rdma: clean up of qemu_rdma_cleanup()

- It can't be determined by RDMAContext::cm_id != NULL if the connection
  is established or not.
- RDMAContext::cm_id is leaked and not destroyed because it is set to NULL
  too early.
- RDMAContext::qp is created by rdma_create_qp() so that it should be destroyed
  by rdma_destroy_qp(). not ibv_destroy_qp()

Cc: Michael R. Hines <mrhines@us.ibm.com>
Signed-off-by: NIsaku Yamahata <yamahata@private.email.ne.jp>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

migration-rdma.c

@@ -356,6 +356,7 @@ typedef struct RDMAContext {
      */
     struct rdma_cm_id *cm_id;               /* connection manager ID */
     struct rdma_cm_id *listen_id;
+    bool connected;
 
     struct ibv_context          *verbs;
     struct rdma_event_channel   *channel;
@@ -2194,7 +2195,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
     struct rdma_cm_event *cm_event;
     int ret, idx;
 
-    if (rdma->cm_id) {
+    if (rdma->cm_id && rdma->connected) {
         if (rdma->error_state) {
             RDMAControlHeader head = { .len = 0,
                                        .type = RDMA_CONTROL_ERROR,
@@ -2213,7 +2214,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
             }
         }
         DDPRINTF("Disconnected.\n");
-        rdma->cm_id = NULL;
+        rdma->connected = false;
     }
 
     g_free(rdma->block);
@@ -2235,7 +2236,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
     }
 
     if (rdma->qp) {
-        ibv_destroy_qp(rdma->qp);
+        rdma_destroy_qp(rdma->cm_id);
         rdma->qp = NULL;
     }
     if (rdma->cq) {
@@ -2372,6 +2373,7 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
         rdma->cm_id = NULL;
         goto err_rdma_source_connect;
     }
+    rdma->connected = true;
 
     memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap));
     network_to_caps(&cap);
@@ -2906,6 +2908,7 @@ static int qemu_rdma_accept(RDMAContext *rdma)
     }
 
     rdma_ack_cm_event(cm_event);
+    rdma->connected = true;
 
     ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
     if (ret) {