Re: [PATCH 22/41] sparc: switch to ->get2()

[Al Viro <viro@xxxxxxxxxxxxxxxxxx>]

On Mon, Jun 29, 2020 at 07:26:09PM +0100, Al Viro wrote:
  
>  static int getregs64_get(struct task_struct *target,
>  			 const struct user_regset *regset,
> -			 unsigned int pos, unsigned int count,
> -			 void *kbuf, void __user *ubuf)
> +			 struct membuf to)
>  {
>  	const struct pt_regs *regs = task_pt_regs(target);
> -	int ret;
>  
>  	if (target == current)
>  		flushw_user();
>  
> -	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> -				  regs->u_regs + 1,
> -				  0, 15 * sizeof(u64));
> -	if (!ret)
> -		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
> -				  15 * sizeof(u64), 16 * sizeof(u64));
> -	if (!ret) {
> -		/* TSTATE, TPC, TNPC */
> -		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> -					  &regs->tstate,
> -					  16 * sizeof(u64),
> -					  19 * sizeof(u64));
> -	}
> -	if (!ret) {
> -		unsigned long y = regs->y;
> -
> -		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
> -					  &y,
> -					  19 * sizeof(u64),
> -					  20 * sizeof(u64));
> -	}
> -	return ret;
> +	membuf_write(&to, regs->u_regs + 1, 15 * sizeof(u64));
> +	return membuf_store(&to, (u64)0);
	^^^^^^
Er...  That should be simply

+	membuf_store(&to, (u64)0);

> +	membuf_write(&to, &regs->tstate, 3 * sizeof(u64));
> +	return membuf_store(&to, (u64)regs->y);
>  }