ctnetlink: remove remaining module refcount usage

ctnetlink: remove remaining module refcount usage

[Florian Westphal]

Hello list,

The following (small) patch converts the remaining module refcounting
in conntrack_netlink to RCU.

First patch does the conversion, 2nd one removes
nf_ct_l4proto_find_get/put (there are no more in-tree users).

Thanks, Florian

[PATCH 1/2] netfilter: ctnetlink: remove remaining module refcounting

[Florian Westphal]

convert the remaining refcount users.
As pointed out by Patrick McHardy, the protocols
can be accessed safely using RCU.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_conntrack_netlink.c |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 9fb7cf7..735ea9c 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -599,7 +599,8 @@ ctnetlink_parse_tuple_ip(struct nlattr *attr, struct nf_conntrack_tuple *tuple)
 
 	nla_parse_nested(tb, CTA_IP_MAX, attr, NULL);
 
-	l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);
+	rcu_read_lock();
+	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);
 
 	if (likely(l3proto->nlattr_to_tuple)) {
 		ret = nla_validate_nested(attr, CTA_IP_MAX,
@@ -608,7 +609,7 @@ ctnetlink_parse_tuple_ip(struct nlattr *attr, struct nf_conntrack_tuple *tuple)
 			ret = l3proto->nlattr_to_tuple(tb, tuple);
 	}
 
-	nf_ct_l3proto_put(l3proto);
+	rcu_read_unlock();
 
 	return ret;
 }
@@ -633,7 +634,8 @@ ctnetlink_parse_tuple_proto(struct nlattr *attr,
 		return -EINVAL;
 	tuple->dst.protonum = nla_get_u8(tb[CTA_PROTO_NUM]);
 
-	l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);
+	rcu_read_lock();
+	l4proto = __nf_ct_l4proto_find(tuple->src.l3num, tuple->dst.protonum);
 
 	if (likely(l4proto->nlattr_to_tuple)) {
 		ret = nla_validate_nested(attr, CTA_PROTO_MAX,
@@ -642,7 +644,7 @@ ctnetlink_parse_tuple_proto(struct nlattr *attr,
 			ret = l4proto->nlattr_to_tuple(tb, tuple);
 	}
 
-	nf_ct_l4proto_put(l4proto);
+	rcu_read_unlock();
 
 	return ret;
 }
@@ -989,10 +991,11 @@ ctnetlink_change_protoinfo(struct nf_conn *ct, struct nlattr *cda[])
 
 	nla_parse_nested(tb, CTA_PROTOINFO_MAX, attr, NULL);
 
-	l4proto = nf_ct_l4proto_find_get(nf_ct_l3num(ct), nf_ct_protonum(ct));
+	rcu_read_lock();
+	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 	if (l4proto->from_nlattr)
 		err = l4proto->from_nlattr(tb, ct);
-	nf_ct_l4proto_put(l4proto);
+	rcu_read_unlock();
 
 	return err;
 }
-- 
1.5.6.5

[PATCH 2/2] netfilter: remove nf_ct_l4proto_find_get/nf_ct_l4proto_put

[Florian Westphal]

users have been moved to __nf_ct_l4proto_find.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/netfilter/nf_conntrack_l4proto.h |    5 -----
 net/netfilter/nf_conntrack_proto.c           |   21 ---------------------
 2 files changed, 0 insertions(+), 26 deletions(-)

diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h
index 16ab604..b01070b 100644
--- a/include/net/netfilter/nf_conntrack_l4proto.h
+++ b/include/net/netfilter/nf_conntrack_l4proto.h
@@ -98,11 +98,6 @@ extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;
 extern struct nf_conntrack_l4proto *
 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto);
 
-extern struct nf_conntrack_l4proto *
-nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t protocol);
-
-extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);
-
 /* Protocol registration. */
 extern int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *proto);
 extern void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *proto);
diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
index 592d733..9a62b4e 100644
--- a/net/netfilter/nf_conntrack_proto.c
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -74,27 +74,6 @@ EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
 
 /* this is guaranteed to always return a valid protocol helper, since
  * it falls back to generic_protocol */
-struct nf_conntrack_l4proto *
-nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
-{
-	struct nf_conntrack_l4proto *p;
-
-	rcu_read_lock();
-	p = __nf_ct_l4proto_find(l3proto, l4proto);
-	if (!try_module_get(p->me))
-		p = &nf_conntrack_l4proto_generic;
-	rcu_read_unlock();
-
-	return p;
-}
-EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
-
-void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
-{
-	module_put(p->me);
-}
-EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
-
 struct nf_conntrack_l3proto *
 nf_ct_l3proto_find_get(u_int16_t l3proto)
 {
-- 
1.5.6.5

Re: ctnetlink: remove remaining module refcount usage

[Patrick McHardy]

Florian Westphal wrote:
> Hello list,
> 
> The following (small) patch converts the remaining module refcounting
> in conntrack_netlink to RCU.
> 
> First patch does the conversion, 2nd one removes
> nf_ct_l4proto_find_get/put (there are no more in-tree users).

Both patches applied, thanks Florian.