[PATCH v7 18/19] RDMA/uverbs: Hand out the P2PDMA provider behind a dma-buf

[Leon Romanovsky <leon@kernel.org>]

From: Leon Romanovsky <leonro@nvidia.com>

An importer attached to a uverbs dma-buf cannot tell whether its
peer-to-peer traffic would reach the exported memory directly, because the
&struct p2pdma_provider describing it stays in ib_uverbs_dmabuf_file.

Implement @p2pdma_provider so dma_buf_p2pdma_map_type() can reach it, and
refuse once the buffer is revoked and the memory it described is gone.

Tested-by: Tushar Dave <tdave@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/uverbs_std_types_dmabuf.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/infiniband/core/uverbs_std_types_dmabuf.c b/drivers/infiniband/core/uverbs_std_types_dmabuf.c
index 2411ebee69e2..5a6a1ee430a7 100644
--- a/drivers/infiniband/core/uverbs_std_types_dmabuf.c
+++ b/drivers/infiniband/core/uverbs_std_types_dmabuf.c
@@ -76,6 +76,17 @@ static void uverbs_dmabuf_release(struct dma_buf *dmabuf)
 	uverbs_uobject_release(&priv->uobj);
 }
 
+static struct p2pdma_provider *
+uverbs_dmabuf_provider(struct dma_buf *dmabuf)
+{
+	struct ib_uverbs_dmabuf_file *priv = dmabuf->priv;
+
+	if (priv->revoked)
+		return NULL;
+
+	return priv->provider;
+}
+
 static const struct dma_buf_ops uverbs_dmabuf_ops = {
 	.attach = uverbs_dmabuf_attach,
 	.map_dma_buf = uverbs_dmabuf_map,
@@ -83,6 +94,7 @@ static const struct dma_buf_ops uverbs_dmabuf_ops = {
 	.pin = uverbs_dmabuf_pin,
 	.unpin = uverbs_dmabuf_unpin,
 	.release = uverbs_dmabuf_release,
+	.p2pdma_provider = uverbs_dmabuf_provider,
 };
 
 static int UVERBS_HANDLER(UVERBS_METHOD_DMABUF_ALLOC)(

-- 
2.55.0