mm: Add DEFINE_PAGE_VMA_WALK and DEFINE_FOLIO_VMA_WALK

Instead of declaring a struct page_vma_mapped_walk directly,
use these helpers to allow us to transition to a PFN approach in the
following patches.
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>

include/linux/rmap.h

@@ -214,6 +214,22 @@ struct page_vma_mapped_walk {
 	unsigned int flags;
 };
 
+#define DEFINE_PAGE_VMA_WALK(name, _page, _vma, _address, _flags)	\
+	struct page_vma_mapped_walk name = {				\
+		.page = _page,						\
+		.vma = _vma,						\
+		.address = _address,					\
+		.flags = _flags,					\
+	}
+
+#define DEFINE_FOLIO_VMA_WALK(name, _folio, _vma, _address, _flags)	\
+	struct page_vma_mapped_walk name = {				\
+		.page = &_folio->page,					\
+		.vma = _vma,						\
+		.address = _address,					\
+		.flags = _flags,					\
+	}
+
 static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
 {
 	/* HugeTLB pte is set to the relevant page table entry without pte_mapped. */

kernel/events/uprobes.c

@@ -155,11 +155,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 				struct page *old_page, struct page *new_page)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct page_vma_mapped_walk pvmw = {
-		.page = compound_head(old_page),
-		.vma = vma,
-		.address = addr,
-	};
+	DEFINE_FOLIO_VMA_WALK(pvmw, page_folio(old_page), vma, addr, 0);
 	int err;
 	struct mmu_notifier_range range;
 

mm/damon/paddr.c

@@ -19,11 +19,7 @@
 static bool __damon_pa_mkold(struct page *page, struct vm_area_struct *vma,
 		unsigned long addr, void *arg)
 {
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = addr,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, addr, 0);
 
 	while (page_vma_mapped_walk(&pvmw)) {
 		addr = pvmw.address;
@@ -93,11 +89,7 @@ static bool __damon_pa_young(struct page *page, struct vm_area_struct *vma,
 		unsigned long addr, void *arg)
 {
 	struct damon_pa_access_chk_result *result = arg;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = addr,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, addr, 0);
 
 	result->accessed = false;
 	result->page_sz = PAGE_SIZE;

mm/ksm.c

@@ -1034,10 +1034,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
 			      pte_t *orig_pte)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, 0, 0);
 	int swapped;
 	int err = -EFAULT;
 	struct mmu_notifier_range range;

mm/migrate.c

@@ -174,12 +174,7 @@ void putback_movable_pages(struct list_head *l)
 static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
 				 unsigned long addr, void *old)
 {
-	struct page_vma_mapped_walk pvmw = {
-		.page = old,
-		.vma = vma,
-		.address = addr,
-		.flags = PVMW_SYNC | PVMW_MIGRATION,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, old, vma, addr, PVMW_SYNC | PVMW_MIGRATION);
 	struct page *new;
 	pte_t pte;
 	swp_entry_t entry;

mm/page_idle.c

@@ -48,11 +48,7 @@ static bool page_idle_clear_pte_refs_one(struct page *page,
 					struct vm_area_struct *vma,
 					unsigned long addr, void *arg)
 {
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = addr,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, addr, 0);
 	bool referenced = false;
 
 	while (page_vma_mapped_walk(&pvmw)) {

mm/rmap.c

@@ -802,11 +802,7 @@ static bool page_referenced_one(struct page *page, struct vm_area_struct *vma,
 			unsigned long address, void *arg)
 {
 	struct page_referenced_arg *pra = arg;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = address,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
 	int referenced = 0;
 
 	while (page_vma_mapped_walk(&pvmw)) {
@@ -934,12 +930,7 @@ int page_referenced(struct page *page,
 static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 			    unsigned long address, void *arg)
 {
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = address,
-		.flags = PVMW_SYNC,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, PVMW_SYNC);
 	struct mmu_notifier_range range;
 	int *cleaned = arg;
 
@@ -1419,11 +1410,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		     unsigned long address, void *arg)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = address,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
 	pte_t pteval;
 	struct page *subpage;
 	bool ret = true;
@@ -1714,11 +1701,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
 		     unsigned long address, void *arg)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = address,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
 	pte_t pteval;
 	struct page *subpage;
 	bool ret = true;
@@ -2001,11 +1984,7 @@ static bool page_make_device_exclusive_one(struct page *page,
 		struct vm_area_struct *vma, unsigned long address, void *priv)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct page_vma_mapped_walk pvmw = {
-		.page = page,
-		.vma = vma,
-		.address = address,
-	};
+	DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
 	struct make_exclusive_args *args = priv;
 	pte_t pteval;
 	struct page *subpage;