netlink: eliminate nl_sk_hash_lock
As rhashtable_lookup_compare_insert() can guarantee the process
of search and insertion is atomic, it's safe to eliminate the
nl_sk_hash_lock. After this, object insertion or removal will
be protected with per bucket lock on write side while object
lookup is guarded with rcu read lock on read side.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Cc: Thomas Graf <tgraf@suug.ch>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/diag.c b/net/netlink/diag.c
index fcca36d..bb59a7e 100644
--- a/net/netlink/diag.c
+++ b/net/netlink/diag.c
@@ -103,7 +103,7 @@
{
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 @@
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 @@
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 @@
} 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 @@
}
read_unlock(&nl_table_lock);
- mutex_unlock(&nl_sk_hash_lock);
+ rcu_read_unlock();
return skb->len;
}