[PATCH] PKT_SCHED: Fix double locking in tcindex destroy path

[Thomas Graf <tgraf@xxxxxxx>]

tcindex's destroy uses its own delete functions to destroy its
configuration. The delete function (correctly) takes the qdisc_tree_lock
to prevent list walkings from happening while removing from the list.
The qdisc_tree_lock is already held if we're comming via the destroy
path and thus a double locking takes place.

Patch not needed for 2.4 since both destroy paths are unlocked but will
be needed if we add them.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>

--- linux-2.6.10-rc2-bk13.orig/net/sched/cls_tcindex.c  2004-11-30 
14:01:12.000000000 +0100
+++ linux-2.6.10-rc2-bk13/net/sched/cls_tcindex.c       2004-12-10 
02:20:51.000000000 +0100
@@ -160,7 +160,8 @@
 }
 
 
-static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
+static int
+__tcindex_delete(struct tcf_proto *tp, unsigned long arg, int already_locked)
 {
        struct tcindex_data *p = PRIV(tp);
        struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
@@ -182,9 +183,11 @@
 
 found:
                f = *walk;
-               tcf_tree_lock(tp); 
+               if (!already_locked)
+                       tcf_tree_lock(tp);
                *walk = f->next;
-               tcf_tree_unlock(tp);
+               if (!already_locked)
+                       tcf_tree_unlock(tp);
        }
        tcf_unbind_filter(tp, &r->res);
 #ifdef CONFIG_NET_CLS_POLICE
@@ -195,6 +198,10 @@
        return 0;
 }
 
+static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
+{
+       return __tcindex_delete(tp, arg, 0);
+}
 
 /*
  * There are no parameters for tcindex_init, so we overload tcindex_change
@@ -384,7 +391,7 @@
 static int tcindex_destroy_element(struct tcf_proto *tp,
     unsigned long arg, struct tcf_walker *walker)
 {
-       return tcindex_delete(tp,arg);
+       return __tcindex_delete(tp,arg, 1);
 }