[PATCH v2] mm/mm_init: remove zone_absent_pages_in_node()

[Sang-Heon Jeon <ekffu200098@gmail.com>]

zone_absent_pages_in_node() returns 0 when the zone is empty and
otherwise calls __absent_pages_in_range(), which already returns 0 for
an empty range.

So add an early return to __absent_pages_in_range() to avoid looping over
the memory ranges, then remove zone_absent_pages_in_node() and call
__absent_pages_in_range() directly.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
Changes from v1 [1]
- Add an early return to __absent_pages_in_range()

[1] https://lore.kernel.org/all/20260827144151.486192-1-ekffu200098@gmail.com/
---
 mm/mm_init.c | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 1533aebafb68..c00ac947a7d6 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1166,6 +1166,10 @@ static unsigned long __init __absent_pages_in_range(int nid,
 	unsigned long start_pfn, end_pfn;
 	int i;
 
+	/* range is empty, nothing to do */
+	if (!nr_absent)
+		return 0;
+
 	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
 		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
 		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
@@ -1187,22 +1191,9 @@ unsigned long __init absent_pages_in_range(unsigned long start_pfn,
 	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
 }
 
-/* Return the number of page frames in holes in a zone on a node */
-static unsigned long __init zone_absent_pages_in_node(int nid,
-					unsigned long zone_type,
-					unsigned long zone_start_pfn,
-					unsigned long zone_end_pfn)
-{
-	/* zone is empty, we don't have any absent pages */
-	if (zone_start_pfn == zone_end_pfn)
-		return 0;
-
-	return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
-}
-
 /*
  * Return the number of pages a zone spans in a node, including holes
- * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
+ * present_pages = zone_spanned_pages_in_node() - __absent_pages_in_range()
  */
 static unsigned long __init zone_spanned_pages_in_node(int nid,
 					unsigned long zone_type,
@@ -1292,9 +1283,8 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
 						     node_end_pfn,
 						     &zone_start_pfn,
 						     &zone_end_pfn);
-		absent = zone_absent_pages_in_node(pgdat->node_id, i,
-						   zone_start_pfn,
-						   zone_end_pfn);
+		absent = __absent_pages_in_range(pgdat->node_id, zone_start_pfn,
+						 zone_end_pfn);
 
 		real_size = spanned - absent;
 
-- 
2.43.0