Make persistent discovery controller configurable for the subsystem

libnvme/doc/config-schema.json.in

@@ -58,6 +58,10 @@
 		    "type": "string",
 		    "maxLength": 223
 		},
+		"persistent_discovery_ctrl": {
+		    "description": "Enable/disable Persistent Discovery Controller",
+		    "type": "boolean"
+		},
 		"ports": {
 		    "description": "Array of NVMe subsystem ports",
 		    "type": "array",

libnvme/libnvme/accessors.i

@@ -176,6 +176,7 @@ struct libnvme_subsystem {
 	const char * firmware;
 	%immutable subsystype;
 	const char * subsystype;
+	bool pdc_enabled;
 	%extend {
 		%immutable iopolicy;
 		const char * iopolicy;

libnvme/src/libnvme.ld

@@ -159,10 +159,12 @@ LIBNVME_3 {
 		libnvme_subsystem_first_ns;
 		libnvme_subsystem_get_host;
 		libnvme_subsystem_get_iopolicy;
+		libnvme_subsystem_get_pdc_enabled;
 		libnvme_subsystem_lookup_namespace;
 		libnvme_subsystem_next_ctrl;
 		libnvme_subsystem_next_ns;
 		libnvme_subsystem_release_fds;
+		libnvme_subsystem_set_pdc_enabled;
 		libnvme_transport_handle_get_fd;
 		libnvme_transport_handle_get_mi_ep;
 		libnvme_transport_handle_get_name;

libnvme/src/nvme/accessors.c

@@ -563,6 +563,19 @@ __libnvme_public const char *libnvme_subsystem_get_subsystype(
 	return p->subsystype;
 }
 
+__libnvme_public void libnvme_subsystem_set_pdc_enabled(
+		struct libnvme_subsystem *p,
+		bool pdc_enabled)
+{
+	p->pdc_enabled = pdc_enabled;
+}
+
+__libnvme_public bool libnvme_subsystem_get_pdc_enabled(
+		const struct libnvme_subsystem *p)
+{
+	return p->pdc_enabled;
+}
+
 /****************************************************************************
  * Accessors for: struct libnvme_host
  ****************************************************************************/

libnvme/src/nvme/accessors.h

@@ -739,6 +739,23 @@ const char *libnvme_subsystem_get_firmware(const struct libnvme_subsystem *p);
  */
 const char *libnvme_subsystem_get_subsystype(const struct libnvme_subsystem *p);
 
+/**
+ * libnvme_subsystem_set_pdc_enabled() - Set pdc_enabled.
+ * @p: The &struct libnvme_subsystem instance to update.
+ * @pdc_enabled: Value to assign to the pdc_enabled field.
+ */
+void libnvme_subsystem_set_pdc_enabled(
+		struct libnvme_subsystem *p,
+		bool pdc_enabled);
+
+/**
+ * libnvme_subsystem_get_pdc_enabled() - Get pdc_enabled.
+ * @p: The &struct libnvme_subsystem instance to query.
+ *
+ * Return: The value of the pdc_enabled field.
+ */
+bool libnvme_subsystem_get_pdc_enabled(const struct libnvme_subsystem *p);
+
 /****************************************************************************
  * Accessors for: struct libnvme_host
  ****************************************************************************/

libnvme/src/nvme/fabrics.c

@@ -2416,9 +2416,8 @@ static int _nvmf_discovery(struct libnvme_global_ctx *ctx,
 				if (!(eflags & NVMF_DISC_EFLAGS_EPCSD))
 					disconnect = true;
 				else
-					disconnect = false;
+					disconnect = libnvme_subsystem_get_pdc_enabled(s);
 			}
-
 			set_discovery_kato(&nfctx);
 		} else {
 			/* NVME_NQN_NVME */

libnvme/src/nvme/json.c

@@ -128,7 +128,7 @@ static void json_parse_port(libnvme_subsystem_t s, struct json_object *port_obj)
 
 static void json_parse_subsys(libnvme_host_t h, struct json_object *subsys_obj)
 {
-	struct json_object *nqn_obj, *port_array;
+	struct json_object *nqn_obj, *port_array, *attr_obj;
 	libnvme_subsystem_t s;
 	const char *nqn = "";
 	int p;
@@ -140,6 +140,10 @@ static void json_parse_subsys(libnvme_host_t h, struct json_object *subsys_obj)
 	if (!s)
 		return;
 
+	attr_obj = json_object_object_get(subsys_obj, "persistent_discovery_ctrl");
+	if (attr_obj)
+		libnvme_subsystem_set_pdc_enabled(s, json_object_get_boolean(attr_obj));
+
 	port_array = json_object_object_get(subsys_obj, "ports");
 	if (!port_array)
 		return;
@@ -378,6 +382,7 @@ static void json_update_subsys(struct json_object *subsys_array,
 	const char *subsysnqn = libnvme_subsystem_get_subsysnqn(s);
 	struct json_object *subsys_obj = json_object_new_object();
 	struct json_object *port_array;
+	bool pdc_enabled = libnvme_subsystem_get_pdc_enabled(s);
 
 	/* Skip discovery subsystems as the nqn is not unique */
 	if (!strcmp(subsysnqn, NVME_DISC_SUBSYS_NAME)) {
@@ -387,6 +392,10 @@ static void json_update_subsys(struct json_object *subsys_array,
 
 	json_object_object_add(subsys_obj, "nqn",
 			       json_object_new_string(subsysnqn));
+	if (pdc_enabled != libnvme_host_is_pdc_enabled(s->h, DEFAULT_PDC_ENABLED))
+		json_object_object_add(subsys_obj, "persistent_discovery_ctrl",
+				       json_object_new_boolean(pdc_enabled));
+
 	port_array = json_object_new_array();
 	libnvme_subsystem_for_each_ctrl(s, c) {
 		json_update_port(port_array, c);
@@ -620,11 +629,15 @@ static void json_dump_subsys(struct json_object *subsys_array,
 {
 	struct json_object *subsys_obj = json_object_new_object();
 	struct json_object *ns_array;
+	bool pdc_enabled = libnvme_subsystem_get_pdc_enabled(s);
 
 	json_object_object_add(subsys_obj, "name",
 			       json_object_new_string(libnvme_subsystem_get_name(s)));
 	json_object_object_add(subsys_obj, "nqn",
 			       json_object_new_string(libnvme_subsystem_get_subsysnqn(s)));
+	if (pdc_enabled != libnvme_host_is_pdc_enabled(s->h, DEFAULT_PDC_ENABLED))
+		json_object_object_add(subsys_obj, "persistent_discovery_ctrl",
+				       json_object_new_boolean(pdc_enabled));
 
 	ns_array = json_object_new_array();
 	if (!json_dump_subsys_multipath(s, ns_array))

libnvme/src/nvme/private.h

@@ -377,6 +377,7 @@ struct libnvme_subsystem {  // !generate-accessors:read=generated,write=none !ge
 	char *firmware;
 	char *subsystype;
 	char *iopolicy;			// !access:read=custom
+	bool pdc_enabled;		// !access:read=generated,write=generated
 };
 
 struct libnvme_host {  // !generate-accessors:read=generated,write=none !generate-python:alias=Host

libnvme/src/nvme/tree.c

@@ -412,6 +412,12 @@ struct libnvme_subsystem *nvme_alloc_subsystem(struct libnvme_host *h,
 		free(s);
 		return NULL;
 	}
+	/*
+	 * Use the default from the host.
+	 * Any value from the 'subsystem' json configuration
+	 * will override it.
+	 */
+	s->pdc_enabled = libnvme_host_is_pdc_enabled(h, DEFAULT_PDC_ENABLED);
 
 	if (name)
 		libnvme_init_subsystem(s, name);
@@ -503,6 +509,7 @@ static int libnvme_create_host(struct libnvme_global_ctx *ctx,
 	list_head_init(&h->subsystems);
 	list_node_init(&h->entry);
 	h->ctx = ctx;
+	h->pdc_enabled = DEFAULT_PDC_ENABLED;
 
 	list_add_tail(&ctx->hosts, &h->entry);