From 1b5b50718fc608d42c4ba985f23fab10816d1853 Mon Sep 17 00:00:00 2001
From: Andy Zhou <azhou@nicira.com>
Date: Thu, 13 Mar 2014 21:48:55 -0700
Subject: [PATCH] udpif:  Bug fix updif_flush

Before this commit, all datapath flows are cleared with dpif_flush(),
but the revalidator thread still holds ukeys, which are caches of the
datapath flows in the revalidaor.  Flushing ukeys causes flow_del
messages to be sent to the datapath again on flows that have been
deleted by the dpif_flush() already.

Double deletion by itself is not problem, per se, may an efficiency
issue. However, for ever flow_del message sent to the datapath, a log
message, at the warning level, will be generated in case datapath
failed to execute the command. In addition to cause spurious log
messages, Double deletion causes unit tests to report erroneous
failures as all warning messages are considered test failures.

The fix is to simply shut down the revalidator threads to flush all
ukeys, then flush the datapth before restarting the revalidator threads.

dpif_flush() was implemented as flush flows of all datapaths while
most of its invocation should only flush its local datapath.
Only megaflow on/off commands should flush all dapapaths. This bug is
also fixed.

Found during development.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
---
 ofproto/ofproto-dpif-upcall.c | 27 +++++++++++++++++++++------
 ofproto/ofproto-dpif-upcall.h |  2 +-
 ofproto/ofproto-dpif.c        |  9 +++++++--
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
index 496593b32..cc4982fe8 100644
--- a/ofproto/ofproto-dpif-upcall.c
+++ b/ofproto/ofproto-dpif-upcall.c
@@ -279,7 +279,7 @@ void
 udpif_destroy(struct udpif *udpif)
 {
     udpif_set_threads(udpif, 0, 0);
-    udpif_flush();
+    udpif_flush(udpif);
 
     list_remove(&udpif->list_node);
     latch_destroy(&udpif->exit_latch);
@@ -470,16 +470,31 @@ udpif_get_memory_usage(struct udpif *udpif, struct simap *usage)
     }
 }
 
-/* Removes all flows from all datapaths. */
+/* Remove flows from a single datapath. */
 void
-udpif_flush(void)
+udpif_flush(struct udpif *udpif)
+{
+    size_t n_handlers, n_revalidators;
+
+    n_handlers = udpif->n_handlers;
+    n_revalidators = udpif->n_revalidators;
+
+    udpif_set_threads(udpif, 0, 0);
+    dpif_flow_flush(udpif->dpif);
+    udpif_set_threads(udpif, n_handlers, n_revalidators);
+}
+
+/* Removes all flows from all datapaths. */
+static void
+udpif_flush_all_datapaths(void)
 {
     struct udpif *udpif;
 
     LIST_FOR_EACH (udpif, list_node, &all_udpifs) {
-        dpif_flow_flush(udpif->dpif);
+        udpif_flush(udpif);
     }
 }
+
 
 /* Destroys and deallocates 'upcall'. */
 static void
@@ -1657,7 +1672,7 @@ upcall_unixctl_disable_megaflows(struct unixctl_conn *conn,
                                  void *aux OVS_UNUSED)
 {
     atomic_store(&enable_megaflows, false);
-    udpif_flush();
+    udpif_flush_all_datapaths();
     unixctl_command_reply(conn, "megaflows disabled");
 }
 
@@ -1672,7 +1687,7 @@ upcall_unixctl_enable_megaflows(struct unixctl_conn *conn,
                                 void *aux OVS_UNUSED)
 {
     atomic_store(&enable_megaflows, true);
-    udpif_flush();
+    udpif_flush_all_datapaths();
     unixctl_command_reply(conn, "megaflows enabled");
 }
 
diff --git a/ofproto/ofproto-dpif-upcall.h b/ofproto/ofproto-dpif-upcall.h
index 9eeee5b90..6846f879c 100644
--- a/ofproto/ofproto-dpif-upcall.h
+++ b/ofproto/ofproto-dpif-upcall.h
@@ -34,6 +34,6 @@ void udpif_destroy(struct udpif *);
 void udpif_revalidate(struct udpif *);
 void udpif_get_memory_usage(struct udpif *, struct simap *usage);
 struct seq *udpif_dump_seq(struct udpif *);
-void udpif_flush(void);
+void udpif_flush(struct udpif *);
 
 #endif /* ofproto-dpif-upcall.h */
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 97eb2b800..bb414f2b3 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1371,9 +1371,14 @@ type_get_memory_usage(const char *type, struct simap *usage)
 }
 
 static void
-flush(struct ofproto *ofproto OVS_UNUSED)
+flush(struct ofproto *ofproto_)
 {
-    udpif_flush();
+    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
+    struct dpif_backer *backer = ofproto->backer;
+
+    if (backer) {
+        udpif_flush(backer->udpif);
+    }
 }
 
 static void
-- 
2.43.0