Re: [PATCH 4/8] snd: make snd_map_bufs() deal with ITER_UBUF

[Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>]

On Tue, Mar 28, 2023 at 10:36 AM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> @@ -3516,23 +3516,28 @@ static void __user **snd_map_bufs(struct snd_pcm_runtime *runtime,
>                                   struct iov_iter *iter,
>                                   snd_pcm_uframes_t *frames, int max_segs)
>  {
> +       int nr_segs = iovec_nr_user_vecs(iter);

This has a WARN_ON_ONCE() for !user_backed, but then..

>         void __user **bufs;
> +       struct iovec iov;
>         unsigned long i;
>
>         if (!iter->user_backed)
>                 return ERR_PTR(-EFAULT);

here the code tries to deal with it.

So I think the two should probably be switched around.

                 Linus