Merge branch 'rhashtable-inlined-interface'

Herbert Xu says:

====================
rhashtable: Introduce inlined interface

This series of patches introduces the inlined rhashtable interface.

The idea is to make all the function pointers visible to the compiler
by providing the rhashtable_params structure explicitly to each
inline rhashtable function.  For example, instead of doing

	obj = rhashtable_lookup(ht, key);

you would now do

	obj = rhashtable_lookup_fast(ht, key, params);

Where params is the same data that you would give to rhashtable_init.
In particular, within rhashtable.c itself we would simply supply
ht->p.

So to convert users over, you simply have to make params globally
accessible, e.g., by placing it in a static const variable, which
can then be used at each inlined call site, as well as by the
rhashtable_init call.

The only ticky bit is that some users (i.e., netfilter) has a
dynamic key length.  This is dealt with by using params.key_len
in the inline functions when it is non-zero, and otherwise falling
back on ht->p.key_len.

Note that I've only tested this on one compiler, gcc 4.7.2.  So
please test this with your compilers as well and make sure that
the code is actually inlined without indirect function calls.
====================

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

1 files changed, 56 insertions, 32 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index d97aed628bda..72c6b55af741 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -116,6 +116,8 @@ static ATOMIC_NOTIFIER_HEAD(netlink_chain);
 static DEFINE_SPINLOCK(netlink_tap_lock);
 static struct list_head netlink_tap_all __read_mostly;
 
+static const struct rhashtable_params netlink_rhashtable_params;
+
 static inline u32 netlink_group_mask(u32 group)
 {
 	return group ? 1 << (group - 1) : 0;
@@ -970,41 +972,49 @@ netlink_unlock_table(void)
 
 struct netlink_compare_arg
 {
-	struct net *net;
+	possible_net_t pnet;
 	u32 portid;
+	char trailer[];
 };
 
-static bool netlink_compare(void *ptr, void *arg)
+#define netlink_compare_arg_len offsetof(struct netlink_compare_arg, trailer)
+
+static inline int netlink_compare(struct rhashtable_compare_arg *arg,
+				  const void *ptr)
 {
-	struct netlink_compare_arg *x = arg;
-	struct sock *sk = ptr;
+	const struct netlink_compare_arg *x = arg->key;
+	const struct netlink_sock *nlk = ptr;
 
-	return nlk_sk(sk)->portid == x->portid &&
-	       net_eq(sock_net(sk), x->net);
+	return nlk->portid != x->portid ||
+	       !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
+}
+
+static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
+				     struct net *net, u32 portid)
+{
+	memset(arg, 0, sizeof(*arg));
+	write_pnet(&arg->pnet, net);
+	arg->portid = portid;
 }
 
 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
 				     struct net *net)
 {
-	struct netlink_compare_arg arg = {
-		.net = net,
-		.portid = portid,
-	};
+	struct netlink_compare_arg arg;
 
-	return rhashtable_lookup_compare(&table->hash, &portid,
-					 &netlink_compare, &arg);
+	netlink_compare_arg_init(&arg, net, portid);
+	return rhashtable_lookup_fast(&table->hash, &arg,
+				      netlink_rhashtable_params);
 }
 
-static bool __netlink_insert(struct netlink_table *table, struct sock *sk)
+static int __netlink_insert(struct netlink_table *table, struct sock *sk)
 {
-	struct netlink_compare_arg arg = {
-		.net = sock_net(sk),
-		.portid = nlk_sk(sk)->portid,
-	};
+	struct netlink_compare_arg arg;
 
-	return rhashtable_lookup_compare_insert(&table->hash,
-						&nlk_sk(sk)->node,
-						&netlink_compare, &arg);
+	netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
+	return rhashtable_lookup_insert_key(&table->hash, &arg,
+					    &nlk_sk(sk)->node,
+					    netlink_rhashtable_params);
 }
 
 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
@@ -1066,9 +1076,10 @@ static int netlink_insert(struct sock *sk, u32 portid)
 	nlk_sk(sk)->portid = portid;
 	sock_hold(sk);
 
-	err = 0;
-	if (!__netlink_insert(table, sk)) {
-		err = -EADDRINUSE;
+	err = __netlink_insert(table, sk);
+	if (err) {
+		if (err == -EEXIST)
+			err = -EADDRINUSE;
 		sock_put(sk);
 	}
 
@@ -1082,7 +1093,8 @@ static void netlink_remove(struct sock *sk)
 	struct netlink_table *table;
 
 	table = &nl_table[sk->sk_protocol];
-	if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node)) {
+	if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
+				    netlink_rhashtable_params)) {
 		WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
 		__sock_put(sk);
 	}
@@ -3114,17 +3126,28 @@ static struct pernet_operations __net_initdata netlink_net_ops = {
 	.exit = netlink_net_exit,
 };
 
+static inline u32 netlink_hash(const void *data, u32 seed)
+{
+	const struct netlink_sock *nlk = data;
+	struct netlink_compare_arg arg;
+
+	netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
+	return jhash(&arg, netlink_compare_arg_len, seed);
+}
+
+static const struct rhashtable_params netlink_rhashtable_params = {
+	.head_offset = offsetof(struct netlink_sock, node),
+	.key_len = netlink_compare_arg_len,
+	.hashfn = jhash,
+	.obj_hashfn = netlink_hash,
+	.obj_cmpfn = netlink_compare,
+	.max_size = 65536,
+};
+
 static int __init netlink_proto_init(void)
 {
 	int i;
 	int err = proto_register(&netlink_proto, 0);
-	struct rhashtable_params ht_params = {
-		.head_offset = offsetof(struct netlink_sock, node),
-		.key_offset = offsetof(struct netlink_sock, portid),
-		.key_len = sizeof(u32), /* portid */
-		.hashfn = jhash,
-		.max_size = 65536,
-	};
 
 	if (err != 0)
 		goto out;
@@ -3136,7 +3159,8 @@ static int __init netlink_proto_init(void)
 		goto panic;
 
 	for (i = 0; i < MAX_LINKS; i++) {
-		if (rhashtable_init(&nl_table[i].hash, &ht_params) < 0) {
+		if (rhashtable_init(&nl_table[i].hash,
+				    &netlink_rhashtable_params) < 0) {
 			while (--i > 0)
 				rhashtable_destroy(&nl_table[i].hash);
 			kfree(nl_table);