Re: [PATCH 2/2] scsi:target:tcmu: reduce once copy by using uio ioctl

[Greg KH]

On Thu, Feb 17, 2022 at 10:29:22AM +0800, Guixin Liu wrote:
> --- a/include/uapi/linux/target_core_user.h
> +++ b/include/uapi/linux/target_core_user.h
> @@ -185,4 +185,13 @@ enum tcmu_genl_attr {
>  };
>  #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
>  
> +struct tcmu_data_xfer {
> +	unsigned short cmd_id;
> +	unsigned long iov_cnt;
> +	struct iovec __user *iovec;
> +};

That is no way to define a structure that crosses the user/kernel
boundry, it just will not work at all, even if we wanted it to :(

sorry,

greg k-h