lib: skip Curl_llist_destroy calls

Linked lists themselves do not carry any allocations, so for the lists
that do not have have a set destructor we can just skip the
Curl_llist_destroy() call and save CPU time.

Closes #10764

lib/conncache.c

@@ -45,13 +45,6 @@
 
 #define HASHKEY_SIZE 128
 
-static void conn_llist_dtor(void *user, void *element)
-{
-  struct connectdata *conn = element;
-  (void)user;
-  conn->bundle = NULL;
-}
-
 static CURLcode bundle_create(struct connectbundle **bundlep)
 {
   DEBUGASSERT(*bundlep == NULL);
@@ -62,17 +55,12 @@ static CURLcode bundle_create(struct connectbundle **bundlep)
   (*bundlep)->num_connections = 0;
   (*bundlep)->multiuse = BUNDLE_UNKNOWN;
 
-  Curl_llist_init(&(*bundlep)->conn_list, (Curl_llist_dtor) conn_llist_dtor);
+  Curl_llist_init(&(*bundlep)->conn_list, NULL);
   return CURLE_OK;
 }
 
 static void bundle_destroy(struct connectbundle *bundle)
 {
-  if(!bundle)
-    return;
-
-  Curl_llist_destroy(&bundle->conn_list, NULL);
-
   free(bundle);
 }
 

lib/multi.c

@@ -445,9 +445,6 @@ struct Curl_multi *Curl_multi_handle(int hashsize, /* socket hash */
   sockhash_destroy(&multi->sockhash);
   Curl_hash_destroy(&multi->hostcache);
   Curl_conncache_destroy(&multi->conn_cache);
-  Curl_llist_destroy(&multi->msglist, NULL);
-  Curl_llist_destroy(&multi->pending, NULL);
-
   free(multi);
   return NULL;
 }
@@ -841,10 +838,6 @@ CURLMcode curl_multi_remove_handle(struct Curl_multi *multi,
 
   Curl_wildcard_dtor(&data->wildcard);
 
-  /* destroy the timeout list that is held in the easy handle, do this *after*
-     multi_done() as that may actually call Curl_expire that uses this */
-  Curl_llist_destroy(&data->state.timeoutlist, NULL);
-
   /* change state without using multistate(), only to make singlesocket() do
      what we want */
   data->mstate = MSTATE_COMPLETED;
@@ -2795,9 +2788,6 @@ CURLMcode curl_multi_cleanup(struct Curl_multi *multi)
 
     sockhash_destroy(&multi->sockhash);
     Curl_conncache_destroy(&multi->conn_cache);
-    Curl_llist_destroy(&multi->msglist, NULL);
-    Curl_llist_destroy(&multi->pending, NULL);
-
     Curl_hash_destroy(&multi->hostcache);
     Curl_psl_destroy(&multi->psl);
 

lib/url.c

@@ -727,8 +727,6 @@ static void conn_free(struct Curl_easy *data, struct connectdata *conn)
   Curl_safefree(conn->conn_to_host.rawalloc); /* host name buffer */
   Curl_safefree(conn->hostname_resolve);
   Curl_safefree(conn->secondaryhostname);
-
-  Curl_llist_destroy(&conn->easyq, NULL);
   Curl_safefree(conn->localdev);
   Curl_free_primary_ssl_config(&conn->ssl_config);
 
@@ -1596,7 +1594,6 @@ static struct connectdata *allocate_conn(struct Curl_easy *data)
   return conn;
   error:
 
-  Curl_llist_destroy(&conn->easyq, NULL);
   free(conn->localdev);
   free(conn);
   return NULL;