inet: reqsk_alloc() needs to take care of dead listeners

We'll soon no longer take a refcount on listeners,
so reqsk_alloc() can not assume a listener refcount is not
zero. We need to use atomic_inc_not_zero()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2016-04-01 08:52:16 -07:00 committed by David S. Miller
parent 2d331915a0
commit 3a5d1c0e7c

View file

@ -85,24 +85,23 @@ reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
struct request_sock *req;
req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
if (req) {
req->rsk_ops = ops;
if (attach_listener) {
sock_hold(sk_listener);
req->rsk_listener = sk_listener;
} else {
req->rsk_listener = NULL;
if (!req)
return NULL;
req->rsk_listener = NULL;
if (attach_listener) {
if (unlikely(!atomic_inc_not_zero(&sk_listener->sk_refcnt))) {
kmem_cache_free(ops->slab, req);
return NULL;
}
req_to_sk(req)->sk_prot = sk_listener->sk_prot;
sk_node_init(&req_to_sk(req)->sk_node);
sk_tx_queue_clear(req_to_sk(req));
req->saved_syn = NULL;
/* Following is temporary. It is coupled with debugging
* helpers in reqsk_put() & reqsk_free()
*/
atomic_set(&req->rsk_refcnt, 0);
req->rsk_listener = sk_listener;
}
req->rsk_ops = ops;
req_to_sk(req)->sk_prot = sk_listener->sk_prot;
sk_node_init(&req_to_sk(req)->sk_node);
sk_tx_queue_clear(req_to_sk(req));
req->saved_syn = NULL;
atomic_set(&req->rsk_refcnt, 0);
return req;
}