---
name: "mlx4dv_set_context_attr"
section: "3"
platform: "linux"
package: "rdma-core"
version: "65.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/mlx4dv_set_context_attr"
---

# mlx4dv\_set\_context\_attr(3)

Set context attributes

## NAME

mlx4dv\_set\_context\_attr - Set context attributes

## SYNOPSIS

-

  ```
  #include <infiniband/mlx4dv.h>
  int mlx4dv_set_context_attr(struct ibv_context *context,
                              enum mlx4dv_set_ctx_attr_type attr_type,
                              void *attr);
  ```

## DESCRIPTION

mlx4dv\_set\_context\_attr gives the ability to set vendor specific attributes on the RDMA context.

## ARGUMENTS

- *context*

  RDMA device context to work on.

- *attr\_type*

  The type of the provided attribute.

- *attr*

  Pointer to the attribute to be set. ## attr\_type

-

  ```
  enum mlx4dv_set_ctx_attr_type {
      /* Attribute type uint8_t */
      MLX4DV_SET_CTX_ATTR_LOG_WQS_RANGE_SZ    = 0,
      MLX4DV_SET_CTX_ATTR_BUF_ALLOCATORS  = 1,
  };
  ```

- *MLX4DV\_SET\_CTX\_ATTR\_LOG\_WQS\_RANGE\_SZ*

  Change the LOG WQs Range size for RSS

- *MLX4DV\_SET\_CTX\_ATTR\_BUF\_ALLOCATORS*

  Provide an external buffer allocator

-

  ```
  struct mlx4dv_ctx_allocators {
      void *(*alloc)(size_t size, void *priv_data);
      void (*free)(void *ptr, void *priv_data);
      void *data;
  };
  ```

- *alloc*

  Function used for buffer allocation instead of libmlx4 internal method

- *free*

  Function used to free buffers allocated by alloc function

- *data*

  Metadata that can be used by alloc and free functions

## RETURN VALUE

Returns 0 on success, or the value of errno on failure (which indicates the failure reason).

\#AUTHOR

Majd Dibbiny ⟨majd@mellanox.com⟩\\c