[DCCP] CCID: Improve CCID infrastructure

1. No need for ->ccid_init nor ->ccid_exit, this is what module_{init,exit}
   does and anynways neither ccid2 nor ccid3 were using it.

2. Rename struct ccid to struct ccid_operations and introduce struct ccid
   with a pointer to ccid_operations and rigth after it the rx or tx
   private state.

3. Remove the pointer to the state of the half connections from struct
   dccp_sock, now its derived thru ccid_priv() from the ccid pointer.

Now we also can implement the setsockopt for changing the CCID easily as
no ccid init routines can affect struct dccp_sock in any way that prevents
other CCIDs from working if a CCID switch operation is asked by apps.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 260 insertions, 210 deletions

diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
index 06b191a5740..ff05e59043c 100644
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
@@ -13,7 +13,7 @@
 
 #include "ccid.h"
 
-static struct ccid *ccids[CCID_MAX];
+static struct ccid_operations *ccids[CCID_MAX];
 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
 static atomic_t ccids_lockct = ATOMIC_INIT(0);
 static DEFINE_SPINLOCK(ccids_lock);
@@ -55,82 +55,202 @@ static inline void ccids_read_unlock(void)
 #define ccids_read_unlock() do { } while(0)
 #endif
 
-int ccid_register(struct ccid *ccid)
+static kmem_cache_t *ccid_kmem_cache_create(int obj_size, const char *fmt,...)
 {
-	int err;
+	kmem_cache_t *slab;
+	char slab_name_fmt[32], *slab_name;
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(slab_name_fmt, sizeof(slab_name_fmt), fmt, args);
+	va_end(args);
+
+	slab_name = kstrdup(slab_name_fmt, GFP_KERNEL);
+	if (slab_name == NULL)
+		return NULL;
+	slab = kmem_cache_create(slab_name, sizeof(struct ccid) + obj_size, 0,
+				 SLAB_HWCACHE_ALIGN, NULL, NULL);
+	if (slab == NULL)
+		kfree(slab_name);
+	return slab;
+}
+
+static void ccid_kmem_cache_destroy(kmem_cache_t *slab)
+{
+	if (slab != NULL) {
+		const char *name = kmem_cache_name(slab);
+
+		kmem_cache_destroy(slab);
+		kfree(name);
+	}
+}
+
+int ccid_register(struct ccid_operations *ccid_ops)
+{
+	int err = -ENOBUFS;
+
+	ccid_ops->ccid_hc_rx_slab =
+			ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
+					       "%s_hc_rx_sock",
+					       ccid_ops->ccid_name);
+	if (ccid_ops->ccid_hc_rx_slab == NULL)
+		goto out;
+
+	ccid_ops->ccid_hc_tx_slab =
+			ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
+					       "%s_hc_tx_sock",
+					       ccid_ops->ccid_name);
+	if (ccid_ops->ccid_hc_tx_slab == NULL)
+		goto out_free_rx_slab;
 
 	ccids_write_lock();
 	err = -EEXIST;
-	if (ccids[ccid->ccid_id] == NULL) {
-		ccids[ccid->ccid_id] = ccid;
+	if (ccids[ccid_ops->ccid_id] == NULL) {
+		ccids[ccid_ops->ccid_id] = ccid_ops;
 		err = 0;
 	}
 	ccids_write_unlock();
-	if (err == 0)
-		pr_info("CCID: Registered CCID %d (%s)\n",
-			ccid->ccid_id, ccid->ccid_name);
+	if (err != 0)
+		goto out_free_tx_slab;
+
+	pr_info("CCID: Registered CCID %d (%s)\n",
+		ccid_ops->ccid_id, ccid_ops->ccid_name);
+out:
 	return err;
+out_free_tx_slab:
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
+	ccid_ops->ccid_hc_tx_slab = NULL;
+	goto out;
+out_free_rx_slab:
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
+	ccid_ops->ccid_hc_rx_slab = NULL;
+	goto out;
 }
 
 EXPORT_SYMBOL_GPL(ccid_register);
 
-int ccid_unregister(struct ccid *ccid)
+int ccid_unregister(struct ccid_operations *ccid_ops)
 {
 	ccids_write_lock();
-	ccids[ccid->ccid_id] = NULL;
+	ccids[ccid_ops->ccid_id] = NULL;
 	ccids_write_unlock();
+
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
+	ccid_ops->ccid_hc_tx_slab = NULL;
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
+	ccid_ops->ccid_hc_rx_slab = NULL;
+
 	pr_info("CCID: Unregistered CCID %d (%s)\n",
-		ccid->ccid_id, ccid->ccid_name);
+		ccid_ops->ccid_id, ccid_ops->ccid_name);
 	return 0;
 }
 
 EXPORT_SYMBOL_GPL(ccid_unregister);
 
-struct ccid *ccid_init(unsigned char id, struct sock *sk)
+struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
 {
-	struct ccid *ccid;
+	struct ccid_operations *ccid_ops;
+	struct ccid *ccid = NULL;
 
+	ccids_read_lock();
 #ifdef CONFIG_KMOD
-	if (ccids[id] == NULL)
+	if (ccids[id] == NULL) {
+		/* We only try to load if in process context */
+		ccids_read_unlock();
+		if (gfp & GFP_ATOMIC)
+			goto out;
 		request_module("net-dccp-ccid-%d", id);
+		ccids_read_lock();
+	}
 #endif
-	ccids_read_lock();
+	ccid_ops = ccids[id];
+	if (ccid_ops == NULL)
+		goto out_unlock;
 
-	ccid = ccids[id];
-	if (ccid == NULL)
-		goto out;
+	if (!try_module_get(ccid_ops->ccid_owner))
+		goto out_unlock;
 
-	if (!try_module_get(ccid->ccid_owner))
-		goto out_err;
+	ccids_read_unlock();
 
-	if (ccid->ccid_init != NULL && ccid->ccid_init(sk) != 0)
+	ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
+				     ccid_ops->ccid_hc_tx_slab, gfp);
+	if (ccid == NULL)
 		goto out_module_put;
+	ccid->ccid_ops = ccid_ops;
+	if (rx) {
+		memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
+		if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
+		    ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
+			goto out_free_ccid;
+	} else {
+		memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
+		if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
+		    ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
+			goto out_free_ccid;
+	}
 out:
-	ccids_read_unlock();
 	return ccid;
-out_module_put:
-	module_put(ccid->ccid_owner);
-out_err:
+out_unlock:
+	ccids_read_unlock();
+	goto out;
+out_free_ccid:
+	kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
+			ccid_ops->ccid_hc_tx_slab, ccid);
 	ccid = NULL;
+out_module_put:
+	module_put(ccid_ops->ccid_owner);
 	goto out;
 }
 
-EXPORT_SYMBOL_GPL(ccid_init);
+EXPORT_SYMBOL_GPL(ccid_new);
 
-void ccid_exit(struct ccid *ccid, struct sock *sk)
+struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp)
 {
+	return ccid_new(id, sk, 1, gfp);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_rx_new);
+
+struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk,  gfp_t gfp)
+{
+	return ccid_new(id, sk, 0, gfp);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_tx_new);
+
+static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx)
+{
+	struct ccid_operations *ccid_ops;
+
 	if (ccid == NULL)
 		return;
 
+	ccid_ops = ccid->ccid_ops;
+	if (rx) {
+		if (ccid_ops->ccid_hc_rx_exit != NULL)
+			ccid_ops->ccid_hc_rx_exit(sk);
+		kmem_cache_free(ccid_ops->ccid_hc_rx_slab,  ccid);
+	} else {
+		if (ccid_ops->ccid_hc_tx_exit != NULL)
+			ccid_ops->ccid_hc_tx_exit(sk);
+		kmem_cache_free(ccid_ops->ccid_hc_tx_slab,  ccid);
+	}
 	ccids_read_lock();
+	if (ccids[ccid_ops->ccid_id] != NULL)
+		module_put(ccid_ops->ccid_owner);
+	ccids_read_unlock();
+}
 
-	if (ccids[ccid->ccid_id] != NULL) {
-		if (ccid->ccid_exit != NULL)
-			ccid->ccid_exit(sk);
-		module_put(ccid->ccid_owner);
-	}
+void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
+{
+	ccid_delete(ccid, sk, 1);
+}
 
-	ccids_read_unlock();
+EXPORT_SYMBOL_GPL(ccid_hc_rx_delete);
+
+void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
+{
+	ccid_delete(ccid, sk, 0);
 }
 
-EXPORT_SYMBOL_GPL(ccid_exit);
+EXPORT_SYMBOL_GPL(ccid_hc_tx_delete);
diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index de681c6ad08..3dec50d4973 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -23,14 +23,16 @@
 
 struct tcp_info;
 
-struct ccid {
+struct ccid_operations {
 	unsigned char	ccid_id;
 	const char	*ccid_name;
 	struct module	*ccid_owner;
-	int		(*ccid_init)(struct sock *sk);
-	void		(*ccid_exit)(struct sock *sk);
-	int		(*ccid_hc_rx_init)(struct sock *sk);
-	int		(*ccid_hc_tx_init)(struct sock *sk);
+	kmem_cache_t	*ccid_hc_rx_slab;
+	__u32		ccid_hc_rx_obj_size;
+	kmem_cache_t	*ccid_hc_tx_slab;
+	__u32		ccid_hc_tx_obj_size;
+	int		(*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
+	int		(*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
 	void		(*ccid_hc_rx_exit)(struct sock *sk);
 	void		(*ccid_hc_tx_exit)(struct sock *sk);
 	void		(*ccid_hc_rx_packet_recv)(struct sock *sk,
@@ -67,75 +69,58 @@ struct ccid {
 						 int __user *optlen);
 };
 
-extern int	   ccid_register(struct ccid *ccid);
-extern int	   ccid_unregister(struct ccid *ccid);
+extern int ccid_register(struct ccid_operations *ccid_ops);
+extern int ccid_unregister(struct ccid_operations *ccid_ops);
 
-extern struct ccid *ccid_init(unsigned char id, struct sock *sk);
-extern void	   ccid_exit(struct ccid *ccid, struct sock *sk);
+struct ccid {
+	struct ccid_operations *ccid_ops;
+	char		       ccid_priv[0];
+};
 
-static inline void __ccid_get(struct ccid *ccid)
+static inline void *ccid_priv(const struct ccid *ccid)
 {
-	__module_get(ccid->ccid_owner);
+	return (void *)ccid->ccid_priv;
 }
 
+extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx,
+			     gfp_t gfp);
+
+extern struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk,
+				   gfp_t gfp);
+extern struct ccid *ccid_hc_tx_new(unsigned char id, struct sock *sk,
+				   gfp_t gfp);
+
+extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
+extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
+
 static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
 					 struct sk_buff *skb, int len)
 {
 	int rc = 0;
-	if (ccid->ccid_hc_tx_send_packet != NULL)
-		rc = ccid->ccid_hc_tx_send_packet(sk, skb, len);
+	if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb, len);
 	return rc;
 }
 
 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
 					  int more, int len)
 {
-	if (ccid->ccid_hc_tx_packet_sent != NULL)
-		ccid->ccid_hc_tx_packet_sent(sk, more, len);
-}
-
-static inline int ccid_hc_rx_init(struct ccid *ccid, struct sock *sk)
-{
-	int rc = 0;
-	if (ccid->ccid_hc_rx_init != NULL)
-		rc = ccid->ccid_hc_rx_init(sk);
-	return rc;
-}
-
-static inline int ccid_hc_tx_init(struct ccid *ccid, struct sock *sk)
-{
-	int rc = 0;
-	if (ccid->ccid_hc_tx_init != NULL)
-		rc = ccid->ccid_hc_tx_init(sk);
-	return rc;
-}
-
-static inline void ccid_hc_rx_exit(struct ccid *ccid, struct sock *sk)
-{
-	if (ccid != NULL && ccid->ccid_hc_rx_exit != NULL &&
-	    dccp_sk(sk)->dccps_hc_rx_ccid_private != NULL)
-		ccid->ccid_hc_rx_exit(sk);
-}
-
-static inline void ccid_hc_tx_exit(struct ccid *ccid, struct sock *sk)
-{
-	if (ccid != NULL && ccid->ccid_hc_tx_exit != NULL &&
-	    dccp_sk(sk)->dccps_hc_tx_ccid_private != NULL)
-		ccid->ccid_hc_tx_exit(sk);
+	if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
+		ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, more, len);
 }
 
 static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
 					  struct sk_buff *skb)
 {
-	if (ccid->ccid_hc_rx_packet_recv != NULL)
-		ccid->ccid_hc_rx_packet_recv(sk, skb);
+	if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
+		ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
 }
 
 static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
 					  struct sk_buff *skb)
 {
-	if (ccid->ccid_hc_tx_packet_recv != NULL)
-		ccid->ccid_hc_tx_packet_recv(sk, skb);
+	if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
+		ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
 }
 
 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
@@ -144,8 +129,8 @@ static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
 					   unsigned char* value)
 {
 	int rc = 0;
-	if (ccid->ccid_hc_tx_parse_options != NULL)
-		rc = ccid->ccid_hc_tx_parse_options(sk, option, len, idx,
+	if (ccid->ccid_ops->ccid_hc_tx_parse_options != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_parse_options(sk, option, len, idx,
 						    value);
 	return rc;
 }
@@ -156,37 +141,37 @@ static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
 					   unsigned char* value)
 {
 	int rc = 0;
-	if (ccid->ccid_hc_rx_parse_options != NULL)
-		rc = ccid->ccid_hc_rx_parse_options(sk, option, len, idx, value);
+	if (ccid->ccid_ops->ccid_hc_rx_parse_options != NULL)
+		rc = ccid->ccid_ops->ccid_hc_rx_parse_options(sk, option, len, idx, value);
 	return rc;
 }
 
 static inline void ccid_hc_tx_insert_options(struct ccid *ccid, struct sock *sk,
 					     struct sk_buff *skb)
 {
-	if (ccid->ccid_hc_tx_insert_options != NULL)
-		ccid->ccid_hc_tx_insert_options(sk, skb);
+	if (ccid->ccid_ops->ccid_hc_tx_insert_options != NULL)
+		ccid->ccid_ops->ccid_hc_tx_insert_options(sk, skb);
 }
 
 static inline void ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
 					     struct sk_buff *skb)
 {
-	if (ccid->ccid_hc_rx_insert_options != NULL)
-		ccid->ccid_hc_rx_insert_options(sk, skb);
+	if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
+		ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
 }
 
 static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
 				       struct tcp_info *info)
 {
-	if (ccid->ccid_hc_rx_get_info != NULL)
-		ccid->ccid_hc_rx_get_info(sk, info);
+	if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
+		ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
 }
 
 static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
 				       struct tcp_info *info)
 {
-	if (ccid->ccid_hc_tx_get_info != NULL)
-		ccid->ccid_hc_tx_get_info(sk, info);
+	if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
+		ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
 }
 
 static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
@@ -194,8 +179,8 @@ static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
 					u32 __user *optval, int __user *optlen)
 {
 	int rc = -ENOPROTOOPT;
-	if (ccid->ccid_hc_rx_getsockopt != NULL)
-		rc = ccid->ccid_hc_rx_getsockopt(sk, optname, len,
+	if (ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
+		rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
 						 optval, optlen);
 	return rc;
 }
@@ -205,8 +190,8 @@ static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
 					u32 __user *optval, int __user *optlen)
 {
 	int rc = -ENOPROTOOPT;
-	if (ccid->ccid_hc_tx_getsockopt != NULL)
-		rc = ccid->ccid_hc_tx_getsockopt(sk, optname, len,
+	if (ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
 						 optval, optlen);
 	return rc;
 }
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 3328d23c4be..b40c4569a82 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -52,16 +52,6 @@ static int ccid2_debug;
 
 static const int ccid2_seq_len = 128;
 
-static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
-{
-	return dccp_sk(sk)->dccps_hc_tx_ccid_private;
-}
-
-static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
-{
-	return dccp_sk(sk)->dccps_hc_rx_ccid_private;
-}
-
 #ifdef CCID2_DEBUG
 static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
 {
@@ -707,19 +697,12 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	ccid2_hc_tx_check_sanity(hctx);
 }
 
-static int ccid2_hc_tx_init(struct sock *sk)
+static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
-        struct ccid2_hc_tx_sock *hctx;
+        struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
 	int seqcount = ccid2_seq_len;
 	int i;
 
-        dp->dccps_hc_tx_ccid_private = kzalloc(sizeof(*hctx), gfp_any());
-        if (dp->dccps_hc_tx_ccid_private == NULL)
-                return -ENOMEM;
-
-        hctx = ccid2_hc_tx_sk(sk);
-
 	/* XXX init variables with proper values */
 	hctx->ccid2hctx_cwnd	  = 1;
 	hctx->ccid2hctx_ssthresh  = 10;
@@ -728,11 +711,9 @@ static int ccid2_hc_tx_init(struct sock *sk)
 	/* XXX init ~ to window size... */
 	hctx->ccid2hctx_seqbuf = kmalloc(sizeof(*hctx->ccid2hctx_seqbuf) *
 					 seqcount, gfp_any());
-	if (hctx->ccid2hctx_seqbuf == NULL) {
-		kfree(dp->dccps_hc_tx_ccid_private);
-		dp->dccps_hc_tx_ccid_private = NULL;
+	if (hctx->ccid2hctx_seqbuf == NULL)
 		return -ENOMEM;
-	}
+
 	for (i = 0; i < (seqcount - 1); i++) {
 		hctx->ccid2hctx_seqbuf[i].ccid2s_next =
 					&hctx->ccid2hctx_seqbuf[i + 1];
@@ -763,15 +744,11 @@ static int ccid2_hc_tx_init(struct sock *sk)
 
 static void ccid2_hc_tx_exit(struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
         struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
 
 	ccid2_hc_tx_kill_rto_timer(sk);
-
 	kfree(hctx->ccid2hctx_seqbuf);
-
-	kfree(dp->dccps_hc_tx_ccid_private);
-	dp->dccps_hc_tx_ccid_private = NULL;
+	hctx->ccid2hctx_seqbuf = NULL;
 }
 
 static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
@@ -791,33 +768,17 @@ static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-static int ccid2_hc_rx_init(struct sock *sk)
-{
-	struct dccp_sock *dp = dccp_sk(sk);
-        dp->dccps_hc_rx_ccid_private = kzalloc(sizeof(struct ccid2_hc_rx_sock),
-					       gfp_any());
-        return dp->dccps_hc_rx_ccid_private == NULL ? -ENOMEM : 0;
-}
-
-static void ccid2_hc_rx_exit(struct sock *sk)
-{
-	struct dccp_sock *dp = dccp_sk(sk);
-
-	kfree(dp->dccps_hc_rx_ccid_private);
-	dp->dccps_hc_rx_ccid_private = NULL;
-}
-
-static struct ccid ccid2 = {
+static struct ccid_operations ccid2 = {
 	.ccid_id		= 2,
 	.ccid_name		= "ccid2",
 	.ccid_owner		= THIS_MODULE,
+	.ccid_hc_tx_obj_size	= sizeof(struct ccid2_hc_tx_sock),
 	.ccid_hc_tx_init	= ccid2_hc_tx_init,
 	.ccid_hc_tx_exit	= ccid2_hc_tx_exit,
 	.ccid_hc_tx_send_packet	= ccid2_hc_tx_send_packet,
 	.ccid_hc_tx_packet_sent	= ccid2_hc_tx_packet_sent,
 	.ccid_hc_tx_packet_recv	= ccid2_hc_tx_packet_recv,
-	.ccid_hc_rx_init	= ccid2_hc_rx_init,
-	.ccid_hc_rx_exit	= ccid2_hc_rx_exit,
+	.ccid_hc_rx_obj_size	= sizeof(struct ccid2_hc_rx_sock),
 	.ccid_hc_rx_packet_recv	= ccid2_hc_rx_packet_recv,
 };
 
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 0b08c90955a..451a87464fa 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -20,6 +20,13 @@
 #ifndef _DCCP_CCID2_H_
 #define _DCCP_CCID2_H_
 
+#include <linux/dccp.h>
+#include <linux/timer.h>
+#include <linux/types.h>
+#include "../ccid.h"
+
+struct sock;
+
 struct ccid2_seq {
 	u64			ccid2s_seq;
 	unsigned long		ccid2s_sent;
@@ -66,4 +73,13 @@ struct ccid2_hc_rx_sock {
 	int	ccid2hcrx_data;
 };
 
+static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
+}
+
+static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
+}
 #endif /* _DCCP_CCID2_H_ */
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index f9e16db09be..0587f52e4af 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -647,17 +647,10 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
 	return rc;
 }
 
-static int ccid3_hc_tx_init(struct sock *sk)
+static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
-	struct ccid3_hc_tx_sock *hctx;
-
-	dp->dccps_hc_tx_ccid_private = kmalloc(sizeof(*hctx), gfp_any());
-	if (dp->dccps_hc_tx_ccid_private == NULL)
-		return -ENOMEM;
-
-	hctx = ccid3_hc_tx_sk(sk);
-	memset(hctx, 0, sizeof(*hctx));
+	struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
 
 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
@@ -680,7 +673,6 @@ static int ccid3_hc_tx_init(struct sock *sk)
 
 static void ccid3_hc_tx_exit(struct sock *sk)
 {
-	struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
 
 	BUG_ON(hctx == NULL);
@@ -690,9 +682,6 @@ static void ccid3_hc_tx_exit(struct sock *sk)
 
 	/* Empty packet history */
 	dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
-
-	kfree(dp->dccps_hc_tx_ccid_private);
-	dp->dccps_hc_tx_ccid_private = NULL;
 }
 
 /*
@@ -1039,20 +1028,13 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-static int ccid3_hc_rx_init(struct sock *sk)
+static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
-	struct ccid3_hc_rx_sock *hcrx;
+	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
 
 	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
 
-	dp->dccps_hc_rx_ccid_private = kmalloc(sizeof(*hcrx), gfp_any());
-	if (dp->dccps_hc_rx_ccid_private == NULL)
-		return -ENOMEM;
-
-	hcrx = ccid3_hc_rx_sk(sk);
-	memset(hcrx, 0, sizeof(*hcrx));
-
 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
 		hcrx->ccid3hcrx_s = dp->dccps_packet_size;
@@ -1071,7 +1053,6 @@ static int ccid3_hc_rx_init(struct sock *sk)
 static void ccid3_hc_rx_exit(struct sock *sk)
 {
 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
-	struct dccp_sock *dp = dccp_sk(sk);
 
 	BUG_ON(hcrx == NULL);
 
@@ -1082,9 +1063,6 @@ static void ccid3_hc_rx_exit(struct sock *sk)
 
 	/* Empty loss interval history */
 	dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
-
-	kfree(dp->dccps_hc_rx_ccid_private);
-	dp->dccps_hc_rx_ccid_private = NULL;
 }
 
 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
@@ -1170,10 +1148,11 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
 	return 0;
 }
 
-static struct ccid ccid3 = {
+static struct ccid_operations ccid3 = {
 	.ccid_id		   = 3,
 	.ccid_name		   = "ccid3",
 	.ccid_owner		   = THIS_MODULE,
+	.ccid_hc_tx_obj_size	   = sizeof(struct ccid3_hc_tx_sock),
 	.ccid_hc_tx_init	   = ccid3_hc_tx_init,
 	.ccid_hc_tx_exit	   = ccid3_hc_tx_exit,
 	.ccid_hc_tx_send_packet	   = ccid3_hc_tx_send_packet,
@@ -1181,6 +1160,7 @@ static struct ccid ccid3 = {
 	.ccid_hc_tx_packet_recv	   = ccid3_hc_tx_packet_recv,
 	.ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
 	.ccid_hc_tx_parse_options  = ccid3_hc_tx_parse_options,
+	.ccid_hc_rx_obj_size	   = sizeof(struct ccid3_hc_rx_sock),
 	.ccid_hc_rx_init	   = ccid3_hc_rx_init,
 	.ccid_hc_rx_exit	   = ccid3_hc_rx_exit,
 	.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index 0bde4583d09..f18b96d4e5a 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -41,6 +41,7 @@
 #include <linux/time.h>
 #include <linux/types.h>
 #include <linux/tfrc.h>
+#include "../ccid.h"
 
 #define TFRC_MIN_PACKET_SIZE	   16
 #define TFRC_STD_PACKET_SIZE	  256
@@ -135,12 +136,12 @@ struct ccid3_hc_rx_sock {
 
 static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
 {
-    return dccp_sk(sk)->dccps_hc_tx_ccid_private;
+    return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
 }
 
 static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
 {
-    return dccp_sk(sk)->dccps_hc_rx_ccid_private;
+    return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
 }
 
 #endif /* _DCCP_CCID3_H_ */
diff --git a/net/dccp/input.c b/net/dccp/input.c
index 4b6d43d8b92..67691a0592a 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -324,14 +324,6 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
 		dccp_set_seqno(&dp->dccps_swl,
 			       max48(dp->dccps_swl, dp->dccps_isr));
 
-		if (ccid_hc_rx_init(dp->dccps_hc_rx_ccid, sk) != 0 ||
-		    ccid_hc_tx_init(dp->dccps_hc_tx_ccid, sk) != 0) {
-			ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
-			ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
-			/* FIXME: send appropriate RESET code */
-			goto out_invalid_packet;
-		}
-
 		dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 
 		/*
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index fcfb486f90c..aa7708fed32 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -1058,14 +1058,16 @@ int dccp_v4_init_sock(struct sock *sk)
 			if (dp->dccps_hc_rx_ackvec == NULL)
 				return -ENOMEM;
 		}
-		dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_rx_ccid,
-						 sk);
-		dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_tx_ccid,
-						 sk);
-	    	if (dp->dccps_hc_rx_ccid == NULL ||
-		    dp->dccps_hc_tx_ccid == NULL) {
-			ccid_exit(dp->dccps_hc_rx_ccid, sk);
-			ccid_exit(dp->dccps_hc_tx_ccid, sk);
+		dp->dccps_hc_rx_ccid =
+				ccid_hc_rx_new(dp->dccps_options.dccpo_rx_ccid,
+					       sk, GFP_KERNEL);
+		dp->dccps_hc_tx_ccid =
+				ccid_hc_tx_new(dp->dccps_options.dccpo_tx_ccid,
+					       sk, GFP_KERNEL);
+	    	if (unlikely(dp->dccps_hc_rx_ccid == NULL ||
+			     dp->dccps_hc_tx_ccid == NULL)) {
+			ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+			ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 			if (dp->dccps_options.dccpo_send_ack_vector) {
 				dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
 				dp->dccps_hc_rx_ackvec = NULL;
@@ -1120,14 +1122,12 @@ int dccp_v4_destroy_sock(struct sock *sk)
 	kfree(dp->dccps_service_list);
 	dp->dccps_service_list = NULL;
 
-	ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
-	ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
 	if (dp->dccps_options.dccpo_send_ack_vector) {
 		dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
 		dp->dccps_hc_rx_ackvec = NULL;
 	}
-	ccid_exit(dp->dccps_hc_rx_ccid, sk);
-	ccid_exit(dp->dccps_hc_tx_ccid, sk);
+	ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+	ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 	dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
 
 	/* clean up feature negotiation state */
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index 9e1de5919ee..5324fcacb34 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -121,23 +121,21 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
 		if (newdp->dccps_options.dccpo_send_ack_vector) {
 			newdp->dccps_hc_rx_ackvec =
 						dccp_ackvec_alloc(GFP_ATOMIC);
-			/*
-			 * XXX: We're using the same CCIDs set on the parent,
-			 * i.e. sk_clone copied the master sock and left the
-			 * CCID pointers for this child, that is why we do the
-			 * __ccid_get calls.
-			 */
 			if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
 				goto out_free;
 		}
 
-		if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid,
-					     newsk) != 0 ||
-			     ccid_hc_tx_init(newdp->dccps_hc_tx_ccid,
-				     	     newsk) != 0)) {
+		newdp->dccps_hc_rx_ccid =
+			    ccid_hc_rx_new(newdp->dccps_options.dccpo_rx_ccid,
+					   newsk, GFP_ATOMIC);
+		newdp->dccps_hc_tx_ccid =
+			    ccid_hc_tx_new(newdp->dccps_options.dccpo_tx_ccid,
+					   newsk, GFP_ATOMIC);
+		if (unlikely(newdp->dccps_hc_rx_ccid == NULL ||
+			     newdp->dccps_hc_tx_ccid == NULL)) {
 			dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
-			ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk);
-			ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk);
+			ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
+			ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
 out_free:
 			/* It is still raw copy of parent, so invalidate
 			 * destructor and make plain sk_free() */
@@ -146,9 +144,6 @@ out_free:
 			return NULL;
 		}
 
-		__ccid_get(newdp->dccps_hc_rx_ccid);
-		__ccid_get(newdp->dccps_hc_tx_ccid);
-
 		/*
 		 * Step 3: Process LISTEN state
 		 *