dax: unify ext2/4_{dax,}_file_operations

The original dax patchset split the ext2/4_file_operations because of the
two NULL splice_read/splice_write in the dax case.

In the vfs if splice_read/splice_write are NULL we then call
default_splice_read/write.

What we do here is make generic_file_splice_read aware of IS_DAX() so the
original ext2/4_file_operations can be used as is.

For write it appears that iter_file_splice_write is just fine.  It uses
the regular f_op->write(file,..) or new_sync_write(file, ...).

Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 3 insertions, 33 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f63c3d5805c4..8a3981ea35d8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2593,7 +2593,6 @@ extern const struct file_operations ext4_dir_operations;
 /* file.c */
 extern const struct inode_operations ext4_file_inode_operations;
 extern const struct file_operations ext4_file_operations;
-extern const struct file_operations ext4_dax_file_operations;
 extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
 
 /* inline.c */
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index aa78c70553f4..e6d4280d66be 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -625,26 +625,6 @@ const struct file_operations ext4_file_operations = {
 	.fallocate	= ext4_fallocate,
 };
 
-#ifdef CONFIG_FS_DAX
-const struct file_operations ext4_dax_file_operations = {
-	.llseek		= ext4_llseek,
-	.read		= new_sync_read,
-	.write		= new_sync_write,
-	.read_iter	= generic_file_read_iter,
-	.write_iter	= ext4_file_write_iter,
-	.unlocked_ioctl = ext4_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= ext4_compat_ioctl,
-#endif
-	.mmap		= ext4_file_mmap,
-	.open		= ext4_file_open,
-	.release	= ext4_release_file,
-	.fsync		= ext4_sync_file,
-	/* Splice not yet supported with DAX */
-	.fallocate	= ext4_fallocate,
-};
-#endif
-
 const struct inode_operations ext4_file_inode_operations = {
 	.setattr	= ext4_setattr,
 	.getattr	= ext4_getattr,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a3f451370bef..035b7a06f1c3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4090,10 +4090,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &ext4_file_inode_operations;
-		if (test_opt(inode->i_sb, DAX))
-			inode->i_fop = &ext4_dax_file_operations;
-		else
-			inode->i_fop = &ext4_file_operations;
+		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = &ext4_dir_inode_operations;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 28fe71a2904c..2291923dae4e 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2235,10 +2235,7 @@ retry:
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &ext4_file_inode_operations;
-		if (test_opt(inode->i_sb, DAX))
-			inode->i_fop = &ext4_dax_file_operations;
-		else
-			inode->i_fop = &ext4_file_operations;
+		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
 		err = ext4_add_nondir(handle, dentry, inode);
 		if (!err && IS_DIRSYNC(dir))
@@ -2302,10 +2299,7 @@ retry:
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &ext4_file_inode_operations;
-		if (test_opt(inode->i_sb, DAX))
-			inode->i_fop = &ext4_dax_file_operations;
-		else
-			inode->i_fop = &ext4_file_operations;
+		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
 		d_tmpfile(dentry, inode);
 		err = ext4_orphan_add(handle, inode);