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vsock/virtio: fix variables initialization during resuming

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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.

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.

Fixes: bd50c5dc18 ("vsock/virtio: add support for device suspend/resume")
Link: https://lore.kernel.org/virtualization/20250207052033.2222629-1-junnan01.wu@samsung.com/
Co-developed-by: Ying Gao <ying01.gao@samsung.com>
Signed-off-by: Ying Gao <ying01.gao@samsung.com>
Signed-off-by: Junnan Wu <junnan01.wu@samsung.com>
Reviewed-by: Luigi Leonardi <leonardi@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20250214012200.1883896-1-junnan01.wu@samsung.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Junnan Wu 2025-02-14 09:22:00 +08:00 • committed by Jakub Kicinski
parent 0d1fac6d26
commit 55eff109e7
1 changed files with 7 additions and 3 deletions
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10
net/vmw_vsock/virtio_transport.c
View file

@ -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);