inet: add proper refcounting to request sock
reqsk_put() is the generic function that should be used
to release a refcount (and automatically call reqsk_free())
reqsk_free() might be called if refcount is known to be 0
or undefined.
refcnt is set to one in inet_csk_reqsk_queue_add()
As request socks are not yet in global ehash table,
I added temporary debugging checks in reqsk_put() and reqsk_free()
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index b9a6b0a..191feec 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -275,6 +275,11 @@
struct sock *child)
{
reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
+ /* before letting lookups find us, make sure all req fields
+ * are committed to memory.
+ */
+ smp_wmb();
+ atomic_set(&req->rsk_refcnt, 1);
}
void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index b3053fd..3d8c09a 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -255,6 +255,11 @@
ireq->opt = NULL;
atomic64_set(&ireq->ir_cookie, 0);
ireq->ireq_state = TCP_NEW_SYN_RECV;
+
+ /* Following is temporary. It is coupled with debugging
+ * helpers in reqsk_put() & reqsk_free()
+ */
+ atomic_set(&ireq->ireq_refcnt, 0);
}
return req;
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 3275cf3..56dc2fa 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -82,19 +82,20 @@
return (struct request_sock *)sk;
}
-static inline void __reqsk_free(struct request_sock *req)
-{
- kmem_cache_free(req->rsk_ops->slab, req);
-}
-
static inline void reqsk_free(struct request_sock *req)
{
+ /* temporary debugging */
+ WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0);
+
req->rsk_ops->destructor(req);
- __reqsk_free(req);
+ kmem_cache_free(req->rsk_ops->slab, req);
}
static inline void reqsk_put(struct request_sock *req)
{
+ /* temporary debugging, until req sock are put into ehash table */
+ WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 1);
+
if (atomic_dec_and_test(&req->rsk_refcnt))
reqsk_free(req);
}
