[Bugfix] fix error of peft lora when xformers enabled (#5697)

* bugfix peft lor

* Apply suggestions from code review

---------
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

src/diffusers/models/attention_processor.py

@@ -879,6 +879,9 @@ class AttnAddedKVProcessor:
         scale: float = 1.0,
     ) -> torch.Tensor:
         residual = hidden_states
+
+        args = () if USE_PEFT_BACKEND else (scale,)
+
         hidden_states = hidden_states.view(hidden_states.shape[0], hidden_states.shape[1], -1).transpose(1, 2)
         batch_size, sequence_length, _ = hidden_states.shape
 
@@ -891,17 +894,17 @@ class AttnAddedKVProcessor:
 
         hidden_states = attn.group_norm(hidden_states.transpose(1, 2)).transpose(1, 2)
 
-        query = attn.to_q(hidden_states, scale=scale)
+        query = attn.to_q(hidden_states, *args)
         query = attn.head_to_batch_dim(query)
 
-        encoder_hidden_states_key_proj = attn.add_k_proj(encoder_hidden_states, scale=scale)
-        encoder_hidden_states_value_proj = attn.add_v_proj(encoder_hidden_states, scale=scale)
+        encoder_hidden_states_key_proj = attn.add_k_proj(encoder_hidden_states, *args)
+        encoder_hidden_states_value_proj = attn.add_v_proj(encoder_hidden_states, *args)
         encoder_hidden_states_key_proj = attn.head_to_batch_dim(encoder_hidden_states_key_proj)
         encoder_hidden_states_value_proj = attn.head_to_batch_dim(encoder_hidden_states_value_proj)
 
         if not attn.only_cross_attention:
-            key = attn.to_k(hidden_states, scale=scale)
-            value = attn.to_v(hidden_states, scale=scale)
+            key = attn.to_k(hidden_states, *args)
+            value = attn.to_v(hidden_states, *args)
             key = attn.head_to_batch_dim(key)
             value = attn.head_to_batch_dim(value)
             key = torch.cat([encoder_hidden_states_key_proj, key], dim=1)
@@ -915,7 +918,7 @@ class AttnAddedKVProcessor:
         hidden_states = attn.batch_to_head_dim(hidden_states)
 
         # linear proj
-        hidden_states = attn.to_out[0](hidden_states, scale=scale)
+        hidden_states = attn.to_out[0](hidden_states, *args)
         # dropout
         hidden_states = attn.to_out[1](hidden_states)
 
@@ -946,6 +949,9 @@ class AttnAddedKVProcessor2_0:
         scale: float = 1.0,
     ) -> torch.Tensor:
         residual = hidden_states
+
+        args = () if USE_PEFT_BACKEND else (scale,)
+
         hidden_states = hidden_states.view(hidden_states.shape[0], hidden_states.shape[1], -1).transpose(1, 2)
         batch_size, sequence_length, _ = hidden_states.shape
 
@@ -958,7 +964,7 @@ class AttnAddedKVProcessor2_0:
 
         hidden_states = attn.group_norm(hidden_states.transpose(1, 2)).transpose(1, 2)
 
-        query = attn.to_q(hidden_states, scale=scale)
+        query = attn.to_q(hidden_states, *args)
         query = attn.head_to_batch_dim(query, out_dim=4)
 
         encoder_hidden_states_key_proj = attn.add_k_proj(encoder_hidden_states)
@@ -967,8 +973,8 @@ class AttnAddedKVProcessor2_0:
         encoder_hidden_states_value_proj = attn.head_to_batch_dim(encoder_hidden_states_value_proj, out_dim=4)
 
         if not attn.only_cross_attention:
-            key = attn.to_k(hidden_states, scale=scale)
-            value = attn.to_v(hidden_states, scale=scale)
+            key = attn.to_k(hidden_states, *args)
+            value = attn.to_v(hidden_states, *args)
             key = attn.head_to_batch_dim(key, out_dim=4)
             value = attn.head_to_batch_dim(value, out_dim=4)
             key = torch.cat([encoder_hidden_states_key_proj, key], dim=2)
@@ -985,7 +991,7 @@ class AttnAddedKVProcessor2_0:
         hidden_states = hidden_states.transpose(1, 2).reshape(batch_size, -1, residual.shape[1])
 
         # linear proj
-        hidden_states = attn.to_out[0](hidden_states, scale=scale)
+        hidden_states = attn.to_out[0](hidden_states, *args)
         # dropout
         hidden_states = attn.to_out[1](hidden_states)
 
@@ -1177,6 +1183,8 @@ class AttnProcessor2_0:
     ) -> torch.FloatTensor:
         residual = hidden_states
 
+        args = () if USE_PEFT_BACKEND else (scale,)
+
         if attn.spatial_norm is not None:
             hidden_states = attn.spatial_norm(hidden_states, temb)
 
@@ -1207,12 +1215,8 @@ class AttnProcessor2_0:
         elif attn.norm_cross:
             encoder_hidden_states = attn.norm_encoder_hidden_states(encoder_hidden_states)
 
-        key = (
-            attn.to_k(encoder_hidden_states, scale=scale) if not USE_PEFT_BACKEND else attn.to_k(encoder_hidden_states)
-        )
-        value = (
-            attn.to_v(encoder_hidden_states, scale=scale) if not USE_PEFT_BACKEND else attn.to_v(encoder_hidden_states)
-        )
+        key = attn.to_k(encoder_hidden_states, *args)
+        value = attn.to_v(encoder_hidden_states, *args)
 
         inner_dim = key.shape[-1]
         head_dim = inner_dim // attn.heads
@@ -1232,9 +1236,7 @@ class AttnProcessor2_0:
         hidden_states = hidden_states.to(query.dtype)
 
         # linear proj
-        hidden_states = (
-            attn.to_out[0](hidden_states, scale=scale) if not USE_PEFT_BACKEND else attn.to_out[0](hidden_states)
-        )
+        hidden_states = attn.to_out[0](hidden_states, *args)
         # dropout
         hidden_states = attn.to_out[1](hidden_states)