lkml.org 
[lkml]   [2024]   [Feb]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH V4 3/5] misc: mlx5ctl: Add info ioctl
From

On 07/02/2024 08:24, Saeed Mahameed wrote:
> +static int mlx5ctl_info_ioctl(struct file *file,
> + struct mlx5ctl_info __user *arg,
> + size_t usize)
> +{
> + struct mlx5ctl_fd *mfd = file->private_data;
> + size_t ksize = sizeof(struct mlx5ctl_info);
> + struct mlx5ctl_dev *mcdev = mfd->mcdev;
> + struct mlx5_core_dev *mdev = mcdev->mdev;
> + struct mlx5ctl_info *info;
> + int err = 0;
> +
> + if (usize < ksize)
> + return -EINVAL;
> +
> + info = kzalloc(ksize, GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;

struct mlx5ctl_info is small, why not put it on the stack or even copy
it directly from the original object, assuming it has no holes/padding?

> +
> + info->dev_uctx_cap = MLX5_CAP_GEN(mdev, uctx_cap);
> + info->uctx_cap = mfd->uctx_cap;
> + info->uctx_uid = mfd->uctx_uid;
> + info->ucap = mfd->ucap;
> +
> + if (copy_to_user(arg, info, ksize))
> + err = -EFAULT;
> +
> + kfree(info);
> + return err;
> +}

Is there even a remote possibility of extending this structure in the
future? If so the size check will not allow you to be backwards
compatible. Should there be a version field in there or would you
just add a new ioctl altogether? Adding linux-api@vger.kernel.org to Cc.

> diff --git a/include/uapi/misc/mlx5ctl.h b/include/uapi/misc/mlx5ctl.h
> new file mode 100644
> index 000000000000..9be944128025
> --- /dev/null
> +++ b/include/uapi/misc/mlx5ctl.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 WITH Linux-syscall-note */
> +/* Copyright (c) 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
> +
> +#ifndef __MLX5CTL_IOCTL_H__
> +#define __MLX5CTL_IOCTL_H__
> +
> +struct mlx5ctl_info {
> + __u16 uctx_uid; /* current process allocated UCTX UID */
> + __u16 reserved1; /* explicit padding must be zero */
> + __u32 uctx_cap; /* current process effective UCTX cap */
> + __u32 dev_uctx_cap; /* device's UCTX capabilities */
> + __u32 ucap; /* process user capability */
> +};
> +
> +#define MLX5CTL_IOCTL_MAGIC 0x5c
> +
> +#define MLX5CTL_IOCTL_INFO \
> + _IOR(MLX5CTL_IOCTL_MAGIC, 0x0, struct mlx5ctl_info)
> +
> +#endif /* __MLX5CTL_IOCTL_H__ */

Should you add anything to Documentation/ABI/ ? (Or add other
documentation for this driver?)


Vegard

\
 
 \ /
  Last update: 2024-05-27 15:28    [W:0.195 / U:1.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site