IB/mlx5: Add function to read WQE from user-space

Add a helper function mlx5_ib_read_user_wqe to read information from
user-space owned work queues.  The function will be used in a later
patch by the page-fault handling code in mlx5_ib.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>

[ Add stub for ib_umem_copy_from() for CONFIG_INFINIBAND_USER_MEM=n
  - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 45bb04bc88cd..a51f4091489a 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -98,7 +98,10 @@ static inline struct ib_umem *ib_umem_get(struct ib_ucontext *context,
 }
 static inline void ib_umem_release(struct ib_umem *umem) { }
 static inline int ib_umem_page_count(struct ib_umem *umem) { return 0; }
-
+static inline int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
+                                    size_t length) {
+        return -EINVAL;
+}
 #endif /* CONFIG_INFINIBAND_USER_MEM */
 
 #endif /* IB_UMEM_H */