cache: Add reference counter to caches

Signed-off-by: Thomas Graf <[email protected]> (cherry picked from commit c658a6e) Conflicts: include/netlink-types.h lib/cache.c Signed-off-by: Thomas Graf <[email protected]>
tgraf · Dec 20, 2012 · 349a87f · 349a87f
1 parent 3ddde65
commit 349a87f
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Showing 3 changed files with 30 additions and 4 deletions.
diff --git a/include/netlink-types.h b/include/netlink-types.h
@@ -75,6 +75,7 @@ struct nl_cache
 	int			c_nitems;
 	int                     c_iarg1;
 	int                     c_iarg2;
+	int			c_refcnt;
 	struct nl_cache_ops *   c_ops;
 };
 

diff --git a/include/netlink/cache.h b/include/netlink/cache.h
@@ -43,6 +43,7 @@ extern struct nl_cache *	nl_cache_alloc_name(const char *);
 extern struct nl_cache *	nl_cache_subset(struct nl_cache *,
 						struct nl_object *);
 extern void			nl_cache_clear(struct nl_cache *);
+extern void			nl_cache_get(struct nl_cache *);
 extern void			nl_cache_free(struct nl_cache *);
 
 /* Cache modification */

diff --git a/lib/cache.c b/lib/cache.c
@@ -6,7 +6,7 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2003-2006 Thomas Graf <[email protected]>
+ * Copyright (c) 2003-2012 Thomas Graf <[email protected]>
  */
 
 /**
@@ -179,6 +179,7 @@ struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops)
 
 	nl_init_list_head(&cache->c_items);
 	cache->c_ops = ops;
+	cache->c_refcnt = 1;
 
 	NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache));
 
@@ -248,6 +249,23 @@ void nl_cache_clear(struct nl_cache *cache)
 		nl_cache_remove(obj);
 }
 
+static void __nl_cache_free(struct nl_cache *cache)
+{
+	nl_cache_clear(cache);
+
+	NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
+	free(cache);
+}
+
+/**
+ * Increase reference counter of cache
+ * @arg cache		Cache
+ */
+void nl_cache_get(struct nl_cache *cache)
+{
+	cache->c_refcnt++;
+}
+
 /**
  * Free a cache.
  * @arg cache		Cache to free.
@@ -258,9 +276,15 @@ void nl_cache_clear(struct nl_cache *cache)
  */
 void nl_cache_free(struct nl_cache *cache)
 {
-	nl_cache_clear(cache);
-	NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache));
-	free(cache);
+	if (!cache)
+		return;
+
+	cache->c_refcnt--;
+	NL_DBG(4, "Returned cache reference %p, %d remaining\n",
+	       cache, cache->c_refcnt);
+
+	if (cache->c_refcnt <= 0)
+		__nl_cache_free(cache);
 }
 
 /** @} */