mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page

The function unmap_hugepage_range() has two kinds of users:
1) unmap_ref_private(), which passes in the head page of a folio.  Since
   unmap_ref_private() already takes folio and there are no other uses
   of the folio struct in the function, it is natural for
   unmap_hugepage_range() to take folio also.
2) All other uses, which pass in NULL pointer.

In both cases, we can pass in folio. Refactor unmap_hugepage_range() to
take folio.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Fan Ni <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Reviewed-by: Sidhartha Kumar <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: "Vishal Moola (Oracle)" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: fancxl

include/linux/hugetlb.h

@@ -129,8 +129,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
 			    struct vm_area_struct *, struct vm_area_struct *);
 void unmap_hugepage_range(struct vm_area_struct *,
-			  unsigned long, unsigned long, struct page *,
-			  zap_flags_t);
+			  unsigned long start, unsigned long end,
+			  struct folio *, zap_flags_t);
 void __unmap_hugepage_range(struct mmu_gather *tlb,
 			  struct vm_area_struct *vma,
 			  unsigned long start, unsigned long end,

mm/hugetlb.c

@@ -6046,7 +6046,7 @@ void __hugetlb_zap_end(struct vm_area_struct *vma,
 }
 
 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
-			  unsigned long end, struct page *ref_page,
+			  unsigned long end, struct folio *folio,
 			  zap_flags_t zap_flags)
 {
 	struct mmu_notifier_range range;
@@ -6058,7 +6058,8 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 	mmu_notifier_invalidate_range_start(&range);
 	tlb_gather_mmu(&tlb, vma->vm_mm);
 
-	__unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
+	__unmap_hugepage_range(&tlb, vma, start, end,
+			       &folio->page, zap_flags);
 
 	mmu_notifier_invalidate_range_end(&range);
 	tlb_finish_mmu(&tlb);
@@ -6116,7 +6117,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
 			unmap_hugepage_range(iter_vma, address,
 					     address + huge_page_size(h),
-					     &folio->page, 0);
+					     folio, 0);
 	}
 	i_mmap_unlock_write(mapping);
 }