rhashtable: Convert bucket iterators to take table and index

This patch is in preparation to introduce per bucket spinlocks. It
extends all iterator macros to take the bucket table and bucket
index. It also introduces a new rht_dereference_bucket() to
handle protected accesses to buckets.

It introduces a barrier() to the RCU iterators to the prevent
the compiler from caching the first element.

The lockdep verifier is introduced as stub which always succeeds
and properly implement in the next patch when the locks are
introduced.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 17 insertions, 11 deletions

diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index 614ee099ba36..d93f1f4c22a9 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -142,7 +142,9 @@ static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
 
 	tbl = rht_dereference_rcu(priv->tbl, priv);
 	for (i = 0; i < tbl->size; i++) {
-		rht_for_each_entry_rcu(he, tbl->buckets[i], node) {
+		struct rhash_head *pos;
+
+		rht_for_each_entry_rcu(he, pos, tbl, i, node) {
 			if (iter->count < iter->skip)
 				goto cont;
 
@@ -197,15 +199,13 @@ static void nft_hash_destroy(const struct nft_set *set)
 {
 	const struct rhashtable *priv = nft_set_priv(set);
 	const struct bucket_table *tbl = priv->tbl;
-	struct nft_hash_elem *he, *next;
+	struct nft_hash_elem *he;
+	struct rhash_head *pos, *next;
 	unsigned int i;
 
 	for (i = 0; i < tbl->size; i++) {
-		for (he = rht_entry(tbl->buckets[i], struct nft_hash_elem, node);
-		     he != NULL; he = next) {
-			next = rht_entry(he->node.next, struct nft_hash_elem, node);
+		rht_for_each_entry_safe(he, pos, next, tbl, i, node)
 			nft_hash_elem_destroy(set, he);
-		}
 	}
 	rhashtable_destroy(priv);
 }
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index a5d7ed627563..57449b6089c2 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2898,7 +2898,9 @@ static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
 		const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
 
 		for (j = 0; j < tbl->size; j++) {
-			rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
+			struct rhash_head *node;
+
+			rht_for_each_entry_rcu(nlk, node, tbl, j, node) {
 				s = (struct sock *)nlk;
 
 				if (sock_net(s) != seq_file_net(seq))
@@ -2926,6 +2928,8 @@ static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct rhashtable *ht;
+	const struct bucket_table *tbl;
+	struct rhash_head *node;
 	struct netlink_sock *nlk;
 	struct nl_seq_iter *iter;
 	struct net *net;
@@ -2942,17 +2946,17 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 
 	i = iter->link;
 	ht = &nl_table[i].hash;
-	rht_for_each_entry(nlk, nlk->node.next, ht, node)
+	tbl = rht_dereference_rcu(ht->tbl, ht);
+	rht_for_each_entry_rcu_continue(nlk, node, nlk->node.next, tbl, iter->hash_idx, node)
 		if (net_eq(sock_net((struct sock *)nlk), net))
 			return nlk;
 
 	j = iter->hash_idx + 1;
 
 	do {
-		const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
 
 		for (; j < tbl->size; j++) {
-			rht_for_each_entry(nlk, tbl->buckets[j], ht, node) {
+			rht_for_each_entry_rcu(nlk, node, tbl, j, node) {
 				if (net_eq(sock_net((struct sock *)nlk), net)) {
 					iter->link = i;
 					iter->hash_idx = j;
diff --git a/net/netlink/diag.c b/net/netlink/diag.c
index de8c74a3c061..fcca36d81a62 100644
--- a/net/netlink/diag.c
+++ b/net/netlink/diag.c
@@ -113,7 +113,9 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 	req = nlmsg_data(cb->nlh);
 
 	for (i = 0; i < htbl->size; i++) {
-		rht_for_each_entry(nlsk, htbl->buckets[i], ht, node) {
+		struct rhash_head *pos;
+
+		rht_for_each_entry(nlsk, pos, htbl, i, node) {
 			sk = (struct sock *)nlsk;
 
 			if (!net_eq(sock_net(sk), net))