[PATCH v2 3/5] xfs: call dax_get_unmapped_area() for DAX pmd mappings

[Toshi Kani <toshi.kani@hpe.com>]

To support DAX pmd mappings with unmodified applications,
filesystems need to align an mmap address by the pmd size.

Call dax_get_unmapped_area() from f_op->get_unmapped_area.

Note, there is no change in behavior for a non-DAX file.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: <xfs@oss.sgi.com>
---
 fs/xfs/xfs_file.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 569938a..51c554b 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1708,6 +1708,9 @@ const struct file_operations xfs_file_operations = {
 	.open		= xfs_file_open,
 	.release	= xfs_file_release,
 	.fsync		= xfs_file_fsync,
+#ifdef CONFIG_FS_DAX
+	.get_unmapped_area = dax_get_unmapped_area,
+#endif
 	.fallocate	= xfs_file_fallocate,
 };