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Commit dd354208 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'rtnetlink-avoid-a-warning-in-rtnl_newlink' 



Jakub Kicinski says:

====================
rtnetlink: avoid a warning in rtnl_newlink()

I've been hoping for some time that someone more competent would fix
the stack frame size warning in rtnl_newlink(), but looks like I'll
have to take a stab at it myself :)  That's the only warning I see
in most of my builds.

First patch refactors away a somewhat surprising if (1) code block.
Reindentation will most likely cause cherry-pick problems but OTOH
rtnl_newlink() doesn't seem to be changed often, so perhaps we can
risk it in the name of cleaner code?

Second patch fixes the warning in simplest possible way.  I was
pondering if there is any more clever solution, but I can't see it..
rtnl_newlink() is quite long with a lot of possible execution paths
so doing memory allocations half way through leads to very ugly
results.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 74315c39 a2939745

net/core/rtnetlink.c

+170 −161
Original line number Diff line number Diff line
@@ -2971,20 +2971,24 @@ static int rtnl_group_changelink(const struct sk_buff *skb, 
	return 0;

}



static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			struct netlink_ext_ack *extack)

static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			  struct nlattr **attr, struct netlink_ext_ack *extack)

{

	struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];

	unsigned char name_assign_type = NET_NAME_USER;

	struct nlattr *linkinfo[IFLA_INFO_MAX + 1];

	const struct rtnl_link_ops *m_ops = NULL;

	struct net_device *master_dev = NULL;

	struct net *net = sock_net(skb->sk);

	const struct rtnl_link_ops *ops;

	const struct rtnl_link_ops *m_ops = NULL;

	struct nlattr *tb[IFLA_MAX + 1];

	struct net *dest_net, *link_net;

	struct nlattr **slave_data;

	char kind[MODULE_NAME_LEN];

	struct net_device *dev;

	struct net_device *master_dev = NULL;

	struct ifinfomsg *ifm;

	char kind[MODULE_NAME_LEN];

	char ifname[IFNAMSIZ];

	struct nlattr *tb[IFLA_MAX+1];

	struct nlattr *linkinfo[IFLA_INFO_MAX+1];

	unsigned char name_assign_type = NET_NAME_USER;

	struct nlattr **data;

	int err;



#ifdef CONFIG_MODULES
@@ -3040,13 +3044,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
		ops = NULL;

	}



	if (1) {

		struct nlattr *attr[RTNL_MAX_TYPE + 1];

		struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];

		struct nlattr **data = NULL;

		struct nlattr **slave_data = NULL;

		struct net *dest_net, *link_net = NULL;



	data = NULL;

	if (ops) {

		if (ops->maxtype > RTNL_MAX_TYPE)

			return -EINVAL;
@@ -3066,17 +3064,16 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
		}

	}



	slave_data = NULL;

	if (m_ops) {

		if (m_ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE)

			return -EINVAL;



		if (m_ops->slave_maxtype &&

		    linkinfo[IFLA_INFO_SLAVE_DATA]) {

				err = nla_parse_nested(slave_attr,

						       m_ops->slave_maxtype,

			err = nla_parse_nested(slave_attr, m_ops->slave_maxtype,

					       linkinfo[IFLA_INFO_SLAVE_DATA],

						       m_ops->slave_policy,

						       extack);

					       m_ops->slave_policy, extack);

			if (err < 0)

				return err;

			slave_data = slave_attr;
@@ -3106,16 +3103,14 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
			if (!m_ops || !m_ops->slave_changelink)

				return -EOPNOTSUPP;



				err = m_ops->slave_changelink(master_dev, dev,

							      tb, slave_data,

							      extack);

			err = m_ops->slave_changelink(master_dev, dev, tb,

						      slave_data, extack);

			if (err < 0)

				return err;

			status |= DO_SETLINK_NOTIFY;

		}



			return do_setlink(skb, dev, ifm, extack, tb, ifname,

					  status);

		return do_setlink(skb, dev, ifm, extack, tb, ifname, status);

	}



	if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
@@ -3168,6 +3163,8 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
		err = -EPERM;

		if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN))

			goto out;

	} else {

		link_net = NULL;

	}



	dev = rtnl_create_link(link_net ? : dest_net, ifname,
@@ -3180,8 +3177,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
	dev->ifindex = ifm->ifi_index;



	if (ops->newlink) {

			err = ops->newlink(link_net ? : net, dev, tb, data,

					   extack);

		err = ops->newlink(link_net ? : net, dev, tb, data, extack);

		/* Drivers should call free_netdev() in ->destructor

		 * and unregister it on failure after registration

		 * so that device could be finally freed in rtnl_unlock.
@@ -3208,8 +3204,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
			goto out_unregister;

	}

	if (tb[IFLA_MASTER]) {

			err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]),

					    extack);

		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);

		if (err)

			goto out_unregister;

	}
@@ -3229,6 +3224,20 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
	}

	goto out;

}



static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			struct netlink_ext_ack *extack)

{

	struct nlattr **attr;

	int ret;



	attr = kmalloc_array(RTNL_MAX_TYPE + 1, sizeof(*attr), GFP_KERNEL);

	if (!attr)

		return -ENOMEM;



	ret = __rtnl_newlink(skb, nlh, attr, extack);

	kfree(attr);

	return ret;

}



static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,