mlx5: Move data direct infrastructure to mlx5_core

Data direct support currently lives in mlx5_ib, which owns the data
direct PCI driver, device matching and resource management. To prepare
for data direct support in netdev, move this infrastructure to mlx5_core
and provide a common interface for its consumers.

The series first replaces the direct IB unbind callback with a blocking
notifier chain, allowing multiple consumers to receive unbind events.
It then separates consumer registration from initialization,
consolidates the per-device state and resources, and keeps IB-specific
locking and MR teardown in mlx5_ib.

With these preparations in place, the final patch moves the shared
implementation and PCI driver to mlx5_core. Data direct initialization
and resource creation run during core load, before consumers attach;
cleanup runs during core unload, after consumers detach.

The data direct PCI driver is also explicitly named "mlx5_dd", replacing
the previous "mlx5_ib" name derived from KBUILD_MODNAME.

This series by Dragos prepares the shared infrastructure for netdev
support.  The netdev consumer will follow in a separate series.

Signed-off-by: Leon Romanovsky <leon@kernel.org>

2 files changed, 55 insertions, 0 deletions

diff --git a/include/linux/mlx5/data_direct.h b/include/linux/mlx5/data_direct.h
new file mode 100644
index 000000000000..4cff5ff5489d
--- /dev/null
+++ b/include/linux/mlx5/data_direct.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved
+ */
+
+#ifndef _MLX5_DATA_DIRECT_H
+#define _MLX5_DATA_DIRECT_H
+
+#include <linux/compiler.h>
+#include <linux/list.h>
+
+struct device;
+struct mlx5_core_dev;
+struct notifier_block;
+struct pci_dev;
+
+enum mlx5_data_direct_event {
+	MLX5_DATA_DIRECT_UNBIND,
+};
+
+struct mlx5_data_direct_dev {
+	struct device *device;
+	struct pci_dev *pdev;
+	char *vuid;
+	struct list_head list;
+};
+
+struct mlx5_data_direct {
+	struct mlx5_data_direct_dev *dev;
+	u32 pdn;
+	u32 mkey;
+	u32 mkey_ro;
+	u8 mkey_ro_valid :1;
+};
+
+static inline struct mlx5_data_direct_dev *
+mlx5_data_direct_get_dev(struct mlx5_data_direct *dd)
+{
+	return dd ? READ_ONCE(dd->dev) : NULL;
+}
+
+int mlx5_data_direct_register(struct mlx5_core_dev *mdev,
+			      struct notifier_block *nb);
+void mlx5_data_direct_unregister(struct mlx5_core_dev *mdev,
+				 struct notifier_block *nb);
+
+#endif
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index 83d0a83bbfbc..abb99371ff13 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -707,6 +707,7 @@ struct mlx5_rsvd_gids {
 
 struct mlx5_clock;
 struct mlx5_clock_dev_state;
+struct mlx5_data_direct;
 struct mlx5_dm;
 struct mlx5_fw_tracer;
 struct mlx5_vxlan;
@@ -801,6 +802,7 @@ struct mlx5_core_dev {
 	/* sync write combining state */
 	struct mutex wc_state_lock;
 	struct devlink *shd;
+	struct mlx5_data_direct *data_direct;
 };
 
 struct mlx5_db {
@@ -1395,4 +1397,10 @@ static inline struct net *mlx5_core_net(struct mlx5_core_dev *dev)
 
 #define MLX5_SW_IMAGE_GUID_MAX_BYTES 9
 
+static inline bool mlx5_data_direct_supported(struct mlx5_core_dev *mdev)
+{
+	return MLX5_CAP_GEN(mdev, data_direct) &&
+	       MLX5_CAP_GEN_2(mdev, query_vuid);
+}
+
 #endif /* MLX5_DRIVER_H */