Subject: Re: [PATCH 12/16] staging/comedi: mark as broken

From: Greg KH <[email-masked]>
Date: Fri, 14 Jun 2019 16:02:39 +0200

On Fri, Jun 14, 2019 at 03:47:22PM +0200, Christoph Hellwig wrote:
> comedi_buf.c abuse the DMA API in gravely broken ways, as it assumes it
> can call virt_to_page on the result, and the just remap it as uncached
> using vmap.  Disable the driver until this API abuse has been fixed.
> 
> Signed-off-by: Christoph Hellwig <[email-masked]>
> ---
>  drivers/staging/comedi/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig
> index 049b659fa6ad..e7c021d76cfa 100644
> --- a/drivers/staging/comedi/Kconfig
> +++ b/drivers/staging/comedi/Kconfig
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  config COMEDI
>  	tristate "Data acquisition support (comedi)"
> +	depends on BROKEN

Um, that's a huge sledgehammer.

Perhaps a hint as to how we can fix this up?  This is the first time
I've heard of the comedi code not handling dma properly.

thanks,

greg k-h