vlib: fix trace number accounting

[vpp.git] / src / vnet / devices / virtio / vhost_user_input.c

diff --git a/src/vnet/devices/virtio/vhost_user_input.c b/src/vnet/devices/virtio/vhost_user_input.c
index da4937b..53230a6 100644 (file)
--- a/src/vnet/devices/virtio/vhost_user_input.c
+++ b/src/vnet/devices/virtio/vhost_user_input.c
@@ -540,10 +540,10 @@ vhost_user_if_input (vlib_main_t * vm,
       b_head->total_length_not_including_first_buffer = 0;
       b_head->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
 
-      if (PREDICT_FALSE (n_trace))
+      if (PREDICT_FALSE
+         (n_trace > 0 && vlib_trace_buffer (vm, node, next_index, b_head,
+                                            /* follow_chain */ 0)))
        {
-         vlib_trace_buffer (vm, node, next_index, b_head,
-                            /* follow_chain */ 0);
          vhost_trace_t *t0 =
            vlib_add_trace (vm, node, b_head, sizeof (t0[0]));
          vhost_user_rx_trace (t0, vui, qid, b_head, txvq, last_avail_idx);
@@ -1362,17 +1362,19 @@ vhost_user_if_input_packed (vlib_main_t * vm, vhost_user_main_t * vum,
       b = cpu->rx_buffers_pdesc;
       while (n_trace && left)
        {
-         vhost_trace_t *t0;
-
-         vlib_trace_buffer (vm, node, next_index, b[0],
-                            /* follow_chain */ 0);
-         t0 = vlib_add_trace (vm, node, b[0], sizeof (t0[0]));
-         b++;
-         vhost_user_rx_trace_packed (t0, vui, qid, txvq, last_used_idx);
-         last_used_idx = (last_used_idx + 1) & mask;
-         n_trace--;
+         if (PREDICT_TRUE
+             (vlib_trace_buffer
+              (vm, node, next_index, b[0], /* follow_chain */ 0)))
+           {
+             vhost_trace_t *t0;
+             t0 = vlib_add_trace (vm, node, b[0], sizeof (t0[0]));
+             vhost_user_rx_trace_packed (t0, vui, qid, txvq, last_used_idx);
+             last_used_idx = (last_used_idx + 1) & mask;
+             n_trace--;
+             vlib_set_trace_count (vm, node, n_trace);
+           }
          left--;
-         vlib_set_trace_count (vm, node, n_trace);
+         b++;
        }
     }