sock: tigthen lockdep checks for sock_owned_by_user

sock_owned_by_user should not be used without socket lock held. It seems
to be a common practice to check .owned before lock reclassification, so
provide a little help to abstract this check away.

Cc: linux-cifs@vger.kernel.org
Cc: linux-bluetooth@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 15 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 81d6fecec0a2..baba58770ac5 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1316,21 +1316,6 @@ static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
 	__kfree_skb(skb);
 }
 
-/* Used by processes to "lock" a socket state, so that
- * interrupts and bottom half handlers won't change it
- * from under us. It essentially blocks any incoming
- * packets, so that we won't get any new data or any
- * packets that change the state of the socket.
- *
- * While locked, BH processing will add new packets to
- * the backlog queue.  This queue is processed by the
- * owner of the socket lock right before it is released.
- *
- * Since ~2.3.5 it is also exclusive sleep lock serializing
- * accesses from user process context.
- */
-#define sock_owned_by_user(sk)	((sk)->sk_lock.owned)
-
 static inline void sock_release_ownership(struct sock *sk)
 {
 	if (sk->sk_lock.owned) {
@@ -1403,6 +1388,35 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow)
 		spin_unlock_bh(&sk->sk_lock.slock);
 }
 
+/* Used by processes to "lock" a socket state, so that
+ * interrupts and bottom half handlers won't change it
+ * from under us. It essentially blocks any incoming
+ * packets, so that we won't get any new data or any
+ * packets that change the state of the socket.
+ *
+ * While locked, BH processing will add new packets to
+ * the backlog queue.  This queue is processed by the
+ * owner of the socket lock right before it is released.
+ *
+ * Since ~2.3.5 it is also exclusive sleep lock serializing
+ * accesses from user process context.
+ */
+
+static inline bool sock_owned_by_user(const struct sock *sk)
+{
+#ifdef CONFIG_LOCKDEP
+	WARN_ON(!lockdep_sock_is_held(sk));
+#endif
+	return sk->sk_lock.owned;
+}
+
+/* no reclassification while locks are held */
+static inline bool sock_allow_reclassification(const struct sock *csk)
+{
+	struct sock *sk = (struct sock *)csk;
+
+	return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
+}
 
 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
 		      struct proto *prot, int kern);