[PATCH rdma-next 14/15] RDMA/mlx5: Support new Unordered access flag
From: Michael Gur <hidden>
Date: 2026-07-26 09:31:16
Also in:
linux-rdma, lkml
Subsystem:
infiniband subsystem, mellanox mlx5 ib driver, the rest · Maintainers:
Jason Gunthorpe, Leon Romanovsky, Linus Torvalds
Add mlx5 driver support for IB_ACCESS_UNORDERED, the new uverbs access flag that enables relaxing the order of read after write on mkeys. 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@nvidia.com> Signed-off-by: Michael Gur <redacted> --- drivers/infiniband/hw/mlx5/mlx5_ib.h | 2 +- drivers/infiniband/hw/mlx5/mr.c | 7 ++++++- drivers/infiniband/hw/mlx5/umr.c | 2 +- drivers/infiniband/hw/mlx5/umr.h | 2 +- 4 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 427e7f706c8a..ab245ec1af6b 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h@@ -1679,7 +1679,7 @@ 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); } int set_roce_addr(struct mlx5_ib_dev *dev, u32 port_num,
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 5f6d91c47483..31879c0ecfb3 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c@@ -71,9 +71,14 @@ static void set_mkc_access_pd_addr_fields(void *mkc, int acc, u64 start_addr, MLX5_SET(mkc, mkc, lw, !!(acc & IB_ACCESS_LOCAL_WRITE)); MLX5_SET(mkc, mkc, lr, 1); - if (acc & IB_ACCESS_RELAXED_ORDERING) + if (acc & (IB_ACCESS_RELAXED_ORDERING | IB_ACCESS_UNORDERED)) mlx5_core_mkey_set_relaxed_ordering(dev->mdev, mkc); + if ((acc & IB_ACCESS_UNORDERED) && + MLX5_CAP_GEN(dev->mdev, mkc_order_read_after_write)) + MLX5_SET(mkc, mkc, order_read_after_write, + MLX5_MKC_ORDER_READ_AFTER_WRITE_RO); + MLX5_SET(mkc, mkc, pd, to_mpd(pd)->pdn); MLX5_SET(mkc, mkc, qpn, 0xffffff); MLX5_SET64(mkc, mkc, start_addr, start_addr);
diff --git a/drivers/infiniband/hw/mlx5/umr.c b/drivers/infiniband/hw/mlx5/umr.c
index b0799f86994d..689d4542d1ad 100644
--- a/drivers/infiniband/hw/mlx5/umr.c
+++ b/drivers/infiniband/hw/mlx5/umr.c@@ -451,7 +451,7 @@ static void mlx5r_umr_set_access_flags(struct mlx5_ib_dev *dev, MLX5_SET(mkc, seg, lw, !!(access_flags & IB_ACCESS_LOCAL_WRITE)); MLX5_SET(mkc, seg, lr, 1); - if (access_flags & IB_ACCESS_RELAXED_ORDERING) + if (access_flags & (IB_ACCESS_RELAXED_ORDERING | IB_ACCESS_UNORDERED)) mlx5_core_mkey_set_relaxed_ordering(dev->mdev, seg); }
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) &&
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2.52.0