[PATCH 03/11] mm/sparse-vmemmap: open-code init_compound_tail()

init_compound_tail() is only used by vmemmap_shared_tail_page(), where
the shared tail page setup intentionally passes NULL as the compound head.

Keeping this helper in mm/internal.h exposes that special case to the rest
of the MM code and can make the NULL head argument look generally valid.
Open-code the initialization at the only call site so the special-case use
stays local to sparse vmemmap optimization.

No functional change intended.

Signed-off-by: Muchun Song <[email protected]>
---
 mm/internal.h       | 9 ---------
 mm/sparse-vmemmap.c | 5 ++++-
 2 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index e16f1250b25c..5ddb49680b06 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -783,15 +783,6 @@ static inline void prep_compound_tail(struct page *tail,
 	VM_WARN_ON_ONCE(tail->private);
 }
 
-static inline void init_compound_tail(struct page *tail,
-		const struct page *head, unsigned int order, struct zone *zone)
-{
-	atomic_set(&tail->_mapcount, -1);
-	set_page_node(tail, zone_to_nid(zone));
-	set_page_zone(tail, zone_idx(zone));
-	prep_compound_tail(tail, head, order);
-}
-
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 
 /*
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 70143dd8b579..e453ce4675a0 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -189,7 +189,10 @@ struct page __ref *vmemmap_shared_tail_page(unsigned int order, struct zone *zon
 	for (int i = 0; i < PAGE_SIZE / sizeof(struct page); i++) {
 		page = (struct page *)addr + i;
 		mm_zero_struct_page(page);
-		init_compound_tail(page, NULL, order, zone);
+		atomic_set(&page->_mapcount, -1);
+		set_page_node(page, zone_to_nid(zone));
+		set_page_zone(page, zone_idx(zone));
+		prep_compound_tail(page, NULL, order);
 	}
 
 	page = virt_to_page(addr);
-- 
2.54.0