1 files changed, 22 insertions, 46 deletions

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14d61bba0b79..8a709f63c5e5 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -323,14 +323,6 @@ static inline void sk_psock_free_link(struct sk_psock_link *link)
 }
 
 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock);
-#if defined(CONFIG_BPF_STREAM_PARSER)
-void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link);
-#else
-static inline void sk_psock_unlink(struct sock *sk,
-				   struct sk_psock_link *link)
-{
-}
-#endif
 
 void __sk_psock_purge_ingress_msg(struct sk_psock *psock);
 
@@ -347,33 +339,37 @@ static inline void sk_psock_update_proto(struct sock *sk,
 					 struct sk_psock *psock,
 					 struct proto *ops)
 {
-	psock->saved_unhash = sk->sk_prot->unhash;
-	psock->saved_close = sk->sk_prot->close;
-	psock->saved_write_space = sk->sk_write_space;
+	/* Initialize saved callbacks and original proto only once, since this
+	 * function may be called multiple times for a psock, e.g. when
+	 * psock->progs.msg_parser is updated.
+	 *
+	 * Since we've not installed the new proto, psock is not yet in use and
+	 * we can initialize it without synchronization.
+	 */
+	if (!psock->sk_proto) {
+		struct proto *orig = READ_ONCE(sk->sk_prot);
 
-	psock->sk_proto = sk->sk_prot;
-	sk->sk_prot = ops;
+		psock->saved_unhash = orig->unhash;
+		psock->saved_close = orig->close;
+		psock->saved_write_space = sk->sk_write_space;
+
+		psock->sk_proto = orig;
+	}
+
+	/* Pairs with lockless read in sk_clone_lock() */
+	WRITE_ONCE(sk->sk_prot, ops);
 }
 
 static inline void sk_psock_restore_proto(struct sock *sk,
 					  struct sk_psock *psock)
 {
 	sk->sk_prot->unhash = psock->saved_unhash;
-
-	if (psock->sk_proto) {
-		struct inet_connection_sock *icsk = inet_csk(sk);
-		bool has_ulp = !!icsk->icsk_ulp_data;
-
-		if (has_ulp) {
-			tcp_update_ulp(sk, psock->sk_proto,
-				       psock->saved_write_space);
-		} else {
-			sk->sk_prot = psock->sk_proto;
-			sk->sk_write_space = psock->saved_write_space;
-		}
-		psock->sk_proto = NULL;
+	if (inet_csk_has_ulp(sk)) {
+		tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 	} else {
 		sk->sk_write_space = psock->saved_write_space;
+		/* Pairs with lockless read in sk_clone_lock() */
+		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
 	}
 }
 
@@ -395,26 +391,6 @@ static inline bool sk_psock_test_state(const struct sk_psock *psock,
 	return test_bit(bit, &psock->state);
 }
 
-static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
-{
-	struct sk_psock *psock;
-
-	rcu_read_lock();
-	psock = sk_psock(sk);
-	if (psock) {
-		if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
-			psock = ERR_PTR(-EBUSY);
-			goto out;
-		}
-
-		if (!refcount_inc_not_zero(&psock->refcnt))
-			psock = ERR_PTR(-EBUSY);
-	}
-out:
-	rcu_read_unlock();
-	return psock;
-}
-
 static inline struct sk_psock *sk_psock_get(struct sock *sk)
 {
 	struct sk_psock *psock;