appletalk: use sock slab cache

diff -Nru a/include/linux/atalk.h b/include/linux/atalk.h
@@ -63,6 +63,8 @@
 };
 	
 struct atalk_sock {
+	/* struct sock has to be the first member of atalk_sock */
+	struct sock	sk;
 	unsigned short	dest_net;
 	unsigned short	src_net;
 	unsigned char	dest_node;

@@ -71,6 +73,11 @@
 	unsigned char	src_port;
 };
 
+static inline struct atalk_sock *at_sk(struct sock *sk)
+{
+	return (struct atalk_sock *)sk;
+}
+
 #ifdef __KERNEL__
 
 #include <asm/byteorder.h>

@@ -196,8 +203,6 @@
 					   struct atalk_addr *sa);
 
 extern void		aarp_cleanup_module(void);
-
-#define at_sk(__sk) ((struct atalk_sock *)(__sk)->sk_protinfo)
 
 extern struct hlist_head atalk_sockets;
 extern rwlock_t atalk_sockets_lock;

diff -Nru a/net/appletalk/ddp.c b/net/appletalk/ddp.c
@@ -74,6 +74,8 @@
 HLIST_HEAD(atalk_sockets);
 DEFINE_RWLOCK(atalk_sockets_lock);
 
+static kmem_cache_t *atalk_sk_slab;
+
 static inline void __atalk_insert_socket(struct sock *sk)
 {
 	sk_add_node(sk, &atalk_sockets);

@@ -1022,7 +1024,6 @@
 static int atalk_create(struct socket *sock, int protocol)
 {
 	struct sock *sk;
-	struct atalk_sock *at;
 	int rc = -ESOCKTNOSUPPORT;
 
 	/*

@@ -1032,13 +1033,10 @@
 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
 		goto out;
 	rc = -ENOMEM;
-	sk = sk_alloc(PF_APPLETALK, GFP_KERNEL, 1, NULL);
+	sk = sk_alloc(PF_APPLETALK, GFP_KERNEL,
+		      sizeof(struct atalk_sock), atalk_sk_slab);
 	if (!sk)
 		goto out;
-	at = sk->sk_protinfo = kmalloc(sizeof(*at), GFP_KERNEL);
-	if (!at)
-		goto outsk;
-	memset(at, 0, sizeof(*at));
 	rc = 0;
 	sock->ops = &atalk_dgram_ops;
 	sock_init_data(sock, sk);

@@ -1048,9 +1046,6 @@
 	sk->sk_zapped = 1;
 out:
 	return rc;
-outsk:
-	sk_free(sk);
-	goto out;
 }
 
 /* Free a socket. No work needed */

@@ -1880,6 +1875,13 @@
 /* Called by proto.c on kernel start up */
 static int __init atalk_init(void)
 {
+	atalk_sk_slab = kmem_cache_create("appletalk_sock",
+					  sizeof(struct atalk_sock), 0,
+					  SLAB_HWCACHE_ALIGN, NULL, NULL);
+
+	if (atalk_sk_slab == NULL)
+		return -ENOMEM;
+
 	(void)sock_register(&atalk_family_ops);
 	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
 	if (!ddp_dl)

@@ -1917,6 +1919,11 @@
 	dev_remove_pack(&ppptalk_packet_type);
 	unregister_snap_client(ddp_dl);
 	sock_unregister(PF_APPLETALK);
+
+	if (atalk_sk_slab != NULL) {
+		kmem_cache_destroy(atalk_sk_slab);
+		atalk_sk_slab = NULL;
+	}
 }
 module_exit(atalk_exit);