Repository: huggingface/transformers
Pull request: Fix: explicit not none check for tensors in flash attention

# What does this PR do?

Current use_mask check in flash attention:
`use_mask = position_ids is not None or all([cu_seq_lens_q, cu_seq_lens_k, max_length_q, max_length_k])`
throws error
```
    use_mask = position_ids is not None or all([cu_seq_lens_q, cu_seq_lens_k, max_length_q, max_length_k])
                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Boolean value of Tensor with more than one value is ambiguous
```

Replace with explicit not None check:
`    use_mask = position_ids is not None or all(k is not None for k in [cu_seq_lens_q, cu_seq_lens_k, max_length_q, max_length_k])`

<!-- Remove if not applicable -->

Fixes # (issue)


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## Who can review?
@ArthurZucker 

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Changed files:
filename: src/transformers/modeling_flash_attention_utils.py
patch: @@ -398,7 +398,7 @@ def _flash_attention_forward(
     query_states, key_states, value_states = fa_peft_integration_check(
         query_states, key_states, value_states, target_dtype
     )
-    use_mask = position_ids is not None or all([cu_seq_lens_q, cu_seq_lens_k, max_length_q, max_length_k])
+    use_mask = position_ids is not None or all(k is not None for k in [cu_seq_lens_q, cu_seq_lens_k, max_length_q, max_length_k])
     if attention_mask is not None:
         q, k, v, idx, (cu_q, cu_k), (mq, mk) = _upad_input(
             query_states, key_states, value_states, attention_mask, query_length, unpad_fn