Re: [PATCH v2 3/3] vdpa/mlx5: defer clear_virtqueues to until DRIVER_OK
From: Eli Cohen <hidden>
Date: 2021-02-11 07:35:14
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On Wed, Feb 10, 2021 at 01:48:00PM -0800, Si-Wei Liu wrote:
While virtq is stopped, get_vq_state() is supposed to
be called to get sync'ed with the latest internal
avail_index from device. The saved avail_index is used
to restate the virtq once device is started. Commit
b35ccebe3ef7 introduced the clear_virtqueues() routine
to reset the saved avail_index, however, the index
gets cleared a bit earlier before get_vq_state() tries
to read it. This would cause consistency problems when
virtq is restarted, e.g. through a series of link down
and link up events. We could defer the clearing of
avail_index to until the device is to be started,
i.e. until VIRTIO_CONFIG_S_DRIVER_OK is set again in
set_status().
Fixes: b35ccebe3ef7 ("vdpa/mlx5: Restore the hardware used index after change map")
Signed-off-by: Si-Wei Liu <redacted>
Acked-by: Jason Wang <redacted>Acked-by: Eli Cohen <redacted>
quoted hunk ↗ jump to hunk
--- drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index 7c1f789..ce6aae8 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c@@ -1777,7 +1777,6 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) if (!status) { mlx5_vdpa_info(mvdev, "performing device reset\n"); teardown_driver(ndev); - clear_virtqueues(ndev); mlx5_vdpa_destroy_mr(&ndev->mvdev); ndev->mvdev.status = 0; ++mvdev->generation;@@ -1786,6 +1785,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) { if (status & VIRTIO_CONFIG_S_DRIVER_OK) { + clear_virtqueues(ndev); err = setup_driver(ndev); if (err) { mlx5_vdpa_warn(mvdev, "failed to setup driver\n");-- 1.8.3.1