Use newly wrapped nans_to_nulls

python/cudf/cudf/_lib/transform.pyx

@@ -20,6 +20,7 @@ from rmm._lib.device_buffer cimport DeviceBuffer, device_buffer
 cimport cudf._lib.pylibcudf.libcudf.transform as libcudf_transform
 from cudf._lib.column cimport Column
 from cudf._lib.expressions cimport Expression
+from cudf._lib.pylibcudf cimport transform as plc_transform
 from cudf._lib.pylibcudf.libcudf.column.column cimport column
 from cudf._lib.pylibcudf.libcudf.column.column_view cimport column_view
 from cudf._lib.pylibcudf.libcudf.expressions cimport expression
@@ -82,18 +83,10 @@ def mask_to_bools(object mask_buffer, size_type begin_bit, size_type end_bit):
 
 @acquire_spill_lock()
 def nans_to_nulls(Column input):
-    cdef column_view c_input = input.view()
-    cdef pair[unique_ptr[device_buffer], size_type] c_output
-    cdef unique_ptr[device_buffer] c_buffer
-
-    with nogil:
-        c_output = move(libcudf_transform.nans_to_nulls(c_input))
-        c_buffer = move(c_output.first)
-
-    if c_output.second == 0:
-        return None
-
-    return as_buffer(DeviceBuffer.c_from_unique_ptr(move(c_buffer)))
+    (mask, _) = plc_transform.nans_to_nulls(
+        input.to_pylibcudf(mode="read")
+    )
+    return as_buffer(mask)
 
 
 @acquire_spill_lock()