bdev/nvme: add RPC returning information about discovery service

The RPC returns a list of active discovery service connections.  Each
discovery service is described by a name, its trid, and a list of
discovery service trids it refers to.

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: Ifa4b9501dd353e7b4948ad830575a6c94dafd86b
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12380
Community-CI: Mellanox Build Bot
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>

doc/jsonrpc.md

@@ -3344,6 +3344,43 @@ Example response:
 }
 ~~~
 
+### bdev_nvme_get_discovery_info {#rpc_bdev_nvme_get_discovery_info}
+
+Get information about the discovery service.
+
+#### Example
+
+Example request:
+~~~json
+{
+  "jsonrpc": "2.0",
+  "method": "bdev_nvme_get_discovery_info",
+  "id": 1
+}
+~~~
+
+Example response:
+
+~~~json
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": [
+    {
+      "name": "nvme-disc",
+      "trid": {
+        "trtype": "TCP",
+        "adrfam": "IPv4",
+        "traddr": "127.0.0.1",
+        "trsvcid": "8009",
+        "subnqn": "nqn.2014-08.org.nvmexpress.discovery"
+      },
+      "referrals": []
+    }
+  ]
+}
+~~~
+
 ### bdev_nvme_get_io_paths {#rpc_bdev_nvme_get_io_paths}
 
 Display all or the specified NVMe bdev's active I/O paths.

module/bdev/nvme/bdev_nvme.c

@@ -6500,4 +6500,34 @@ nvme_io_path_info_json(struct spdk_json_write_ctx *w, struct nvme_io_path *io_pa
 	spdk_json_write_object_end(w);
 }
 
+void
+bdev_nvme_get_discovery_info(struct spdk_json_write_ctx *w)
+{
+	struct discovery_ctx *ctx;
+	struct discovery_entry_ctx *entry_ctx;
+
+	spdk_json_write_array_begin(w);
+	TAILQ_FOREACH(ctx, &g_discovery_ctxs, tailq) {
+		spdk_json_write_object_begin(w);
+		spdk_json_write_named_string(w, "name", ctx->name);
+
+		spdk_json_write_named_object_begin(w, "trid");
+		nvme_bdev_dump_trid_json(&ctx->trid, w);
+		spdk_json_write_object_end(w);
+
+		spdk_json_write_named_array_begin(w, "referrals");
+		TAILQ_FOREACH(entry_ctx, &ctx->discovery_entry_ctxs, tailq) {
+			spdk_json_write_object_begin(w);
+			spdk_json_write_named_object_begin(w, "trid");
+			nvme_bdev_dump_trid_json(&entry_ctx->trid, w);
+			spdk_json_write_object_end(w);
+			spdk_json_write_object_end(w);
+		}
+		spdk_json_write_array_end(w);
+
+		spdk_json_write_object_end(w);
+	}
+	spdk_json_write_array_end(w);
+}
+
 SPDK_LOG_REGISTER_COMPONENT(bdev_nvme)

module/bdev/nvme/bdev_nvme.h

@@ -300,6 +300,7 @@ int bdev_nvme_start_discovery(struct spdk_nvme_transport_id *trid, const char *b
 			      spdk_bdev_nvme_start_discovery_fn cb_fn, void *cb_ctx);
 int bdev_nvme_stop_discovery(const char *name, spdk_bdev_nvme_stop_discovery_fn cb_fn,
 			     void *cb_ctx);
+void bdev_nvme_get_discovery_info(struct spdk_json_write_ctx *w);
 
 struct spdk_nvme_ctrlr *bdev_nvme_get_ctrlr(struct spdk_bdev *bdev);
 

module/bdev/nvme/bdev_nvme_rpc.c

@@ -1766,6 +1766,19 @@ cleanup:
 SPDK_RPC_REGISTER("bdev_nvme_stop_discovery", rpc_bdev_nvme_stop_discovery,
 		  SPDK_RPC_RUNTIME)
 
+static void
+rpc_bdev_nvme_get_discovery_info(struct spdk_jsonrpc_request *request,
+				 const struct spdk_json_val *params)
+{
+	struct spdk_json_write_ctx *w;
+
+	w = spdk_jsonrpc_begin_result(request);
+	bdev_nvme_get_discovery_info(w);
+	spdk_jsonrpc_end_result(request, w);
+}
+SPDK_RPC_REGISTER("bdev_nvme_get_discovery_info", rpc_bdev_nvme_get_discovery_info,
+		  SPDK_RPC_RUNTIME)
+
 enum error_injection_cmd_type {
 	NVME_ADMIN_CMD = 1,
 	NVME_IO_CMD,

python/spdk/rpc/bdev.py

@@ -811,6 +811,12 @@ def bdev_nvme_stop_discovery(client, name):
     return client.call('bdev_nvme_stop_discovery', params)
 
 
+def bdev_nvme_get_discovery_info(client):
+    """Get information about the automatic discovery
+    """
+    return client.call('bdev_nvme_get_discovery_info')
+
+
 def bdev_nvme_get_io_paths(client, name):
     """Display all or the specified NVMe bdev's active I/O paths
 

scripts/rpc.py

@@ -761,6 +761,12 @@ if __name__ == "__main__":
     p.add_argument('-b', '--name', help="Name of the service to stop", required=True)
     p.set_defaults(func=bdev_nvme_stop_discovery)
 
+    def bdev_nvme_get_discovery_info(args):
+        print_dict(rpc.bdev.bdev_nvme_get_discovery_info(args.client))
+
+    p = subparsers.add_parser('bdev_nvme_get_discovery_info', help='Get information about the automatic discovery')
+    p.set_defaults(func=bdev_nvme_get_discovery_info)
+
     def bdev_nvme_get_io_paths(args):
         print_dict(rpc.bdev.bdev_nvme_get_io_paths(args.client, name=args.name))