net: Convert atomic_t net::count to refcount_t
Since net could be obtained from RCU lists,
and there is a race with net destruction,
the patch converts net::count to refcount_t.
This provides sanity checks for the cases of
incrementing counter of already dead net,
when maybe_get_net() has to used instead
of get_net().
Drivers: allyesconfig and allmodconfig are OK.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 10f99da..f8a84a2 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -51,7 +51,7 @@ struct net {
refcount_t passive; /* To decided when the network
* namespace should be freed.
*/
- atomic_t count; /* To decided when the network
+ refcount_t count; /* To decided when the network
* namespace should be shut down.
*/
spinlock_t rules_mod_lock;
@@ -195,7 +195,7 @@ void __put_net(struct net *net);
static inline struct net *get_net(struct net *net)
{
- atomic_inc(&net->count);
+ refcount_inc(&net->count);
return net;
}
@@ -206,14 +206,14 @@ static inline struct net *maybe_get_net(struct net *net)
* exists. If the reference count is zero this
* function fails and returns NULL.
*/
- if (!atomic_inc_not_zero(&net->count))
+ if (!refcount_inc_not_zero(&net->count))
net = NULL;
return net;
}
static inline void put_net(struct net *net)
{
- if (atomic_dec_and_test(&net->count))
+ if (refcount_dec_and_test(&net->count))
__put_net(net);
}