nvmf: allow to query only specified transport

Similar is already done for json-rpc bdev_get_bdevs, it might be
useful for the upper layer which has no interest in all but only
in one specified.

Signed-off-by: Jacek Kalwas <jacek.kalwas@intel.com>
Change-Id: Ie1af1cb4778edd265914bbfdc2777f66c6c76572
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9362
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

doc/jsonrpc.md

@@ -6767,9 +6767,13 @@ Example response:
 
 #### Parameters
 
+The user may specify no parameters in order to list all transports, or a transport may be
+specified by type.
+
 Name                        | Optional | Type        | Description
 --------------------------- | -------- | ------------| -----------
 tgt_name                    | Optional | string      | Parent NVMe-oF target name.
+trtype                      | Optional | string      | Transport type.
 
 #### Example
 

lib/nvmf/nvmf_rpc.c

@@ -2009,10 +2009,12 @@ rpc_nvmf_create_transport(struct spdk_jsonrpc_request *request,
 SPDK_RPC_REGISTER("nvmf_create_transport", rpc_nvmf_create_transport, SPDK_RPC_RUNTIME)
 
 struct rpc_get_transport {
+	char *trtype;
 	char *tgt_name;
 };
 
 static const struct spdk_json_object_decoder rpc_get_transport_decoders[] = {
+	{"trtype", offsetof(struct rpc_get_transport, trtype), spdk_json_decode_string, true},
 	{"tgt_name", offsetof(struct rpc_get_transport, tgt_name), spdk_json_decode_string, true},
 };
 
@@ -2022,7 +2024,7 @@ rpc_nvmf_get_transports(struct spdk_jsonrpc_request *request,
 {
 	struct rpc_get_transport req = { 0 };
 	struct spdk_json_write_ctx *w;
-	struct spdk_nvmf_transport *transport;
+	struct spdk_nvmf_transport *transport = NULL;
 	struct spdk_nvmf_tgt *tgt;
 
 	if (params) {
@@ -2039,19 +2041,37 @@ rpc_nvmf_get_transports(struct spdk_jsonrpc_request *request,
 	if (!tgt) {
 		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
 						 "Unable to find a target.");
+		free(req.trtype);
 		free(req.tgt_name);
 		return;
 	}
 
+	if (req.trtype) {
+		transport = spdk_nvmf_tgt_get_transport(tgt, req.trtype);
+		if (transport == NULL) {
+			SPDK_ERRLOG("transport '%s' does not exist\n", req.trtype);
+			spdk_jsonrpc_send_error_response(request, -ENODEV, spdk_strerror(ENODEV));
+			free(req.trtype);
+			free(req.tgt_name);
+			return;
+		}
+	}
+
 	w = spdk_jsonrpc_begin_result(request);
 	spdk_json_write_array_begin(w);
-	transport = spdk_nvmf_transport_get_first(tgt);
-	while (transport) {
+
+	if (transport) {
 		nvmf_transport_dump_opts(transport, w, false);
-		transport = spdk_nvmf_transport_get_next(transport);
+	} else {
+		for (transport = spdk_nvmf_transport_get_first(tgt); transport != NULL;
+		     transport = spdk_nvmf_transport_get_next(transport)) {
+			nvmf_transport_dump_opts(transport, w, false);
+		}
 	}
+
 	spdk_json_write_array_end(w);
 	spdk_jsonrpc_end_result(request, w);
+	free(req.trtype);
 	free(req.tgt_name);
 }
 SPDK_RPC_REGISTER("nvmf_get_transports", rpc_nvmf_get_transports, SPDK_RPC_RUNTIME)

scripts/rpc.py

@@ -1942,10 +1942,11 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
     p.set_defaults(func=nvmf_create_transport)
 
     def nvmf_get_transports(args):
-        print_dict(rpc.nvmf.nvmf_get_transports(args.client, tgt_name=args.tgt_name))
+        print_dict(rpc.nvmf.nvmf_get_transports(args.client, trtype=args.trtype, tgt_name=args.tgt_name))
 
     p = subparsers.add_parser('nvmf_get_transports', aliases=['get_nvmf_transports'],
-                              help='Display nvmf transports')
+                              help='Display nvmf transports or required transport')
+    p.add_argument('--trtype', help='Transport type (optional)')
     p.add_argument('-t', '--tgt-name', help='The name of the parent NVMe-oF target (optional)', type=str)
     p.set_defaults(func=nvmf_get_transports)
 

scripts/rpc/nvmf.py

@@ -134,9 +134,10 @@ def nvmf_create_transport(client, **params):
 
 
 @deprecated_alias('get_nvmf_transports')
-def nvmf_get_transports(client, tgt_name=None):
+def nvmf_get_transports(client, trtype=None, tgt_name=None):
     """Get list of NVMe-oF transports.
     Args:
+        trtype: Transport type (optional; if omitted, query all transports).
         tgt_name: name of the parent NVMe-oF target (optional).
 
     Returns:
@@ -146,9 +147,10 @@ def nvmf_get_transports(client, tgt_name=None):
     params = {}
 
     if tgt_name:
-        params = {
-            'tgt_name': tgt_name,
-        }
+        params['tgt_name'] = tgt_name
+
+    if trtype:
+        params['trtype'] = trtype
 
     return client.call('nvmf_get_transports', params)