if sd_model is None, do not always try to load it

class SdModelData:

    def __init__(self):

        self.sd_model = None

        self.was_loaded_at_least_once = False

        self.lock = threading.Lock()

    def get_sd_model(self):

        if self.was_loaded_at_least_once:

            return self.sd_model

        if self.sd_model is None:

            with self.lock:

                if self.sd_model is not None:

                if self.sd_model is not None or self.was_loaded_at_least_once:

                    return self.sd_model

                try:

    sd_model.eval()

    model_data.sd_model = sd_model

    model_data.was_loaded_at_least_once = True

    sd_hijack.model_hijack.embedding_db.load_textual_inversion_embeddings(force_reload=True)  # Reload embeddings after model load as they may or may not fit the model