[PATCH] mm: hugetlb: fix hugetlb_cma_reserve() if CONFIG_NUMA isn't set

[Roman Gushchin <guro@fb.com>]

If CONFIG_NUMA isn't set, there is no need to ensure that
the hugetlb cma area belongs to a specific numa node.

min/max_low_pfn can be used for limiting the maximum size
of the hugetlb_cma area.

Also for_each_mem_pfn_range() is defined only if
CONFIG_HAVE_MEMBLOCK_NODE_MAP is set, and on arm (unlike most
other architectures) it depends on CONFIG_NUMA. This makes the
build fail if CONFIG_NUMA isn't set.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Andreas Schaufler <andreas.schaufler@gmx.de>
---
 mm/hugetlb.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7a20cae7c77a..a6161239abde 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5439,16 +5439,21 @@ void __init hugetlb_cma_reserve(int order)
 
 	reserved = 0;
 	for_each_node_state(nid, N_ONLINE) {
-		unsigned long start_pfn, end_pfn;
 		unsigned long min_pfn = 0, max_pfn = 0;
-		int res, i;
+		int res;
+#ifdef CONFIG_NUMA
+		unsigned long start_pfn, end_pfn;
+		int i;
 
 		for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
 			if (!min_pfn)
 				min_pfn = start_pfn;
 			max_pfn = end_pfn;
 		}
-
+#else
+		min_pfn = min_low_pfn;
+		max_pfn = max_low_pfn;
+#endif
 		size = max(per_node, hugetlb_cma_size - reserved);
 		size = round_up(size, PAGE_SIZE << order);
 
-- 
2.24.1