dax_lock_entry
old = dax_lock_entry(xas, new_entry);
dax_lock_entry(xas, entry);
dax_lock_entry(&xas, entry);
dax_lock_entry(&xas, entry);
dax_lock_entry(&xas, entry);
dax_lock_entry(xas, entry);
dax_lock_entry(xas, entry);
dax_lock_entry(xas, entry);