[PATCH v3 2/2] ext2/4, xfs, blk: call dax_get_unmapped_area() for DAX pmd mappings

[Toshi Kani]

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.k...@hpe.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Alexander Viro <v...@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Matthew Wilcox <wi...@linux.intel.com>
Cc: Ross Zwisler <ross.zwis...@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Cc: Dave Chinner <da...@fromorbit.com>
Cc: Jan Kara <j...@suse.cz>
Cc: Theodore Ts'o <ty...@mit.edu>
Cc: Andreas Dilger <adilger.ker...@dilger.ca>
---
 fs/block_dev.c    |    1 +
 fs/ext2/file.c    |    1 +
 fs/ext4/file.c    |    1 +
 fs/xfs/xfs_file.c |    1 +
 4 files changed, 4 insertions(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 20a2c02..52518e0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1798,6 +1798,7 @@ const struct file_operations def_blk_fops = {
        .write_iter     = blkdev_write_iter,
        .mmap           = blkdev_mmap,
        .fsync          = blkdev_fsync,
+       .get_unmapped_area = dax_get_unmapped_area,
        .unlocked_ioctl = block_ioctl,
 #ifdef CONFIG_COMPAT
        .compat_ioctl   = compat_blkdev_ioctl,
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index c1400b1..dbf11eb 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -172,6 +172,7 @@ const struct file_operations ext2_file_operations = {
        .open           = dquot_file_open,
        .release        = ext2_release_file,
        .fsync          = ext2_fsync,
+       .get_unmapped_area = dax_get_unmapped_area,
        .splice_read    = generic_file_splice_read,
        .splice_write   = iter_file_splice_write,
 };
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index fa2208b..6c268f8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -708,6 +708,7 @@ const struct file_operations ext4_file_operations = {
        .open           = ext4_file_open,
        .release        = ext4_release_file,
        .fsync          = ext4_sync_file,
+       .get_unmapped_area = dax_get_unmapped_area,
        .splice_read    = generic_file_splice_read,
        .splice_write   = iter_file_splice_write,
        .fallocate      = ext4_fallocate,
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 569938a..1e409a6 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1708,6 +1708,7 @@ const struct file_operations xfs_file_operations = {
        .open           = xfs_file_open,
        .release        = xfs_file_release,
        .fsync          = xfs_file_fsync,
+       .get_unmapped_area = dax_get_unmapped_area,
        .fallocate      = xfs_file_fallocate,
 };