mm: add vma_alloc_zeroed_movable_folio()

Replace alloc_zeroed_user_highpage_movable().  The main difference is
returning a folio containing a single page instead of returning the page,
but take the opportunity to rename the function to match other allocation
functions a little better and rewrite the documentation to place more
emphasis on the zeroing rather than the highmem aspect.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Matthew Wilcox (Oracle)

arch/alpha/include/asm/page.h

@@ -17,9 +17,8 @@
 extern void clear_page(void *page);
 #define clear_user_page(page, vaddr, pg)	clear_page(page)
 
-#define alloc_zeroed_user_highpage_movable(vma, vaddr) \
-	alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr)
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
 
 extern void copy_page(void * _to, void * _from);
 #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)

arch/arm64/include/asm/page.h

@@ -29,9 +29,9 @@ void copy_user_highpage(struct page *to, struct page *from,
 void copy_highpage(struct page *to, struct page *from);
 #define __HAVE_ARCH_COPY_HIGHPAGE
 
-struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
 						unsigned long vaddr);
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#define vma_alloc_zeroed_movable_folio vma_alloc_zeroed_movable_folio
 
 void tag_clear_highpage(struct page *to);
 #define __HAVE_ARCH_TAG_CLEAR_HIGHPAGE

arch/arm64/mm/fault.c

@@ -925,7 +925,7 @@ NOKPROBE_SYMBOL(do_debug_exception);
 /*
  * Used during anonymous page fault handling.
  */
-struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
 						unsigned long vaddr)
 {
 	gfp_t flags = GFP_HIGHUSER_MOVABLE | __GFP_ZERO;
@@ -938,7 +938,7 @@ struct page *alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 	if (vma->vm_flags & VM_MTE)
 		flags |= __GFP_ZEROTAGS;
 
-	return alloc_page_vma(flags, vma, vaddr);
+	return vma_alloc_folio(flags, 0, vma, vaddr, false);
 }
 
 void tag_clear_highpage(struct page *page)

arch/ia64/include/asm/page.h

@@ -82,17 +82,15 @@ do {						\
 } while (0)
 
 
-#define alloc_zeroed_user_highpage_movable(vma, vaddr)			\
+#define vma_alloc_zeroed_movable_folio(vma, vaddr)			\
 ({									\
-	struct page *page = alloc_page_vma(				\
-		GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr);		\
-	if (page)							\
- 		flush_dcache_page(page);				\
-	page;								\
+	struct folio *folio = vma_alloc_folio(				\
+		GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false); \
+	if (folio)							\
+		flush_dcache_folio(folio);				\
+	folio;								\
 })
 
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
-
 #define virt_addr_valid(kaddr)	pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
 #include <asm-generic/memory_model.h>

arch/m68k/include/asm/page_no.h

@@ -13,9 +13,8 @@ extern unsigned long memory_end;
 #define clear_user_page(page, vaddr, pg)	clear_page(page)
 #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
 
-#define alloc_zeroed_user_highpage_movable(vma, vaddr) \
-	alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr)
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
 
 #define __pa(vaddr)		((unsigned long)(vaddr))
 #define __va(paddr)		((void *)((unsigned long)(paddr)))

arch/s390/include/asm/page.h

@@ -73,9 +73,8 @@ static inline void copy_page(void *to, void *from)
 #define clear_user_page(page, vaddr, pg)	clear_page(page)
 #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
 
-#define alloc_zeroed_user_highpage_movable(vma, vaddr) \
-	alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr)
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
 
 /*
  * These are used to make use of C type-checking..

arch/x86/include/asm/page.h

@@ -34,9 +34,8 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
 	copy_page(to, from);
 }
 
-#define alloc_zeroed_user_highpage_movable(vma, vaddr) \
-	alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr)
-#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
 
 #ifndef __pa
 #define __pa(x)		__phys_addr((unsigned long)(x))

include/linux/highmem.h

@@ -207,31 +207,30 @@ static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 }
 #endif
 
-#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+#ifndef vma_alloc_zeroed_movable_folio
 /**
- * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
- * @vma: The VMA the page is to be allocated for
- * @vaddr: The virtual address the page will be inserted into
+ * vma_alloc_zeroed_movable_folio - Allocate a zeroed page for a VMA.
+ * @vma: The VMA the page is to be allocated for.
+ * @vaddr: The virtual address the page will be inserted into.
  *
- * Returns: The allocated and zeroed HIGHMEM page
+ * This function will allocate a page suitable for inserting into this
+ * VMA at this virtual address.  It may be allocated from highmem or
+ * the movable zone.  An architecture may provide its own implementation.
  *
- * This function will allocate a page for a VMA that the caller knows will
- * be able to migrate in the future using move_pages() or reclaimed
- *
- * An architecture may override this function by defining
- * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE and providing their own
- * implementation.
+ * Return: A folio containing one allocated and zeroed page or NULL if
+ * we are out of memory.
  */
-static inline struct page *
-alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+static inline
+struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
 				   unsigned long vaddr)
 {
-	struct page *page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
+	struct folio *folio;
 
-	if (page)
-		clear_user_highpage(page, vaddr);
+	folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr, false);
+	if (folio)
+		clear_user_highpage(&folio->page, vaddr);
 
-	return page;
+	return folio;
 }
 #endif
 

mm/memory.c

@@ -3056,10 +3056,12 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 		goto oom;
 
 	if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
-		new_page = alloc_zeroed_user_highpage_movable(vma,
-							      vmf->address);
-		if (!new_page)
+		struct folio *new_folio;
+
+		new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address);
+		if (!new_folio)
 			goto oom;
+		new_page = &new_folio->page;
 	} else {
 		new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
 				vmf->address);
@@ -3995,6 +3997,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *page;
+	struct folio *folio;
 	vm_fault_t ret = 0;
 	pte_t entry;
 
@@ -4044,11 +4047,12 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 	/* Allocate our own private page. */
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
-	page = alloc_zeroed_user_highpage_movable(vma, vmf->address);
-	if (!page)
+	folio = vma_alloc_zeroed_movable_folio(vma, vmf->address);
+	if (!folio)
 		goto oom;
 
-	if (mem_cgroup_charge(page_folio(page), vma->vm_mm, GFP_KERNEL))
+	page = &folio->page;
+	if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL))
 		goto oom_free_page;
 	cgroup_throttle_swaprate(page, GFP_KERNEL);