nvmet-fc: implement host_traddr()

Implement callback to display the host transport address by
adding a callback 'host_traddr' for nvmet_fc_target_template.
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/target/fc.c

@@ -2934,6 +2934,38 @@ nvmet_fc_discovery_chg(struct nvmet_port *port)
 		tgtport->ops->discovery_event(&tgtport->fc_target_port);
 }
 
+static ssize_t
+nvmet_fc_host_traddr(struct nvmet_ctrl *ctrl,
+		char *traddr, size_t traddr_size)
+{
+	struct nvmet_sq *sq = ctrl->sqs[0];
+	struct nvmet_fc_tgt_queue *queue =
+		container_of(sq, struct nvmet_fc_tgt_queue, nvme_sq);
+	struct nvmet_fc_tgtport *tgtport = queue->assoc ? queue->assoc->tgtport : NULL;
+	struct nvmet_fc_hostport *hostport = queue->assoc ? queue->assoc->hostport : NULL;
+	u64 wwnn, wwpn;
+	ssize_t ret = 0;
+
+	if (!tgtport || !nvmet_fc_tgtport_get(tgtport))
+		return -ENODEV;
+	if (!hostport || !nvmet_fc_hostport_get(hostport)) {
+		ret = -ENODEV;
+		goto out_put;
+	}
+
+	if (tgtport->ops->host_traddr) {
+		ret = tgtport->ops->host_traddr(hostport->hosthandle, &wwnn, &wwpn);
+		if (ret)
+			goto out_put_host;
+		ret = snprintf(traddr, traddr_size, "nn-0x%llx:pn-0x%llx", wwnn, wwpn);
+	}
+out_put_host:
+	nvmet_fc_hostport_put(hostport);
+out_put:
+	nvmet_fc_tgtport_put(tgtport);
+	return ret;
+}
+
 static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
 	.owner			= THIS_MODULE,
 	.type			= NVMF_TRTYPE_FC,
@@ -2943,6 +2975,7 @@ static const struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
 	.queue_response		= nvmet_fc_fcp_nvme_cmd_done,
 	.delete_ctrl		= nvmet_fc_delete_ctrl,
 	.discovery_chg		= nvmet_fc_discovery_chg,
+	.host_traddr		= nvmet_fc_host_traddr,
 };
 
 static int __init nvmet_fc_init_module(void)

include/linux/nvme-fc-driver.h

@@ -920,6 +920,9 @@ struct nvmet_fc_target_port {
  *       further references to hosthandle.
  *       Entrypoint is Mandatory if the lldd calls nvmet_fc_invalidate_host().
  *
+ * @host_traddr: called by the transport to retrieve the node name and
+ *       port name of the host port address.
+ *
  * @max_hw_queues:  indicates the maximum number of hw queues the LLDD
  *       supports for cpu affinitization.
  *       Value is Mandatory. Must be at least 1.
@@ -975,6 +978,7 @@ struct nvmet_fc_target_template {
 	void (*ls_abort)(struct nvmet_fc_target_port *targetport,
 				void *hosthandle, struct nvmefc_ls_req *lsreq);
 	void (*host_release)(void *hosthandle);
+	int (*host_traddr)(void *hosthandle, u64 *wwnn, u64 *wwpn);
 
 	u32	max_hw_queues;
 	u16	max_sgl_segments;