From: Leon Romanovsky <[email protected]>

IOMMUFD relies on a private protocol with VFIO, and this always operated
in pinned mode.

Now that VFIO can support pinned importers update IOMMUFD to invoke the
normal dma-buf flow to request pin.

This isn't enough to allow IOMMUFD to work with other exporters, it still
needs a way to get the physical address list which is another series.

IOMMUFD supports the defined revoke semantics. It immediately stops and
fences access to the memory inside it's invalidate_mappings() callback,
and it currently doesn't use scatterlists so doesn't call map/unmap at
all.

It is expected that a future revision can synchronously call unmap from
the move_notify callback as well.

Acked-by: Christian König <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
---
 drivers/iommu/iommufd/pages.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index 76f900fa1687..a5eb2bc4ef48 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -1501,16 +1501,22 @@ static int iopt_map_dmabuf(struct iommufd_ctx *ictx, 
struct iopt_pages *pages,
                mutex_unlock(&pages->mutex);
        }
 
-       rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys);
+       rc = dma_buf_pin(attach);
        if (rc)
                goto err_detach;
 
+       rc = sym_vfio_pci_dma_buf_iommufd_map(attach, &pages->dmabuf.phys);
+       if (rc)
+               goto err_unpin;
+
        dma_resv_unlock(dmabuf->resv);
 
        /* On success iopt_release_pages() will detach and put the dmabuf. */
        pages->dmabuf.attach = attach;
        return 0;
 
+err_unpin:
+       dma_buf_unpin(attach);
 err_detach:
        dma_resv_unlock(dmabuf->resv);
        dma_buf_detach(dmabuf, attach);
@@ -1656,6 +1662,7 @@ void iopt_release_pages(struct kref *kref)
        if (iopt_is_dmabuf(pages) && pages->dmabuf.attach) {
                struct dma_buf *dmabuf = pages->dmabuf.attach->dmabuf;
 
+               dma_buf_unpin(pages->dmabuf.attach);
                dma_buf_detach(dmabuf, pages->dmabuf.attach);
                dma_buf_put(dmabuf);
                WARN_ON(!list_empty(&pages->dmabuf.tracker));

-- 
2.52.0

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