mm: memory: rename page_copy_prealloc() to folio_prealloc()

Let's rename page_copy_prealloc() to folio_prealloc(), which could be
reused in more functons, as it maybe zero the new page, pass a new
need_zero to it, and call the vma_alloc_zeroed_movable_folio() if
need_zero is true.

Link: https://lkml.kernel.org/r/20231118023232.1409103-4-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory.c

@@ -992,12 +992,17 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 	return 0;
 }
 
-static inline struct folio *page_copy_prealloc(struct mm_struct *src_mm,
-		struct vm_area_struct *vma, unsigned long addr)
+static inline struct folio *folio_prealloc(struct mm_struct *src_mm,
+		struct vm_area_struct *vma, unsigned long addr, bool need_zero)
 {
 	struct folio *new_folio;
 
-	new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, addr, false);
+	if (need_zero)
+		new_folio = vma_alloc_zeroed_movable_folio(vma, addr);
+	else
+		new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma,
+					    addr, false);
+
 	if (!new_folio)
 		return NULL;
 
@@ -1129,7 +1134,7 @@ copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 	} else if (ret == -EBUSY) {
 		goto out;
 	} else if (ret ==  -EAGAIN) {
-		prealloc = page_copy_prealloc(src_mm, src_vma, addr);
+		prealloc = folio_prealloc(src_mm, src_vma, addr, false);
 		if (!prealloc)
 			return -ENOMEM;
 	} else if (ret) {