Re: [PATCH v4 3/7] soc: qcom: add pd-mapper implementation

[Johan Hovold <johan@kernel.org>]

On Mon, Mar 11, 2024 at 05:34:03PM +0200, Dmitry Baryshkov wrote:
> Existing userspace protection domain mapper implementation has several
> issue. It doesn't play well with CONFIG_EXTRA_FIRMWARE, it doesn't
> reread JSON files if firmware location is changed (or if firmware was
> not available at the time pd-mapper was started but the corresponding
> directory is mounted later), etc.
> 
> Provide in-kernel service implementing protection domain mapping
> required to work with several services, which are provided by the DSP
> firmware.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Just a couple of drive-by comments below.

> +int qcom_pdm_add_domains(const struct qcom_pdm_domain_data * const *data, size_t num_data)
> +{
> +	int ret;
> +	int i;
> +
> +	mutex_lock(&qcom_pdm_mutex);
> +
> +	if (qcom_pdm_server_added) {
> +		ret = qmi_del_server(&qcom_pdm_handle, SERVREG_QMI_SERVICE,
> +				     SERVREG_QMI_VERSION, SERVREG_QMI_INSTANCE);
> +		if (ret)
> +			goto err_out;

Name error labels after what they do, that is, 'err_unlock' in this
case.

> +	}
> +
> +	for (i = 0; i < num_data; i++) {
> +		ret = qcom_pdm_add_domain_locked(data[i]);
> +		if (ret)
> +			goto err;

And err_del_domains here.

> +	}
> +
> +	ret = qmi_add_server(&qcom_pdm_handle, SERVREG_QMI_SERVICE,
> +			     SERVREG_QMI_VERSION, SERVREG_QMI_INSTANCE);
> +	if (ret) {
> +		pr_err("PDM: error adding server %d\n", ret);
> +		goto err;
> +	}
> +
> +	qcom_pdm_server_added = true;
> +
> +	mutex_unlock(&qcom_pdm_mutex);
> +
> +	return 0;
> +
> +err:
> +	while (--i >= 0)
> +		qcom_pdm_del_domain_locked(data[i]);
> +
> +	qmi_add_server(&qcom_pdm_handle, SERVREG_QMI_SERVICE,
> +		       SERVREG_QMI_VERSION, SERVREG_QMI_INSTANCE);

Should the server really be added unconditionally here? And if so,
shouldn't you update that flag?

> +
> +err_out:
> +	mutex_unlock(&qcom_pdm_mutex);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(qcom_pdm_add_domains);

> +static void qcom_pdm_get_domain_list(struct qmi_handle *qmi,
> +				     struct sockaddr_qrtr *sq,
> +				     struct qmi_txn *txn,
> +				     const void *decoded)
> +{
> +	const struct servreg_loc_get_domain_list_req *req = decoded;
> +	struct servreg_loc_get_domain_list_resp *rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
> +	struct qcom_pdm_service *service;
> +	u32 offset;
> +	int ret;
> +
> +	offset = req->offset_valid ? req->offset : 0;
> +
> +	rsp->rsp.result = QMI_RESULT_SUCCESS_V01;
> +	rsp->rsp.error = QMI_ERR_NONE_V01;
> +
> +	rsp->db_revision_valid = true;
> +	rsp->db_revision = 1;
> +
> +	rsp->total_domains_valid = true;
> +	rsp->total_domains = 0;
> +
> +	mutex_lock(&qcom_pdm_mutex);
> +
> +	service = qcom_pdm_find_locked(req->name);
> +	if (service) {
> +		struct qcom_pdm_domain *domain;
> +
> +		rsp->domain_list_valid = true;
> +		rsp->domain_list_len = 0;
> +
> +		list_for_each_entry(domain, &service->domains, list) {
> +			u32 i = rsp->total_domains++;
> +
> +			if (i >= offset && i < SERVREG_LOC_MAX_DOMAINS) {
> +				u32 j = rsp->domain_list_len++;
> +
> +				strscpy(rsp->domain_list[j].name, domain->name,
> +					sizeof(rsp->domain_list[i].name));
> +				rsp->domain_list[j].instance_id = domain->instance_id;
> +
> +				pr_debug("PDM: found %s / %d\n", domain->name,
> +					 domain->instance_id);
> +			}
> +		}
> +

Stray newline.

> +	}
> +
> +	mutex_unlock(&qcom_pdm_mutex);
> +
> +	pr_debug("PDM: service '%s' offset %d returning %d domains (of %d)\n", req->name,
> +		 req->offset_valid ? req->offset : -1, rsp->domain_list_len, rsp->total_domains);
> +
> +	ret = qmi_send_response(qmi, sq, txn, SERVREG_LOC_GET_DOMAIN_LIST,
> +				2658,
> +				servreg_loc_get_domain_list_resp_ei, rsp);
> +	if (ret)
> +		pr_err("Error sending servreg response: %d\n", ret);
> +
> +	kfree(rsp);
> +}

Johan