commit 9a3973e3a36bfd4dd8dbffe130a92649fc1b73d3
author Benoît Ganne <bganne@cisco.com> Fri Oct 02 19:36:57 2020 +0200
committer Dave Barach <openvpp@barachs.net> Mon Nov 09 11:51:34 2020 +0000
tree 1ed9e9c7a3b13edd68f7e78d66dbb995cbe79a2a
parent f6b02e0d0bfd7e0f1d79e8ee426f48ca37ae5ff3

vlib: fix trace number accounting

When using classifier to filter traces, not all packets will be traced.
In that case, we should only count traced packets.

Type: fix

Change-Id: I87d1e217b580ebff8c6ade7860eb43950420ae78
Signed-off-by: Benoît Ganne <bganne@cisco.com>

src/vnet/devices/af_packet/node.c

diff --git a/src/vnet/devices/af_packet/node.c b/src/vnet/devices/af_packet/node.c
index 196c088..61d4ce2 100644
--- a/src/vnet/devices/af_packet/node.c
+++ b/src/vnet/devices/af_packet/node.c
@@ -310,11 +310,11 @@
 
 	  /* trace */
 	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (first_b0);
-	  if (PREDICT_FALSE (n_trace > 0))
+	  if (PREDICT_FALSE
+	      (n_trace > 0 && vlib_trace_buffer (vm, node, next0, first_b0,
+						 /* follow_chain */ 0)))
 	    {
 	      af_packet_input_trace_t *tr;
-	      vlib_trace_buffer (vm, node, next0, first_b0,	/* follow_chain */
-				 0);
 	      vlib_set_trace_count (vm, node, --n_trace);
 	      tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
 	      tr->next_index = next0;

src/vnet/devices/virtio/node.c

diff --git a/src/vnet/devices/virtio/node.c b/src/vnet/devices/virtio/node.c
index 94bf097..91e788e 100644
--- a/src/vnet/devices/virtio/node.c
+++ b/src/vnet/devices/virtio/node.c
@@ -388,11 +388,10 @@
 	  /* trace */
 	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
 
-	  if (PREDICT_FALSE (n_trace > 0))
+	  if (PREDICT_FALSE (n_trace > 0 && vlib_trace_buffer (vm, node, next0, b0,	/* follow_chain */
+							       1)))
 	    {
 	      virtio_input_trace_t *tr;
-	      vlib_trace_buffer (vm, node, next0, b0,
-				 /* follow_chain */ 1);
 	      vlib_set_trace_count (vm, node, --n_trace);
 	      tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
 	      tr->next_index = next0;

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
--- a/src/vnet/devices/virtio/vhost_user_input.c
+++ b/src/vnet/devices/virtio/vhost_user_input.c
@@ -540,10 +540,10 @@
       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 @@
       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++;
 	}
     }