diff mbox

[02/17] netfilter: nat: remove module reference counting from NAT protocols

Message ID 1321854369-3432-3-git-send-email-kaber@trash.net
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Patrick McHardy Nov. 21, 2011, 5:45 a.m. UTC 
From: Patrick McHardy <kaber@trash.net>

The only remaining user of NAT protocol module reference counting is NAT
ctnetlink support. Since this is a fairly short sequence of code, convert
over to use RCU and remove module reference counting.

Signed-off-by: Patrick McHardy <kaber@trash.net>
---
 include/net/netfilter/nf_nat_protocol.h   |    2 --
 net/ipv4/netfilter/nf_nat_core.c          |   26 ++++----------------------
 net/ipv4/netfilter/nf_nat_proto_dccp.c    |    1 -
 net/ipv4/netfilter/nf_nat_proto_gre.c     |    1 -
 net/ipv4/netfilter/nf_nat_proto_icmp.c    |    1 -
 net/ipv4/netfilter/nf_nat_proto_sctp.c    |    1 -
 net/ipv4/netfilter/nf_nat_proto_tcp.c     |    1 -
 net/ipv4/netfilter/nf_nat_proto_udp.c     |    1 -
 net/ipv4/netfilter/nf_nat_proto_udplite.c |    1 -
 net/ipv4/netfilter/nf_nat_proto_unknown.c |    1 -
 10 files changed, 4 insertions(+), 32 deletions(-)

Comments

Eric Dumazet Nov. 21, 2011, 7:36 a.m. UTC | #1 
Le lundi 21 novembre 2011 à 06:45 +0100, kaber@trash.net a écrit :
> From: Patrick McHardy <kaber@trash.net>
> 
> The only remaining user of NAT protocol module reference counting is NAT
> ctnetlink support. Since this is a fairly short sequence of code, convert
> over to use RCU and remove module reference counting.
> 
> Signed-off-by: Patrick McHardy <kaber@trash.net>

> @@ -612,16 +592,18 @@ static int nfnetlink_parse_nat_proto(struct nlattr *attr,
>  	if (err < 0)
>  		return err;
>  
> -	npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
> +	rcu_read_lock();
> +	npt = __nf_nat_proto_find(nf_ct_protonum(ct));
>  	if (npt->nlattr_to_range)
>  		err = npt->nlattr_to_range(tb, range);
> -	nf_nat_proto_put(npt);
> +	rcu_read_unlock();
>  	return err;
>  }

Seems good, but you should explain in changelog why its safe.

(Using rcu also means special action must be taken in the write side,
here the module removal)

>  
>  static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
>  	[CTA_NAT_MINIP]		= { .type = NLA_U32 },
>  	[CTA_NAT_MAXIP]		= { .type = NLA_U32 },
> +	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
>  };

I just dont understand this part :-(



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Patrick McHardy Nov. 21, 2011, 2:59 p.m. UTC | #2 
On 11/21/2011 08:36 AM, Eric Dumazet wrote:
> Le lundi 21 novembre 2011 à 06:45 +0100, kaber@trash.net a écrit :
>> From: Patrick McHardy<kaber@trash.net>
>>
>> The only remaining user of NAT protocol module reference counting is NAT
>> ctnetlink support. Since this is a fairly short sequence of code, convert
>> over to use RCU and remove module reference counting.
>>
>> Signed-off-by: Patrick McHardy<kaber@trash.net>
>> @@ -612,16 +592,18 @@ static int nfnetlink_parse_nat_proto(struct nlattr *attr,
>>   	if (err<  0)
>>   		return err;
>>
>> -	npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
>> +	rcu_read_lock();
>> +	npt = __nf_nat_proto_find(nf_ct_protonum(ct));
>>   	if (npt->nlattr_to_range)
>>   		err = npt->nlattr_to_range(tb, range);
>> -	nf_nat_proto_put(npt);
>> +	rcu_read_unlock();
>>   	return err;
>>   }
> Seems good, but you should explain in changelog why its safe.
>
> (Using rcu also means special action must be taken in the write side,
> here the module removal)

I'll update the changelog for the next submission.

>>
>>   static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
>>   	[CTA_NAT_MINIP]		= { .type = NLA_U32 },
>>   	[CTA_NAT_MAXIP]		= { .type = NLA_U32 },
>> +	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
>>   };
> I just dont understand this part :-

Yeah, it doesn't belong into this patch.

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diff mbox

Patch

diff --git a/include/net/netfilter/nf_nat_protocol.h b/include/net/netfilter/nf_nat_protocol.h
index 93cc90d..c951c6f 100644
--- a/include/net/netfilter/nf_nat_protocol.h
+++ b/include/net/netfilter/nf_nat_protocol.h
@@ -10,8 +10,6 @@  struct nf_nat_protocol {
 	/* Protocol number. */
 	unsigned int protonum;
 
-	struct module *me;
-
 	/* Translate a packet to the target according to manip type.
 	   Return true if succeeded. */
 	bool (*manip_pkt)(struct sk_buff *skb,
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index ffb0c94..d830a47 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -575,26 +575,6 @@  static struct nf_ct_ext_type nat_extend __read_mostly = {
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_conntrack.h>
 
-static const struct nf_nat_protocol *
-nf_nat_proto_find_get(u_int8_t protonum)
-{
-	const struct nf_nat_protocol *p;
-
-	rcu_read_lock();
-	p = __nf_nat_proto_find(protonum);
-	if (!try_module_get(p->me))
-		p = &nf_nat_unknown_protocol;
-	rcu_read_unlock();
-
-	return p;
-}
-
-static void
-nf_nat_proto_put(const struct nf_nat_protocol *p)
-{
-	module_put(p->me);
-}
-
 static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
 	[CTA_PROTONAT_PORT_MIN]	= { .type = NLA_U16 },
 	[CTA_PROTONAT_PORT_MAX]	= { .type = NLA_U16 },
@@ -612,16 +592,18 @@  static int nfnetlink_parse_nat_proto(struct nlattr *attr,
 	if (err < 0)
 		return err;
 
-	npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
+	rcu_read_lock();
+	npt = __nf_nat_proto_find(nf_ct_protonum(ct));
 	if (npt->nlattr_to_range)
 		err = npt->nlattr_to_range(tb, range);
-	nf_nat_proto_put(npt);
+	rcu_read_unlock();
 	return err;
 }
 
 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
 	[CTA_NAT_MINIP]		= { .type = NLA_U32 },
 	[CTA_NAT_MAXIP]		= { .type = NLA_U32 },
+	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
 };
 
 static int
diff --git a/net/ipv4/netfilter/nf_nat_proto_dccp.c b/net/ipv4/netfilter/nf_nat_proto_dccp.c
index 570faf2..17edd75 100644
--- a/net/ipv4/netfilter/nf_nat_proto_dccp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_dccp.c
@@ -80,7 +80,6 @@  dccp_manip_pkt(struct sk_buff *skb,
 
 static const struct nf_nat_protocol nf_nat_protocol_dccp = {
 	.protonum		= IPPROTO_DCCP,
-	.me			= THIS_MODULE,
 	.manip_pkt		= dccp_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= dccp_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index bc8d83a..d177e61 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -119,7 +119,6 @@  gre_manip_pkt(struct sk_buff *skb, unsigned int iphdroff,
 
 static const struct nf_nat_protocol gre = {
 	.protonum		= IPPROTO_GRE,
-	.me			= THIS_MODULE,
 	.manip_pkt		= gre_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= gre_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_icmp.c b/net/ipv4/netfilter/nf_nat_proto_icmp.c
index 5744c3e..5ff91f1 100644
--- a/net/ipv4/netfilter/nf_nat_proto_icmp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_icmp.c
@@ -73,7 +73,6 @@  icmp_manip_pkt(struct sk_buff *skb,
 
 const struct nf_nat_protocol nf_nat_protocol_icmp = {
 	.protonum		= IPPROTO_ICMP,
-	.me			= THIS_MODULE,
 	.manip_pkt		= icmp_manip_pkt,
 	.in_range		= icmp_in_range,
 	.unique_tuple		= icmp_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_sctp.c b/net/ipv4/netfilter/nf_nat_proto_sctp.c
index 756331d..eac0b82 100644
--- a/net/ipv4/netfilter/nf_nat_proto_sctp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_sctp.c
@@ -69,7 +69,6 @@  sctp_manip_pkt(struct sk_buff *skb,
 
 static const struct nf_nat_protocol nf_nat_protocol_sctp = {
 	.protonum		= IPPROTO_SCTP,
-	.me			= THIS_MODULE,
 	.manip_pkt		= sctp_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= sctp_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_tcp.c b/net/ipv4/netfilter/nf_nat_proto_tcp.c
index aa460a5..ec37036 100644
--- a/net/ipv4/netfilter/nf_nat_proto_tcp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_tcp.c
@@ -81,7 +81,6 @@  tcp_manip_pkt(struct sk_buff *skb,
 
 const struct nf_nat_protocol nf_nat_protocol_tcp = {
 	.protonum		= IPPROTO_TCP,
-	.me			= THIS_MODULE,
 	.manip_pkt		= tcp_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= tcp_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_udp.c b/net/ipv4/netfilter/nf_nat_proto_udp.c
index dfe65c7..4ba8c2c 100644
--- a/net/ipv4/netfilter/nf_nat_proto_udp.c
+++ b/net/ipv4/netfilter/nf_nat_proto_udp.c
@@ -72,7 +72,6 @@  udp_manip_pkt(struct sk_buff *skb,
 
 const struct nf_nat_protocol nf_nat_protocol_udp = {
 	.protonum		= IPPROTO_UDP,
-	.me			= THIS_MODULE,
 	.manip_pkt		= udp_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= udp_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_udplite.c b/net/ipv4/netfilter/nf_nat_proto_udplite.c
index 3cc8c8a..f45c1a6 100644
--- a/net/ipv4/netfilter/nf_nat_proto_udplite.c
+++ b/net/ipv4/netfilter/nf_nat_proto_udplite.c
@@ -71,7 +71,6 @@  udplite_manip_pkt(struct sk_buff *skb,
 
 static const struct nf_nat_protocol nf_nat_protocol_udplite = {
 	.protonum		= IPPROTO_UDPLITE,
-	.me			= THIS_MODULE,
 	.manip_pkt		= udplite_manip_pkt,
 	.in_range		= nf_nat_proto_in_range,
 	.unique_tuple		= udplite_unique_tuple,
diff --git a/net/ipv4/netfilter/nf_nat_proto_unknown.c b/net/ipv4/netfilter/nf_nat_proto_unknown.c
index a50f2bc..549c5b5 100644
--- a/net/ipv4/netfilter/nf_nat_proto_unknown.c
+++ b/net/ipv4/netfilter/nf_nat_proto_unknown.c
@@ -46,7 +46,6 @@  unknown_manip_pkt(struct sk_buff *skb,
 }
 
 const struct nf_nat_protocol nf_nat_unknown_protocol = {
-	/* .me isn't set: getting a ref to this cannot fail. */
 	.manip_pkt		= unknown_manip_pkt,
 	.in_range		= unknown_in_range,
 	.unique_tuple		= unknown_unique_tuple,