[PATCH RFC nf-next 08/12] netfilter: ipset: replace internal hash table with rhashtable

[Florian Westphal <fw@strlen.de>]

Not yet ready, too many tests in ipset fail with this,
its possible those are false-positives.

 - existing ip_set_init_comment() alters set->ext_size, I don't
   see how region locking protects this.
   This adds full set->lock serialization, meaning no parallel
   insertion for elements with comment extension.
 - FORCEADD is removed to reduce diff size, its added back later
   in the series.

Sending this early to gather more feedback.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/ipset/ip_set_hash_gen.h | 1252 +++++--------------------
 1 file changed, 259 insertions(+), 993 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 8f5f15fdf61b..e4d26f064c48 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -5,7 +5,6 @@
 #define _IP_SET_HASH_GEN_H
 
 #include <linux/rcupdate.h>
-#include <linux/rcupdate_wait.h>
 #include <linux/jhash.h>
 #include <linux/types.h>
 #include <linux/rhashtable.h>
@@ -17,84 +16,15 @@
 #define ipset_dereference_nfnl(p)	\
 	rcu_dereference_protected(p,	\
 		lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET))
-#define ipset_dereference_set(p, set) 	\
-	rcu_dereference_protected(p,	\
-		lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET) || \
-		lockdep_is_held(&(set)->lock))
 #define ipset_dereference_bh_nfnl(p)	\
 	rcu_dereference_bh_check(p, 	\
 		lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET))
 
-/* Hashing which uses arrays to resolve clashing. The hash table is resized
- * (doubled) when searching becomes too long.
- * Internally jhash is used with the assumption that the size of the
- * stored data is a multiple of sizeof(u32).
- *
- * Readers and resizing
- *
- * Resizing can be triggered by userspace command only, and those
- * are serialized by the nfnl mutex. During resizing the set is
- * read-locked, so the only possible concurrent operations are
- * the kernel side readers. Those must be protected by proper RCU locking.
- */
-
-/* Number of elements to store in an initial array block */
-#define AHASH_INIT_SIZE			2
-/* Max number of elements to store in an array block */
-#define AHASH_MAX_SIZE			(6 * AHASH_INIT_SIZE)
-/* Max muber of elements in the array block when tuned */
-#define AHASH_MAX_TUNED			64
-#define AHASH_MAX(h)			((h)->bucketsize)
-
-/* A hash bucket */
-struct hbucket {
-	struct rcu_head rcu;	/* for call_rcu */
-	/* Which positions are used in the array */
-	DECLARE_BITMAP(used, AHASH_MAX_TUNED);
-	u8 size;		/* size of the array */
-	u8 pos;			/* position of the first free entry */
-	unsigned char value[]	/* the array of the values */
-		__aligned(__alignof__(u64));
-};
-
-/* Region size for locking == 2^HTABLE_REGION_BITS */
-#define HTABLE_REGION_BITS	10
-#define ahash_numof_locks(htable_bits)		\
-	((htable_bits) < HTABLE_REGION_BITS ? 1	\
-		: jhash_size((htable_bits) - HTABLE_REGION_BITS))
-#define ahash_sizeof_regions(htable_bits)		\
-	(ahash_numof_locks(htable_bits) * sizeof(struct ip_set_region))
-#define ahash_region(n)		\
-	((n) / jhash_size(HTABLE_REGION_BITS))
-#define ahash_bucket_start(h,  htable_bits)	\
-	((htable_bits) < HTABLE_REGION_BITS ? 0	\
-		: (h) * jhash_size(HTABLE_REGION_BITS))
-#define ahash_bucket_end(h,  htable_bits)	\
-	((htable_bits) < HTABLE_REGION_BITS ? jhash_size(htable_bits)	\
-		: ((h) + 1) * jhash_size(HTABLE_REGION_BITS))
-
 struct htable_gc {
 	struct delayed_work dwork;
 	struct ip_set *set;	/* Set the gc belongs to */
-	spinlock_t lock;	/* Lock to exclude gc and resize */
-	u32 region;		/* Last gc run position */
-};
-
-/* The hash table: the table size stored here in order to make resizing easy */
-struct htable {
-	bool resizing;		/* Mark ongoing resize */
-	atomic_t uref;		/* References for dumping and gc */
-	u8 htable_bits;		/* size of hash table == 2^htable_bits */
-	u32 maxelem;		/* Maxelem per region */
-	struct list_head ad;	/* Resize add|del backlist */
-	struct ip_set_region *hregion;	/* Region locks and ext sizes */
-	struct hbucket __rcu *bucket[]; /* hashtable buckets */
 };
 
-#define hbucket(h, i)		((h)->bucket[i])
-#define ext_size(n, dsize)	\
-	(sizeof(struct hbucket) + (n) * (dsize))
-
 #ifndef IPSET_NET_COUNT
 #define IPSET_NET_COUNT		1
 #endif
@@ -112,23 +42,6 @@ struct net_prefixes {
 		__aligned(__alignof__(u64));
 };
 
-/* Compute the hash table size */
-static size_t
-htable_size(u8 hbits)
-{
-	size_t hsize;
-
-	/* We must fit both into u32 in jhash and INT_MAX in kvmalloc_node() */
-	if (hbits > 31)
-		return 0;
-	hsize = jhash_size(hbits);
-	if ((INT_MAX - sizeof(struct htable)) / sizeof(struct hbucket *)
-	    < hsize)
-		return 0;
-
-	return hsize * sizeof(struct hbucket *) + sizeof(struct htable);
-}
-
 #ifdef IP_SET_HASH_WITH_NETS
 #if IPSET_NET_COUNT > 1
 #define __CIDR(cidr, i)		(cidr[i])
@@ -180,7 +93,6 @@ static const union nf_inet_addr zeromask = {};
 
 /* Family dependent templates */
 
-#undef ahash_data
 #undef mtype_data_equal
 #undef mtype_do_data_match
 #undef mtype_data_set_flags
@@ -191,8 +103,6 @@ static const union nf_inet_addr zeromask = {};
 #undef mtype_data_next
 #undef mtype_elem
 
-#undef mtype_ahash_destroy
-#undef mtype_ext_cleanup
 #undef mtype_rht_elem
 #undef mtype_rht_hashfn
 #undef mtype_rht_obj_hashfn
@@ -203,7 +113,6 @@ static const union nf_inet_addr zeromask = {};
 #undef mtype_del_cidr
 #undef mtype_del_cidr_all
 #undef mtype_flush_elem
-#undef mtype_ahash_memsize
 #undef mtype_flush
 #undef mtype_destroy
 #undef mtype_same_set
@@ -217,12 +126,9 @@ static const union nf_inet_addr zeromask = {};
 #undef mtype_test_cidrs
 #undef mtype_test
 #undef mtype_uref
-#undef mtype_resize
 #undef mtype_ext_size
-#undef mtype_resize_ad
 #undef mtype_head
 #undef mtype_list
-#undef mtype_gc_do
 #undef mtype_gc
 #undef mtype_gc_init
 #undef mtype_cancel_gc
@@ -230,7 +136,7 @@ static const union nf_inet_addr zeromask = {};
 #undef mtype_data_match
 
 #undef htype
-#undef HKEY
+#undef HKEY_DATALEN
 
 #define mtype_data_equal	IPSET_TOKEN(MTYPE, _data_equal)
 #ifdef IP_SET_HASH_WITH_NETS
@@ -246,9 +152,6 @@ static const union nf_inet_addr zeromask = {};
 #define mtype_data_next		IPSET_TOKEN(MTYPE, _data_next)
 #define mtype_elem		IPSET_TOKEN(MTYPE, _elem)
 
-#define mtype_ahash_destroy	IPSET_TOKEN(MTYPE, _ahash_destroy)
-#define mtype_ext_cleanup	IPSET_TOKEN(MTYPE, _ext_cleanup)
-
 #define mtype_rht_elem		IPSET_TOKEN(MTYPE, _rht_elem)
 #define mtype_rht_hashfn	IPSET_TOKEN(MTYPE, _rht_hashfn)
 #define mtype_rht_obj_hashfn	IPSET_TOKEN(MTYPE, _rht_obj_hashfn)
@@ -259,7 +162,6 @@ static const union nf_inet_addr zeromask = {};
 #define mtype_del_cidr		IPSET_TOKEN(MTYPE, _del_cidr)
 #define mtype_del_cidr_all	IPSET_TOKEN(MTYPE, _del_cidr_all)
 #define mtype_flush_elem	IPSET_TOKEN(MTYPE, _flush_elem)
-#define mtype_ahash_memsize	IPSET_TOKEN(MTYPE, _ahash_memsize)
 #define mtype_flush		IPSET_TOKEN(MTYPE, _flush)
 #define mtype_destroy		IPSET_TOKEN(MTYPE, _destroy)
 #define mtype_same_set		IPSET_TOKEN(MTYPE, _same_set)
@@ -273,12 +175,9 @@ static const union nf_inet_addr zeromask = {};
 #define mtype_test_cidrs	IPSET_TOKEN(MTYPE, _test_cidrs)
 #define mtype_test		IPSET_TOKEN(MTYPE, _test)
 #define mtype_uref		IPSET_TOKEN(MTYPE, _uref)
-#define mtype_resize		IPSET_TOKEN(MTYPE, _resize)
 #define mtype_ext_size		IPSET_TOKEN(MTYPE, _ext_size)
-#define mtype_resize_ad		IPSET_TOKEN(MTYPE, _resize_ad)
 #define mtype_head		IPSET_TOKEN(MTYPE, _head)
 #define mtype_list		IPSET_TOKEN(MTYPE, _list)
-#define mtype_gc_do		IPSET_TOKEN(MTYPE, _gc_do)
 #define mtype_gc		IPSET_TOKEN(MTYPE, _gc)
 #define mtype_gc_init		IPSET_TOKEN(MTYPE, _gc_init)
 #define mtype_cancel_gc		IPSET_TOKEN(MTYPE, _cancel_gc)
@@ -345,28 +244,15 @@ static const struct rhashtable_params mtype_rht_params = {
 	.automatic_shrinking = true,
 };
 
-#define HKEY(data, initval, htable_bits)			\
-({								\
-	const u32 *__k = (const u32 *)data;			\
-	u32 __l = HKEY_DATALEN / sizeof(u32);			\
-								\
-	BUILD_BUG_ON(HKEY_DATALEN % sizeof(u32) != 0);		\
-								\
-	jhash2(__k, __l, initval) & jhash_mask(htable_bits);	\
-})
-
-/* The generic hash structure */
+/* The hash set type */
 struct htype {
-	struct htable __rcu *table; /* the hash table */
 	struct rhashtable ht;	/* the hash table */
+	u32 maxelem;		/* max element limit (user-requested) */
 	struct net_prefixes __rcu *rnets[IPSET_NET_COUNT]; /* cidr prefixes */
 	struct htable_gc gc;	/* gc workqueue */
-	u32 maxelem;		/* max elements in the hash */
-	u32 initval;		/* random jhash init value */
 #ifdef IP_SET_HASH_WITH_MARKMASK
 	u32 markmask;		/* markmask value for mark mask to store */
 #endif
-	u8 bucketsize;		/* max elements in an array block */
 #if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
 	u8 netmask;		/* netmask value for subnets to store */
 	union nf_inet_addr bitmask;	/* stores bitmask */
@@ -377,16 +263,6 @@ struct htype {
 	struct mtype_elem next; /* temporary storage for uadd */
 };
 
-/* ADD|DEL entries saved during resize */
-struct mtype_resize_ad {
-	struct list_head list;
-	enum ipset_adt ad;	/* ADD|DEL element */
-	struct mtype_elem d;	/* Element value */
-	struct ip_set_ext ext;	/* Extensions for ADD */
-	struct ip_set_ext mext;	/* Target extensions for ADD */
-	u32 flags;		/* Flags for ADD */
-};
-
 #ifdef IP_SET_HASH_WITH_NETS
 /* Network cidr size book keeping when the hash stores different
  * sized networks. cidr == real cidr + 1 to support /0.
@@ -505,105 +381,34 @@ mtype_flush_elem(void *ptr, void *arg)
 	ip_set_ext_destroy(set, &e->elem);
 	kfree_rcu(e, rcu);
 }
-/* Calculate the actual memory size of the set data */
-static size_t
-mtype_ahash_memsize(const struct htype *h, const struct htable *t)
-{
-	return sizeof(*h) + sizeof(*t) + ahash_sizeof_regions(t->htable_bits);
-}
-
-/* Get the ith element from the array block n */
-#define ahash_data(n, i, dsize)	\
-	((struct mtype_elem *)((n)->value + ((i) * (dsize))))
-
-static void
-mtype_ext_cleanup(struct ip_set *set, struct hbucket *n)
-{
-	int i;
-	u8 pos = smp_load_acquire(&n->pos);
-
-	for (i = 0; i < pos; i++)
-		if (test_bit(i, n->used))
-			ip_set_ext_destroy_slow(set, ahash_data(n, i, set->dsize));
-}
 
 /* Flush a hash type of set: destroy all elements */
 static void
 mtype_flush(struct ip_set *set)
 {
 	struct htype *h = set->data;
-#ifdef IP_SET_HASH_WITH_NETS
-	struct net_prefixes *nets, *tmp;
-#endif
-	struct htable *t;
-	struct hbucket *n;
-	u32 r, i;
+	struct rhashtable_iter hti;
+	struct mtype_rht_elem *e;
 
-	rhashtable_free_and_destroy(&h->ht, mtype_flush_elem, set);
-	rhashtable_init(&h->ht, &mtype_rht_params);
-
-	t = ipset_dereference_nfnl(h->table);
-	for (r = 0; r < ahash_numof_locks(t->htable_bits); r++) {
-		spin_lock_bh(&t->hregion[r].lock);
-		for (i = ahash_bucket_start(r, t->htable_bits);
-		     i < ahash_bucket_end(r, t->htable_bits); i++) {
-			n = __ipset_dereference(hbucket(t, i));
-			if (!n)
+	rhashtable_walk_enter(&h->ht, &hti);
+	rhashtable_walk_start(&hti);
+
+	while ((e = rhashtable_walk_next(&hti))) {
+		if (IS_ERR(e)) {
+			if (PTR_ERR(e) == -EAGAIN)
 				continue;
-			if (set->extensions & IPSET_EXT_DESTROY)
-				mtype_ext_cleanup(set, n);
-			/* FIXME: use slab cache */
-			rcu_assign_pointer(hbucket(t, i), NULL);
-			kfree_rcu(n, rcu);
-		}
-		t->hregion[r].ext_size = 0;
-		t->hregion[r].elements = 0;
-		spin_unlock_bh(&t->hregion[r].lock);
-	}
-#ifdef IP_SET_HASH_WITH_NETS
-	for (i = 0; i < IPSET_NET_COUNT; i++) {
-		nets = ipset_dereference_nfnl(h->rnets[i]);
-		tmp = kzalloc(sizeof(struct net_prefixes), GFP_ATOMIC);
-		if (!tmp) {
-			u8 j;
-
-			for (j = 0; j < nets->len; j++)
-				nets->nets[j].count = 0;
-		} else {
-			rcu_assign_pointer(h->rnets[i], tmp);
-			kfree_rcu(nets, rcu);
+			break;
 		}
-	}
-#endif
-}
 
-/* Destroy the hashtable part of the set */
-static void
-mtype_ahash_destroy(struct ip_set *set, struct htable *t, bool ext_destroy)
-{
-#ifdef IP_SET_HASH_WITH_NETS
-	struct htype *h = set->data;
-#endif
-	struct hbucket *n;
-	u32 i;
+		if (rhashtable_remove_fast(&h->ht, &e->node, mtype_rht_params))
+			continue; /* Concurrent delete? skip */
 
-	for (i = 0; i < jhash_size(t->htable_bits); i++) {
-		n = (__force struct hbucket *)hbucket(t, i);
-		if (!n)
-			continue;
-		if (set->extensions & IPSET_EXT_DESTROY && ext_destroy)
-			mtype_ext_cleanup(set, n);
-		/* FIXME: use slab cache */
-		kfree(n);
+		mtype_del_cidr_all(set, h, &e->elem);
+		ip_set_ext_destroy_slow(set, &e->elem);
+		kfree_rcu(e, rcu);
 	}
-
-#ifdef IP_SET_HASH_WITH_NETS
-	if (ext_destroy)
-		for (i = 0; i < IPSET_NET_COUNT; i++)
-			kfree(h->rnets[i]);
-#endif
-	ip_set_free(t->hregion);
-	ip_set_free(t);
+	rhashtable_walk_stop(&hti);
+	rhashtable_walk_exit(&hti);
 }
 
 /* Destroy a hash type of set */
@@ -611,16 +416,16 @@ static void
 mtype_destroy(struct ip_set *set)
 {
 	struct htype *h = set->data;
-	struct htable *t = (__force struct htable *)h->table;
-	struct list_head *l, *lt;
+#ifdef IP_SET_HASH_WITH_NETS
+	u32 i;
+#endif
 
 	rhashtable_free_and_destroy(&h->ht, mtype_flush_elem, set);
 
-	list_for_each_safe(l, lt, &t->ad) {
-		list_del(l);
-		kfree(l);
-	}
-	mtype_ahash_destroy(set, t, true);
+#ifdef IP_SET_HASH_WITH_NETS
+	for (i = 0; i < IPSET_NET_COUNT; i++)
+		kfree(h->rnets[i]);
+#endif
 	kfree(h);
 
 	set->data = NULL;
@@ -632,7 +437,6 @@ mtype_same_set(const struct ip_set *a, const struct ip_set *b)
 	const struct htype *x = a->data;
 	const struct htype *y = b->data;
 
-	/* Resizing changes htable_bits, so we ignore it */
 	return x->maxelem == y->maxelem &&
 	       a->timeout == b->timeout &&
 #if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
@@ -644,111 +448,45 @@ mtype_same_set(const struct ip_set *a, const struct ip_set *b)
 	       a->extensions == b->extensions;
 }
 
-static void
-mtype_gc_do(struct ip_set *set, struct htype *h, struct htable *t, u32 r)
-{
-	struct hbucket *n, *tmp;
-	struct mtype_elem *data;
-	u32 i, j, d;
-	size_t dsize = set->dsize;
-	u8 pos, htable_bits = t->htable_bits;
-
-	spin_lock_bh(&t->hregion[r].lock);
-	for (i = ahash_bucket_start(r, htable_bits);
-	     i < ahash_bucket_end(r, htable_bits); i++) {
-		n = __ipset_dereference(hbucket(t, i));
-		if (!n)
-			continue;
-		pos = smp_load_acquire(&n->pos);
-		for (j = 0, d = 0; j < pos; j++) {
-			if (!test_bit(j, n->used)) {
-				d++;
-				continue;
-			}
-			data = ahash_data(n, j, dsize);
-			if (!ip_set_timeout_expired(ext_timeout(data, set)))
-				continue;
-			pr_debug("expired %u/%u\n", i, j);
-			clear_bit(j, n->used);
-			smp_mb__after_atomic();
-			mtype_del_cidr_all(set, h, data);
-			t->hregion[r].elements--;
-			ip_set_ext_destroy_slow(set, data);
-			d++;
-		}
-		if (d >= AHASH_INIT_SIZE) {
-			if (d >= n->size) {
-				t->hregion[r].ext_size -=
-					ext_size(n->size, dsize);
-				rcu_assign_pointer(hbucket(t, i), NULL);
-				kfree_rcu(n, rcu);
-				continue;
-			}
-			tmp = kzalloc(sizeof(*tmp) +
-				(n->size - AHASH_INIT_SIZE) * dsize,
-				GFP_ATOMIC);
-			if (!tmp)
-				/* Still try to delete expired elements. */
-				continue;
-			tmp->size = n->size - AHASH_INIT_SIZE;
-			for (j = 0, d = 0; j < pos; j++) {
-				if (!test_bit(j, n->used))
-					continue;
-				data = ahash_data(n, j, dsize);
-				memcpy(tmp->value + d * dsize,
-				       data, dsize);
-				set_bit(d, tmp->used);
-				d++;
-			}
-			tmp->pos = d;
-			t->hregion[r].ext_size -=
-				ext_size(AHASH_INIT_SIZE, dsize);
-			rcu_assign_pointer(hbucket(t, i), tmp);
-			kfree_rcu(n, rcu);
-		}
-	}
-	spin_unlock_bh(&t->hregion[r].lock);
-}
-
 static void
 mtype_gc(struct work_struct *work)
 {
 	struct htable_gc *gc;
 	struct ip_set *set;
 	struct htype *h;
-	struct htable *t;
-	u32 r, numof_locks;
+	struct rhashtable_iter hti;
+	struct mtype_rht_elem *e;
 	unsigned int next_run;
 
 	gc = container_of(work, struct htable_gc, dwork.work);
 	set = gc->set;
 	h = set->data;
 
-	rcu_read_lock_bh();
-	t = rcu_dereference_bh(h->table);
-	atomic_inc(&t->uref);
-	rcu_read_unlock_bh();
-	numof_locks = ahash_numof_locks(t->htable_bits);
-	r = gc->region++;
-	if (r >= numof_locks) {
-		r = gc->region = 0;
-	}
-	next_run = (IPSET_GC_PERIOD(set->timeout) * HZ) / numof_locks;
-	if (next_run < HZ/10)
-		next_run = HZ/10;
-
-	spin_lock_bh(&gc->lock);
-	if (!t->resizing)
-		mtype_gc_do(set, h, t, r);
-	spin_unlock_bh(&gc->lock);
-
-	if (atomic_dec_and_test(&t->uref) && t->resizing) {
-		pr_debug("Table destroy after resize by expire: %p\n", t);
-		mtype_ahash_destroy(set, t, false);
+	next_run = IPSET_GC_PERIOD(set->timeout) * HZ;
+	if (next_run < HZ)
+		next_run = HZ;
+
+	rhashtable_walk_enter(&h->ht, &hti);
+	rhashtable_walk_start(&hti);
+	while ((e = rhashtable_walk_next(&hti))) {
+		if (IS_ERR(e)) {
+			if (PTR_ERR(e) == -EAGAIN)
+				continue;
+			break;
+		}
+		if (!ip_set_timeout_expired(ext_timeout(&e->elem, set)))
+			continue;
+		if (rhashtable_remove_fast(&h->ht, &e->node, mtype_rht_params))
+			continue; /* Concurrent delete? skip */
+
+		mtype_del_cidr_all(set, h, &e->elem);
+		ip_set_ext_destroy_slow(set, &e->elem);
+		kfree_rcu(e, rcu);
 	}
+	rhashtable_walk_stop(&hti);
+	rhashtable_walk_exit(&hti);
 
 	queue_delayed_work(system_power_efficient_wq, &gc->dwork, next_run);
-
 }
 
 static void
@@ -767,248 +505,15 @@ mtype_cancel_gc(struct ip_set *set)
 		disable_delayed_work_sync(&h->gc.dwork);
 }
 
-static int
-mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
-	  struct ip_set_ext *mext, u32 flags);
-static int
-mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
-	  struct ip_set_ext *mext, u32 flags);
-
-/* Resize a hash: create a new hash table with doubling the hashsize
- * and inserting the elements to it. Repeat until we succeed or
- * fail due to memory pressures.
- */
-static int
-mtype_resize(struct ip_set *set, bool retried)
-{
-	struct htype *h = set->data;
-	struct htable *t, *orig;
-	u8 pos, htable_bits;
-	size_t hsize, dsize = set->dsize;
-#ifdef IP_SET_HASH_WITH_NETS
-	u8 flags;
-	struct mtype_elem *tmp;
-#endif
-	struct mtype_elem *data;
-	struct mtype_elem *d;
-	struct hbucket *n, *m;
-	struct list_head *l, *lt;
-	struct mtype_resize_ad *x;
-	u32 i, j, r, nr, key;
-	int ret;
-
-#ifdef IP_SET_HASH_WITH_NETS
-	tmp = kmalloc(dsize, GFP_KERNEL);
-	if (!tmp)
-		return -ENOMEM;
-#endif
-	orig = ipset_dereference_bh_nfnl(h->table);
-	htable_bits = orig->htable_bits;
-
-retry:
-	ret = 0;
-	htable_bits++;
-	if (!htable_bits)
-		goto hbwarn;
-	hsize = htable_size(htable_bits);
-	if (!hsize)
-		goto hbwarn;
-	t = ip_set_alloc(hsize);
-	if (!t) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	t->hregion = ip_set_alloc(ahash_sizeof_regions(htable_bits));
-	if (!t->hregion) {
-		ip_set_free(t);
-		ret = -ENOMEM;
-		goto out;
-	}
-	t->htable_bits = htable_bits;
-	t->maxelem = h->maxelem / ahash_numof_locks(htable_bits);
-	INIT_LIST_HEAD(&t->ad);
-	for (i = 0; i < ahash_numof_locks(htable_bits); i++)
-		spin_lock_init(&t->hregion[i].lock);
-
-	/* There can't be another parallel resizing,
-	 * but dumping and kernel side add/del are possible
-	 */
-	orig = ipset_dereference_bh_nfnl(h->table);
-	atomic_inc(&orig->uref);
-	spin_lock_bh(&h->gc.lock);
-	orig->resizing = true;
-	spin_unlock_bh(&h->gc.lock);
-	pr_debug("attempt to resize set %s from %u to %u, t %p\n",
-		 set->name, orig->htable_bits, htable_bits, orig);
-	for (r = 0; r < ahash_numof_locks(orig->htable_bits); r++) {
-		/* Expire may replace a hbucket with another one */
-		rcu_read_lock_bh();
-		for (i = ahash_bucket_start(r, orig->htable_bits);
-		     i < ahash_bucket_end(r, orig->htable_bits); i++) {
-			n = __ipset_dereference(hbucket(orig, i));
-			if (!n)
-				continue;
-			pos = smp_load_acquire(&n->pos);
-			for (j = 0; j < pos; j++) {
-				if (!test_bit_acquire(j, n->used))
-					continue;
-				data = ahash_data(n, j, dsize);
-				if (SET_ELEM_EXPIRED(set, data))
-					continue;
-#ifdef IP_SET_HASH_WITH_NETS
-				/* We have readers running parallel with us,
-				 * so the live data cannot be modified.
-				 */
-				flags = 0;
-				memcpy(tmp, data, dsize);
-				data = tmp;
-				mtype_data_reset_flags(data, &flags);
-#endif
-				key = HKEY(data, h->initval, htable_bits);
-				m = __ipset_dereference(hbucket(t, key));
-				nr = ahash_region(key);
-				if (!m) {
-					m = kzalloc(sizeof(*m) +
-					    AHASH_INIT_SIZE * dsize,
-					    GFP_ATOMIC);
-					if (!m) {
-						ret = -ENOMEM;
-						goto cleanup;
-					}
-					m->size = AHASH_INIT_SIZE;
-					t->hregion[nr].ext_size +=
-						ext_size(AHASH_INIT_SIZE,
-							 dsize);
-					RCU_INIT_POINTER(hbucket(t, key), m);
-				} else if (m->pos >= m->size) {
-					struct hbucket *ht;
-
-					if (m->size >= AHASH_MAX(h)) {
-						ret = -EAGAIN;
-					} else {
-						ht = kzalloc(sizeof(*ht) +
-						(m->size + AHASH_INIT_SIZE)
-						* dsize,
-						GFP_ATOMIC);
-						if (!ht)
-							ret = -ENOMEM;
-					}
-					if (ret < 0)
-						goto cleanup;
-					memcpy(ht, m, sizeof(struct hbucket) +
-					       m->size * dsize);
-					ht->size = m->size + AHASH_INIT_SIZE;
-					t->hregion[nr].ext_size +=
-						ext_size(AHASH_INIT_SIZE,
-							 dsize);
-					kfree(m);
-					m = ht;
-					RCU_INIT_POINTER(hbucket(t, key), ht);
-				}
-				d = ahash_data(m, m->pos, dsize);
-				memcpy(d, data, dsize);
-				set_bit(m->pos++, m->used);
-				t->hregion[nr].elements++;
-#ifdef IP_SET_HASH_WITH_NETS
-				mtype_data_reset_flags(d, &flags);
-#endif
-			}
-		}
-		rcu_read_unlock_bh();
-	}
-
-	/* There can't be any other writer. */
-	rcu_assign_pointer(h->table, t);
-
-	/* Give time to other readers of the set */
-	synchronize_rcu();
-
-	pr_debug("set %s resized from %u (%p) to %u (%p)\n", set->name,
-		 orig->htable_bits, orig, t->htable_bits, t);
-	/* Add/delete elements processed by the SET target during resize.
-	 * Kernel-side add cannot trigger a resize and userspace actions
-	 * are serialized by the mutex.
-	 */
-	list_for_each_safe(l, lt, &orig->ad) {
-		x = list_entry(l, struct mtype_resize_ad, list);
-		if (x->ad == IPSET_ADD) {
-			mtype_add(set, &x->d, &x->ext, &x->mext, x->flags);
-		} else {
-			mtype_del(set, &x->d, NULL, NULL, 0);
-		}
-		list_del(l);
-		kfree(l);
-	}
-	/* If there's nobody else using the table, destroy it */
-	if (atomic_dec_and_test(&orig->uref)) {
-		pr_debug("Table destroy by resize %p\n", orig);
-		mtype_ahash_destroy(set, orig, false);
-	}
-
-out:
-#ifdef IP_SET_HASH_WITH_NETS
-	kfree(tmp);
-#endif
-	return ret;
-
-cleanup:
-	rcu_read_unlock_bh();
-	spin_lock_bh(&h->gc.lock);
-	orig->resizing = false;
-	spin_unlock_bh(&h->gc.lock);
-	/* Make sure parallel readers see that orig->resizing is false
-	 * before we decrement uref */
-	synchronize_rcu();
-	atomic_dec(&orig->uref);
-	mtype_ahash_destroy(set, t, false);
-	if (ret == -EAGAIN)
-		goto retry;
-
-	/* Cleanup the backlog of ADD/DEL elements */
-	spin_lock_bh(&set->lock);
-	list_for_each_safe(l, lt, &orig->ad) {
-		list_del(l);
-		kfree(l);
-	}
-	spin_unlock_bh(&set->lock);
-	goto out;
-
-hbwarn:
-	/* In case we have plenty of memory :-) */
-	pr_warn("Cannot increase the hashsize of set %s further\n", set->name);
-	ret = -IPSET_ERR_HASH_FULL;
-	goto out;
-}
-
-/* Get the current number of elements and ext_size in the set  */
+/* Get the current number of elements and per-element memory in the set */
 static void
 mtype_ext_size(struct ip_set *set, u32 *elements, size_t *ext_size)
 {
-	struct htype *h = set->data;
-	const struct htable *t;
-	struct hbucket *n;
-	struct mtype_elem *data;
-	u32 i, j, r;
-	u8 pos;
-
-	t = rcu_dereference_bh(h->table);
-	for (r = 0; r < ahash_numof_locks(t->htable_bits); r++) {
-		for (i = ahash_bucket_start(r, t->htable_bits);
-		     i < ahash_bucket_end(r, t->htable_bits); i++) {
-			n = rcu_dereference_bh(hbucket(t, i));
-			if (!n)
-				continue;
-			pos = smp_load_acquire(&n->pos);
-			for (j = 0; j < pos; j++) {
-				if (!test_bit_acquire(j, n->used))
-					continue;
-				data = ahash_data(n, j, set->dsize);
-				if (!SET_ELEM_EXPIRED(set, data))
-					(*elements)++;
-			}
-		}
-		*ext_size += t->hregion[r].ext_size;
-	}
+	const struct htype *h = set->data;
+
+	*elements = atomic_read(&h->ht.nelems);
+	*ext_size = *elements *
+		    (offsetof(struct mtype_rht_elem, elem) + set->dsize);
 }
 
 /* Add an element to a hash and update the internal counters when succeeded,
@@ -1019,298 +524,127 @@ mtype_add(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 	  struct ip_set_ext *mext, u32 flags)
 {
 	struct htype *h = set->data;
-	struct htable *t;
 	const struct mtype_elem *d = value;
-	struct mtype_elem *data;
-	struct hbucket *n, *old = ERR_PTR(-ENOENT);
-	int i, j = -1, ret;
+	struct mtype_rht_elem *e, *old;
 	bool flag_exist = flags & IPSET_FLAG_EXIST;
-	bool deleted = false, forceadd = false, reuse = false;
-	u32 r, key, multi = 0, elements, maxelem;
-	u8 npos = 0;
+	int ret = 0;
+#ifdef IP_SET_HASH_WITH_NETS
+	int i;
+#endif
 
+	/* Check for an existing entry with the same key */
 	rcu_read_lock_bh();
-	t = rcu_dereference_bh(h->table);
-	key = HKEY(value, h->initval, t->htable_bits);
-	r = ahash_region(key);
-	atomic_inc(&t->uref);
-	rcu_read_unlock_bh();
-	elements = t->hregion[r].elements;
-	maxelem = t->maxelem;
-	if (elements >= maxelem) {
-		u32 e;
-		if (SET_WITH_TIMEOUT(set))
-			mtype_gc_do(set, h, t, r);
-		maxelem = h->maxelem;
-		elements = 0;
-		for (e = 0; e < ahash_numof_locks(t->htable_bits); e++)
-			elements += t->hregion[e].elements;
-		if (elements >= maxelem && SET_WITH_FORCEADD(set))
-			forceadd = true;
-	}
-
-	spin_lock_bh(&t->hregion[r].lock);
-	n = rcu_dereference_bh(hbucket(t, key));
-	if (!n) {
-		if (forceadd || elements >= maxelem)
-			goto set_full;
-		old = NULL;
-		n = kzalloc(sizeof(*n) + AHASH_INIT_SIZE * set->dsize,
-			    GFP_ATOMIC);
-		if (!n) {
-			ret = -ENOMEM;
-			goto unlock;
-		}
-		n->size = AHASH_INIT_SIZE;
-		t->hregion[r].ext_size +=
-			ext_size(AHASH_INIT_SIZE, set->dsize);
-		goto copy_elem;
-	}
-	npos = smp_load_acquire(&n->pos);
-	for (i = 0; i < npos; i++) {
-		if (!test_bit(i, n->used)) {
-			/* Reuse first deleted entry */
-			if (j == -1) {
-				deleted = reuse = true;
-				j = i;
-			}
-			continue;
-		}
-		data = ahash_data(n, i, set->dsize);
-		if (mtype_data_equal(data, d, &multi)) {
-			if (flag_exist || SET_ELEM_EXPIRED(set, data)) {
-				/* Just the extensions could be overwritten */
-				j = i;
-				goto overwrite_extensions;
+	old = rhashtable_lookup(&h->ht, d, mtype_rht_params);
+	if (old) {
+		if (!SET_ELEM_EXPIRED(set, &old->elem)) {
+			if (!flag_exist) {
+				rcu_read_unlock_bh();
+				return -IPSET_ERR_EXIST;
 			}
-			ret = -IPSET_ERR_EXIST;
-			goto unlock;
-		}
-		/* Reuse first timed out entry */
-		if (SET_ELEM_EXPIRED(set, data) && j == -1) {
-			j = i;
-			reuse = true;
-		}
-	}
-	if (reuse || forceadd) {
-		if (j == -1)
-			j = 0;
-		data = ahash_data(n, j, set->dsize);
-		if (!deleted) {
-			mtype_del_cidr_all(set, h, data);
-			ip_set_ext_destroy_slow(set, data);
-			t->hregion[r].elements--;
-		}
-		goto copy_data;
-	}
-	if (elements >= maxelem)
-		goto set_full;
-	/* Create a new slot */
-	if (npos >= n->size) {
-#ifdef IP_SET_HASH_WITH_MULTI
-		if (h->bucketsize >= AHASH_MAX_TUNED)
-			goto set_full;
-		else if (h->bucketsize <= multi)
-			h->bucketsize += AHASH_INIT_SIZE;
+			/* flag_exist: overwrite extensions in-place.
+			 * Hold set->lock to serialize ext_size accounting in
+			 * ip_set_init_comment against concurrent kernel-side adds.
+			 * rcu_read_lock_bh() must remain held to keep old alive.
+			 */
+			spin_lock_bh(&set->lock);
+#ifdef IP_SET_HASH_WITH_NETS
+			mtype_data_set_flags(&old->elem, flags);
 #endif
-		if (n->size >= AHASH_MAX(h)) {
-			/* Trigger rehashing */
-			mtype_data_next(&h->next, d);
-			ret = -EAGAIN;
-			goto resize;
+			if (SET_WITH_COUNTER(set))
+				ip_set_init_counter(ext_counter(&old->elem, set),
+						    ext);
+			if (SET_WITH_COMMENT(set))
+				ip_set_init_comment(set,
+						    ext_comment(&old->elem, set),
+						    ext);
+			if (SET_WITH_SKBINFO(set))
+				ip_set_init_skbinfo(ext_skbinfo(&old->elem, set),
+						    ext);
+			if (SET_WITH_TIMEOUT(set))
+				ip_set_timeout_set(ext_timeout(&old->elem, set),
+						   ext->timeout);
+			spin_unlock_bh(&set->lock);
+			rcu_read_unlock_bh();
+			return 0;
 		}
-		old = n;
-		n = kzalloc(sizeof(*n) +
-			    (old->size + AHASH_INIT_SIZE) * set->dsize,
-			    GFP_ATOMIC);
-		if (!n) {
-			ret = -ENOMEM;
-			goto unlock;
+		/* Expired entry: remove it to make room */
+		if (rhashtable_remove_fast(&h->ht, &old->node,
+					   mtype_rht_params) == 0) {
+			mtype_del_cidr_all(set, h, &old->elem);
+			ip_set_ext_destroy_slow(set, &old->elem);
+			kfree_rcu(old, rcu);
 		}
-		memcpy(n, old, sizeof(struct hbucket) +
-		       old->size * set->dsize);
-		n->size = old->size + AHASH_INIT_SIZE;
-		t->hregion[r].ext_size +=
-			ext_size(AHASH_INIT_SIZE, set->dsize);
 	}
+	rcu_read_unlock_bh();
+
+	if (atomic_read(&h->ht.nelems) >= h->maxelem) {
+		if (net_ratelimit())
+			pr_warn("Set %s is full, maxelem %u reached\n",
+				set->name, h->maxelem);
+		mtype_data_next(&h->next, d);
+		return -IPSET_ERR_HASH_FULL;
+	}
+
+	e = kzalloc(offsetof(struct mtype_rht_elem, elem) + set->dsize,
+		    GFP_ATOMIC);
+	if (!e)
+		return -ENOMEM;
+
+	memcpy(&e->elem, d, sizeof(struct mtype_elem));
 
-copy_elem:
-	j = npos++;
-	data = ahash_data(n, j, set->dsize);
-copy_data:
-	t->hregion[r].elements++;
 #ifdef IP_SET_HASH_WITH_NETS
 	for (i = 0; i < IPSET_NET_COUNT; i++)
 		mtype_add_cidr(set, h, DCIDR_GET(d->cidr, i), i);
-#endif
-	memcpy(data, d, sizeof(struct mtype_elem));
-overwrite_extensions:
-#ifdef IP_SET_HASH_WITH_NETS
-	mtype_data_set_flags(data, flags);
+
+	mtype_data_set_flags(&e->elem, flags);
 #endif
 	if (SET_WITH_COUNTER(set))
-		ip_set_init_counter(ext_counter(data, set), ext);
+		ip_set_init_counter(ext_counter(&e->elem, set), ext);
 	if (SET_WITH_COMMENT(set))
-		ip_set_init_comment_slow(set, ext_comment(data, set), ext);
+		ip_set_init_comment_slow(set, ext_comment(&e->elem, set), ext);
 	if (SET_WITH_SKBINFO(set))
-		ip_set_init_skbinfo(ext_skbinfo(data, set), ext);
+		ip_set_init_skbinfo(ext_skbinfo(&e->elem, set), ext);
 	/* Must come last for the case when timed out entry is reused */
 	if (SET_WITH_TIMEOUT(set))
-		ip_set_timeout_set(ext_timeout(data, set), ext->timeout);
-	smp_mb__before_atomic();
-	/* Ensure all data writes are visible before updating position */
-	smp_store_release(&n->pos, npos);
-	set_bit(j, n->used);
-	if (old != ERR_PTR(-ENOENT)) {
-		rcu_assign_pointer(hbucket(t, key), n);
-		if (old)
-			kfree_rcu(old, rcu);
-	}
-	ret = 0;
-resize:
-	spin_unlock_bh(&t->hregion[r].lock);
-	if (t->resizing && ext && ext->target) {
-		/* Resize is in process and kernel side add, save values */
-		struct mtype_resize_ad *x;
-
-		x = kzalloc_obj(struct mtype_resize_ad, GFP_ATOMIC);
-		if (!x)
-			/* Don't bother */
-			goto out;
-		x->ad = IPSET_ADD;
-		memcpy(&x->d, value, sizeof(struct mtype_elem));
-		memcpy(&x->ext, ext, sizeof(struct ip_set_ext));
-		memcpy(&x->mext, mext, sizeof(struct ip_set_ext));
-		x->flags = flags;
-		spin_lock_bh(&set->lock);
-		list_add_tail(&x->list, &t->ad);
-		spin_unlock_bh(&set->lock);
-	}
-	goto out;
+		ip_set_timeout_set(ext_timeout(&e->elem, set), ext->timeout);
 
-set_full:
-	if (net_ratelimit())
-		pr_warn("Set %s is full, maxelem %u reached\n",
-			set->name, maxelem);
-	ret = -IPSET_ERR_HASH_FULL;
-unlock:
-	spin_unlock_bh(&t->hregion[r].lock);
-out:
-	if (atomic_dec_and_test(&t->uref) && t->resizing) {
-		pr_debug("Table destroy after resize by add: %p\n", t);
-		mtype_ahash_destroy(set, t, false);
+	ret = rhashtable_insert_fast(&h->ht, &e->node, mtype_rht_params);
+	if (ret) {
+		mtype_del_cidr_all(set, h, d);
+		ip_set_ext_destroy_slow(set, &e->elem);
+		kfree(e);
+		if (ret == -EEXIST)
+			ret = flag_exist ? 0 : -IPSET_ERR_EXIST;
 	}
 	return ret;
 }
 
-/* Delete an element from the hash and free up space if possible.
- */
+/* Delete an element from the hash */
 static int
 mtype_del(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 	  struct ip_set_ext *mext, u32 flags)
 {
 	struct htype *h = set->data;
-	struct htable *t;
 	const struct mtype_elem *d = value;
-	struct mtype_elem *data;
-	struct hbucket *n;
-	struct mtype_resize_ad *x = NULL;
-	int i, j, k, r, ret = -IPSET_ERR_EXIST;
-	u32 key, multi = 0;
-	size_t dsize = set->dsize;
-	u8 pos;
-
-	/* Userspace add and resize is excluded by the mutex.
-	 * Kernespace add does not trigger resize.
-	 */
+	struct mtype_rht_elem *e;
+	int ret = -IPSET_ERR_EXIST;
+
 	rcu_read_lock_bh();
-	t = rcu_dereference_bh(h->table);
-	key = HKEY(value, h->initval, t->htable_bits);
-	r = ahash_region(key);
-	atomic_inc(&t->uref);
+	e = rhashtable_lookup(&h->ht, d, mtype_rht_params);
+	if (!e) {
+		rcu_read_unlock_bh();
+		return -IPSET_ERR_EXIST;
+	}
+	ret = rhashtable_remove_fast(&h->ht, &e->node, mtype_rht_params);
 	rcu_read_unlock_bh();
 
-	spin_lock_bh(&t->hregion[r].lock);
-	n = rcu_dereference_bh(hbucket(t, key));
-	if (!n)
-		goto out;
-	pos = smp_load_acquire(&n->pos);
-	for (i = 0, k = 0; i < pos; i++) {
-		if (!test_bit(i, n->used)) {
-			k++;
-			continue;
-		}
-		data = ahash_data(n, i, dsize);
-		if (!mtype_data_equal(data, d, &multi))
-			continue;
-		if (SET_ELEM_EXPIRED(set, data))
-			goto out;
-
-		ret = 0;
-		clear_bit(i, n->used);
-		smp_mb__after_atomic();
-		if (i + 1 == pos)
-			smp_store_release(&n->pos, --pos);
-		t->hregion[r].elements--;
-		mtype_del_cidr_all(set, h, d);
-		ip_set_ext_destroy_slow(set, data);
-
-		if (t->resizing && ext && ext->target) {
-			/* Resize is in process and kernel side del,
-			 * save values
-			 */
-			x = kzalloc_obj(struct mtype_resize_ad, GFP_ATOMIC);
-			if (x) {
-				x->ad = IPSET_DEL;
-				memcpy(&x->d, value,
-				       sizeof(struct mtype_elem));
-				x->flags = flags;
-			}
-		}
-		for (; i < pos; i++) {
-			if (!test_bit(i, n->used))
-				k++;
-		}
-		if (k == pos) {
-			t->hregion[r].ext_size -= ext_size(n->size, dsize);
-			rcu_assign_pointer(hbucket(t, key), NULL);
-			kfree_rcu(n, rcu);
-		} else if (k >= AHASH_INIT_SIZE) {
-			struct hbucket *tmp = kzalloc(sizeof(*tmp) +
-					(n->size - AHASH_INIT_SIZE) * dsize,
-					GFP_ATOMIC);
-			if (!tmp)
-				goto out;
-			tmp->size = n->size - AHASH_INIT_SIZE;
-			for (j = 0, k = 0; j < pos; j++) {
-				if (!test_bit(j, n->used))
-					continue;
-				data = ahash_data(n, j, dsize);
-				memcpy(tmp->value + k * dsize, data, dsize);
-				set_bit(k, tmp->used);
-				k++;
-			}
-			tmp->pos = k;
-			t->hregion[r].ext_size -=
-				ext_size(AHASH_INIT_SIZE, dsize);
-			rcu_assign_pointer(hbucket(t, key), tmp);
-			kfree_rcu(n, rcu);
-		}
-		goto out;
-	}
+	if (ret)
+		return -IPSET_ERR_EXIST;
 
-out:
-	spin_unlock_bh(&t->hregion[r].lock);
-	if (x) {
-		spin_lock_bh(&set->lock);
-		list_add(&x->list, &t->ad);
-		spin_unlock_bh(&set->lock);
-	}
-	if (atomic_dec_and_test(&t->uref) && t->resizing) {
-		pr_debug("Table destroy after resize by del: %p\n", t);
-		mtype_ahash_destroy(set, t, false);
-	}
-	return ret;
+	mtype_del_cidr_all(set, h, d);
+	ip_set_ext_destroy_slow(set, &e->elem);
+	kfree_rcu(e, rcu);
+	return 0;
 }
 
 static int
@@ -1333,25 +667,21 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
 		 struct ip_set_ext *mext, u32 flags)
 {
 	struct htype *h = set->data;
-	struct htable *t = rcu_dereference_bh(h->table);
 	struct net_prefixes *nets0;
-	struct hbucket *n;
-	struct mtype_elem *data;
+	struct mtype_rht_elem *e;
 #if IPSET_NET_COUNT == 2
 	struct net_prefixes *nets1;
 	struct mtype_elem orig = *d;
-	int ret, i, j, k;
+	int ret, j, k;
 #else
-	int ret, i, j;
+	int ret, j;
 #endif
-	u32 key, multi = 0;
-	u8 pos;
+	u32 multi = 0;
 
 	pr_debug("test by nets\n");
-	rcu_read_lock_bh();
-	nets0 = rcu_dereference_bh(h->rnets[0]);
+	nets0 = ipset_dereference_bh_nfnl(h->rnets[0]);
 #if IPSET_NET_COUNT == 2
-	nets1 = rcu_dereference_bh(h->rnets[1]);
+	nets1 = ipset_dereference_bh_nfnl(h->rnets[1]);
 #endif
 	for (j = 0; j < nets0->len && !multi; j++) {
 		if (!nets0->nets[j].count)
@@ -1366,20 +696,11 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
 #else
 		mtype_data_netmask(d, nets0->nets[j].cidr);
 #endif
-		key = HKEY(d, h->initval, t->htable_bits);
-		n = rcu_dereference_bh(hbucket(t, key));
-		if (!n)
-			continue;
-		pos = smp_load_acquire(&n->pos);
-		for (i = 0; i < pos; i++) {
-			if (!test_bit_acquire(i, n->used))
-				continue;
-			data = ahash_data(n, i, set->dsize);
-			if (!mtype_data_equal(data, d, &multi))
-				continue;
-			ret = mtype_data_match(data, ext, mext, set, flags);
+		e = rhashtable_lookup(&h->ht, d, mtype_rht_params);
+		if (e) {
+			ret = mtype_data_match(&e->elem, ext, mext, set, flags);
 			if (ret != 0)
-				goto unlock;
+				return ret;
 #ifdef IP_SET_HASH_WITH_MULTI
 			/* No match, reset multiple match flag */
 			multi = 0;
@@ -1389,10 +710,7 @@ mtype_test_cidrs(struct ip_set *set, struct mtype_elem *d,
 		}
 #endif
 	}
-	ret = 0;
-unlock:
-	rcu_read_unlock_bh();
-	return ret;
+	return 0;
 }
 #endif
 
@@ -1402,16 +720,14 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 	   struct ip_set_ext *mext, u32 flags)
 {
 	struct htype *h = set->data;
-	struct htable *t;
 	struct mtype_elem *d = value;
-	struct hbucket *n;
-	struct mtype_elem *data;
-	int i, ret = 0;
-	u32 key, multi = 0;
-	u8 pos;
+	struct mtype_rht_elem *e;
+	int ret = 0;
+#ifdef IP_SET_HASH_WITH_NETS
+	int i;
+#endif
 
 	rcu_read_lock_bh();
-	t = rcu_dereference_bh(h->table);
 #ifdef IP_SET_HASH_WITH_NETS
 	/* If we test an IP address and not a network address,
 	 * try all possible network sizes
@@ -1425,23 +741,13 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 	}
 #endif
 
-	key = HKEY(d, h->initval, t->htable_bits);
-	n = rcu_dereference_bh(hbucket(t, key));
-	if (!n) {
+	e = rhashtable_lookup(&h->ht, d, mtype_rht_params);
+	if (!e || SET_ELEM_EXPIRED(set, &e->elem)) {
 		ret = 0;
 		goto out;
 	}
-	pos = smp_load_acquire(&n->pos);
-	for (i = 0; i < pos; i++) {
-		if (!test_bit_acquire(i, n->used))
-			continue;
-		data = ahash_data(n, i, set->dsize);
-		if (!mtype_data_equal(data, d, &multi))
-			continue;
-		ret = mtype_data_match(data, ext, mext, set, flags);
-		if (ret != 0)
-			goto out;
-	}
+
+	ret = mtype_data_match(&e->elem, ext, mext, set, flags);
 out:
 	rcu_read_unlock_bh();
 	return ret;
@@ -1449,20 +755,24 @@ mtype_test(struct ip_set *set, void *value, const struct ip_set_ext *ext,
 
 static u32 mtype_hash_size(const struct htype *h)
 {
-	const struct htable *t;
-	u8 htable_bits;
+	const struct bucket_table *tbl;
+	u32 size = 0;
 
 	rcu_read_lock();
-	t = rcu_dereference(h->table);
-	htable_bits = t->htable_bits;
+	tbl = rcu_dereference(h->ht.tbl);
+	if (tbl)
+		size = tbl->size;
 	rcu_read_unlock();
 
-	return jhash_size(htable_bits);
+	return size;
 }
 
 static u32 mtype_bucket_size(const struct htype *h)
 {
-	return h->bucketsize;
+	unsigned int nelems = atomic_read(&h->ht.nelems);
+	u32 size = mtype_hash_size(h);
+
+	return nelems / size;
 }
 
 /* Reply a HEADER request: fill out the header part of the set */
@@ -1470,17 +780,13 @@ static int
 mtype_head(struct ip_set *set, struct sk_buff *skb)
 {
 	struct htype *h = set->data;
-	const struct htable *t;
 	struct nlattr *nested;
 	size_t memsize;
 	u32 elements = 0;
 	size_t ext_size = 0;
 
-	rcu_read_lock_bh();
-	t = rcu_dereference_bh(h->table);
 	mtype_ext_size(set, &elements, &ext_size);
-	memsize = mtype_ahash_memsize(h, t) + ext_size + set->ext_size;
-	rcu_read_unlock_bh();
+	memsize = sizeof(*h) + ext_size + set->ext_size;
 
 	nested = nla_nest_start(skb, IPSET_ATTR_DATA);
 	if (!nested)
@@ -1514,7 +820,7 @@ mtype_head(struct ip_set *set, struct sk_buff *skb)
 	if (set->flags & IPSET_CREATE_FLAG_BUCKETSIZE) {
 		if (nla_put_u8(skb, IPSET_ATTR_BUCKETSIZE, mtype_bucket_size(h)))
 			goto nla_put_failure;
-		if (nla_put_net32(skb, IPSET_ATTR_INITVAL, htonl(h->initval)))
+		if (nla_put_u32(skb, IPSET_ATTR_INITVAL, 0))
 			goto nla_put_failure;
 	}
 	if (nla_put_net32(skb, IPSET_ATTR_REFERENCES, htonl(set->ref)) ||
@@ -1530,25 +836,23 @@ mtype_head(struct ip_set *set, struct sk_buff *skb)
 	return -EMSGSIZE;
 }
 
-/* Make possible to run dumping parallel with resizing */
+/* Manage the rhashtable_iter lifetime for dump operations */
 static void
 mtype_uref(struct ip_set *set, struct netlink_callback *cb, bool start)
 {
 	struct htype *h = set->data;
-	struct htable *t;
+	struct rhashtable_iter *hti;
 
 	if (start) {
-		rcu_read_lock_bh();
-		t = ipset_dereference_bh_nfnl(h->table);
-		atomic_inc(&t->uref);
-		cb->args[IPSET_CB_PRIVATE] = (unsigned long)t;
-		rcu_read_unlock_bh();
-	} else if (cb->args[IPSET_CB_PRIVATE]) {
-		t = (struct htable *)cb->args[IPSET_CB_PRIVATE];
-		if (atomic_dec_and_test(&t->uref) && t->resizing) {
-			pr_debug("Table destroy after resize "
-				 " by dump: %p\n", t);
-			mtype_ahash_destroy(set, t, false);
+		hti = kmalloc(sizeof(*hti), GFP_ATOMIC);
+		if (hti)
+			rhashtable_walk_enter(&h->ht, hti);
+		cb->args[IPSET_CB_PRIVATE] = (unsigned long)hti;
+	} else {
+		hti = (struct rhashtable_iter *)cb->args[IPSET_CB_PRIVATE];
+		if (hti) {
+			rhashtable_walk_exit(hti);
+			kfree(hti);
 		}
 		cb->args[IPSET_CB_PRIVATE] = 0;
 	}
@@ -1559,77 +863,77 @@ static int
 mtype_list(const struct ip_set *set,
 	   struct sk_buff *skb, struct netlink_callback *cb)
 {
-	const struct htable *t;
+	struct rhashtable_iter *hti =
+		(struct rhashtable_iter *)cb->args[IPSET_CB_PRIVATE];
+	struct mtype_rht_elem *e, *peeked;
 	struct nlattr *atd, *nested;
-	const struct hbucket *n;
-	const struct mtype_elem *e;
-	u32 first = cb->args[IPSET_CB_ARG0];
-	/* We assume that one hash bucket fills into one page */
 	void *incomplete;
-	int i, ret = 0;
-	u8 pos;
+	u32 emitted = 0;
+	int ret = 0;
+
+	if (!hti)
+		return -EMSGSIZE;
 
 	atd = nla_nest_start(skb, IPSET_ATTR_ADT);
 	if (!atd)
 		return -EMSGSIZE;
 
-	pr_debug("list hash set %s\n", set->name);
-	t = (const struct htable *)cb->args[IPSET_CB_PRIVATE];
-	/* Expire may replace a hbucket with another one */
-	rcu_read_lock();
-	for (; cb->args[IPSET_CB_ARG0] < jhash_size(t->htable_bits);
-	     cb->args[IPSET_CB_ARG0]++) {
-		cond_resched_rcu();
-		incomplete = skb_tail_pointer(skb);
-		n = rcu_dereference(hbucket(t, cb->args[IPSET_CB_ARG0]));
-		pr_debug("cb->arg bucket: %lu, t %p n %p\n",
-			 cb->args[IPSET_CB_ARG0], t, n);
-		if (!n)
-			continue;
-		pos = smp_load_acquire(&n->pos);
-		for (i = 0; i < pos; i++) {
-			if (!test_bit_acquire(i, n->used))
+	rhashtable_walk_start(hti);
+	while ((e = rhashtable_walk_peek(hti))) {
+		if (IS_ERR(e)) {
+			if (PTR_ERR(e) == -EAGAIN)
 				continue;
-			e = ahash_data(n, i, set->dsize);
-			if (SET_ELEM_EXPIRED(set, e))
-				continue;
-			pr_debug("list hash %lu hbucket %p i %u, data %p\n",
-				 cb->args[IPSET_CB_ARG0], n, i, e);
-			nested = nla_nest_start(skb, IPSET_ATTR_DATA);
-			if (!nested) {
-				if (cb->args[IPSET_CB_ARG0] == first) {
-					nla_nest_cancel(skb, atd);
-					ret = -EMSGSIZE;
-					goto out;
-				}
-				goto nla_put_failure;
-			}
-			if (mtype_data_list(skb, e))
-				goto nla_put_failure;
-			if (ip_set_put_extensions(skb, set, e, true))
-				goto nla_put_failure;
-			nla_nest_end(skb, nested);
+			ret = PTR_ERR(e);
+			break;
+		}
+		peeked = e;
+next_dump:
+		if (SET_ELEM_EXPIRED(set, &e->elem))
+			goto next_entry;
+
+		incomplete = skb_tail_pointer(skb);
+		nested = nla_nest_start(skb, IPSET_ATTR_DATA);
+		if (!nested) {
+			nlmsg_trim(skb, incomplete);
+			goto paused;
+		}
+		if (mtype_data_list(skb, &e->elem) ||
+		    ip_set_put_extensions(skb, set, &e->elem, true)) {
+			nla_nest_cancel(skb, nested);
+			nlmsg_trim(skb, incomplete);
+			goto paused;
+		}
+		nla_nest_end(skb, nested);
+		emitted++;
+next_entry:
+		e = rhashtable_walk_next(hti);
+		if (IS_ERR(e)) {
+			ret = PTR_ERR(e);
+			if (ret != -EAGAIN)
+				break;
+			ret = 0;
+		} else if (peeked && e != peeked) {
+			peeked = NULL;
+			if (e)
+				goto next_dump;
 		}
 	}
+	/* Walk exhausted: listing done */
 	nla_nest_end(skb, atd);
-	/* Set listing finished */
+	rhashtable_walk_stop(hti);
 	cb->args[IPSET_CB_ARG0] = 0;
+	return ret;
 
-	goto out;
-
-nla_put_failure:
-	nlmsg_trim(skb, incomplete);
-	if (unlikely(first == cb->args[IPSET_CB_ARG0])) {
-		pr_warn("Can't list set %s: one bucket does not fit into a message. Please report it!\n",
-			set->name);
-		cb->args[IPSET_CB_ARG0] = 0;
-		ret = -EMSGSIZE;
-	} else {
-		nla_nest_end(skb, atd);
+paused:
+	if (emitted == 0) {
+		nla_nest_cancel(skb, atd);
+		rhashtable_walk_stop(hti);
+		return -EMSGSIZE;
 	}
-out:
-	rcu_read_unlock();
-	return ret;
+	cb->args[IPSET_CB_ARG0] = 1;
+	nla_nest_end(skb, atd);
+	rhashtable_walk_stop(hti);
+	return 0;
 }
 
 static int
@@ -1655,7 +959,7 @@ static const struct ip_set_type_variant mtype_variant = {
 	.head	= mtype_head,
 	.list	= mtype_list,
 	.uref	= mtype_uref,
-	.resize	= mtype_resize,
+	.resize	= NULL,
 	.same_set = mtype_same_set,
 	.cancel_gc = mtype_cancel_gc,
 	.region_lock = true,
@@ -1671,7 +975,6 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 #ifdef IP_SET_HASH_WITH_MARKMASK
 	u32 markmask;
 #endif
-	u8 hbits;
 #if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
 	int ret __attribute__((unused)) = 0;
 	u8 netmask = set->family == NFPROTO_IPV4 ? 32 : 128;
@@ -1679,12 +982,11 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 #endif
 #ifdef IP_SET_HASH_WITH_NETS
 	struct net_prefixes *nets;
+	int i;
 #endif
 	size_t hsize;
 	struct htype *h;
-	struct htable *t;
 	int err;
-	u32 i;
 
 	pr_debug("Create set %s with family %s\n",
 		 set->name, set->family == NFPROTO_IPV4 ? "inet" : "inet6");
@@ -1765,17 +1067,21 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 
 #ifdef IP_SET_PROTO_UNDEF
 	hsize = sizeof(struct htype);
+	params = mtype_rht_params;
 #else
-	hsize = set->family == NFPROTO_IPV6 ?
-		sizeof(struct IPSET_TOKEN(HTYPE, 6)) :
-		sizeof(struct IPSET_TOKEN(HTYPE, 4));
+	if (set->family == NFPROTO_IPV6) {
+		hsize = sizeof(struct IPSET_TOKEN(HTYPE, 6));
+		params = IPSET_TOKEN(HTYPE, 6_rht_params);
+	} else {
+		hsize = sizeof(struct IPSET_TOKEN(HTYPE, 4));
+		params = IPSET_TOKEN(HTYPE, 4_rht_params);
+	}
 #endif
 	h = kzalloc(hsize, GFP_KERNEL);
 	if (!h)
 		return -ENOMEM;
 
 	/* Initialize rhashtable with the user-requested size as hint */
-	params = mtype_rht_params;
 	params.nelem_hint = hashsize;
 	/* maxsize: maximum bucket table size to expand to */
 	params.max_size = maxelem;
@@ -1784,36 +1090,19 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 	if (err)
 		goto free_h;
 
-	/* Compute htable_bits from the user input parameter hashsize.
-	 * Assume that hashsize == 2^htable_bits,
-	 * otherwise round up to the first 2^n value.
-	 */
-	hbits = fls(hashsize - 1);
-	hsize = htable_size(hbits);
-	if (hsize == 0)
-		goto free_rht;
-	t = ip_set_alloc(hsize);
-	if (!t)
-		goto free_rht;
-	t->hregion = ip_set_alloc(ahash_sizeof_regions(hbits));
-	if (!t->hregion)
-		goto free_t;
 #ifdef IP_SET_HASH_WITH_NETS
 	for (i = 0; i < IPSET_NET_COUNT; i++) {
 		nets = kzalloc(sizeof(struct net_prefixes), GFP_KERNEL);
 		if (!nets) {
 			while (i > 0)
 				kfree(h->rnets[--i]);
-			goto free_hregion;
+			goto free_rht;
 		}
 		RCU_INIT_POINTER(h->rnets[i], nets);
 	}
 #endif
-	h->gc.set = set;
-	spin_lock_init(&h->gc.lock);
-	for (i = 0; i < ahash_numof_locks(hbits); i++)
-		spin_lock_init(&t->hregion[i].lock);
 	h->maxelem = maxelem;
+	h->gc.set = set;
 #if defined(IP_SET_HASH_WITH_NETMASK) || defined(IP_SET_HASH_WITH_BITMASK)
 	h->bitmask = bitmask;
 	h->netmask = netmask;
@@ -1821,24 +1110,6 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 #ifdef IP_SET_HASH_WITH_MARKMASK
 	h->markmask = markmask;
 #endif
-	if (tb[IPSET_ATTR_INITVAL])
-		h->initval = ntohl(nla_get_be32(tb[IPSET_ATTR_INITVAL]));
-	else
-		get_random_bytes(&h->initval, sizeof(h->initval));
-	h->bucketsize = AHASH_MAX_SIZE;
-	if (tb[IPSET_ATTR_BUCKETSIZE]) {
-		h->bucketsize = nla_get_u8(tb[IPSET_ATTR_BUCKETSIZE]);
-		if (h->bucketsize < AHASH_INIT_SIZE)
-			h->bucketsize = AHASH_INIT_SIZE;
-		else if (h->bucketsize > AHASH_MAX_SIZE)
-			h->bucketsize = AHASH_MAX_SIZE;
-		else if (h->bucketsize % 2)
-			h->bucketsize += 1;
-	}
-	t->htable_bits = hbits;
-	t->maxelem = h->maxelem / ahash_numof_locks(hbits);
-	INIT_LIST_HEAD(&t->ad);
-	RCU_INIT_POINTER(h->table, t);
 	set->data = h;
 
 #ifndef IP_SET_PROTO_UNDEF
@@ -1868,23 +1139,18 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 			IPSET_TOKEN(HTYPE, 6_gc_init)(&h->gc);
 #endif
 	}
-	pr_debug("create %s hashsize %u (%u) maxelem %u: %p(%p)\n",
-		 set->name, mtype_hash_size(h),
-		 t->htable_bits, h->maxelem, set->data, t);
+	pr_debug("create %s hashsize %u maxelem %u\n",
+		 set->name, mtype_hash_size(h), h->maxelem);
 
 	return 0;
 
 #ifdef IP_SET_HASH_WITH_NETS
-free_hregion:
-	ip_set_free(t->hregion);
-#endif
-free_t:
-	ip_set_free(t);
 free_rht:
 	rhashtable_free_and_destroy(&h->ht, mtype_flush_elem, set);
+#endif
 free_h:
 	kfree(h);
-	return -ENOMEM;
+	return err ? err : -ENOMEM;
 }
 #endif /* IP_SET_EMIT_CREATE */
 
-- 
2.54.0