librdmacm: Provide an interface to write an event into a CM

Support writing an event to a CM channel and add a new user API
"rdma_write_cm_event()". Two new events are added and supported to be
written:
- RDMA_CM_EVENT_USER: User-defined, event details are specified by the
  user and not interpreted by the librdmacm.  This event is useful for
  a multi-threaded application to signal a thread which may be waiting
  on the RDMA CM event channel. This is the only event that users can
  write;
- RDMA_CM_EVENT_INTERNAL: Used and consumed internally by the
  librdmacm. Users should not write this event.

A new event parameter "arg" is supported, which will be passed from
sender to receiver along with the event.

Signed-off-by: Mark Zhang <[email protected]>

Author: MarkZhang81

debian/librdmacm1.symbols

@@ -52,6 +52,7 @@ librdmacm.so.1 librdmacm1 #MINVER#
  rdma_resolve_route@RDMACM_1.0 1.0.15
  rdma_set_local_ece@RDMACM_1.3 31
  rdma_set_option@RDMACM_1.0 1.0.15
+ rdma_write_cm_event@RDMACM_1.4 57
  rfcntl@RDMACM_1.0 1.0.16
  rgetpeername@RDMACM_1.0 1.0.16
  rgetsockname@RDMACM_1.0 1.0.16

librdmacm/cma.c

@@ -2752,6 +2752,12 @@ int rdma_get_cm_event(struct rdma_event_channel *channel,
 	case RDMA_CM_EVENT_ADDRINFO_ERROR:
 		clear_resolving_ai_flag(evt->id_priv);
 		break;
+	case RDMA_CM_EVENT_USER:
+		memcpy(&evt->event.param.arg, resp.param.arg32,
+		       sizeof(evt->event.param.arg));
+		break;
+	case RDMA_CM_EVENT_INTERNAL:
+		break;
 	default:
 		evt->id_priv = (void *) (uintptr_t) resp.uid;
 		evt->event.id = &evt->id_priv->id;
@@ -3089,6 +3095,36 @@ static void resolve_ai_set_cmd_service(const char *service,
 	}
 }
 
+static int __rdma_write_cm_event(struct rdma_cm_id *id, enum rdma_cm_event_type event,
+				 int status, uint64_t arg)
+{
+	struct ucma_abi_write_cm_event cmd;
+	struct cma_id_private *id_priv;
+	int ret;
+
+	CMA_INIT_CMD(&cmd, sizeof(cmd), WRITE_CM_EVENT);
+
+	id_priv = container_of(id, struct cma_id_private, id);
+	cmd.id = id_priv->handle;
+	cmd.event = event;
+	cmd.status = status;
+	cmd.param.arg = arg;
+	ret = write(id->channel->fd, &cmd, sizeof(cmd));
+	if (ret != sizeof(cmd))
+		return (ret >= 0) ? ERR(ENODATA) : -1;
+
+	return 0;
+}
+
+int rdma_write_cm_event(struct rdma_cm_id *id, enum rdma_cm_event_type event,
+			int status, uint64_t arg)
+{
+	if (event != RDMA_CM_EVENT_USER)
+		return ERR(EINVAL);
+
+	return __rdma_write_cm_event(id, event, status, arg);
+}
+
 static int resolve_ai_sa(struct cma_id_private *id_priv, const char *service)
 {
 	struct ucma_abi_resolve_ib_service cmd;

librdmacm/librdmacm.map

@@ -92,4 +92,5 @@ RDMACM_1.4 {
 	global:
 		rdma_query_addrinfo;
 		rdma_resolve_addrinfo;
+		rdma_write_cm_event;
 } RDMACM_1.3;

librdmacm/rdma_cma.h

@@ -66,6 +66,8 @@ enum rdma_cm_event_type {
 	RDMA_CM_EVENT_TIMEWAIT_EXIT,
 	RDMA_CM_EVENT_ADDRINFO_RESOLVED,
 	RDMA_CM_EVENT_ADDRINFO_ERROR,
+	RDMA_CM_EVENT_USER,
+	RDMA_CM_EVENT_INTERNAL,
 };
 
 enum rdma_port_space {
@@ -173,6 +175,7 @@ struct rdma_cm_event {
 	union {
 		struct rdma_conn_param conn;
 		struct rdma_ud_param   ud;
+		uint64_t arg;
 	} param;
 };
 
@@ -798,6 +801,12 @@ int rdma_resolve_addrinfo(struct rdma_cm_id *id, const char *node,
  */
 int rdma_query_addrinfo(struct rdma_cm_id *id, struct rdma_addrinfo **info);
 
+/**
+ * rdma_write_cm_event - Write an event into a cm channel.
+ */
+int rdma_write_cm_event(struct rdma_cm_id *id, enum rdma_cm_event_type event,
+			int status, uint64_t arg);
+
 #ifdef __cplusplus
 }
 #endif

librdmacm/rdma_cma_abi.h

@@ -71,7 +71,8 @@ enum {
 	UCMA_CMD_BIND,
 	UCMA_CMD_RESOLVE_ADDR,
 	UCMA_CMD_JOIN_MCAST,
-	UCMA_CMD_RESOLVE_IB_SERVICE
+	UCMA_CMD_RESOLVE_IB_SERVICE,
+	UCMA_CMD_WRITE_CM_EVENT,
 };
 
 struct ucma_abi_cmd_hdr {
@@ -335,6 +336,7 @@ struct ucma_abi_event_resp {
 	union {
 		struct ucma_abi_conn_param conn;
 		struct ucma_abi_ud_param   ud;
+		__u32 arg32[2];
 	} param;
 	struct ucma_abi_ece ece;
 };
@@ -403,4 +405,19 @@ struct ucma_abi_query_ib_service_resp {
 	struct ucma_user_service_rec recs[];
 };
 
+struct ucma_abi_write_cm_event {
+	__u32 cmd;
+	__u16 in;
+	__u16 out;
+	__u32 id;
+	__u32 reserved;
+	__u32 event;
+	__u32 status;
+	union {
+		struct ucma_abi_conn_param conn;
+		struct ucma_abi_ud_param   ud;
+		__u64 arg;
+	} param;
+};
+
 #endif /* RDMA_CMA_ABI_H */