lib/iscsi: Add iscsi_start_portal_group RPC to start listening if not yet

Add an new RPC, iscsi_start_portal_group, to start listening on
portals if the specified portal group is not started yet.
The next patch will add an new parameter wait to the existing RPC,
iscsi_create_portal_group.

The RPC allows the specified portal group to be already started,
and returns a success response in this case.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I631d6bccffb38092c95694f922f10648e24d6ff7
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/5090
Community-CI: Broadcom CI
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

doc/jsonrpc.md

@@ -4472,6 +4472,42 @@ Example response:
 }
 ~~~
 
+## iscsi_start_portal_group method {#rpc_iscsi_start_portal_group}
+
+Start listening on portals if the portal group is not started yet, or do nothing
+if the portal group already started. Return a success response for both cases.
+
+### Parameters
+
+Name                        | Optional | Type    | Description
+--------------------------- | -------- | --------| -----------
+tag                         | Required | number  | Existing portal group tag
+
+### Example
+
+Example request:
+
+~~~
+{
+  "params": {
+    "tag": 1
+  },
+  "jsonrpc": "2.0",
+  "method": "iscsi_start_portal_group",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## iscsi_delete_portal_group method {#rpc_iscsi_delete_portal_group}
 
 Delete an existing portal group.

lib/iscsi/iscsi_rpc.c

@@ -881,6 +881,28 @@ rpc_iscsi_delete_portal_group(struct spdk_jsonrpc_request *request,
 SPDK_RPC_REGISTER("iscsi_delete_portal_group", rpc_iscsi_delete_portal_group, SPDK_RPC_RUNTIME)
 SPDK_RPC_REGISTER_ALIAS_DEPRECATED(iscsi_delete_portal_group, delete_portal_group)
 
+static int
+_rpc_iscsi_start_portal_group(int pg_tag)
+{
+	struct spdk_iscsi_portal_grp *pg;
+
+	pg = iscsi_portal_grp_find_by_tag(pg_tag);
+	if (!pg) {
+		return -ENODEV;
+	}
+
+	iscsi_portal_grp_resume(pg);
+	return 0;
+}
+
+static void
+rpc_iscsi_start_portal_group(struct spdk_jsonrpc_request *request,
+			     const struct spdk_json_val *params)
+{
+	_rpc_iscsi_change_portal_group(request, params, _rpc_iscsi_start_portal_group);
+}
+SPDK_RPC_REGISTER("iscsi_start_portal_group", rpc_iscsi_start_portal_group, SPDK_RPC_RUNTIME)
+
 struct rpc_portal_group_auth {
 	int32_t tag;
 	bool disable_chap;

scripts/rpc.py

@@ -1197,6 +1197,15 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
     portal must be from a private portal group.""", action='store_true')
     p.set_defaults(func=iscsi_create_portal_group)
 
+    def iscsi_start_portal_group(args):
+        rpc.iscsi.iscsi_start_portal_group(args.client, tag=args.tag)
+
+    p = subparsers.add_parser('iscsi_start_portal_group',
+                              help='Start listening on portals if it is not started yet.')
+    p.add_argument(
+        'tag', help='Portal group tag (unique, integer > 0)', type=int)
+    p.set_defaults(func=iscsi_start_portal_group)
+
     def iscsi_create_initiator_group(args):
         initiators = []
         netmasks = []

scripts/rpc/iscsi.py

@@ -442,6 +442,19 @@ def iscsi_create_portal_group(client, portals, tag, private):
     return client.call('iscsi_create_portal_group', params)
 
 
+def iscsi_start_portal_group(client, tag):
+    """Start listening on portals if it is not started yet.
+
+    Args:
+        tag: Portal group tag (unique, integer > 0)
+
+    Returns:
+        True or False
+    """
+    params = {'tag': tag}
+    return client.call('iscsi_start_portal_group', params)
+
+
 @deprecated_alias('add_initiator_group')
 def iscsi_create_initiator_group(client, tag, initiators, netmasks):
     """Add an initiator group.