Re: [patch net-next v2 1/2] rtnetlink: allow to register ops without ops->setup set
From: Eric W. Biederman <hidden>
Date: 2014-06-25 17:20:14
Jiri Pirko [off-list ref] writes:
So far, it is assumed that ops->setup is filled up. But there might be case that ops might make sense even without ->setup. In that case, forbid to newlink and dellink. This allows to register simple rtnl link ops containing only ->kind. That allows consistent way of passing device kind (either device-kind or slave-kind) to userspace. Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Nacked-by: "Eric W. Biederman" [off-list ref] This is absolutely unmaintainable. You can't even write the patch correctly when specific problems are pointed out I can't imagine anyone else will be able to cope. As it happens default_device_exit_batch is more broken with this version of your patch.
quoted hunk ↗ jump to hunk
--- v1->v2: included comments from Eric fixing default_device_exit_batch, not checking setup in dellink and added hopefully clearer description and comment. net/core/rtnetlink.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 1063996..27acaf7 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c@@ -299,7 +299,12 @@ int __rtnl_link_register(struct rtnl_link_ops *ops) if (rtnl_link_ops_get(ops->kind)) return -EEXIST; - if (!ops->dellink) + /* The check for setup is here because if ops + * does not have that filled up, it is not possible + * to use the ops for creating device. So do not + * fill up dellink as well. That disables rtnl_dellink. + */ + if (ops->setup && !ops->dellink) ops->dellink = unregister_netdevice_queue; list_add_tail(&ops->list, &link_ops);@@ -1777,7 +1782,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh) return -ENODEV; ops = dev->rtnl_link_ops; - if (!ops) + if (!ops || !ops->dellink) return -EOPNOTSUPP; ops->dellink(dev, &list_kill);@@ -2038,6 +2043,9 @@ replay: return -EOPNOTSUPP; } + if (!ops->setup) + return -EOPNOTSUPP; + if (!ifname[0]) snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);