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Diffstat (limited to 'net/llc/llc_input.c')
-rw-r--r--net/llc/llc_input.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index e32cab44ea95..dd3e83328ad5 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -42,6 +42,7 @@ static void (*llc_type_handlers[2])(struct llc_sap *sap,
void llc_add_pack(int type, void (*handler)(struct llc_sap *sap,
struct sk_buff *skb))
{
+ smp_wmb(); /* ensure initialisation is complete before it's called */
if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
llc_type_handlers[type - 1] = handler;
}
@@ -50,11 +51,19 @@ void llc_remove_pack(int type)
{
if (type == LLC_DEST_SAP || type == LLC_DEST_CONN)
llc_type_handlers[type - 1] = NULL;
+ synchronize_net();
}
void llc_set_station_handler(void (*handler)(struct sk_buff *skb))
{
+ /* Ensure initialisation is complete before it's called */
+ if (handler)
+ smp_wmb();
+
llc_station_handler = handler;
+
+ if (!handler)
+ synchronize_net();
}
/**
@@ -150,6 +159,8 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
int dest;
int (*rcv)(struct sk_buff *, struct net_device *,
struct packet_type *, struct net_device *);
+ void (*sta_handler)(struct sk_buff *skb);
+ void (*sap_handler)(struct llc_sap *sap, struct sk_buff *skb);
if (!net_eq(dev_net(dev), &init_net))
goto drop;
@@ -182,7 +193,8 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
*/
rcv = rcu_dereference(sap->rcv_func);
dest = llc_pdu_type(skb);
- if (unlikely(!dest || !llc_type_handlers[dest - 1])) {
+ sap_handler = dest ? ACCESS_ONCE(llc_type_handlers[dest - 1]) : NULL;
+ if (unlikely(!sap_handler)) {
if (rcv)
rcv(skb, dev, pt, orig_dev);
else
@@ -193,7 +205,7 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
if (cskb)
rcv(cskb, dev, pt, orig_dev);
}
- llc_type_handlers[dest - 1](sap, skb);
+ sap_handler(sap, skb);
}
llc_sap_put(sap);
out:
@@ -202,9 +214,10 @@ drop:
kfree_skb(skb);
goto out;
handle_station:
- if (!llc_station_handler)
+ sta_handler = ACCESS_ONCE(llc_station_handler);
+ if (!sta_handler)
goto drop;
- llc_station_handler(skb);
+ sta_handler(skb);
goto out;
}