Patchwork [net-next,v2,04/12] netfilter: regard users as refcount for l4proto's per-net data

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Submitter Gao feng
Date June 16, 2012, 3:41 a.m.
Message ID <1339818083-31356-4-git-send-email-gaofeng@cn.fujitsu.com>
Download mbox | patch
Permalink /patch/165279/
State Superseded
Headers show

Comments

Gao feng - June 16, 2012, 3:41 a.m.
Now, nf_proto_net's users is confusing.
we should regard it as the refcount for l4proto's per-net data,
because maybe there are two l4protos use the same per-net data.

so increment pn->users when nf_conntrack_l4proto_register
success, and decrement it for nf_conntrack_l4_unregister case.

because nf_conntrack_l3proto_ipv[4|6] don't use the same per-net
data,so we don't need to add a refcnt for their per-net data.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
---
 net/netfilter/nf_conntrack_proto.c |   71 +++++++++++++++++++++++-------------
 1 files changed, 46 insertions(+), 25 deletions(-)
Pablo Neira - June 16, 2012, 10:54 a.m.
On Sat, Jun 16, 2012 at 11:41:15AM +0800, Gao feng wrote:
> Now, nf_proto_net's users is confusing.
> we should regard it as the refcount for l4proto's per-net data,
> because maybe there are two l4protos use the same per-net data.
> 
> so increment pn->users when nf_conntrack_l4proto_register
> success, and decrement it for nf_conntrack_l4_unregister case.
> 
> because nf_conntrack_l3proto_ipv[4|6] don't use the same per-net
> data,so we don't need to add a refcnt for their per-net data.
> 
> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
> ---
>  net/netfilter/nf_conntrack_proto.c |   71 +++++++++++++++++++++++-------------
>  1 files changed, 46 insertions(+), 25 deletions(-)
> 
> diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
> index 1033ee6..86dbf9d 100644
> --- a/net/netfilter/nf_conntrack_proto.c
> +++ b/net/netfilter/nf_conntrack_proto.c
> @@ -39,16 +39,13 @@ static int
>  nf_ct_register_sysctl(struct net *net,
>  		      struct ctl_table_header **header,
>  		      const char *path,
> -		      struct ctl_table *table,
> -		      unsigned int *users)
> +		      struct ctl_table *table)
>  {
>  	if (*header == NULL) {
>  		*header = register_net_sysctl(net, path, table);
>  		if (*header == NULL)
>  			return -ENOMEM;
>  	}
> -	if (users != NULL)
> -		(*users)++;
>  
>  	return 0;
>  }
> @@ -58,7 +55,7 @@ nf_ct_unregister_sysctl(struct ctl_table_header **header,
>  			struct ctl_table **table,
>  			unsigned int *users)
>  {
> -	if (users != NULL && --*users > 0)
> +	if (users != NULL && *users > 0)

We're not decrementing users anymore. Use unsigned int users instead.
Pass 0 for the layer 3 case to emulate the users refcnt.

>  		return;
>  
>  	unregister_net_sysctl_table(*header);
> @@ -191,8 +188,8 @@ static int nf_ct_l3proto_register_sysctl(struct net *net,
>  		err = nf_ct_register_sysctl(net,
>  					    &in->ctl_table_header,
>  					    l3proto->ctl_table_path,
> -					    in->ctl_table,
> -					    NULL);
> +					    in->ctl_table);
> +
>  		if (err < 0) {
>  			kfree(in->ctl_table);
>  			in->ctl_table = NULL;
> @@ -338,20 +335,17 @@ EXPORT_SYMBOL_GPL(nf_ct_kfree_compat_sysctl_table);
>  
>  static
>  int nf_ct_l4proto_register_sysctl(struct net *net,
> +				  struct nf_proto_net *pn,
>  				  struct nf_conntrack_l4proto *l4proto)
>  {
>  	int err = 0;
> -	struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto);
> -	if (pn == NULL)
> -		return 0;
>  
>  #ifdef CONFIG_SYSCTL
>  	if (pn->ctl_table != NULL) {
>  		err = nf_ct_register_sysctl(net,
>  					    &pn->ctl_table_header,
>  					    "net/netfilter",
> -					    pn->ctl_table,
> -					    &pn->users);
> +					    pn->ctl_table);
>  		if (err < 0) {
>  			if (!pn->users) {
>  				kfree(pn->ctl_table);
> @@ -365,8 +359,7 @@ int nf_ct_l4proto_register_sysctl(struct net *net,
>  		err = nf_ct_register_sysctl(net,
>  					    &pn->ctl_compat_header,
>  					    "net/ipv4/netfilter",
> -					    pn->ctl_compat_table,
> -					    NULL);
> +					    pn->ctl_compat_table);
>  		if (err == 0)
>  			goto out;
>  
> @@ -383,11 +376,9 @@ out:
>  
>  static
>  void nf_ct_l4proto_unregister_sysctl(struct net *net,
> +				     struct nf_proto_net *pn,
>  				     struct nf_conntrack_l4proto *l4proto)
>  {
> -	struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto);
> -	if (pn == NULL)
> -		return;
>  #ifdef CONFIG_SYSCTL
>  	if (pn->ctl_table_header != NULL)
>  		nf_ct_unregister_sysctl(&pn->ctl_table_header,
> @@ -400,8 +391,6 @@ void nf_ct_l4proto_unregister_sysctl(struct net *net,
>  					&pn->ctl_compat_table,
>  					NULL);
>  #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
> -#else
> -	pn->users--;
>  #endif /* CONFIG_SYSCTL */
>  }
>  
> @@ -467,22 +456,33 @@ int nf_conntrack_l4proto_register(struct net *net,
>  				  struct nf_conntrack_l4proto *l4proto)
>  {
>  	int ret = 0;
> +

why this extra line above?

> +	struct nf_proto_net *pn = NULL;
> +
>  	if (l4proto->init_net) {
>  		ret = l4proto->init_net(net, l4proto->l3proto);
>  		if (ret < 0)
> -			return ret;
> +			goto out;
>  	}
>  
> -	ret = nf_ct_l4proto_register_sysctl(net, l4proto);
> +	pn = nf_ct_l4proto_net(net, l4proto);
> +	if (pn == NULL)
> +		goto out;
> +
> +	ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto);
>  	if (ret < 0)
> -		return ret;
> +		goto out;
>  
>  	if (net == &init_net) {
>  		ret = nf_conntrack_l4proto_register_net(l4proto);
> -		if (ret < 0)
> -			nf_ct_l4proto_unregister_sysctl(net, l4proto);
> +		if (ret < 0) {
> +			nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
> +			goto out;
> +		}
>  	}
>  
> +	pn->users++;
> +out:
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
> @@ -507,10 +507,17 @@ nf_conntrack_l4proto_unregister_net(struct nf_conntrack_l4proto *l4proto)
>  void nf_conntrack_l4proto_unregister(struct net *net,
>  				     struct nf_conntrack_l4proto *l4proto)
>  {
> +	struct nf_proto_net *pn = NULL;
>  	if (net == &init_net)
>  		nf_conntrack_l4proto_unregister_net(l4proto);
>  
> -	nf_ct_l4proto_unregister_sysctl(net, l4proto);
> +	pn = nf_ct_l4proto_net(net, l4proto);
> +	if (pn == NULL)
> +		return;
> +
> +	pn->users--;
> +	nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
> +
>  	/* Remove all contrack entries for this protocol */
>  	rtnl_lock();
>  	nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
> @@ -522,11 +529,15 @@ int nf_conntrack_proto_init(struct net *net)
>  {
>  	unsigned int i;
>  	int err;
> +	struct nf_proto_net *pn = nf_ct_l4proto_net(net,
> +					&nf_conntrack_l4proto_generic);
> +
>  	err = nf_conntrack_l4proto_generic.init_net(net,
>  					nf_conntrack_l4proto_generic.l3proto);
>  	if (err < 0)
>  		return err;
>  	err = nf_ct_l4proto_register_sysctl(net,
> +					    pn,
>  					    &nf_conntrack_l4proto_generic);
>  	if (err < 0)
>  		return err;
> @@ -536,13 +547,23 @@ int nf_conntrack_proto_init(struct net *net)
>  			rcu_assign_pointer(nf_ct_l3protos[i],
>  					   &nf_conntrack_l3proto_generic);
>  	}
> +
> +	/* increase generic proto's nf_proto_net refcnt */
> +	pn->users++;
> +
>  	return 0;
>  }
>  
>  void nf_conntrack_proto_fini(struct net *net)
>  {
>  	unsigned int i;
> +	struct nf_proto_net *pn = nf_ct_l4proto_net(net,
> +					&nf_conntrack_l4proto_generic);
> +
> +	/* decrease generic proto's nf_proto_net refcnt */

I asked you to remove this comment, it's superfluous.

> +	pn->users--;
>  	nf_ct_l4proto_unregister_sysctl(net,
> +					pn,
>  					&nf_conntrack_l4proto_generic);
>  	if (net == &init_net) {
>  		/* free l3proto protocol tables */
> -- 
> 1.7.7.6
> 
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Patch

diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
index 1033ee6..86dbf9d 100644
--- a/net/netfilter/nf_conntrack_proto.c
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -39,16 +39,13 @@  static int
 nf_ct_register_sysctl(struct net *net,
 		      struct ctl_table_header **header,
 		      const char *path,
-		      struct ctl_table *table,
-		      unsigned int *users)
+		      struct ctl_table *table)
 {
 	if (*header == NULL) {
 		*header = register_net_sysctl(net, path, table);
 		if (*header == NULL)
 			return -ENOMEM;
 	}
-	if (users != NULL)
-		(*users)++;
 
 	return 0;
 }
@@ -58,7 +55,7 @@  nf_ct_unregister_sysctl(struct ctl_table_header **header,
 			struct ctl_table **table,
 			unsigned int *users)
 {
-	if (users != NULL && --*users > 0)
+	if (users != NULL && *users > 0)
 		return;
 
 	unregister_net_sysctl_table(*header);
@@ -191,8 +188,8 @@  static int nf_ct_l3proto_register_sysctl(struct net *net,
 		err = nf_ct_register_sysctl(net,
 					    &in->ctl_table_header,
 					    l3proto->ctl_table_path,
-					    in->ctl_table,
-					    NULL);
+					    in->ctl_table);
+
 		if (err < 0) {
 			kfree(in->ctl_table);
 			in->ctl_table = NULL;
@@ -338,20 +335,17 @@  EXPORT_SYMBOL_GPL(nf_ct_kfree_compat_sysctl_table);
 
 static
 int nf_ct_l4proto_register_sysctl(struct net *net,
+				  struct nf_proto_net *pn,
 				  struct nf_conntrack_l4proto *l4proto)
 {
 	int err = 0;
-	struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto);
-	if (pn == NULL)
-		return 0;
 
 #ifdef CONFIG_SYSCTL
 	if (pn->ctl_table != NULL) {
 		err = nf_ct_register_sysctl(net,
 					    &pn->ctl_table_header,
 					    "net/netfilter",
-					    pn->ctl_table,
-					    &pn->users);
+					    pn->ctl_table);
 		if (err < 0) {
 			if (!pn->users) {
 				kfree(pn->ctl_table);
@@ -365,8 +359,7 @@  int nf_ct_l4proto_register_sysctl(struct net *net,
 		err = nf_ct_register_sysctl(net,
 					    &pn->ctl_compat_header,
 					    "net/ipv4/netfilter",
-					    pn->ctl_compat_table,
-					    NULL);
+					    pn->ctl_compat_table);
 		if (err == 0)
 			goto out;
 
@@ -383,11 +376,9 @@  out:
 
 static
 void nf_ct_l4proto_unregister_sysctl(struct net *net,
+				     struct nf_proto_net *pn,
 				     struct nf_conntrack_l4proto *l4proto)
 {
-	struct nf_proto_net *pn = nf_ct_l4proto_net(net, l4proto);
-	if (pn == NULL)
-		return;
 #ifdef CONFIG_SYSCTL
 	if (pn->ctl_table_header != NULL)
 		nf_ct_unregister_sysctl(&pn->ctl_table_header,
@@ -400,8 +391,6 @@  void nf_ct_l4proto_unregister_sysctl(struct net *net,
 					&pn->ctl_compat_table,
 					NULL);
 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
-#else
-	pn->users--;
 #endif /* CONFIG_SYSCTL */
 }
 
@@ -467,22 +456,33 @@  int nf_conntrack_l4proto_register(struct net *net,
 				  struct nf_conntrack_l4proto *l4proto)
 {
 	int ret = 0;
+
+	struct nf_proto_net *pn = NULL;
+
 	if (l4proto->init_net) {
 		ret = l4proto->init_net(net, l4proto->l3proto);
 		if (ret < 0)
-			return ret;
+			goto out;
 	}
 
-	ret = nf_ct_l4proto_register_sysctl(net, l4proto);
+	pn = nf_ct_l4proto_net(net, l4proto);
+	if (pn == NULL)
+		goto out;
+
+	ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	if (net == &init_net) {
 		ret = nf_conntrack_l4proto_register_net(l4proto);
-		if (ret < 0)
-			nf_ct_l4proto_unregister_sysctl(net, l4proto);
+		if (ret < 0) {
+			nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
+			goto out;
+		}
 	}
 
+	pn->users++;
+out:
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
@@ -507,10 +507,17 @@  nf_conntrack_l4proto_unregister_net(struct nf_conntrack_l4proto *l4proto)
 void nf_conntrack_l4proto_unregister(struct net *net,
 				     struct nf_conntrack_l4proto *l4proto)
 {
+	struct nf_proto_net *pn = NULL;
 	if (net == &init_net)
 		nf_conntrack_l4proto_unregister_net(l4proto);
 
-	nf_ct_l4proto_unregister_sysctl(net, l4proto);
+	pn = nf_ct_l4proto_net(net, l4proto);
+	if (pn == NULL)
+		return;
+
+	pn->users--;
+	nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
+
 	/* Remove all contrack entries for this protocol */
 	rtnl_lock();
 	nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
@@ -522,11 +529,15 @@  int nf_conntrack_proto_init(struct net *net)
 {
 	unsigned int i;
 	int err;
+	struct nf_proto_net *pn = nf_ct_l4proto_net(net,
+					&nf_conntrack_l4proto_generic);
+
 	err = nf_conntrack_l4proto_generic.init_net(net,
 					nf_conntrack_l4proto_generic.l3proto);
 	if (err < 0)
 		return err;
 	err = nf_ct_l4proto_register_sysctl(net,
+					    pn,
 					    &nf_conntrack_l4proto_generic);
 	if (err < 0)
 		return err;
@@ -536,13 +547,23 @@  int nf_conntrack_proto_init(struct net *net)
 			rcu_assign_pointer(nf_ct_l3protos[i],
 					   &nf_conntrack_l3proto_generic);
 	}
+
+	/* increase generic proto's nf_proto_net refcnt */
+	pn->users++;
+
 	return 0;
 }
 
 void nf_conntrack_proto_fini(struct net *net)
 {
 	unsigned int i;
+	struct nf_proto_net *pn = nf_ct_l4proto_net(net,
+					&nf_conntrack_l4proto_generic);
+
+	/* decrease generic proto's nf_proto_net refcnt */
+	pn->users--;
 	nf_ct_l4proto_unregister_sysctl(net,
+					pn,
 					&nf_conntrack_l4proto_generic);
 	if (net == &init_net) {
 		/* free l3proto protocol tables */