[PATCH v5 7/8] vfio: Permit VFIO to work with pinned importers

[Leon Romanovsky]

From: Leon Romanovsky <leonro@xxxxxxxxxx>

Till now VFIO has rejected pinned importers, largely to avoid being used
with the RDMA pinned importer that cannot handle a move_notify() to revoke
access.

Using dma_buf_attach_revocable() it can tell the difference between pinned
importers that support the flow described in dma_buf_invalidate_mappings()
and those that don't.

Thus permit compatible pinned importers.

This is one of two items IOMMUFD requires to remove its private interface
to VFIO's dma-buf.

Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
---
 drivers/vfio/pci/vfio_pci_dmabuf.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index 485515629fe4..3c8dc56e2238 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -22,16 +22,6 @@ struct vfio_pci_dma_buf {
 	u8 revoked : 1;
 };
 
-static int vfio_pci_dma_buf_pin(struct dma_buf_attachment *attachment)
-{
-	return -EOPNOTSUPP;
-}
-
-static void vfio_pci_dma_buf_unpin(struct dma_buf_attachment *attachment)
-{
-	/* Do nothing */
-}
-
 static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf,
 				   struct dma_buf_attachment *attachment)
 {
@@ -43,6 +33,9 @@ static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf,
 	if (priv->revoked)
 		return -ENODEV;
 
+	if (!dma_buf_attach_revocable(attachment))
+		return -EOPNOTSUPP;
+
 	return 0;
 }
 
@@ -107,8 +100,6 @@ static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
 }
 
 static const struct dma_buf_ops vfio_pci_dmabuf_ops = {
-	.pin = vfio_pci_dma_buf_pin,
-	.unpin = vfio_pci_dma_buf_unpin,
 	.attach = vfio_pci_dma_buf_attach,
 	.map_dma_buf = vfio_pci_dma_buf_map,
 	.unmap_dma_buf = vfio_pci_dma_buf_unmap,

-- 
2.52.0