Commit a01a67ab authored by Gilad Naaman's avatar Gilad Naaman Committed by Jakub Kicinski
Browse files

neighbour: Remove bare neighbour::next pointer 



Remove the now-unused neighbour::next pointer, leaving struct neighbour
solely with the hlist_node implementation.

Signed-off-by: default avatarGilad Naaman <gnaaman@drivenets.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241107160444.2913124-6-gnaaman@drivenets.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 0e3bcb0f

include/net/neighbour.h

+1 −3
Original line number Diff line number Diff line
@@ -135,7 +135,6 @@ struct neigh_statistics { 
#define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)



struct neighbour {

	struct neighbour __rcu	*next;

	struct hlist_node	hash;

	struct neigh_table	*tbl;

	struct neigh_parms	*parms;
@@ -191,7 +190,6 @@ struct pneigh_entry { 
#define NEIGH_NUM_HASH_RND	4



struct neigh_hash_table {

	struct neighbour __rcu	**hash_buckets;

	struct hlist_head	*hash_heads;

	unsigned int		hash_shift;

	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
@@ -354,7 +352,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb, 
int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,

		 u32 nlmsg_pid);

void __neigh_set_probe_once(struct neighbour *neigh);

bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);

bool neigh_remove_one(struct neighbour *ndel);

void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);

int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);

int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);

net/core/neighbour.c

+10 −80
Original line number Diff line number Diff line
@@ -204,18 +204,12 @@ static void neigh_update_flags(struct neighbour *neigh, u32 flags, int *notify, 
	}

}



static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np,

		      struct neigh_table *tbl)

bool neigh_remove_one(struct neighbour *n)

{

	bool retval = false;



	write_lock(&n->lock);

	if (refcount_read(&n->refcnt) == 1) {

		struct neighbour *neigh;



		neigh = rcu_dereference_protected(n->next,

						  lockdep_is_held(&tbl->lock));

		rcu_assign_pointer(*np, neigh);

		hlist_del_rcu(&n->hash);

		neigh_mark_dead(n);

		retval = true;
@@ -226,29 +220,6 @@ static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np, 
	return retval;

}



bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl)

{

	struct neigh_hash_table *nht;

	void *pkey = ndel->primary_key;

	u32 hash_val;

	struct neighbour *n;

	struct neighbour __rcu **np;



	nht = rcu_dereference_protected(tbl->nht,

					lockdep_is_held(&tbl->lock));

	hash_val = tbl->hash(pkey, ndel->dev, nht->hash_rnd);

	hash_val = hash_val >> (32 - nht->hash_shift);



	np = &nht->hash_buckets[hash_val];

	while ((n = rcu_dereference_protected(*np,

					      lockdep_is_held(&tbl->lock)))) {

		if (n == ndel)

			return neigh_del(n, np, tbl);

		np = &n->next;

	}

	return false;

}



static int neigh_forced_gc(struct neigh_table *tbl)

{

	int max_clean = atomic_read(&tbl->gc_entries) -
@@ -276,7 +247,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) 
				remove = true;

			write_unlock(&n->lock);



			if (remove && neigh_remove_one(n, tbl))

			if (remove && neigh_remove_one(n))

				shrunk++;

			if (shrunk >= max_clean)

				break;
@@ -387,22 +358,15 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev, 
					lockdep_is_held(&tbl->lock));



	for (i = 0; i < (1 << nht->hash_shift); i++) {

		struct neighbour __rcu **np = &nht->hash_buckets[i];

		struct hlist_node *tmp;

		struct neighbour *n;



		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {

			if (dev && n->dev != dev) {

				np = &n->next;

			if (dev && n->dev != dev)

				continue;

			}

			if (skip_perm && n->nud_state & NUD_PERMANENT) {

				np = &n->next;

			if (skip_perm && n->nud_state & NUD_PERMANENT)

				continue;

			}

			rcu_assign_pointer(*np,

				   rcu_dereference_protected(n->next,

						lockdep_is_held(&tbl->lock)));



			hlist_del_rcu(&n->hash);

			write_lock(&n->lock);

			neigh_del_timer(n);
@@ -531,9 +495,7 @@ static void neigh_get_hash_rnd(u32 *x) 


static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)

{

	size_t hash_heads_size = (1 << shift) * sizeof(struct hlist_head);

	size_t size = (1 << shift) * sizeof(struct neighbour *);

	struct neighbour __rcu **buckets;

	size_t size = (1 << shift) * sizeof(struct hlist_head);

	struct hlist_head *hash_heads;

	struct neigh_hash_table *ret;

	int i;
@@ -542,18 +504,11 @@ static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift) 
	if (!ret)

		return NULL;



	buckets = kvzalloc(size, GFP_ATOMIC);

	if (!buckets) {

		kfree(ret);

		return NULL;

	}

	hash_heads = kvzalloc(hash_heads_size, GFP_ATOMIC);

	hash_heads = kvzalloc(size, GFP_ATOMIC);

	if (!hash_heads) {

		kvfree(buckets);

		kfree(ret);

		return NULL;

	}

	ret->hash_buckets = buckets;

	ret->hash_heads = hash_heads;

	ret->hash_shift = shift;

	for (i = 0; i < NEIGH_NUM_HASH_RND; i++)
@@ -567,7 +522,6 @@ static void neigh_hash_free_rcu(struct rcu_head *head) 
						    struct neigh_hash_table,

						    rcu);



	kvfree(nht->hash_buckets);

	kvfree(nht->hash_heads);

	kfree(nht);

}
@@ -596,11 +550,6 @@ static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl, 


			hash >>= (32 - new_nht->hash_shift);



			rcu_assign_pointer(n->next,

					   rcu_dereference_protected(

						new_nht->hash_buckets[hash],

						lockdep_is_held(&tbl->lock)));

			rcu_assign_pointer(new_nht->hash_buckets[hash], n);

			hlist_del_rcu(&n->hash);

			hlist_add_head_rcu(&n->hash, &new_nht->hash_heads[hash]);

		}
@@ -705,10 +654,6 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey, 
		list_add_tail(&n->managed_list, &n->tbl->managed_list);

	if (want_ref)

		neigh_hold(n);

	rcu_assign_pointer(n->next,

			   rcu_dereference_protected(nht->hash_buckets[hash_val],

						     lockdep_is_held(&tbl->lock)));

	rcu_assign_pointer(nht->hash_buckets[hash_val], n);

	hlist_add_head_rcu(&n->hash, &nht->hash_heads[hash_val]);

	write_unlock_bh(&tbl->lock);

	neigh_dbg(2, "neigh %p is created\n", n);
@@ -942,7 +887,6 @@ static void neigh_periodic_work(struct work_struct *work) 
{

	struct neigh_table *tbl = container_of(work, struct neigh_table, gc_work.work);

	struct neigh_hash_table *nht;

	struct neighbour __rcu **np;

	struct hlist_node *tmp;

	struct neighbour *n;

	unsigned int i;
@@ -970,8 +914,6 @@ static void neigh_periodic_work(struct work_struct *work) 
		goto out;



	for (i = 0 ; i < (1 << nht->hash_shift); i++) {

		np = &nht->hash_buckets[i];



		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {

			unsigned int state;
@@ -981,7 +923,7 @@ static void neigh_periodic_work(struct work_struct *work) 
			if ((state & (NUD_PERMANENT | NUD_IN_TIMER)) ||

			    (n->flags & NTF_EXT_LEARNED)) {

				write_unlock(&n->lock);

				goto next_elt;

				continue;

			}



			if (time_before(n->used, n->confirmed) &&
@@ -992,9 +934,6 @@ static void neigh_periodic_work(struct work_struct *work) 
			    (state == NUD_FAILED ||

			     !time_in_range_open(jiffies, n->used,

						 n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) {

				rcu_assign_pointer(*np,

					rcu_dereference_protected(n->next,

						lockdep_is_held(&tbl->lock)));

				hlist_del_rcu(&n->hash);

				neigh_mark_dead(n);

				write_unlock(&n->lock);
@@ -1002,9 +941,6 @@ static void neigh_periodic_work(struct work_struct *work) 
				continue;

			}

			write_unlock(&n->lock);



next_elt:

			np = &n->next;

		}

		/*

		 * It's fine to release lock here, even if hash table
@@ -1951,7 +1887,7 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh, 
			     NETLINK_CB(skb).portid, extack);

	write_lock_bh(&tbl->lock);

	neigh_release(neigh);

	neigh_remove_one(neigh, tbl);

	neigh_remove_one(neigh);

	write_unlock_bh(&tbl->lock);



out:
@@ -3108,24 +3044,18 @@ void __neigh_for_each_release(struct neigh_table *tbl, 
	nht = rcu_dereference_protected(tbl->nht,

					lockdep_is_held(&tbl->lock));

	for (chain = 0; chain < (1 << nht->hash_shift); chain++) {

		struct neighbour __rcu **np;

		struct hlist_node *tmp;

		struct neighbour *n;



		np = &nht->hash_buckets[chain];

		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[chain]) {

			int release;



			write_lock(&n->lock);

			release = cb(n);

			if (release) {

				rcu_assign_pointer(*np,

					rcu_dereference_protected(n->next,

						lockdep_is_held(&tbl->lock)));

				hlist_del_rcu(&n->hash);

				neigh_mark_dead(n);

			} else

				np = &n->next;

			}

			write_unlock(&n->lock);

			if (release)

				neigh_cleanup_and_release(n);

net/ipv4/arp.c

+1 −1
Original line number Diff line number Diff line
@@ -1215,7 +1215,7 @@ int arp_invalidate(struct net_device *dev, __be32 ip, bool force) 
					   NEIGH_UPDATE_F_ADMIN, 0);

		write_lock_bh(&tbl->lock);

		neigh_release(neigh);

		neigh_remove_one(neigh, tbl);

		neigh_remove_one(neigh);

		write_unlock_bh(&tbl->lock);

	}