nvmet: add 'host_traddr' callback for debugfs

We want to display the transport address of the connected host
in debugfs, but this is a property of the transport.
So add a callback 'host_traddr' to allow the transport drivers
to fill in the data.
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/target/core.c

@@ -1542,6 +1542,14 @@ void nvmet_ctrl_fatal_error(struct nvmet_ctrl *ctrl)
 }
 EXPORT_SYMBOL_GPL(nvmet_ctrl_fatal_error);
 
+ssize_t nvmet_ctrl_host_traddr(struct nvmet_ctrl *ctrl,
+		char *traddr, size_t traddr_len)
+{
+	if (!ctrl->ops->host_traddr)
+		return -EOPNOTSUPP;
+	return ctrl->ops->host_traddr(ctrl, traddr, traddr_len);
+}
+
 static struct nvmet_subsys *nvmet_find_get_subsys(struct nvmet_port *port,
 		const char *subsysnqn)
 {

drivers/nvme/target/debugfs.c

@@ -115,6 +115,23 @@ static ssize_t nvmet_ctrl_state_write(struct file *file, const char __user *buf,
 }
 NVMET_DEBUGFS_RW_ATTR(nvmet_ctrl_state);
 
+static int nvmet_ctrl_host_traddr_show(struct seq_file *m, void *p)
+{
+	struct nvmet_ctrl *ctrl = m->private;
+	ssize_t size;
+	char buf[NVMF_TRADDR_SIZE + 1];
+
+	size = nvmet_ctrl_host_traddr(ctrl, buf, NVMF_TRADDR_SIZE);
+	if (size < 0) {
+		buf[0] = '\0';
+		size = 0;
+	}
+	buf[size] = '\0';
+	seq_printf(m, "%s\n", buf);
+	return 0;
+}
+NVMET_DEBUGFS_ATTR(nvmet_ctrl_host_traddr);
+
 int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl)
 {
 	char name[32];
@@ -138,6 +155,8 @@ int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl)
 			    &nvmet_ctrl_kato_fops);
 	debugfs_create_file("state", S_IRUSR | S_IWUSR, ctrl->debugfs_dir, ctrl,
 			    &nvmet_ctrl_state_fops);
+	debugfs_create_file("host_traddr", S_IRUSR, ctrl->debugfs_dir, ctrl,
+			    &nvmet_ctrl_host_traddr_fops);
 	return 0;
 }
 

drivers/nvme/target/nvmet.h

@@ -354,6 +354,8 @@ struct nvmet_fabrics_ops {
 	void (*delete_ctrl)(struct nvmet_ctrl *ctrl);
 	void (*disc_traddr)(struct nvmet_req *req,
 			struct nvmet_port *port, char *traddr);
+	ssize_t (*host_traddr)(struct nvmet_ctrl *ctrl,
+			char *traddr, size_t traddr_len);
 	u16 (*install_queue)(struct nvmet_sq *nvme_sq);
 	void (*discovery_chg)(struct nvmet_port *port);
 	u8 (*get_mdts)(const struct nvmet_ctrl *ctrl);
@@ -502,6 +504,8 @@ struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
 				       struct nvmet_req *req);
 void nvmet_ctrl_put(struct nvmet_ctrl *ctrl);
 u16 nvmet_check_ctrl_status(struct nvmet_req *req);
+ssize_t nvmet_ctrl_host_traddr(struct nvmet_ctrl *ctrl,
+		char *traddr, size_t traddr_len);
 
 struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		enum nvme_subsys_type type);