Merge branch 'rhashtable-next'

Ying Xue says:

====================
remove nl_sk_hash_lock from netlink socket

After tipc socket successfully avoids the involvement of an extra lock
with rhashtable_lookup_insert(), it's possible for netlink socket to
remove its hash socket lock now. But as netlink socket needs a compare
function to look for an object, we first introduce a new function
called rhashtable_lookup_compare_insert() in commit #1 which is
implemented based on original rhashtable_lookup_insert(). We
subsequently remove nl_sk_hash_lock from netlink socket with the new
introduced function in commit #2. Lastly, as Thomas requested, we add
commit #3 to indicate the implementation of what the grow and shrink
decision function must enforce min/max shift.

v2:
 As Thomas pointed out, there was a race between checking portid and
 then setting it in commit #2. Now use socket lock to make the process
 of both checking and setting portid atomic, and then eliminate the
 race.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/net/netlink/diag.c b/net/netlink/diag.c
index fcca36d81a6..bb59a7ed085 100644
--- a/net/netlink/diag.c
+++ b/net/netlink/diag.c
@@ -103,7 +103,7 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 {
 	struct netlink_table *tbl = &nl_table[protocol];
 	struct rhashtable *ht = &tbl->hash;
-	const struct bucket_table *htbl = rht_dereference(ht->tbl, ht);
+	const struct bucket_table *htbl = rht_dereference_rcu(ht->tbl, ht);
 	struct net *net = sock_net(skb->sk);
 	struct netlink_diag_req *req;
 	struct netlink_sock *nlsk;
@@ -115,7 +115,7 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 	for (i = 0; i < htbl->size; i++) {
 		struct rhash_head *pos;
 
-		rht_for_each_entry(nlsk, pos, htbl, i, node) {
+		rht_for_each_entry_rcu(nlsk, pos, htbl, i, node) {
 			sk = (struct sock *)nlsk;
 
 			if (!net_eq(sock_net(sk), net))
@@ -172,7 +172,7 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 	req = nlmsg_data(cb->nlh);
 
-	mutex_lock(&nl_sk_hash_lock);
+	rcu_read_lock();
 	read_lock(&nl_table_lock);
 
 	if (req->sdiag_protocol == NDIAG_PROTO_ALL) {
@@ -186,7 +186,7 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	} else {
 		if (req->sdiag_protocol >= MAX_LINKS) {
 			read_unlock(&nl_table_lock);
-			mutex_unlock(&nl_sk_hash_lock);
+			rcu_read_unlock();
 			return -ENOENT;
 		}
 
@@ -194,7 +194,7 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	}
 
 	read_unlock(&nl_table_lock);
-	mutex_unlock(&nl_sk_hash_lock);
+	rcu_read_unlock();
 
 	return skb->len;
 }