Commit 3dfe0b57 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

neighbour: Allocate skb in neigh_get(). 



We will remove RTNL for neigh_get() and run it under RCU instead.

neigh_get_reply() and pneigh_get_reply() allocate skb with GFP_KERNEL.

Let's move the allocation before __dev_get_by_index() in neigh_get().

Now, neigh_get_reply() and pneigh_get_reply() are inlined and
rtnl_unicast() is factorised.

We will convert pneigh_lookup() to __pneigh_lookup() later.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-4-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f5046fbc

net/core/neighbour.c

+32 −56
Original line number Diff line number Diff line
@@ -2988,27 +2988,6 @@ static inline size_t neigh_nlmsg_size(void) 
	       + nla_total_size(1); /* NDA_PROTOCOL */

}



static int neigh_get_reply(struct net *net, struct neighbour *neigh,

			   u32 pid, u32 seq)

{

	struct sk_buff *skb;

	int err = 0;



	skb = nlmsg_new(neigh_nlmsg_size(), GFP_KERNEL);

	if (!skb)

		return -ENOBUFS;



	err = neigh_fill_info(skb, neigh, pid, seq, RTM_NEWNEIGH, 0);

	if (err) {

		kfree_skb(skb);

		goto errout;

	}



	err = rtnl_unicast(skb, net, pid);

errout:

	return err;

}



static inline size_t pneigh_nlmsg_size(void)

{

	return NLMSG_ALIGN(sizeof(struct ndmsg))
@@ -3017,34 +2996,16 @@ static inline size_t pneigh_nlmsg_size(void) 
	       + nla_total_size(1); /* NDA_PROTOCOL */

}



static int pneigh_get_reply(struct net *net, struct pneigh_entry *neigh,

			    u32 pid, u32 seq, struct neigh_table *tbl)

{

	struct sk_buff *skb;

	int err = 0;



	skb = nlmsg_new(pneigh_nlmsg_size(), GFP_KERNEL);

	if (!skb)

		return -ENOBUFS;



	err = pneigh_fill_info(skb, neigh, pid, seq, RTM_NEWNEIGH, 0, tbl);

	if (err) {

		kfree_skb(skb);

		goto errout;

	}



	err = rtnl_unicast(skb, net, pid);

errout:

	return err;

}



static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,

		     struct netlink_ext_ack *extack)

{

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

	u32 pid = NETLINK_CB(in_skb).portid;

	struct net_device *dev = NULL;

	struct neigh_table *tbl = NULL;

	u32 seq = nlh->nlmsg_seq;

	struct neighbour *neigh;

	struct sk_buff *skb;

	struct ndmsg *ndm;

	void *dst = NULL;

	int err;
@@ -3053,11 +3014,19 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	if (IS_ERR(ndm))

		return PTR_ERR(ndm);



	if (ndm->ndm_flags & NTF_PROXY)

		skb = nlmsg_new(neigh_nlmsg_size(), GFP_KERNEL);

	else

		skb = nlmsg_new(pneigh_nlmsg_size(), GFP_KERNEL);

	if (!skb)

		return -ENOBUFS;



	if (ndm->ndm_ifindex) {

		dev = __dev_get_by_index(net, ndm->ndm_ifindex);

		if (!dev) {

			NL_SET_ERR_MSG(extack, "Unknown device ifindex");

			return -ENODEV;

			err = -ENODEV;

			goto err_free_skb;

		}

	}
@@ -3067,23 +3036,30 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
		pn = pneigh_lookup(tbl, net, dst, dev, 0);

		if (!pn) {

			NL_SET_ERR_MSG(extack, "Proxy neighbour entry not found");

			return -ENOENT;

		}

		return pneigh_get_reply(net, pn, NETLINK_CB(in_skb).portid,

					nlh->nlmsg_seq, tbl);

			err = -ENOENT;

			goto err_free_skb;

		}



		err = pneigh_fill_info(skb, pn, pid, seq, RTM_NEWNEIGH, 0, tbl);

		if (err)

			goto err_free_skb;

	} else {

		neigh = neigh_lookup(tbl, dst, dev);

		if (!neigh) {

			NL_SET_ERR_MSG(extack, "Neighbour entry not found");

		return -ENOENT;

			err = -ENOENT;

			goto err_free_skb;

		}



	err = neigh_get_reply(net, neigh, NETLINK_CB(in_skb).portid,

			      nlh->nlmsg_seq);



		err = neigh_fill_info(skb, neigh, pid, seq, RTM_NEWNEIGH, 0);

		neigh_release(neigh);

		if (err)

			goto err_free_skb;

	}



	return rtnl_unicast(skb, net, pid);

err_free_skb:

	kfree_skb(skb);

	return err;

}