ipc: handle unsupported IPC in sync request

Currently, IPC API will silently ignore unsupported IPC.
Fix the API call and its callers to explicitly handle
unsupported IPC cases.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

drivers/net/mlx4/mlx4_mp.c

@@ -178,8 +178,9 @@ mp_req_on_rxtx(struct rte_eth_dev *dev, enum mlx4_mp_req_type type)
 	mp_init_msg(dev, &mp_req, type);
 	ret = rte_mp_request_sync(&mp_req, &mp_rep, &ts);
 	if (ret) {
-		ERROR("port %u failed to request stop/start Rx/Tx (%d)",
+		if (rte_errno != ENOTSUP)
-		      dev->data->port_id, type);
+			ERROR("port %u failed to request stop/start Rx/Tx (%d)",
+					dev->data->port_id, type);
 		goto exit;
 	}
 	if (mp_rep.nb_sent != mp_rep.nb_received) {

drivers/net/mlx5/mlx5_mp.c

@@ -180,8 +180,9 @@ mp_req_on_rxtx(struct rte_eth_dev *dev, enum mlx5_mp_req_type type)
 	mp_init_msg(dev, &mp_req, type);
 	ret = rte_mp_request_sync(&mp_req, &mp_rep, &ts);
 	if (ret) {
-		DRV_LOG(ERR, "port %u failed to request stop/start Rx/Tx (%d)",
+		if (rte_errno != ENOTSUP)
-			dev->data->port_id, type);
+			DRV_LOG(ERR, "port %u failed to request stop/start Rx/Tx (%d)",
+				dev->data->port_id, type);
 		goto exit;
 	}
 	if (mp_rep.nb_sent != mp_rep.nb_received) {

lib/librte_eal/common/eal_common_proc.c

@@ -969,7 +969,8 @@ rte_mp_request_sync(struct rte_mp_msg *req, struct rte_mp_reply *reply,
 
 	if (internal_config.no_shconf) {
 		RTE_LOG(DEBUG, EAL, "No shared files mode enabled, IPC is disabled\n");
-		return 0;
+		rte_errno = ENOTSUP;
+		return -1;
 	}
 
 	if (gettimeofday(&now, NULL) < 0) {

lib/librte_eal/common/hotplug_mp.c

@@ -405,7 +405,11 @@ int eal_dev_hotplug_request_to_secondary(struct eal_dev_mp_req *req)
 
 	ret = rte_mp_request_sync(&mp_req, &mp_reply, &ts);
 	if (ret != 0) {
-		RTE_LOG(ERR, EAL, "rte_mp_request_sync failed\n");
+		/* if IPC is not supported, behave as if the call succeeded */
+		if (rte_errno != ENOTSUP)
+			RTE_LOG(ERR, EAL, "rte_mp_request_sync failed\n");
+		else
+			ret = 0;
 		return ret;
 	}
 

lib/librte_eal/common/include/rte_eal.h

@@ -331,6 +331,9 @@ rte_mp_sendmsg(struct rte_mp_msg *msg);
  * @note This API must not be used inside memory-related or IPC callbacks, and
  *   no memory allocations should take place inside such callback.
  *
+ * @note IPC may be unsupported in certain circumstances, so caller should check
+ *    for ENOTSUP error.
+ *
  * @param req
  *   The req argument contains the customized request message.
  *

lib/librte_eal/common/malloc_mp.c

@@ -573,7 +573,7 @@ request_sync(void)
 	struct rte_mp_reply reply;
 	struct malloc_mp_req *req = (struct malloc_mp_req *)msg.param;
 	struct timespec ts;
-	int i, ret;
+	int i, ret = -1;
 
 	memset(&msg, 0, sizeof(msg));
 	memset(&reply, 0, sizeof(reply));
@@ -596,14 +596,16 @@ request_sync(void)
 		ret = rte_mp_request_sync(&msg, &reply, &ts);
 	} while (ret != 0 && rte_errno == EEXIST);
 	if (ret != 0) {
-		RTE_LOG(ERR, EAL, "Could not send sync request to secondary process\n");
+		/* if IPC is unsupported, behave as if the call succeeded */
-		ret = -1;
+		if (rte_errno != ENOTSUP)
+			RTE_LOG(ERR, EAL, "Could not send sync request to secondary process\n");
+		else
+			ret = 0;
 		goto out;
 	}
 
 	if (reply.nb_received != reply.nb_sent) {
 		RTE_LOG(ERR, EAL, "Not all secondaries have responded\n");
-		ret = -1;
 		goto out;
 	}
 
@@ -612,17 +614,14 @@ request_sync(void)
 				(struct malloc_mp_req *)reply.msgs[i].param;
 		if (resp->t != REQ_TYPE_SYNC) {
 			RTE_LOG(ERR, EAL, "Unexpected response from secondary\n");
-			ret = -1;
 			goto out;
 		}
 		if (resp->id != req->id) {
 			RTE_LOG(ERR, EAL, "Wrong request ID\n");
-			ret = -1;
 			goto out;
 		}
 		if (resp->result != REQ_RESULT_SUCCESS) {
 			RTE_LOG(ERR, EAL, "Secondary process failed to synchronize\n");
-			ret = -1;
 			goto out;
 		}
 	}