[PATCH rdma-next 5/8] RDMA/umem: Introduce an option to revoke DMABUF umem

[Leon Romanovsky]

From: Yishai Hadas <yishaih at nvidia.com>

Introduce an option to revoke DMABUF umem.

This option will retain the umem allocation while revoking its DMA
mapping. Furthermore, any subsequent attempts to map the pages should
fail once the umem has been revoked.

This functionality will be utilized in the upcoming patches in the
series, where we aim to delay umem deallocation until the mkey
deregistration. However, we must unmap its pages immediately.

Signed-off-by: Yishai Hadas <yishaih at nvidia.com>
Signed-off-by: Leon Romanovsky <leonro at nvidia.com>
---
 drivers/infiniband/core/umem_dmabuf.c | 21 +++++++++++++++++++--
 include/rdma/ib_umem.h                |  3 +++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
index 726a09786547..9fcd37761264 100644
--- a/drivers/infiniband/core/umem_dmabuf.c
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -23,6 +23,9 @@ int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
 
 	dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
 
+	if (umem_dmabuf->revoked)
+		return -EINVAL;
+
 	if (umem_dmabuf->sgt)
 		goto wait_fence;
 
@@ -242,15 +245,29 @@ struct ib_umem_dmabuf *ib_umem_dmabuf_get_pinned(struct ib_device *device,
 }
 EXPORT_SYMBOL(ib_umem_dmabuf_get_pinned);
 
-void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
+void ib_umem_dmabuf_revoke(struct ib_umem_dmabuf *umem_dmabuf)
 {
 	struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
 
 	dma_resv_lock(dmabuf->resv, NULL);
+	if (umem_dmabuf->revoked)
+		goto end;
 	ib_umem_dmabuf_unmap_pages(umem_dmabuf);
-	if (umem_dmabuf->pinned)
+	if (umem_dmabuf->pinned) {
 		dma_buf_unpin(umem_dmabuf->attach);
+		umem_dmabuf->pinned = 0;
+	}
+	umem_dmabuf->revoked = 1;
+end:
 	dma_resv_unlock(dmabuf->resv);
+}
+EXPORT_SYMBOL(ib_umem_dmabuf_revoke);
+
+void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
+{
+	struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
+
+	ib_umem_dmabuf_revoke(umem_dmabuf);
 
 	dma_buf_detach(dmabuf, umem_dmabuf->attach);
 	dma_buf_put(dmabuf);
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index de05268ed632..7dc7b1cc71b5 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -38,6 +38,7 @@ struct ib_umem_dmabuf {
 	unsigned long last_sg_trim;
 	void *private;
 	u8 pinned : 1;
+	u8 revoked : 1;
 };
 
 static inline struct ib_umem_dmabuf *to_ib_umem_dmabuf(struct ib_umem *umem)
@@ -158,6 +159,7 @@ ib_umem_dmabuf_get_pinned_with_dma_device(struct ib_device *device,
 int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf);
 void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf);
 void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf);
+void ib_umem_dmabuf_revoke(struct ib_umem_dmabuf *umem_dmabuf);
 
 #else /* CONFIG_INFINIBAND_USER_MEM */
 
@@ -217,6 +219,7 @@ static inline int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
 }
 static inline void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf) { }
 static inline void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf) { }
+static inline void ib_umem_dmabuf_revoke(struct ib_umem_dmabuf *umem_dmabuf) {}
 
 #endif /* CONFIG_INFINIBAND_USER_MEM */
 #endif /* IB_UMEM_H */
-- 
2.45.2