s3-memcache: update memcache to use new DLIST macros

we don't need a separate lru pointer any more
(cherry picked from commit 4ffd7aca3e38728077bd80c2a65c4efbcfd216fc)

diff --git a/source3/lib/memcache.c b/source3/lib/memcache.c
index 606d72ab5ac5428bdf44fc5ba55b6139bc20d21b..5c4bafa17d075c8bee7b99dd323c488c8a2428dc 100644 (file)
--- a/source3/lib/memcache.c
+++ b/source3/lib/memcache.c
@@ -31,7 +31,7 @@ struct memcache_element {
 };
 
 struct memcache {
-       struct memcache_element *mru, *lru;
+       struct memcache_element *mru;
        struct rb_root tree;
        size_t size;
        size_t max_size;
@@ -161,16 +161,7 @@ bool memcache_lookup(struct memcache *cache, enum memcache_number n,
        }
 
        if (cache->size != 0) {
-               /*
-                * Do LRU promotion only when we will ever shrink
-                */
-               if (e == cache->lru) {
-                       cache->lru = e->prev;
-               }
                DLIST_PROMOTE(cache->mru, e);
-               if (cache->mru == NULL) {
-                       cache->mru = e;
-               }
        }
 
        memcache_element_parse(e, &key, value);
@@ -201,9 +192,6 @@ static void memcache_delete_element(struct memcache *cache,
 {
        rb_erase(&e->rb_node, &cache->tree);
 
-       if (e == cache->lru) {
-               cache->lru = e->prev;
-       }
        DLIST_REMOVE(cache->mru, e);
 
        if (memcache_is_talloc(e->n)) {
@@ -227,8 +215,8 @@ static void memcache_trim(struct memcache *cache)
                return;
        }
 
-       while ((cache->size > cache->max_size) && (cache->lru != NULL)) {
-               memcache_delete_element(cache, cache->lru);
+       while ((cache->size > cache->max_size) && DLIST_TAIL(cache->mru)) {
+               memcache_delete_element(cache, DLIST_TAIL(cache->mru));
        }
 }
 
@@ -331,9 +319,6 @@ void memcache_add(struct memcache *cache, enum memcache_number n,
        rb_insert_color(&e->rb_node, &cache->tree);
 
        DLIST_ADD(cache->mru, e);
-       if (cache->lru == NULL) {
-               cache->lru = e;
-       }
 
        cache->size += element_size;
        memcache_trim(cache);