mm: export various functions for the benefit of DAX

Orabug: 22913653

To use the huge zero page in DAX, we need these functions exported.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit fc43704437ebe40f642ac53f7ee73661fe74e6b8)
Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 1c53c7d7ef7e6048a6c2fb2746e82c74c41afa20..70587ea079c3acb39e3e6f075d6b2206039584b1 100644 (file)
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -155,6 +155,16 @@ static inline bool is_huge_zero_page(struct page *page)
        return ACCESS_ONCE(huge_zero_page) == page;
 }
 
+static inline bool is_huge_zero_pmd(pmd_t pmd)
+{
+       return is_huge_zero_page(pmd_page(pmd));
+}
+
+struct page *get_huge_zero_page(void);
+bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+               struct vm_area_struct *vma, unsigned long haddr,
+               pmd_t *pmd, struct page *zero_page);
+
 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
 #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 80148c246d47f4187be9b998a710906d34e4d7d0..410e264dba5753c342b1190989b6fcb2b8ac3fd2 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -172,12 +172,7 @@ fail:
 static atomic_t huge_zero_refcount;
 struct page *huge_zero_page __read_mostly;
 
-static inline bool is_huge_zero_pmd(pmd_t pmd)
-{
-       return is_huge_zero_page(pmd_page(pmd));
-}
-
-static struct page *get_huge_zero_page(void)
+struct page *get_huge_zero_page(void)
 {
        struct page *zero_page;
 retry: