mm: convert prep_transhuge_page() to folio_prep_large_rmappable()

Match folio_undo_large_rmappable(), and move the casting from page to
folio into the callers (which they were largely doing anyway).

Link: https://lkml.kernel.org/r/20230816151201.3655946-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/huge_mm.h

@@ -140,7 +140,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags,
 unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
 		unsigned long len, unsigned long pgoff, unsigned long flags);
 
-void prep_transhuge_page(struct page *page);
+void folio_prep_large_rmappable(struct folio *folio);
 bool can_split_folio(struct folio *folio, int *pextra_pins);
 int split_huge_page_to_list(struct page *page, struct list_head *list);
 static inline int split_huge_page(struct page *page)
@@ -280,7 +280,7 @@ static inline bool hugepage_vma_check(struct vm_area_struct *vma,
 	return false;
 }
 
-static inline void prep_transhuge_page(struct page *page) {}
+static inline void folio_prep_large_rmappable(struct folio *folio) {}
 
 #define transparent_hugepage_flags 0UL
 

mm/huge_memory.c

@@ -577,10 +577,8 @@ struct deferred_split *get_deferred_split_queue(struct folio *folio)
 }
 #endif
 
-void prep_transhuge_page(struct page *page)
+void folio_prep_large_rmappable(struct folio *folio)
 {
-	struct folio *folio = (struct folio *)page;
-
 	VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio);
 	INIT_LIST_HEAD(&folio->_deferred_list);
 	folio_set_compound_dtor(folio, TRANSHUGE_PAGE_DTOR);

mm/khugepaged.c

@@ -896,7 +896,7 @@ static bool hpage_collapse_alloc_page(struct page **hpage, gfp_t gfp, int node,
 		return false;
 	}
 
-	prep_transhuge_page(*hpage);
+	folio_prep_large_rmappable((struct folio *)*hpage);
 	count_vm_event(THP_COLLAPSE_ALLOC);
 	return true;
 }

mm/mempolicy.c

@@ -2195,9 +2195,9 @@ 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);
-		if (page && order > 1)
-			prep_transhuge_page(page);
 		folio = (struct folio *)page;
+		if (folio && order > 1)
+			folio_prep_large_rmappable(folio);
 		goto out;
 	}
 
@@ -2208,9 +2208,9 @@ 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);
-		if (page && order > 1)
-			prep_transhuge_page(page);
 		folio = (struct folio *)page;
+		if (folio && order > 1)
+			folio_prep_large_rmappable(folio);
 		goto out;
 	}
 
@@ -2306,10 +2306,11 @@ 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 (page && order > 1)
-		prep_transhuge_page(page);
-	return (struct folio *)page;
+	if (folio && order > 1)
+		folio_prep_large_rmappable(folio);
+	return folio;
 }
 EXPORT_SYMBOL(folio_alloc);
 

mm/page_alloc.c

@@ -4489,10 +4489,11 @@ struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid,
 {
 	struct page *page = __alloc_pages(gfp | __GFP_COMP, order,
 			preferred_nid, nodemask);
+	struct folio *folio = (struct folio *)page;
 
-	if (page && order > 1)
-		prep_transhuge_page(page);
-	return (struct folio *)page;
+	if (folio && order > 1)
+		folio_prep_large_rmappable(folio);
+	return folio;
 }
 EXPORT_SYMBOL(__folio_alloc);