Remove some Kosmos-2 `copied from` (#27149)

* fix

* fix

* fix

* fix

---------
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

src/transformers/models/kosmos2/modeling_kosmos2.py

@@ -52,7 +52,6 @@ KOSMOS2_PRETRAINED_MODEL_ARCHIVE_LIST = [
 ]
 
 
-# Copied from transformers.models.bart.modeling_bart._expand_mask
 def _expand_mask(mask: torch.Tensor, dtype: torch.dtype, tgt_len: Optional[int] = None):
     """
     Expands attention_mask from `[bsz, seq_len]` to `[bsz, 1, tgt_seq_len, src_seq_len]`.
@@ -67,7 +66,6 @@ def _expand_mask(mask: torch.Tensor, dtype: torch.dtype, tgt_len: Optional[int]
     return inverted_mask.masked_fill(inverted_mask.to(torch.bool), torch.finfo(dtype).min)
 
 
-# Copied from transformers.models.bart.modeling_bart._make_causal_mask
 def _make_causal_mask(
     input_ids_shape: torch.Size, dtype: torch.dtype, device: torch.device, past_key_values_length: int = 0
 ):
@@ -660,7 +658,7 @@ class Kosmos2VisionEncoder(nn.Module):
             if output_hidden_states:
                 encoder_states = encoder_states + (hidden_states,)
             if self.gradient_checkpointing and self.training:
-                layer_outputs = self.gradient_checkpointing_func(
+                layer_outputs = self._gradient_checkpointing_func(
                     encoder_layer.__call__,
                     hidden_states,
                     attention_mask,
@@ -1114,7 +1112,6 @@ class Kosmos2TextTransformer(nn.Module):
 
         self.gradient_checkpointing = False
 
-    # Copied from transformers.models.bart.modeling_bart.BartDecoder._prepare_decoder_attention_mask
     def _prepare_decoder_attention_mask(self, attention_mask, input_shape, inputs_embeds, past_key_values_length):
         # create causal mask
         # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len]
@@ -1268,7 +1265,7 @@ class Kosmos2TextTransformer(nn.Module):
             past_key_value = past_key_values[idx] if past_key_values is not None else None
 
             if self.gradient_checkpointing and self.training:
-                layer_outputs = self.gradient_checkpointing_func(
+                layer_outputs = self._gradient_checkpointing_func(
                     decoder_layer.__call__,
                     hidden_states,
                     attention_mask,
@@ -1428,11 +1425,6 @@ class Kosmos2PreTrainedModel(PreTrainedModel):
             if module.embed_tokens.padding_idx is not None:
                 module.embed_tokens.weight.data[module.embed_tokens.padding_idx].zero_()
 
-    def _set_gradient_checkpointing(self, module, gradient_checkpointing_func=None):
-        if isinstance(module, (Kosmos2TextTransformer, Kosmos2VisionEncoder)):
-            module.gradient_checkpointing_func = gradient_checkpointing_func
-            module.gradient_checkpointing = gradient_checkpointing_func is not None
-
 
 class Kosmos2VisionModel(Kosmos2PreTrainedModel):
     config_class = Kosmos2VisionConfig