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>

1 files changed, 11 insertions, 9 deletions

diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 8d3a55b4a30c..ed65da251b6a 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -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);