in device.c [353:370]
static int dax_open(struct inode *inode, struct file *filp)
{
struct dax_device *dax_dev = inode_dax(inode);
struct inode *__dax_inode = dax_inode(dax_dev);
struct dev_dax *dev_dax = dax_get_private(dax_dev);
dev_dbg(&dev_dax->dev, "trace\n");
inode->i_mapping = __dax_inode->i_mapping;
inode->i_mapping->host = __dax_inode;
inode->i_mapping->a_ops = &dev_dax_aops;
filp->f_mapping = inode->i_mapping;
filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
filp->f_sb_err = file_sample_sb_err(filp);
filp->private_data = dev_dax;
inode->i_flags = S_DAX;
return 0;
}