[PATCH rdma-next v2 14/15] RDMA/mlx5: Support new Unordered access flag
From: Michael Gur
Date: Mon Nov 02 2026 - 18:10:43 EST
Add mlx5 driver support for IB_ACCESS_UNORDERED, the new uverbs access
flag that enables relaxing the order of read after write on mkeys.
Map IB_ACCESS_UNORDERED to the Unordered mkey ordering level of the
mlx5 core helper, which sets relaxed ordering and, when supported,
relaxed read-after-write ordering.
Extend the current enablement of ATS over DMABUF with RO access to also
enable for DMABUF with Unordered access.
Mark IB_ACCESS_UNORDERED as non-UMR-modifiable: there is no UMR
mkey-mask bit for order_read_after_write, so UMR cannot drive it.
Reviewed-by: Yishai Hadas <yishaih@xxxxxxxxxx>
Signed-off-by: Michael Gur <michaelgur@xxxxxxxxxx>
---
drivers/infiniband/hw/mlx5/mlx5_ib.h | 4 +++-
drivers/infiniband/hw/mlx5/umr.h | 2 +-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index dd1fe8fd4220..75ea3f91e931 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1672,11 +1672,13 @@ static inline bool mlx5_umem_needs_ats(struct mlx5_ib_dev *dev,
{
if (!MLX5_CAP_GEN(dev->mdev, ats) || !umem->is_dmabuf)
return false;
- return access_flags & IB_ACCESS_RELAXED_ORDERING;
+ return access_flags & (IB_ACCESS_RELAXED_ORDERING | IB_ACCESS_UNORDERED);
}
static inline enum mlx5_mkey_order mlx5r_access_to_mkey_order(int access_flags)
{
+ if (access_flags & IB_ACCESS_UNORDERED)
+ return MLX5_MKEY_ORDER_UNORDERED;
if (access_flags & IB_ACCESS_RELAXED_ORDERING)
return MLX5_MKEY_ORDER_RELAXED;
return MLX5_MKEY_ORDER_STRICT;
diff --git a/drivers/infiniband/hw/mlx5/umr.h b/drivers/infiniband/hw/mlx5/umr.h
index a6c4f35b75e6..78b91d614a17 100644
--- a/drivers/infiniband/hw/mlx5/umr.h
+++ b/drivers/infiniband/hw/mlx5/umr.h
@@ -49,7 +49,7 @@ static inline unsigned int
mlx5r_umr_get_unchangeable_access_flags(struct mlx5_ib_dev *dev,
unsigned int access_flags)
{
- unsigned int ret = 0;
+ unsigned int ret = access_flags & IB_ACCESS_UNORDERED;
if ((access_flags & IB_ACCESS_REMOTE_ATOMIC) &&
MLX5_CAP_GEN(dev->mdev, atomic) &&
--
2.52.0