You need to update the title now that you're moving also queued_replies.

Well, I will update the title in V3 version.

On Tue, Feb 11, 2025 at 03:19:21PM +0800, Junnan Wu wrote:

quoted

When executing suspend to ram twice in a row,
the `rx_buf_nr` and `rx_buf_max_nr` increase to three times vq->num_free.
Then after virtqueue_get_buf and `rx_buf_nr` decreased
in function virtio_transport_rx_work,
the condition to fill rx buffer
(rx_buf_nr < rx_buf_max_nr / 2) will never be met.

It is because that `rx_buf_nr` and `rx_buf_max_nr`
are initialized only in virtio_vsock_probe(),
but they should be reset whenever virtqueues are recreated,
like after a suspend/resume.

Move the `rx_buf_nr` and `rx_buf_max_nr` initialization in
virtio_vsock_vqs_init(), so we are sure that they are properly
initialized, every time we initialize the virtqueues, either when we
load the driver or after a suspend/resume.
At the same time, also move `queued_replies`.

Why?

As I mentioned the commit description should explain why the changes are 
being made for both reviewers and future references to this patch.

After your kindly remind, I have double checked all locations where `queued_replies`
used, and we think for order to prevent erroneous atomic load operations 
on the `queued_replies` in the virtio_transport_send_pkt_work() function
which may disrupt the scheduling of vsock->rx_work
when transmitting reply-required socket packets,
this atomic variable must undergo synchronized initialization
alongside the preceding two variables after a suspend/resume.

If we reach agreement on it, I will add this description in V3 version.

BRs
Junnan Wu

The rest LGTM.

Stefano

quoted

Fixes: bd50c5dc182b ("vsock/virtio: add support for device suspend/resume")
Co-developed-by: Ying Gao <redacted>
Signed-off-by: Ying Gao <redacted>
Signed-off-by: Junnan Wu <redacted>
---
net/vmw_vsock/virtio_transport.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index b58c3818f284..f0e48e6911fc 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c

@@ -670,6 +670,13 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)

	};
	int ret;

+	mutex_lock(&vsock->rx_lock);
+	vsock->rx_buf_nr = 0;
+	vsock->rx_buf_max_nr = 0;
+	mutex_unlock(&vsock->rx_lock);
+
+	atomic_set(&vsock->queued_replies, 0);
+
	ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, vqs_info, NULL);
	if (ret < 0)
		return ret;

@@ -779,9 +786,6 @@ static int virtio_vsock_probe(struct virtio_device *vdev)

	vsock->vdev = vdev;

-	vsock->rx_buf_nr = 0;
-	vsock->rx_buf_max_nr = 0;
-	atomic_set(&vsock->queued_replies, 0);

	mutex_init(&vsock->tx_lock);
	mutex_init(&vsock->rx_lock);
-- 
2.34.1