atm: add owner of push() callback to atmvcc

The atm is using atmvcc->push(vcc, NULL) callback to notify protocol
that vcc will be closed and protocol must detach from it. This callback
is usually used by protocol to decrement module usage count by module_put(),
but it leaves small window then module is still used after module_put().

Now the owner of push() callback is kept in atmvcc and
module_put(atmvcc->owner) is called after the protocol is detached from vcc.

Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Chas Williams <chas@cmf.nrl.navy.mil>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/atm/common.c b/net/atm/common.c
index 0c0ad930a632..24216642d696 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -156,6 +156,7 @@ int vcc_create(struct net *net, struct socket *sock, int protocol, int family)
         atomic_set(&sk->sk_rmem_alloc, 0);
         vcc->push = NULL;
         vcc->pop = NULL;
+        vcc->owner = NULL;
         vcc->push_oam = NULL;
         vcc->vpi = vcc->vci = 0; /* no VCI/VPI yet */
         vcc->atm_options = vcc->aal_options = 0;
@@ -175,6 +176,7 @@ static void vcc_destroy_socket(struct sock *sk)
                         vcc->dev->ops->close(vcc);
                 if (vcc->push)
                         vcc->push(vcc, NULL); /* atmarpd has no push */
+                module_put(vcc->owner);
 
                 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
                         atm_return(vcc, skb->truesize);