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

[Al Viro]

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);
>  }