From: Leon Romanovsky Date: Sat, 31 Jan 2026 05:34:18 +0000 (+0200) Subject: iommufd: Add dma_buf_pin() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c5f9645c3893f0db679d9affe4fe4e665b990dd;p=thirdparty%2Fkernel%2Flinux.git iommufd: Add dma_buf_pin() 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. Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Acked-by: Christian König Signed-off-by: Leon Romanovsky Signed-off-by: Christian König Link: https://lore.kernel.org/r/20260131-dmabuf-revoke-v7-8-463d956bd527@nvidia.com --- diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c index 1d41ac625c982..8124c554f2cc3 100644 --- a/drivers/iommu/iommufd/pages.c +++ b/drivers/iommu/iommufd/pages.c @@ -1502,16 +1502,22 @@ 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); @@ -1657,6 +1663,7 @@ 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));