vswitchd: Fix documentation of "agent" column in "sFlow" table.

[openvswitch] / lib / dpif.c

diff --git a/lib/dpif.c b/lib/dpif.c
index 8e5cf9ffcb36af7650f6485a46456b9289907e45..097b38d8c22aa7eeaf359d4912bb2d20995cceb9 100644 (file)
--- a/lib/dpif.c
+++ b/lib/dpif.c
@@ -724,6 +724,11 @@ dpif_flow_get(const struct dpif *dpif, struct odp_flow *flow)
     if (!error) {
         error = flow->stats.error;
     }
+    if (error) {
+        /* Make the results predictable on error. */
+        memset(&flow->stats, 0, sizeof flow->stats);
+        flow->n_actions = 0;
+    }
     if (should_log_flow_message(error)) {
         log_flow_operation(dpif, "flow_get", error, flow);
     }
@@ -1010,7 +1015,8 @@ dpif_set_sflow_probability(struct dpif *dpif, uint32_t probability)
 
 /* Attempts to receive a message from 'dpif'.  If successful, stores the
  * message into '*packetp'.  The message, if one is received, will begin with
- * 'struct odp_msg' as a header.  Only messages of the types selected with
+ * 'struct odp_msg' as a header, and will have at least DPIF_RECV_MSG_PADDING
+ * bytes of headroom.  Only messages of the types selected with
  * dpif_set_listen_mask() will ordinarily be received (but if a message type is
  * enabled and then later disabled, some stragglers might pop up).
  *
@@ -1021,8 +1027,10 @@ dpif_recv(struct dpif *dpif, struct ofpbuf **packetp)
 {
     int error = dpif->dpif_class->recv(dpif, packetp);
     if (!error) {
+        struct ofpbuf *buf = *packetp;
+
+        assert(ofpbuf_headroom(buf) >= DPIF_RECV_MSG_PADDING);
         if (VLOG_IS_DBG_ENABLED()) {
-            struct ofpbuf *buf = *packetp;
             struct odp_msg *msg = buf->data;
             void *payload = msg + 1;
             size_t payload_len = buf->size - sizeof *msg;