nvmf: Add a transport notification when listeners are associated with

subsystems

This is optional and most transports will not implement it.

Change-Id: I51e0f1289b0e61a8bdb9a719e0a2aae51ecb451c
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/629
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Jacek Kalwas <jacek.kalwas@intel.com>

include/spdk/nvmf_transport.h

@@ -217,6 +217,24 @@ struct spdk_nvmf_transport_ops {
 	void (*stop_listen)(struct spdk_nvmf_transport *transport,
 			    const struct spdk_nvme_transport_id *trid);
 
+	/**
+	 * A listener has been associated with a subsystem with the given NQN.
+	 * This is only a notification. Most transports will not need to take any
+	 * action here, as the enforcement of the association is done in the generic
+	 * code.
+	 *
+	 * The association is not considered complete until cb_fn is called. New
+	 * connections on the listener targeting this subsystem will be rejected
+	 * until that time.
+	 *
+	 * Pass a negated errno code to `cb_fn` to block the association. 0 to allow.
+	 */
+	void (*listen_associate)(struct spdk_nvmf_transport *transport,
+				 const struct spdk_nvmf_subsystem *subsystem,
+				 const struct spdk_nvme_transport_id *trid,
+				 spdk_nvmf_tgt_subsystem_listen_done_fn cb_fn,
+				 void *cb_arg);
+
 	/**
 	 * Check for new connections on the transport.
 	 */

lib/nvmf/nvmf_internal.h

@@ -81,6 +81,9 @@ struct spdk_nvmf_host {
 };
 
 struct spdk_nvmf_subsystem_listener {
+	struct spdk_nvmf_subsystem			*subsystem;
+	spdk_nvmf_tgt_subsystem_listen_done_fn		cb_fn;
+	void						*cb_arg;
 	struct spdk_nvme_transport_id			*trid;
 	struct spdk_nvmf_transport			*transport;
 	TAILQ_ENTRY(spdk_nvmf_subsystem_listener)	link;

lib/nvmf/subsystem.c

@@ -747,6 +747,28 @@ spdk_nvmf_subsystem_find_listener(struct spdk_nvmf_subsystem *subsystem,
 	return NULL;
 }
 
+/**
+ * Function to be called once the target is listening.
+ *
+ * \param ctx Context argument passed to this function.
+ * \param status 0 if it completed successfully, or negative errno if it failed.
+ */
+static void
+_nvmf_subsystem_add_listener_done(void *ctx, int status)
+{
+	struct spdk_nvmf_subsystem_listener *listener = ctx;
+
+	if (status) {
+		listener->cb_fn(listener->cb_arg, status);
+		free(listener);
+		return;
+	}
+
+	TAILQ_INSERT_HEAD(&listener->subsystem->listeners, listener, link);
+	listener->subsystem->tgt->discovery_genctr++;
+	listener->cb_fn(listener->cb_arg, status);
+}
+
 void
 spdk_nvmf_subsystem_add_listener(struct spdk_nvmf_subsystem *subsystem,
 				 struct spdk_nvme_transport_id *trid,
@@ -793,11 +815,17 @@ spdk_nvmf_subsystem_add_listener(struct spdk_nvmf_subsystem *subsystem,
 
 	listener->trid = &tr_listener->trid;
 	listener->transport = transport;
+	listener->cb_fn = cb_fn;
+	listener->cb_arg = cb_arg;
+	listener->subsystem = subsystem;
 
-	TAILQ_INSERT_HEAD(&subsystem->listeners, listener, link);
-	subsystem->tgt->discovery_genctr++;
-
-	cb_fn(cb_arg, 0);
+	if (transport->ops->listen_associate != NULL) {
+		transport->ops->listen_associate(transport, subsystem, trid,
+						 _nvmf_subsystem_add_listener_done,
+						 listener);
+	} else {
+		_nvmf_subsystem_add_listener_done(listener, 0);
+	}
 }
 
 int

test/unit/lib/nvmf/ctrlr_discovery.c/ctrlr_discovery_ut.c

@@ -101,7 +101,11 @@ spdk_nvmf_transport_listener_discover(struct spdk_nvmf_transport *transport,
 	entry->trtype = 42;
 }
 
-static struct spdk_nvmf_transport g_transport = {};
+struct spdk_nvmf_transport_ops g_transport_ops = {};
+
+static struct spdk_nvmf_transport g_transport = {
+	.ops = &g_transport_ops
+};
 
 struct spdk_nvmf_transport *
 spdk_nvmf_transport_create(const char *transport_name,