Commit dc2a27e5 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

neighbour: Update pneigh_entry in pneigh_create(). 



neigh_add() updates pneigh_entry() found or created by pneigh_create().

This update is serialised by RTNL, but we will remove it.

Let's move the update part to pneigh_create() and make it return errno
instead of a pointer of pneigh_entry.

Now, the pneigh code is RTNL free.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-16-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 13a936bb

include/net/neighbour.h

+3 −2
Original line number Diff line number Diff line
@@ -382,8 +382,9 @@ void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p, 
		    struct sk_buff *skb);

struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,

				   const void *key, struct net_device *dev);

struct pneigh_entry *pneigh_create(struct neigh_table *tbl, struct net *net,

				   const void *key, struct net_device *dev);

int pneigh_create(struct neigh_table *tbl, struct net *net, const void *key,

		  struct net_device *dev, u32 flags, u8 protocol,

		  bool permanent);

int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,

		  struct net_device *dev);

net/core/neighbour.c

+16 −18
Original line number Diff line number Diff line
@@ -747,24 +747,27 @@ struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, 
}

EXPORT_IPV6_MOD(pneigh_lookup);



struct pneigh_entry *pneigh_create(struct neigh_table *tbl,

				   struct net *net, const void *pkey,

				   struct net_device *dev)

int pneigh_create(struct neigh_table *tbl, struct net *net,

		  const void *pkey, struct net_device *dev,

		  u32 flags, u8 protocol, bool permanent)

{

	struct pneigh_entry *n;

	unsigned int key_len;

	u32 hash_val;

	int err = 0;



	mutex_lock(&tbl->phash_lock);



	n = pneigh_lookup(tbl, net, pkey, dev);

	if (n)

		goto out;

		goto update;



	key_len = tbl->key_len;

	n = kzalloc(sizeof(*n) + key_len, GFP_KERNEL);

	if (!n)

	if (!n) {

		err = -ENOBUFS;

		goto out;

	}



	write_pnet(&n->net, net);

	memcpy(n->key, pkey, key_len);
@@ -774,16 +777,20 @@ struct pneigh_entry *pneigh_create(struct neigh_table *tbl, 
	if (tbl->pconstructor && tbl->pconstructor(n)) {

		netdev_put(dev, &n->dev_tracker);

		kfree(n);

		n = NULL;

		err = -ENOBUFS;

		goto out;

	}



	hash_val = pneigh_hash(pkey, key_len);

	n->next = tbl->phash_buckets[hash_val];

	rcu_assign_pointer(tbl->phash_buckets[hash_val], n);

update:

	WRITE_ONCE(n->flags, flags);

	n->permanent = permanent;

	WRITE_ONCE(n->protocol, protocol);

out:

	mutex_unlock(&tbl->phash_lock);

	return n;

	return err;

}



static void pneigh_destroy(struct rcu_head *rcu)
@@ -2015,22 +2022,13 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (tb[NDA_PROTOCOL])

		protocol = nla_get_u8(tb[NDA_PROTOCOL]);

	if (ndm_flags & NTF_PROXY) {

		struct pneigh_entry *pn;



		if (ndm_flags & (NTF_MANAGED | NTF_EXT_VALIDATED)) {

			NL_SET_ERR_MSG(extack, "Invalid NTF_* flag combination");

			goto out;

		}



		err = -ENOBUFS;

		pn = pneigh_create(tbl, net, dst, dev);

		if (pn) {

			WRITE_ONCE(pn->flags, ndm_flags);

			pn->permanent = !!(ndm->ndm_state & NUD_PERMANENT);

			if (protocol)

				WRITE_ONCE(pn->protocol, protocol);

			err = 0;

		}

		err = pneigh_create(tbl, net, dst, dev, ndm_flags, protocol,

				    !!(ndm->ndm_state & NUD_PERMANENT));

		goto out;

	}

net/ipv4/arp.c

+1 −3
Original line number Diff line number Diff line
@@ -1089,9 +1089,7 @@ static int arp_req_set_public(struct net *net, struct arpreq *r, 
	if (mask) {

		__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;



		if (!pneigh_create(&arp_tbl, net, &ip, dev))

			return -ENOBUFS;

		return 0;

		return pneigh_create(&arp_tbl, net, &ip, dev, 0, 0, false);

	}



	return arp_req_set_proxy(net, dev, 1);