[ovs-dev] [PATCH] dpif: Don't clear argument in dp_enumerate_types().

[Ben Pfaff]

All but one of the callers of dp_enumerate_types() hands it an sset that is
known to be empty.  The one exception is the implementation of the
ofproto-provider 'enumerate_types' function in ofproto-dpif.  That function
isn't supposed to clear the existing contents of the sset passed in.
Therefore, this commit changes dp_enumerate_types() to not clear the sset
before it adds new members.

The ofproto-provider comment wasn't clear about the desired behavior so
this commit also clarifies that.

Reported-by: Zoltán Balogh <zoltan.balogh at ericsson.com>
Signed-off-by: Ben Pfaff <blp at nicira.com>
---
 AUTHORS                    |    1 +
 lib/dpif.c                 |    5 ++---
 ofproto/ofproto-provider.h |    7 ++++---
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 09540f4..346a75d 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -319,6 +319,7 @@ Yeming Zhao             zhaoyeming at gmail.com
 Ying Chen               yingchen at vmware.com
 Yongqiang Liu           liuyq7809 at gmail.com
 Ziyou Wang              ziyouw at vmware.com
+Zoltán Balogh           zoltan.balogh at ericsson.com
 ankur dwivedi           ankurengg2003 at gmail.com
 chen zhang              3zhangchen9211 at gmail.com
 kk yap                  yapkke at stanford.edu
diff --git a/lib/dpif.c b/lib/dpif.c
index e39d7cd..b6be485 100644
--- a/lib/dpif.c
+++ b/lib/dpif.c
@@ -225,15 +225,14 @@ dp_blacklist_provider(const char *type)
     ovs_mutex_unlock(&dpif_mutex);
 }
 
-/* Clears 'types' and enumerates the types of all currently registered datapath
- * providers into it.  The caller must first initialize the sset. */
+/* Adds the types of all currently registered datapath providers to 'types'.
+ * The caller must first initialize the sset. */
 void
 dp_enumerate_types(struct sset *types)
 {
     struct shash_node *node;
 
     dp_initialize();
-    sset_clear(types);
 
     ovs_mutex_lock(&dpif_mutex);
     SHASH_FOR_EACH(node, &dpif_classes) {
diff --git a/ofproto/ofproto-provider.h b/ofproto/ofproto-provider.h
index 0911333..4dc8adb 100644
--- a/ofproto/ofproto-provider.h
+++ b/ofproto/ofproto-provider.h
@@ -629,9 +629,10 @@ struct ofproto_class {
      * may choose to remove it all. */
     void (*init)(const struct shash *iface_hints);
 
-    /* Enumerates the types of all support ofproto types into 'types'.  The
-     * caller has already initialized 'types' and other ofproto classes might
-     * already have added names to it. */
+    /* Enumerates the types of all supported ofproto types into 'types'.  The
+     * caller has already initialized 'types'.  The implementation should add
+     * its own types to 'types' but not remove any existing ones, because other
+     * ofproto classes might already have added names to it. */
     void (*enumerate_types)(struct sset *types);
 
     /* Enumerates the names of all existing datapath of the specified 'type'
-- 
1.7.10.4