[PATCH v2 09/12] mm: add page_rmappable_folio() wrapper

[Hugh Dickins]

folio_prep_large_rmappable() is being used repeatedly along with a
conversion from page to folio, a check non-NULL, a check order > 1:
wrap it all up into struct folio *page_rmappable_folio(struct page *).

Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
 mm/internal.h   |  9 +++++++++
 mm/mempolicy.c  | 17 +++--------------
 mm/page_alloc.c |  8 ++------
 3 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index d7916f1e9e98..b2b3716d1df6 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -415,6 +415,15 @@ static inline void folio_set_order(struct folio *folio, unsigned int order)
 
 void folio_undo_large_rmappable(struct folio *folio);
 
+static inline struct folio *page_rmappable_folio(struct page *page)
+{
+	struct folio *folio = (struct folio *)page;
+
+	if (folio && folio_order(folio) > 1)
+		folio_prep_large_rmappable(folio);
+	return folio;
+}
+
 static inline void prep_compound_head(struct page *page, unsigned int order)
 {
 	struct folio *folio = (struct folio *)page;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f3224a8b0f6c..bfcc523a2860 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2142,10 +2142,7 @@ struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma,
 		mpol_cond_put(pol);
 		gfp |= __GFP_COMP;
 		page = alloc_page_interleave(gfp, order, nid);
-		folio = (struct folio *)page;
-		if (folio && order > 1)
-			folio_prep_large_rmappable(folio);
-		goto out;
+		return page_rmappable_folio(page);
 	}
 
 	if (pol->mode == MPOL_PREFERRED_MANY) {
@@ -2155,10 +2152,7 @@ struct folio *vma_alloc_folio(gfp_t gfp, int order, struct vm_area_struct *vma,
 		gfp |= __GFP_COMP;
 		page = alloc_pages_preferred_many(gfp, order, node, pol);
 		mpol_cond_put(pol);
-		folio = (struct folio *)page;
-		if (folio && order > 1)
-			folio_prep_large_rmappable(folio);
-		goto out;
+		return page_rmappable_folio(page);
 	}
 
 	if (unlikely(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hugepage)) {
@@ -2252,12 +2246,7 @@ EXPORT_SYMBOL(alloc_pages);
 
 struct folio *folio_alloc(gfp_t gfp, unsigned order)
 {
-	struct page *page = alloc_pages(gfp | __GFP_COMP, order);
-	struct folio *folio = (struct folio *)page;
-
-	if (folio && order > 1)
-		folio_prep_large_rmappable(folio);
-	return folio;
+	return page_rmappable_folio(alloc_pages(gfp | __GFP_COMP, order));
 }
 EXPORT_SYMBOL(folio_alloc);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7df77b58a961..00f94dd88355 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4619,12 +4619,8 @@ struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid,
 		nodemask_t *nodemask)
 {
 	struct page *page = __alloc_pages(gfp | __GFP_COMP, order,
-			preferred_nid, nodemask);
-	struct folio *folio = (struct folio *)page;
-
-	if (folio && order > 1)
-		folio_prep_large_rmappable(folio);
-	return folio;
+					preferred_nid, nodemask);
+	return page_rmappable_folio(page);
 }
 EXPORT_SYMBOL(__folio_alloc);
 
-- 
2.35.3