[RFC PATCH 2/6] mm: pass gfp flags and order to vma_alloc_zeroed_movable_folio()

[Ryan Roberts <ryan.roberts@arm.com>]

Allow allocation of large folios with vma_alloc_zeroed_movable_folio().
This prepares the ground for large anonymous folios. The generic
implementation of vma_alloc_zeroed_movable_folio() now uses
clear_huge_page() to zero the allocated folio since it may now be a
non-0 order.

Currently the function is always called with order 0 and no extra gfp
flags, so no functional change intended.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 arch/alpha/include/asm/page.h   |  5 +++--
 arch/arm64/include/asm/page.h   |  3 ++-
 arch/arm64/mm/fault.c           |  7 ++++---
 arch/ia64/include/asm/page.h    |  5 +++--
 arch/m68k/include/asm/page_no.h |  7 ++++---
 arch/s390/include/asm/page.h    |  5 +++--
 arch/x86/include/asm/page.h     |  5 +++--
 include/linux/highmem.h         | 23 +++++++++++++----------
 mm/memory.c                     |  5 +++--
 9 files changed, 38 insertions(+), 27 deletions(-)

diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index 4db1ebc0ed99..6fc7fe91b6cb 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h
@@ -17,8 +17,9 @@
 extern void clear_page(void *page);
 #define clear_user_page(page, vaddr, pg)	clear_page(page)

-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
-	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
+			order, vma, vaddr, false)

 extern void copy_page(void * _to, void * _from);
 #define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 2312e6ee595f..47710852f872 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -30,7 +30,8 @@ void copy_highpage(struct page *to, struct page *from);
 #define __HAVE_ARCH_COPY_HIGHPAGE

 struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
-						unsigned long vaddr);
+						unsigned long vaddr,
+						gfp_t gfp, int order);
 #define vma_alloc_zeroed_movable_folio vma_alloc_zeroed_movable_folio

 void tag_clear_highpage(struct page *to);
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index f4cb0f85ccf4..3b4cc04f7a23 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -926,9 +926,10 @@ NOKPROBE_SYMBOL(do_debug_exception);
  * Used during anonymous page fault handling.
  */
 struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
-						unsigned long vaddr)
+						unsigned long vaddr,
+						gfp_t gfp, int order)
 {
-	gfp_t flags = GFP_HIGHUSER_MOVABLE | __GFP_ZERO;
+	gfp_t flags = GFP_HIGHUSER_MOVABLE | __GFP_ZERO | gfp;

 	/*
 	 * If the page is mapped with PROT_MTE, initialise the tags at the
@@ -938,7 +939,7 @@ struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
 	if (vma->vm_flags & VM_MTE)
 		flags |= __GFP_ZEROTAGS;

-	return vma_alloc_folio(flags, 0, vma, vaddr, false);
+	return vma_alloc_folio(flags, order, vma, vaddr, false);
 }

 void tag_clear_highpage(struct page *page)
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index 310b09c3342d..ebdf04274023 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -82,10 +82,11 @@ do {						\
 } while (0)


-#define vma_alloc_zeroed_movable_folio(vma, vaddr)			\
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order)		\
 ({									\
 	struct folio *folio = vma_alloc_folio(				\
-		GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false); \
+		GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp),		\
+		order, vma, vaddr, false);				\
 	if (folio)							\
 		flush_dcache_folio(folio);				\
 	folio;								\
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index 060e4c0e7605..4a2fe57fef5e 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -3,7 +3,7 @@
 #define _M68K_PAGE_NO_H

 #ifndef __ASSEMBLY__
-
+
 extern unsigned long memory_start;
 extern unsigned long memory_end;

@@ -13,8 +13,9 @@ 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 vma_alloc_zeroed_movable_folio(vma, vaddr) \
-	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
+			order, vma, vaddr, false)

 #define __pa(vaddr)		((unsigned long)(vaddr))
 #define __va(paddr)		((void *)((unsigned long)(paddr)))
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 8a2a3b5d1e29..b749564140f1 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -73,8 +73,9 @@ 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 vma_alloc_zeroed_movable_folio(vma, vaddr) \
-	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
+			order, vma, vaddr, false)

 /*
  * These are used to make use of C type-checking..
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index d18e5c332cb9..34deab1a8dae 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -34,8 +34,9 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
 	copy_page(to, from);
 }

-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
-	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
+	vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
+			order, vma, vaddr, false)

 #ifndef __pa
 #define __pa(x)		__phys_addr((unsigned long)(x))
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index b06254e76d99..e2127af4997b 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -209,26 +209,29 @@ static inline void clear_user_highpage(struct page *page, unsigned long vaddr)

 #ifndef vma_alloc_zeroed_movable_folio
 /**
- * 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.
- *
- * This function will allocate a page suitable for inserting into this
- * VMA at this virtual address.  It may be allocated from highmem or
+ * vma_alloc_zeroed_movable_folio - Allocate a zeroed folio for a VMA.
+ * @vma: The start VMA the folio is to be allocated for.
+ * @vaddr: The virtual address the folio will be inserted into.
+ * @gfp: Additional gfp falgs to mix in or 0.
+ * @order: The order of the folio (2^order pages).
+ *
+ * This function will allocate a folio suitable for inserting into this
+ * VMA starting at this virtual address.  It may be allocated from highmem or
  * the movable zone.  An architecture may provide its own implementation.
  *
- * Return: A folio containing one allocated and zeroed page or NULL if
+ * Return: A folio containing 2^order allocated and zeroed pages or NULL if
  * we are out of memory.
  */
 static inline
 struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
-				   unsigned long vaddr)
+				   unsigned long vaddr, gfp_t gfp, int order)
 {
 	struct folio *folio;

-	folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr, false);
+	folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE | gfp,
+					order, vma, vaddr, false);
 	if (folio)
-		clear_user_highpage(&folio->page, vaddr);
+		clear_huge_page(&folio->page, vaddr, 1U << order);

 	return folio;
 }
diff --git a/mm/memory.c b/mm/memory.c
index c08645908ee2..8798da968686 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3061,7 +3061,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 		goto oom;

 	if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
-		new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address);
+		new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address,
+									0, 0);
 		if (!new_folio)
 			goto oom;
 	} else {
@@ -4049,7 +4050,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 	/* Allocate our own private page. */
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
-	folio = vma_alloc_zeroed_movable_folio(vma, vmf->address);
+	folio = vma_alloc_zeroed_movable_folio(vma, vmf->address, 0, 0);
 	if (!folio)
 		goto oom;

--
2.25.1