[PATCH v4 7/8] vfio: Wait for dma-buf invalidation to complete

[Leon Romanovsky]

From: Leon Romanovsky <leo...@nvidia.com>

dma-buf invalidation is performed asynchronously by hardware, so VFIO must
wait until all affected objects have been fully invalidated.

Fixes: 5d74781ebc86 ("vfio/pci: Add dma-buf export support for MMIO regions")
Signed-off-by: Leon Romanovsky <leo...@nvidia.com>
---
 drivers/vfio/pci/vfio_pci_dmabuf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c 
b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 362e3d149817..5fceefc40e27 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -321,6 +321,9 @@ void vfio_pci_dma_buf_move(struct vfio_pci_core_device 
*vdev, bool revoked)
                        dma_resv_lock(priv->dmabuf->resv, NULL);
                        priv->revoked = revoked;
                        dma_buf_invalidate_mappings(priv->dmabuf);
+                       dma_resv_wait_timeout(priv->dmabuf->resv,
+                                             DMA_RESV_USAGE_BOOKKEEP, false,
+                                             MAX_SCHEDULE_TIMEOUT);
                        dma_resv_unlock(priv->dmabuf->resv);
                }
                fput(priv->dmabuf->file);
@@ -342,6 +345,9 @@ void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device 
*vdev)
                priv->vdev = NULL;
                priv->revoked = true;
                dma_buf_invalidate_mappings(priv->dmabuf);
+               dma_resv_wait_timeout(priv->dmabuf->resv,
+                                     DMA_RESV_USAGE_BOOKKEEP, false,
+                                     MAX_SCHEDULE_TIMEOUT);
                dma_resv_unlock(priv->dmabuf->resv);
                vfio_device_put_registration(&vdev->vdev);
                fput(priv->dmabuf->file);

-- 
2.52.0