On 5/6/25 11:53, Stefano Garzarella wrote:

On Thu, May 01, 2025 at 10:05:23AM +0200, Michal Luczaj wrote:

quoted

Lingering should be transport-independent in the long run. In preparation
for supporting other transports, as well the linger on shutdown(), move
code to core.

Generalize by querying vsock_transport::unsent_bytes(), guard against the
callback being unimplemented. Do not pass sk_lingertime explicitly. Pull
SOCK_LINGER check into vsock_linger().

Flatten the function. Remove the nested block by inverting the condition:
return early on !timeout.

Suggested-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Michal Luczaj <redacted>
---
include/net/af_vsock.h                  |  1 +
net/vmw_vsock/af_vsock.c                | 30 ++++++++++++++++++++++++++++++
net/vmw_vsock/virtio_transport_common.c | 23 ++---------------------
3 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 9e85424c834353d016a527070dd62e15ff3bfce1..d56e6e135158939087d060dfcf65d3fdaea53bf3 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h

@@ -221,6 +221,7 @@ void vsock_for_each_connected_socket(struct vsock_transport *transport,

				     void (*fn)(struct sock *sk));
int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock 
*psk);
bool vsock_find_cid(unsigned int cid);
+void vsock_linger(struct sock *sk);

/**** TAP ****/

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index fc6afbc8d6806a4d98c66abc3af4bd139c583b08..a31ad6b141cd38d1806df4b5d417924bb8607e32 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c

@@ -1013,6 +1013,36 @@ static int vsock_getname(struct socket *sock,

	return err;
}

+void vsock_linger(struct sock *sk)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	ssize_t (*unsent)(struct vsock_sock *vsk);
+	struct vsock_sock *vsk = vsock_sk(sk);
+	long timeout;
+
+	if (!sock_flag(sk, SOCK_LINGER))
+		return;
+
+	timeout = sk->sk_lingertime;
+	if (!timeout)
+		return;
+
+	/* unsent_bytes() may be unimplemented. */

This comment IMO should be enriched, as it is now it doesn't add much to 
the code. I'm thinking on something like this:
     Transports must implement `unsent_bytes` if they want to support
     SOCK_LINGER through `vsock_linger()` since we use it to check when
     the socket can be closed.

OK, will do.

Thanks,
Michal