jsonrpc: add internal poll handler

As preparation for non blocking mode make the
spdk_jsonrpc_client_send_request functon just queue the request. Then in
spdk_jsonrpc_client_recv_response we actually send it. Without this
change send function will stay blocking.


Change-Id: Ida2290696d78afcb06d84a4538b74e2311043911
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-on: https://review.gerrithub.io/429910
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

include/spdk/jsonrpc.h

@@ -219,7 +219,10 @@ struct spdk_jsonrpc_client *spdk_jsonrpc_client_connect(const char *rpc_sock_add
 		int addr_family);
 
 /**
- * Close the JSON-RPC client.
+ * Close JSON-RPC connection and free \c client object.
+ *
+ * This function is not thread safe and should only be called from one thread at
+ * a time while no other threads are actively \c client object.
  *
  * \param client JSON-RPC client.
  */
@@ -245,10 +248,14 @@ void spdk_jsonrpc_client_free_request(struct spdk_jsonrpc_client_request *req);
  * Send the JSON-RPC request in JSON-RPC client. Library takes ownership of the
  * request object and will free it when done.
  *
+ * This function is not thread safe and should only be called from one thread at
+ * a time while no other threads are actively \c client object.
+ *
  * \param client JSON-RPC client.
  * \param req JSON-RPC request.
  *
  * \return 0 on success or negative error code.
+ * -ENOSPC - no space left to queue another request. Try again later.
  */
 int spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client,
 				     struct spdk_jsonrpc_client_request *req);
@@ -256,6 +263,9 @@ int spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client,
 /**
  * Receive the JSON-RPC response in JSON-RPC client.
  *
+ * This function is not thread safe and should only be called from one thread at
+ * a time while no other threads are actively \c client object.
+ *
  * \param client JSON-RPC client.
  *
  * \return 0 on success.
@@ -266,6 +276,9 @@ int spdk_jsonrpc_client_recv_response(struct spdk_jsonrpc_client *client);
  * Return JSON RPC response object representing next available response from client connection.
  * Returned pointer must be freed using \c spdk_jsonrpc_client_free_response
  *
+ * This function is not thread safe and should only be called from one thread at
+ * a time while no other threads are actively \c client object.
+ *
  * \param client
  * \return pointer to JSON RPC response object or NULL if no response available.
  */

lib/jsonrpc/jsonrpc_client.c

@@ -144,9 +144,12 @@ spdk_jsonrpc_parse_response(struct spdk_jsonrpc_client *client)
 		goto err;
 	}
 
+	r->ready = 1;
+
 	return 0;
 
 err:
+	client->resp = NULL;
 	spdk_jsonrpc_client_free_response(&r->jsonrpc);
 	return -EINVAL;
 }

lib/jsonrpc/jsonrpc_client_tcp.c

@@ -36,6 +36,8 @@
 
 #define RPC_DEFAULT_PORT	"5260"
 
+static int _spdk_jsonrpc_client_poll(struct spdk_jsonrpc_client *client);
+
 static struct spdk_jsonrpc_client *
 _spdk_jsonrpc_client_connect(int domain, int protocol,
 			     struct sockaddr *server_addr, socklen_t addrlen)
@@ -176,11 +178,15 @@ spdk_jsonrpc_client_free_request(struct spdk_jsonrpc_client_request *req)
 	free(req);
 }
 
-int
-spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client,
-				 struct spdk_jsonrpc_client_request *request)
+static int
+_spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client)
 {
 	ssize_t rc;
+	struct spdk_jsonrpc_client_request *request = client->request;
+
+	if (!request) {
+		return 0;
+	}
 
 	/* Reset offset in request */
 	request->send_offset = 0;
@@ -200,6 +206,9 @@ spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client,
 		request->send_len -= rc;
 	}
 
+	client->request = NULL;
+
+	spdk_jsonrpc_client_free_request(request);
 	return 0;
 }
 
@@ -225,12 +234,14 @@ recv_buf_expand(struct spdk_jsonrpc_client *client)
 	return 0;
 }
 
-int
-spdk_jsonrpc_client_recv_response(struct spdk_jsonrpc_client *client)
+static int
+_spdk_jsonrpc_client_poll(struct spdk_jsonrpc_client *client)
 {
 	ssize_t rc = 0;
 	size_t recv_avail;
 
+	_spdk_jsonrpc_client_send_request(client);
+
 	if (client->recv_buf == NULL) {
 		/* memory malloc for recv-buf */
 		client->recv_buf = malloc(SPDK_JSONRPC_SEND_BUF_SIZE_INIT);
@@ -284,12 +295,30 @@ spdk_jsonrpc_client_recv_response(struct spdk_jsonrpc_client *client)
 	return 0;
 }
 
+int
+spdk_jsonrpc_client_recv_response(struct spdk_jsonrpc_client *client)
+{
+	return _spdk_jsonrpc_client_poll(client);
+}
+
+int spdk_jsonrpc_client_send_request(struct spdk_jsonrpc_client *client,
+				     struct spdk_jsonrpc_client_request *req)
+{
+	if (client->request != NULL) {
+		return -ENOSPC;
+	}
+
+	client->request = req;
+	return 0;
+}
+
 struct spdk_jsonrpc_client_response *
 spdk_jsonrpc_client_get_response(struct spdk_jsonrpc_client *client)
 {
-	struct spdk_jsonrpc_client_response_internal *r = client->resp;
+	struct spdk_jsonrpc_client_response_internal *r;
 
-	if (r == NULL) {
+	r = client->resp;
+	if (r == NULL || r->ready == false) {
 		return NULL;
 	}
 

lib/jsonrpc/jsonrpc_internal.h

@@ -108,6 +108,7 @@ struct spdk_jsonrpc_client_request {
 
 struct spdk_jsonrpc_client_response_internal {
 	struct spdk_jsonrpc_client_response jsonrpc;
+	bool ready;
 	uint8_t *buf;
 	size_t values_cnt;
 	struct spdk_json_val values[];
@@ -116,12 +117,13 @@ struct spdk_jsonrpc_client_response_internal {
 struct spdk_jsonrpc_client {
 	int sockfd;
 
-	/* Parsed response */
-	struct spdk_jsonrpc_client_response_internal *resp;
-
 	size_t recv_buf_size;
 	size_t recv_offset;
 	char *recv_buf;
+
+	/* Parsed response */
+	struct spdk_jsonrpc_client_response_internal *resp;
+	struct spdk_jsonrpc_client_request *request;
 };
 
 /* jsonrpc_server_tcp */

test/rpc_client/rpc_client_test.c

@@ -72,7 +72,6 @@ spdk_jsonrpc_client_check_rpc_method(struct spdk_jsonrpc_client *client, char *m
 	w = spdk_jsonrpc_begin_request(request, 1, "get_rpc_methods");
 	spdk_jsonrpc_end_request(request, w);
 	spdk_jsonrpc_client_send_request(client, request);
-	spdk_jsonrpc_client_free_request(request);
 
 	rc = spdk_jsonrpc_client_recv_response(client);
 	if (rc) {