[PATCH] mm: export folio_pte_batch as a couple of modules might need it

[Barry Song <21cnbao@gmail.com>]

From: Barry Song <v-songbaohua@oppo.com>

madvise and some others might need folio_pte_batch to check if a range
of PTEs are completely mapped to a large folio with contiguous physcial
addresses. Let's export it for others to use.

Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
---
 -v1:
 at least two jobs madv_free and madv_pageout depend on it. To avoid
 conflicts and dependencies, after discussing with Lance, we prefer
 this one can land earlier.

 mm/internal.h | 13 +++++++++++++
 mm/memory.c   | 11 +----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 13b59d384845..8e2bc304f671 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -83,6 +83,19 @@ static inline void *folio_raw_mapping(struct folio *folio)
 	return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
 }
 
+/* Flags for folio_pte_batch(). */
+typedef int __bitwise fpb_t;
+
+/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */
+#define FPB_IGNORE_DIRTY		((__force fpb_t)BIT(0))
+
+/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */
+#define FPB_IGNORE_SOFT_DIRTY		((__force fpb_t)BIT(1))
+
+extern int folio_pte_batch(struct folio *folio, unsigned long addr,
+		pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags,
+		bool *any_writable);
+
 void __acct_reclaim_writeback(pg_data_t *pgdat, struct folio *folio,
 						int nr_throttled);
 static inline void acct_reclaim_writeback(struct folio *folio)
diff --git a/mm/memory.c b/mm/memory.c
index 1c45b6a42a1b..319b3be05e75 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -953,15 +953,6 @@ static __always_inline void __copy_present_ptes(struct vm_area_struct *dst_vma,
 	set_ptes(dst_vma->vm_mm, addr, dst_pte, pte, nr);
 }
 
-/* Flags for folio_pte_batch(). */
-typedef int __bitwise fpb_t;
-
-/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */
-#define FPB_IGNORE_DIRTY		((__force fpb_t)BIT(0))
-
-/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */
-#define FPB_IGNORE_SOFT_DIRTY		((__force fpb_t)BIT(1))
-
 static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags)
 {
 	if (flags & FPB_IGNORE_DIRTY)
@@ -982,7 +973,7 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags)
  * If "any_writable" is set, it will indicate if any other PTE besides the
  * first (given) PTE is writable.
  */
-static inline int folio_pte_batch(struct folio *folio, unsigned long addr,
+int folio_pte_batch(struct folio *folio, unsigned long addr,
 		pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags,
 		bool *any_writable)
 {
-- 
2.34.1