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

Call thp_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 <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <redacted>
Cc: Matthew Wilcox <redacted>
Cc: Ross Zwisler <redacted>
Cc: Kirill A. Shutemov <redacted>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Mike Kravetz <redacted>
---
 fs/ext2/file.c    |    1 +
 fs/ext4/file.c    |    1 +
 fs/xfs/xfs_file.c |    1 +
 3 files changed, 3 insertions(+)

diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 5efeefe..d86831c 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 = thp_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 261ac37..28f542b 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c

@@ -703,6 +703,7 @@ const struct file_operations ext4_file_operations = {
 	.open		= ext4_file_open,
 	.release	= ext4_release_file,
 	.fsync		= ext4_sync_file,
+	.get_unmapped_area = thp_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 e612a02..7f71bb8 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c

@@ -1662,6 +1662,7 @@ const struct file_operations xfs_file_operations = {
 	.open		= xfs_file_open,
 	.release	= xfs_file_release,
 	.fsync		= xfs_file_fsync,
+	.get_unmapped_area = thp_get_unmapped_area,
 	.fallocate	= xfs_file_fallocate,
 };
 

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