From: Vegard Nossum <vegard.nossum@oracle.com>
To: Saeed Mahameed <saeed@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-api@vger.kernel.org,
Linux Documentation <linux-doc@vger.kernel.org>
Cc: Leon Romanovsky <leonro@nvidia.com>,
Jason Gunthorpe <jgg@nvidia.com>, Jiri Pirko <jiri@nvidia.com>,
Leonid Bloch <lbloch@nvidia.com>,
Itay Avraham <itayavr@nvidia.com>,
Jakub Kicinski <kuba@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
David Ahern <dsahern@kernel.org>,
Aron Silverton <aron.silverton@oracle.com>,
Christoph Hellwig <hch@infradead.org>,
andrew.gospodarek@broadcom.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V4 3/5] misc: mlx5ctl: Add info ioctl
Date: Thu, 29 Feb 2024 12:47:59 +0100 [thread overview]
Message-ID: <bb259840-35b6-4483-8e76-8046cae1269b@oracle.com> (raw)
In-Reply-To: <20240207072435.14182-4-saeed@kernel.org>
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
next parent reply other threads:[~2024-02-29 11:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240207072435.14182-1-saeed@kernel.org>
[not found] ` <20240207072435.14182-4-saeed@kernel.org>
2024-02-29 11:47 ` Vegard Nossum [this message]
2024-03-02 8:03 ` [PATCH V4 3/5] misc: mlx5ctl: Add info ioctl Saeed Mahameed
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