[patch 076/114] mm: export follow_pte()

[patch 076/114] mm: export follow_pte()

[akpm]

From: Jan Kara <jack@suse.cz>
Subject: mm: export follow_pte()

DAX will need to implement its own version of page_check_address().  To
avoid duplicating page table walking code, export follow_pte() which does
what we need.

Link: http://lkml.kernel.org/r/1479460644-25076-18-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h |    2 ++
 mm/memory.c        |    4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff -puN include/linux/mm.h~mm-export-follow_pte include/linux/mm.h
--- a/include/linux/mm.h~mm-export-follow_pte
+++ a/include/linux/mm.h
@@ -1210,6 +1210,8 @@ int copy_page_range(struct mm_struct *ds
 			struct vm_area_struct *vma);
 void unmap_mapping_range(struct address_space *mapping,
 		loff_t const holebegin, loff_t const holelen, int even_cows);
+int follow_pte(struct mm_struct *mm, unsigned long address, pte_t **ptepp,
+	       spinlock_t **ptlp);
 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
 	unsigned long *pfn);
 int follow_phys(struct vm_area_struct *vma, unsigned long address,
diff -puN mm/memory.c~mm-export-follow_pte mm/memory.c
--- a/mm/memory.c~mm-export-follow_pte
+++ a/mm/memory.c
@@ -3817,8 +3817,8 @@ out:
 	return -EINVAL;
 }
 
-static inline int follow_pte(struct mm_struct *mm, unsigned long address,
-			     pte_t **ptepp, spinlock_t **ptlp)
+int follow_pte(struct mm_struct *mm, unsigned long address, pte_t **ptepp,
+	       spinlock_t **ptlp)
 {
 	int res;
 
_