__pa(numa_distance),
 					__pa(numa_distance) + size);
-		numa_distance_cnt = 0;
-	}
+	numa_distance_cnt = 0;
 	numa_distance = NULL;
 }