librdmacm/cmtime: Use atomic for 'use_qpn' and 'disc_events'

Once multi-thread support is added to cmtime, the use_qpn
and disc_events variables will be access by multiple threads.
Use an atomic variable instead of volatiles.

Signed-off-by: Sean Hefty <[email protected]>

librdmacm/examples/cmtime.c

@@ -59,7 +59,7 @@ static char *src_addr;
 static int timeout = 2000;
 static int retries = 2;
 static uint32_t base_qpn = 1000;
-static uint32_t use_qpn;
+static _Atomic(uint32_t) cur_qpn;
 static uint32_t mimic_qp_delay;
 static bool mimic;
 
@@ -123,7 +123,7 @@ static int node_index;
 static uint64_t times[STEP_CNT][2];
 static int connections;
 static int num_threads = 1;
-static volatile int disc_events;
+static _Atomic(int) disc_events;
 
 static _Atomic(int) completed[STEP_CNT];
 
@@ -222,7 +222,7 @@ static void create_qp(struct work_item *item)
  attr.cap.max_inline_data = 0;
 
  start_perf(n, STEP_CREATE_QP);
- if (!use_qpn) {
+ if (atomic_load(&cur_qpn) == 0) {
  n->qp = ibv_create_qp(pd, &attr);
  if (!n->qp) {
  perror("ibv_create_qp");
@@ -282,7 +282,7 @@ static void init_conn_param(struct node *n, struct rdma_conn_param *param)
  param->retry_count = 0;
  param->rnr_retry_count = 0;
  param->srq = 0;
- param->qp_num = n->qp ? n->qp->qp_num : use_qpn++;
+ param->qp_num = n->qp ? n->qp->qp_num : atomic_fetch_add(&cur_qpn, 1);
 }
 
 static void connect_qp(struct node *n)
@@ -382,7 +382,7 @@ static void server_disconnect(struct work_item *item)
  rdma_disconnect(n->id);
  end_perf(n, STEP_DISCONNECT);
 
- if (disc_events >= connections)
+ if (atomic_load(&disc_events) >= connections)
  end_time(STEP_DISCONNECT);
  atomic_fetch_add(&completed[STEP_DISCONNECT], 1);
 }
@@ -453,11 +453,10 @@ static void cma_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
  atomic_fetch_add(&completed[STEP_DISCONNECT], 1);
  } else {
  */
- if (disc_events == 0) {
+ if (atomic_fetch_add(&disc_events, 1) == 0) {
  printf("\tDisconnecting\n");
  start_time(STEP_DISCONNECT);
  }
- disc_events++;
  wq_insert(&wq, &n->work, server_disconnect);
  }
  break;
@@ -566,7 +565,7 @@ static void reset_test(int iter)
  int i;
 
  node_index = 0;
- disc_events = 0;
+ atomic_store(&disc_events, 0);
  connections = iter;
 
  memset(times, 0, sizeof times);
@@ -706,13 +705,13 @@ static void run_client(int iter)
  } else {
  printf("Connect (%d) simulated QPs test (delay %d us)\n",
  iter, mimic_qp_delay);
- use_qpn = base_qpn;
+ atomic_store(&cur_qpn, base_qpn);
  }
  client_connect(iter);
  show_perf(iter);
 
  printf("Connect (%d) test - no QPs\n", iter);
- use_qpn = base_qpn;
+ atomic_store(&cur_qpn, base_qpn);
  mimic_qp_delay = 0;
  client_connect(iter);
  show_perf(iter);
@@ -741,13 +740,13 @@ static void run_server(int iter)
  } else {
  printf("Accept (%d) simulated QPs test (delay %d us)\n",
  iter, mimic_qp_delay);
- use_qpn = base_qpn;
+ atomic_store(&cur_qpn, base_qpn);
  }
  server_connect(iter);
  show_perf(iter);
 
  printf("Accept (%d) test - no QPs\n", iter);
- use_qpn = base_qpn;
+ atomic_store(&cur_qpn, base_qpn);
  mimic_qp_delay = 0;
  server_connect(iter);
  show_perf(iter);