[bug report] ASoC: SOF: ipc4-control: Add support for generic bytes control

[Dan Carpenter <dan.carpenter@linaro.org>]

[ Smatch checking is paused while we raise funding.  #SadFace
  https://lore.kernel.org/all/aTaiGSbWZ9DJaGo7@stanley.mountain/ -dan ]

Hello Peter Ujfalusi,

Commit 2a28b5240f2b ("ASoC: SOF: ipc4-control: Add support for
generic bytes control") from Dec 17, 2025 (linux-next), leads to the
following Smatch static checker warning:

	sound/soc/sof/ipc4-control.c:365 sof_ipc4_refresh_bytes_control()
	warn: missing error code here? '_dev_err()' failed. 'ret' = '0'

sound/soc/sof/ipc4-control.c
    324 static int
    325 sof_ipc4_refresh_bytes_control(struct snd_sof_control *scontrol, bool lock)
    326 {
    327         struct sof_ipc4_control_data *cdata = scontrol->ipc_control_data;
    328         struct snd_soc_component *scomp = scontrol->scomp;
    329         struct sof_ipc4_control_msg_payload *msg_data;
    330         struct sof_abi_hdr *data = cdata->data;
    331         struct sof_ipc4_msg *msg = &cdata->msg;
    332         size_t data_size;
    333         int ret = 0;
    334 
    335         if (!scontrol->comp_data_dirty)
    336                 return 0;
    337 
    338         if (!pm_runtime_active(scomp->dev))
    339                 return 0;
    340 
    341         data_size = scontrol->max_size - sizeof(*data);
    342         if (data_size < sizeof(*msg_data))
    343                 data_size = sizeof(*msg_data);
    344 
    345         msg_data = kzalloc(data_size, GFP_KERNEL);
    346         if (!msg_data)
    347                 return -ENOMEM;
    348 
    349         msg->extension = SOF_IPC4_MOD_EXT_MSG_PARAM_ID(data->type);
    350 
    351         msg_data->id = cdata->index;
    352         msg_data->num_elems = 0; /* ignored for bytes */
    353 
    354         msg->data_ptr = msg_data;
    355         msg->data_size = data_size;
    356 
    357         scontrol->comp_data_dirty = false;
    358         ret = sof_ipc4_set_get_kcontrol_data(scontrol, false, lock);
    359         if (!ret) {
    360                 if (msg->data_size > scontrol->max_size - sizeof(*data)) {
    361                         dev_err(scomp->dev,
    362                                 "%s: no space for data in %s (%zu, %zu)\n",
    363                                 __func__, scontrol->name, msg->data_size,
    364                                 scontrol->max_size - sizeof(*data));
--> 365                         goto out;

ret = -EINVAL;

    366                 }
    367 
    368                 data->size = msg->data_size;
    369                 scontrol->size = sizeof(*cdata) + sizeof(*data) + data->size;
    370                 memcpy(data->data, msg->data_ptr, data->size);
    371         } else {
    372                 dev_err(scomp->dev, "Failed to read control data for %s\n",
    373                         scontrol->name);
    374                 scontrol->comp_data_dirty = true;
    375         }
    376 
    377 out:
    378         msg->data_ptr = NULL;
    379         msg->data_size = 0;
    380 
    381         kfree(msg_data);
    382 
    383         return ret;
    384 }

regards,
dan carpenter