From: Ben Pfaff <blp@nicira.com>
Date: Tue, 3 Jul 2012 21:00:38 +0000 (-0700)
Subject: ofproto: Add extra comments and checking for expiring a pending rule.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e2a3d183f60b93265c095ede1379194916444822;p=openvswitch

ofproto: Add extra comments and checking for expiring a pending rule.

A given rule may only have one pending operation at a time, so when an
operation is pending we must not allow a flow expiration to be started on
that rule.

This doesn't fix a user-visible bug in ofproto-dpif because ofproto-dpif
always completes operations immediately, that is, no operations will be
pending when expiration runs.  (Technically there is a bug if the user
runs "ovs-appctl ofproto/clog", but that feature is for debugging only and
there is no reason for a user to ever run it.)

Signed-off-by: Ben Pfaff <blp@nicira.com>
---

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 2451d44d..5265d7bc 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -3562,6 +3562,11 @@ rule_expire(struct rule_dpif *rule)
     long long int now;
     uint8_t reason;
 
+    if (rule->up.pending) {
+        /* We'll have to expire it later. */
+        return;
+    }
+
     /* Has 'rule' expired? */
     now = time_msec();
     if (rule->up.hard_timeout
diff --git a/ofproto/ofproto-provider.h b/ofproto/ofproto-provider.h
index afd17a60..f22c9f61 100644
--- a/ofproto/ofproto-provider.h
+++ b/ofproto/ofproto-provider.h
@@ -388,6 +388,9 @@ struct ofproto_class {
      *   - Call ofproto_rule_expire() for each OpenFlow flow that has reached
      *     its hard_timeout or idle_timeout, to expire the flow.
      *
+     *     (But rules that are part of a pending operation, e.g. rules for
+     *     which ->pending is true, may not expire.)
+     *
      * Returns 0 if successful, otherwise a positive errno value. */
     int (*run)(struct ofproto *ofproto);
 
diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index 90cf343b..93401919 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -3128,6 +3128,9 @@ ofproto_rule_update_used(struct rule *rule, long long int used)
  * OFPRR_HARD_TIMEOUT or OFPRR_IDLE_TIMEOUT), and then removes 'rule' from its
  * ofproto.
  *
+ * 'rule' must not have a pending operation (that is, 'rule->pending' must be
+ * NULL).
+ *
  * ofproto implementation ->run() functions should use this function to expire
  * OpenFlow flows. */
 void