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Phonet: put protocols array under RCU 

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rémi Denis-Courmont 2009-11-13 05:01:18 +00:00 committed by David S. Miller
parent 998221c26b
commit 7ed0132f23
1 changed files with 11 additions and 9 deletions
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20
net/phonet/af_phonet.c
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@ -35,7 +35,6 @@
/* Transport protocol registration */
static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
static DEFINE_SPINLOCK(proto_tab_lock);
static struct phonet_protocol *phonet_proto_get(int protocol)
{
@ -44,11 +43,11 @@ static struct phonet_protocol *phonet_proto_get(int protocol)
if (protocol >= PHONET_NPROTO)
return NULL;
spin_lock(&proto_tab_lock);
rcu_read_lock();
pp = proto_tab[protocol];
if (pp && !try_module_get(pp->prot->owner))
pp = NULL;
spin_unlock(&proto_tab_lock);
rcu_read_unlock();
return pp;
}
@ -439,6 +438,8 @@ static struct packet_type phonet_packet_type __read_mostly = {
.func = phonet_rcv,
};
static DEFINE_MUTEX(proto_tab_lock);
int __init_or_module phonet_proto_register(int protocol,
struct phonet_protocol *pp)
{
@ -451,12 +452,12 @@ int __init_or_module phonet_proto_register(int protocol,
if (err)
return err;
spin_lock(&proto_tab_lock);
mutex_lock(&proto_tab_lock);
if (proto_tab[protocol])
err = -EBUSY;
else
proto_tab[protocol] = pp;
spin_unlock(&proto_tab_lock);
rcu_assign_pointer(proto_tab[protocol], pp);
mutex_unlock(&proto_tab_lock);
return err;
}
@ -464,10 +465,11 @@ EXPORT_SYMBOL(phonet_proto_register);
void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
{
spin_lock(&proto_tab_lock);
mutex_lock(&proto_tab_lock);
BUG_ON(proto_tab[protocol] != pp);
proto_tab[protocol] = NULL;
spin_unlock(&proto_tab_lock);
rcu_assign_pointer(proto_tab[protocol], NULL);
mutex_unlock(&proto_tab_lock);
synchronize_rcu();
proto_unregister(pp->prot);
}
EXPORT_SYMBOL(phonet_proto_unregister);