[RFC] [PATCH v2 06/13] soc: qcom: qmi_helpers: optionally bind to QRTR endpoint ID in qmi_sock_create

[Mihai Moldovan <ionic@ionic.de>]

For clients that already know the QRTR endpoint ID before actually
creating the QMI socket and set it in struct qmi_handle, optionally try
to bind to this QRTR endpoint ID when creating the socket.

This can fail, and qmi_sock_create will issue diagnostic messages, but
otherwise ignore the error.

Signed-off-by: Mihai Moldovan <ionic@ionic.de>
---
 drivers/soc/qcom/qmi_interface.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/soc/qcom/qmi_interface.c b/drivers/soc/qcom/qmi_interface.c
index bb98b06e87f8..dd3978682c09 100644
--- a/drivers/soc/qcom/qmi_interface.c
+++ b/drivers/soc/qcom/qmi_interface.c
@@ -586,6 +586,7 @@ static struct socket *qmi_sock_create(struct qmi_handle *qmi,
 				      struct sockaddr_qrtr *sq)
 {
 	struct socket *sock;
+	const struct proto_ops *ops = NULL;
 	int ret;
 
 	ret = sock_create_kern(&init_net, AF_QIPCRTR, SOCK_DGRAM,
@@ -593,6 +594,33 @@ static struct socket *qmi_sock_create(struct qmi_handle *qmi,
 	if (ret < 0)
 		return ERR_PTR(ret);
 
+	ops = READ_ONCE(sock->ops);
+
+	if (!ops) {
+		pr_warn("sock->ops not available for QMI socket\n");
+		pr_warn("will not be able to bind to endpoint ID.\n");
+		/* N.B.: this error value will not be passed out. */
+		ret = -ENXIO;
+	}
+
+	if (!ret && !ops->setsockopt) {
+		pr_warn("ops->setsockopt not available for QMI socket\n");
+		pr_warn("will not be able to bind to endpoint ID.\n");
+		/* N.B.: this error value will not be passed out. */
+		ret = -ENXIO;
+	}
+
+	/* Only bind to a specific endpoint if a valid one was provided. */
+	if (!ret && qmi->endpoint_id) {
+		ret = ops->setsockopt(sock, SOL_QRTR, QRTR_BIND_ENDPOINT,
+				      KERNEL_SOCKPTR(&qmi->endpoint_id),
+				      sizeof(qmi->endpoint_id));
+
+		if (ret < 0)
+			pr_warn("binding to QRTR endpoint ID failed: %d\n",
+				ret);
+	}
+
 	ret = kernel_getsockname(sock, (struct sockaddr *)sq);
 	if (ret < 0) {
 		sock_release(sock);
-- 
2.45.2