net_sched: fix a regression in tcf_proto_lookup_ops()

list_for_each_entry(t, &tcf_proto_base, head) doesn't
exit with t = NULL if we reached the end of the list.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 3627287463b4 ("net_sched: convert tcf_proto_ops to use struct
list_head")
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 6b085cf27a65cfbbdcf319c061ce23c174ac4fbe..12e882ef596bb986b1a9ab9b8abf12f8f1121954 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -40,20 +40,20 @@ static DEFINE_RWLOCK(cls_mod_lock);
 
 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
 {
-       const struct tcf_proto_ops *t = NULL;
+       const struct tcf_proto_ops *t, *res = NULL;
 
        if (kind) {
                read_lock(&cls_mod_lock);
                list_for_each_entry(t, &tcf_proto_base, head) {
                        if (nla_strcmp(kind, t->kind) == 0) {
-                               if (!try_module_get(t->owner))
-                                       t = NULL;
+                               if (try_module_get(t->owner))
+                                       res = t;
                                break;
                        }
                }
                read_unlock(&cls_mod_lock);
        }
-       return t;
+       return res;
 }
 
 /* Register(unregister) new classifier type */
@@ -82,15 +82,13 @@ int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
        int rc = -ENOENT;
 
        write_lock(&cls_mod_lock);
-       list_for_each_entry(t, &tcf_proto_base, head)
-               if (t == ops)
+       list_for_each_entry(t, &tcf_proto_base, head) {
+               if (t == ops) {
+                       list_del(&t->head);
+                       rc = 0;
                        break;
-
-       if (!t)
-               goto out;
-       list_del(&t->head);
-       rc = 0;
-out:
+               }
+       }
        write_unlock(&cls_mod_lock);
        return rc;
 }