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authorPablo Neira Ayuso <pablo@netfilter.org>2013-02-05 01:50:26 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2013-02-05 04:07:35 +0100
commitc14b78e7decd0d1d5add6a4604feb8609fe920a9 (patch)
tree820b4a0a2f3702581452e05d53d44097cb240d81 /net/netfilter/nfnetlink.c
parent5474f57f7d686ac918355419cb71496f835aaf5d (diff)
netfilter: nfnetlink: add mutex per subsystem
This patch replaces the global lock to one lock per subsystem. The per-subsystem lock avoids that processes operating with different subsystems are synchronized. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nfnetlink.c')
-rw-r--r--net/netfilter/nfnetlink.c52
1 files changed, 32 insertions, 20 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 58a09b7c3f6d..d578ec251712 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -36,8 +36,10 @@ MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
static char __initdata nfversion[] = "0.30";
-static const struct nfnetlink_subsystem __rcu *subsys_table[NFNL_SUBSYS_COUNT];
-static DEFINE_MUTEX(nfnl_mutex);
+static struct {
+ struct mutex mutex;
+ const struct nfnetlink_subsystem __rcu *subsys;
+} table[NFNL_SUBSYS_COUNT];
static const int nfnl_group2type[NFNLGRP_MAX+1] = {
[NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
@@ -48,27 +50,32 @@ static const int nfnl_group2type[NFNLGRP_MAX+1] = {
[NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
};
-void nfnl_lock(void)
+void nfnl_lock(__u8 subsys_id)
{
- mutex_lock(&nfnl_mutex);
+ mutex_lock(&table[subsys_id].mutex);
}
EXPORT_SYMBOL_GPL(nfnl_lock);
-void nfnl_unlock(void)
+void nfnl_unlock(__u8 subsys_id)
{
- mutex_unlock(&nfnl_mutex);
+ mutex_unlock(&table[subsys_id].mutex);
}
EXPORT_SYMBOL_GPL(nfnl_unlock);
+static struct mutex *nfnl_get_lock(__u8 subsys_id)
+{
+ return &table[subsys_id].mutex;
+}
+
int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
{
- nfnl_lock();
- if (subsys_table[n->subsys_id]) {
- nfnl_unlock();
+ nfnl_lock(n->subsys_id);
+ if (table[n->subsys_id].subsys) {
+ nfnl_unlock(n->subsys_id);
return -EBUSY;
}
- rcu_assign_pointer(subsys_table[n->subsys_id], n);
- nfnl_unlock();
+ rcu_assign_pointer(table[n->subsys_id].subsys, n);
+ nfnl_unlock(n->subsys_id);
return 0;
}
@@ -76,9 +83,9 @@ EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
{
- nfnl_lock();
- subsys_table[n->subsys_id] = NULL;
- nfnl_unlock();
+ nfnl_lock(n->subsys_id);
+ table[n->subsys_id].subsys = NULL;
+ nfnl_unlock(n->subsys_id);
synchronize_rcu();
return 0;
}
@@ -91,7 +98,7 @@ static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t t
if (subsys_id >= NFNL_SUBSYS_COUNT)
return NULL;
- return rcu_dereference(subsys_table[subsys_id]);
+ return rcu_dereference(table[subsys_id].subsys);
}
static inline const struct nfnl_callback *
@@ -175,6 +182,7 @@ replay:
struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
struct nlattr *attr = (void *)nlh + min_len;
int attrlen = nlh->nlmsg_len - min_len;
+ __u8 subsys_id = NFNL_SUBSYS_ID(type);
err = nla_parse(cda, ss->cb[cb_id].attr_count,
attr, attrlen, ss->cb[cb_id].policy);
@@ -189,10 +197,9 @@ replay:
rcu_read_unlock();
} else {
rcu_read_unlock();
- nfnl_lock();
- if (rcu_dereference_protected(
- subsys_table[NFNL_SUBSYS_ID(type)],
- lockdep_is_held(&nfnl_mutex)) != ss ||
+ nfnl_lock(subsys_id);
+ if (rcu_dereference_protected(table[subsys_id].subsys,
+ lockdep_is_held(nfnl_get_lock(subsys_id))) != ss ||
nfnetlink_find_client(type, ss) != nc)
err = -EAGAIN;
else if (nc->call)
@@ -200,7 +207,7 @@ replay:
(const struct nlattr **)cda);
else
err = -EINVAL;
- nfnl_unlock();
+ nfnl_unlock(subsys_id);
}
if (err == -EAGAIN)
goto replay;
@@ -267,6 +274,11 @@ static struct pernet_operations nfnetlink_net_ops = {
static int __init nfnetlink_init(void)
{
+ int i;
+
+ for (i=0; i<NFNL_SUBSYS_COUNT; i++)
+ mutex_init(&table[i].mutex);
+
pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
return register_pernet_subsys(&nfnetlink_net_ops);
}