rdma_cm: add rdma_is_consumer_reject() helper function

Return true if the peer consumer application rejected the
connection attempt.

Reviewed-by: Sagi Grimberg <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Steve Wise <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Signed-off-by: Doug Ledford <[e-mail]>

drivers/infiniband/core/cma.c

···
 }
 EXPORT_SYMBOL(rdma_reject_msg);
 
+bool rdma_is_consumer_reject(struct rdma_cm_id *id, int reason)
+{
+	if (rdma_ib_or_roce(id->device, id->port_num))
+		return reason == IB_CM_REJ_CONSUMER_DEFINED;
+
+	if (rdma_protocol_iwarp(id->device, id->port_num))
+		return reason == -ECONNREFUSED;
+
+	WARN_ON_ONCE(1);
+	return false;
+}
+EXPORT_SYMBOL(rdma_is_consumer_reject);
+
 static void cma_add_one(struct ib_device *device);
 static void cma_remove_one(struct ib_device *device, void *client_data);
 

include/rdma/rdma_cm.h

···
  */
 const char *__attribute_const__ rdma_reject_msg(struct rdma_cm_id *id,
 						int reason);
+/**
+ * rdma_is_consumer_reject - return true if the consumer rejected the connect
+ *                           request.
+ * @id: Communication identifier that received the REJECT event.
+ * @reason: Value returned in the REJECT event status field.
+ */
+bool rdma_is_consumer_reject(struct rdma_cm_id *id, int reason);
 
 #endif /* RDMA_CM_H */