[PATCH v2 1/8] mm/gup: perform check_dax_vmas only when FS_DAX is enabled

[Pavel Tatashin]

There is no need to check_dax_vmas() and run through the npage loop of
pinned pages if FS_DAX is not enabled.

Add a stub check_dax_vmas() function for no-FS_DAX case.

Signed-off-by: Pavel Tatashin <pasha.tatas...@soleen.com>
Reviewed-by: John Hubbard <jhubb...@nvidia.com>
---
 mm/gup.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 98eb8e6d2609..cdb8b9eeb016 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1568,6 +1568,7 @@ struct page *get_dump_page(unsigned long addr)
 #endif /* CONFIG_ELF_CORE */
 
 #if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
+#ifdef CONFIG_FS_DAX
 static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
 {
        long i;
@@ -1586,6 +1587,12 @@ static bool check_dax_vmas(struct vm_area_struct **vmas, 
long nr_pages)
        }
        return false;
 }
+#else
+static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
+{
+       return false;
+}
+#endif
 
 #ifdef CONFIG_CMA
 static long check_and_migrate_cma_pages(struct mm_struct *mm,
-- 
2.25.1