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, 31 deletions

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 678f9ab08c48..8d15febd0aa3 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -793,7 +793,6 @@ extern int ext2_fsync(struct file *file, loff_t start, loff_t end,
                       int datasync);
 extern const struct inode_operations ext2_file_inode_operations;
 extern const struct file_operations ext2_file_operations;
-extern const struct file_operations ext2_dax_file_operations;
 
 /* inode.c */
 extern const struct address_space_operations ext2_aops;
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 866a3ce3f864..19cac93a65d3 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -109,24 +109,6 @@ const struct file_operations ext2_file_operations = {
         .splice_write   = iter_file_splice_write,
 };
 
-#ifdef CONFIG_FS_DAX
-const struct file_operations ext2_dax_file_operations = {
-        .llseek         = generic_file_llseek,
-        .read           = new_sync_read,
-        .write          = new_sync_write,
-        .read_iter      = generic_file_read_iter,
-        .write_iter     = generic_file_write_iter,
-        .unlocked_ioctl = ext2_ioctl,
-#ifdef CONFIG_COMPAT
-        .compat_ioctl   = ext2_compat_ioctl,
-#endif
-        .mmap           = ext2_file_mmap,
-        .open           = dquot_file_open,
-        .release        = ext2_release_file,
-        .fsync          = ext2_fsync,
-};
-#endif
-
 const struct inode_operations ext2_file_inode_operations = {
 #ifdef CONFIG_EXT2_FS_XATTR
         .setxattr       = generic_setxattr,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index df9d6afbc5d5..b29eb6747116 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1388,10 +1388,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 
         if (S_ISREG(inode->i_mode)) {
                 inode->i_op = &ext2_file_inode_operations;
-                if (test_opt(inode->i_sb, DAX)) {
-                        inode->i_mapping->a_ops = &ext2_aops;
-                        inode->i_fop = &ext2_dax_file_operations;
-                } else if (test_opt(inode->i_sb, NOBH)) {
+                if (test_opt(inode->i_sb, NOBH)) {
                         inode->i_mapping->a_ops = &ext2_nobh_aops;
                         inode->i_fop = &ext2_file_operations;
                 } else {
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 148f6e3789ea..ce422931f411 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -104,10 +104,7 @@ static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode
                 return PTR_ERR(inode);
 
         inode->i_op = &ext2_file_inode_operations;
-        if (test_opt(inode->i_sb, DAX)) {
-                inode->i_mapping->a_ops = &ext2_aops;
-                inode->i_fop = &ext2_dax_file_operations;
-        } else if (test_opt(inode->i_sb, NOBH)) {
+        if (test_opt(inode->i_sb, NOBH)) {
                 inode->i_mapping->a_ops = &ext2_nobh_aops;
                 inode->i_fop = &ext2_file_operations;
         } else {
@@ -125,10 +122,7 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
                 return PTR_ERR(inode);
 
         inode->i_op = &ext2_file_inode_operations;
-        if (test_opt(inode->i_sb, DAX)) {
-                inode->i_mapping->a_ops = &ext2_aops;
-                inode->i_fop = &ext2_dax_file_operations;
-        } else if (test_opt(inode->i_sb, NOBH)) {
+        if (test_opt(inode->i_sb, NOBH)) {
                 inode->i_mapping->a_ops = &ext2_nobh_aops;
                 inode->i_fop = &ext2_file_operations;
         } else {