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>

1 files changed, 10 insertions, 12 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 6b085cf27a65..12e882ef596b 100644
--- 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;
 }