[PATCH v6 4/6] soc: qcom: qmi: add a way to remove running service

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

Add qmi_del_server(), a pair to qmi_add_server(), a way to remove
running server from the QMI socket. This is e.g. necessary for
pd-mapper, which needs to readd a server each time the DSP is started or
stopped.

Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/soc/qcom/qmi_interface.c | 67 ++++++++++++++++++++++++++++++++++++++++
 include/linux/soc/qcom/qmi.h     |  2 ++
 2 files changed, 69 insertions(+)

diff --git a/drivers/soc/qcom/qmi_interface.c b/drivers/soc/qcom/qmi_interface.c
index bb98b06e87f8..18ff2015c682 100644
--- a/drivers/soc/qcom/qmi_interface.c
+++ b/drivers/soc/qcom/qmi_interface.c
@@ -289,6 +289,73 @@ int qmi_add_server(struct qmi_handle *qmi, unsigned int service,
 }
 EXPORT_SYMBOL_GPL(qmi_add_server);
 
+static void qmi_send_del_server(struct qmi_handle *qmi, struct qmi_service *svc)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = { };
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	int ret;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_DEL_SERVER);
+	pkt.server.service = cpu_to_le32(svc->service);
+	pkt.server.instance = cpu_to_le32(svc->version | svc->instance << 8);
+	pkt.server.node = cpu_to_le32(qmi->sq.sq_node);
+	pkt.server.port = cpu_to_le32(qmi->sq.sq_port);
+
+	sq.sq_family = qmi->sq.sq_family;
+	sq.sq_node = qmi->sq.sq_node;
+	sq.sq_port = QRTR_PORT_CTRL;
+
+	msg.msg_name = &sq;
+	msg.msg_namelen = sizeof(sq);
+
+	mutex_lock(&qmi->sock_lock);
+	if (qmi->sock) {
+		ret = kernel_sendmsg(qmi->sock, &msg, &iv, 1, sizeof(pkt));
+		if (ret < 0)
+			pr_err("send service deregistration failed: %d\n", ret);
+	}
+	mutex_unlock(&qmi->sock_lock);
+}
+
+/**
+ * qmi_del_server() - register a service with the name service
+ * @qmi:	qmi handle
+ * @service:	type of the service
+ * @instance:	instance of the service
+ * @version:	version of the service
+ *
+ * Remove registration of the service with the name service. This notifies
+ * clients that they should no longer send messages to the client associated
+ * with @qmi.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int qmi_del_server(struct qmi_handle *qmi, unsigned int service,
+		   unsigned int version, unsigned int instance)
+{
+	struct qmi_service *svc;
+	struct qmi_service *tmp;
+
+	list_for_each_entry_safe(svc, tmp, &qmi->services, list_node) {
+		if (svc->service != service ||
+		    svc->version != version ||
+		    svc->instance != instance)
+			continue;
+
+		qmi_send_del_server(qmi, svc);
+		list_del(&svc->list_node);
+		kfree(svc);
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(qmi_del_server);
+
 /**
  * qmi_txn_init() - allocate transaction id within the given QMI handle
  * @qmi:	QMI handle
diff --git a/include/linux/soc/qcom/qmi.h b/include/linux/soc/qcom/qmi.h
index 469e02d2aa0d..5039c30e4bdc 100644
--- a/include/linux/soc/qcom/qmi.h
+++ b/include/linux/soc/qcom/qmi.h
@@ -241,6 +241,8 @@ int qmi_add_lookup(struct qmi_handle *qmi, unsigned int service,
 		   unsigned int version, unsigned int instance);
 int qmi_add_server(struct qmi_handle *qmi, unsigned int service,
 		   unsigned int version, unsigned int instance);
+int qmi_del_server(struct qmi_handle *qmi, unsigned int service,
+		   unsigned int version, unsigned int instance);
 
 int qmi_handle_init(struct qmi_handle *qmi, size_t max_msg_len,
 		    const struct qmi_ops *ops,

-- 
2.39.2