From 2a4ae6357eb447e185599ec1ca7c95b1e4183c19 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Wed, 6 Apr 2011 15:31:22 -0700
Subject: [PATCH] mac-learning: Change mac_learning_set_flood_vlans() to not
 take ownership.

These new semantics are less efficient in the case where the flood_vlans
actually changed, but that should be very rare.

There are no advantages to this change on its own, but upcoming commits
will add multiple layers between the code supplying the flood_vlans and
actually calling mac_learning_set_flood_vlans().  Consistency in this
multilayered interface seems valuable, and the rest of it does not transfer
ownership from the caller to the callee.
---
 lib/bitmap.h       |  8 +++++++-
 lib/mac-learning.c | 20 +++++++++++---------
 lib/mac-learning.h |  2 +-
 lib/vlan-bitmap.h  |  7 +++++++
 vswitchd/bridge.c  |  1 +
 5 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/lib/bitmap.h b/lib/bitmap.h
index fd05d3da1..f6feff085 100644
--- a/lib/bitmap.h
+++ b/lib/bitmap.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,12 @@ bitmap_allocate(size_t n_bits)
     return xzalloc(bitmap_n_bytes(n_bits));
 }
 
+static inline unsigned long *
+bitmap_clone(const unsigned long *bitmap, size_t n_bits)
+{
+    return xmemdup(bitmap, bitmap_n_bytes(n_bits));
+}
+
 static inline void
 bitmap_free(unsigned long *bitmap)
 {
diff --git a/lib/mac-learning.c b/lib/mac-learning.c
index a57bbc759..981578d8a 100644
--- a/lib/mac-learning.c
+++ b/lib/mac-learning.c
@@ -139,17 +139,19 @@ mac_learning_destroy(struct mac_learning *ml)
 }
 
 /* Provides a bitmap of VLANs which have learning disabled, that is, VLANs on
- * which all packets are flooded.  It takes ownership of the bitmap.  Returns
- * true if the set has changed from the previous value. */
+ * which all packets are flooded.  Returns true if the set has changed from the
+ * previous value. */
 bool
-mac_learning_set_flood_vlans(struct mac_learning *ml, unsigned long *bitmap)
+mac_learning_set_flood_vlans(struct mac_learning *ml,
+                             const unsigned long *bitmap)
 {
-    bool ret = vlan_bitmap_equal(ml->flood_vlans, bitmap);
-
-    bitmap_free(ml->flood_vlans);
-    ml->flood_vlans = bitmap;
-
-    return ret;
+    if (vlan_bitmap_equal(ml->flood_vlans, bitmap)) {
+        return false;
+    } else {
+        bitmap_free(ml->flood_vlans);
+        ml->flood_vlans = vlan_bitmap_clone(bitmap);
+        return true;
+    }
 }
 
 static bool
diff --git a/lib/mac-learning.h b/lib/mac-learning.h
index 51a7ac738..d9fa433cd 100644
--- a/lib/mac-learning.h
+++ b/lib/mac-learning.h
@@ -96,7 +96,7 @@ void mac_learning_wait(struct mac_learning *);
 
 /* Configuration. */
 bool mac_learning_set_flood_vlans(struct mac_learning *,
-                                  unsigned long *bitmap);
+                                  const unsigned long *bitmap);
 
 /* Learning. */
 bool mac_learning_may_learn(const struct mac_learning *,
diff --git a/lib/vlan-bitmap.h b/lib/vlan-bitmap.h
index eca42fea9..6d74d4008 100644
--- a/lib/vlan-bitmap.h
+++ b/lib/vlan-bitmap.h
@@ -37,4 +37,11 @@ vlan_bitmap_contains(const unsigned long *vlans, uint16_t vid)
     return !vlans || bitmap_is_set(vlans, vid);
 }
 
+/* Returns a new copy of 'vlans'. */
+static inline unsigned long *
+vlan_bitmap_clone(const unsigned long *vlans)
+{
+    return vlans ? bitmap_clone(vlans, 4096) : NULL;
+}
+
 #endif /* lib/vlan-bitmap.h */
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index e3e5a4c71..9e9566cc3 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -3621,6 +3621,7 @@ mirror_reconfigure(struct bridge *br)
         bridge_flush(br);
         mac_learning_flush(br->ml);
     }
+    free(rspan_vlans);
 }
 
 static void
-- 
2.20.1