netdev - [PATCH bpf 3/4] bpf, vsock: Invoke proto::close on close()

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Message-Id: <20241118-vsock-bpf-poll-close-v1-3-f1b9669cacdc@rbox.co>
Date: Mon, 18 Nov 2024 22:03:43 +0100
From: Michal Luczaj <mhal@...x.co>
To: Stefano Garzarella <sgarzare@...hat.com>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Simon Horman <horms@...nel.org>, 
 Bobby Eshleman <bobby.eshleman@...edance.com>, 
 "Michael S. Tsirkin" <mst@...hat.com>, Alexei Starovoitov <ast@...nel.org>, 
 Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>, 
 Martin KaFai Lau <martin.lau@...ux.dev>, 
 Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
 Yonghong Song <yonghong.song@...ux.dev>, 
 John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>, 
 Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, 
 Jiri Olsa <jolsa@...nel.org>, Mykola Lysenko <mykolal@...com>, 
 Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Michal Luczaj <mhal@...x.co>
Subject: [PATCH bpf 3/4] bpf, vsock: Invoke proto::close on close()

vsock defines a BPF callback to be invoked when close() is called. However,
this callback is never actually executed. As a result, a closed vsock
socket is not automatically removed from the sockmap/sockhash.

Introduce a dummy vsock_close() and make vsock_release() call proto::close.

Note: changes in __vsock_release() look messy, but it's only due to indent
level reduction and variables xmas tree reorder.

Fixes: 634f1a7110b4 ("vsock: support sockmap")
Signed-off-by: Michal Luczaj <mhal@...x.co>
---
 net/vmw_vsock/af_vsock.c | 67 +++++++++++++++++++++++++++++-------------------
 1 file changed, 40 insertions(+), 27 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 919da8edd03c838cbcdbf1618425da6c5ec2df1a..b52b798aa4c2926c3f233aad6cd31b4056f6fee2 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -117,12 +117,14 @@
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
 static void vsock_sk_destruct(struct sock *sk);
 static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
+static void vsock_close(struct sock *sk, long timeout);

 /* Protocol family. */
 struct proto vsock_proto = {
 	.name = "AF_VSOCK",
 	.owner = THIS_MODULE,
 	.obj_size = sizeof(struct vsock_sock),
+	.close = vsock_close,
 #ifdef CONFIG_BPF_SYSCALL
 	.psock_update_sk_prot = vsock_bpf_update_proto,
 #endif
@@ -797,39 +799,37 @@ static bool sock_type_connectible(u16 type)

 static void __vsock_release(struct sock *sk, int level)
 {
-	if (sk) {
-		struct sock *pending;
-		struct vsock_sock *vsk;
-
-		vsk = vsock_sk(sk);
-		pending = NULL;	/* Compiler warning. */
+	struct vsock_sock *vsk;
+	struct sock *pending;

-		/* When "level" is SINGLE_DEPTH_NESTING, use the nested
-		 * version to avoid the warning "possible recursive locking
-		 * detected". When "level" is 0, lock_sock_nested(sk, level)
-		 * is the same as lock_sock(sk).
-		 */
-		lock_sock_nested(sk, level);
+	vsk = vsock_sk(sk);
+	pending = NULL;	/* Compiler warning. */

-		if (vsk->transport)
-			vsk->transport->release(vsk);
-		else if (sock_type_connectible(sk->sk_type))
-			vsock_remove_sock(vsk);
+	/* When "level" is SINGLE_DEPTH_NESTING, use the nested
+	 * version to avoid the warning "possible recursive locking
+	 * detected". When "level" is 0, lock_sock_nested(sk, level)
+	 * is the same as lock_sock(sk).
+	 */
+	lock_sock_nested(sk, level);

-		sock_orphan(sk);
-		sk->sk_shutdown = SHUTDOWN_MASK;
+	if (vsk->transport)
+		vsk->transport->release(vsk);
+	else if (sock_type_connectible(sk->sk_type))
+		vsock_remove_sock(vsk);

-		skb_queue_purge(&sk->sk_receive_queue);
+	sock_orphan(sk);
+	sk->sk_shutdown = SHUTDOWN_MASK;

-		/* Clean up any sockets that never were accepted. */
-		while ((pending = vsock_dequeue_accept(sk)) != NULL) {
-			__vsock_release(pending, SINGLE_DEPTH_NESTING);
-			sock_put(pending);
-		}
+	skb_queue_purge(&sk->sk_receive_queue);

-		release_sock(sk);
-		sock_put(sk);
+	/* Clean up any sockets that never were accepted. */
+	while ((pending = vsock_dequeue_accept(sk)) != NULL) {
+		__vsock_release(pending, SINGLE_DEPTH_NESTING);
+		sock_put(pending);
 	}
+
+	release_sock(sk);
+	sock_put(sk);
 }

 static void vsock_sk_destruct(struct sock *sk)
@@ -901,9 +901,22 @@ void vsock_data_ready(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(vsock_data_ready);

+/* Dummy callback required by sockmap.
+ * See unconditional call of saved_close() in sock_map_close().
+ */
+static void vsock_close(struct sock *sk, long timeout)
+{
+}
+
 static int vsock_release(struct socket *sock)
 {
-	__vsock_release(sock->sk, 0);
+	struct sock *sk = sock->sk;
+
+	if (!sk)
+		return 0;
+
+	sk->sk_prot->close(sk, 0);
+	__vsock_release(sk, 0);
 	sock->sk = NULL;
 	sock->state = SS_FREE;

-- 
2.46.2