[PATCH v4 1/4] mm/memory: Add vm_normal_folio()

["Vishal Moola (Oracle)" <vishal.moola@gmail.com>]

Introduce a wrapper function called vm_normal_folio(). This function
calls vm_normal_page() and returns the folio of the page found, or null
if no page is found.

This function allows callers to get a folio from a pte, which will
eventually allow them to completely replace their struct page variables
with struct folio instead.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm.h |  2 ++
 mm/memory.c        | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ff46dcab2004..d29bfae4b71f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1968,6 +1968,8 @@ static inline bool can_do_mlock(void) { return false; }
 extern int user_shm_lock(size_t, struct ucounts *);
 extern void user_shm_unlock(size_t, struct ucounts *);
 
+struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr,
+			     pte_t pte);
 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 			     pte_t pte);
 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
diff --git a/mm/memory.c b/mm/memory.c
index 37d1763c4d47..4000e9f017e0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -625,6 +625,16 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
 	return pfn_to_page(pfn);
 }
 
+struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr,
+			    pte_t pte)
+{
+	struct page *page = vm_normal_page(vma, addr, pte);
+
+	if (page)
+		return page_folio(page);
+	return NULL;
+}
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
 				pmd_t pmd)
-- 
2.38.1