Re: [PATCH net-deletions] caif: remove CAIF NETWORK LAYER

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Apr 16, 2026 at 11:28:28AM -0700, Jakub Kicinski wrote:
> Remove CAIF (Communication CPU to Application CPU Interface), the
> ST-Ericsson modem protocol. The subsystem has been orphaned since 2013.
> The last meaningful changes from the maintainers were in March 2013:
>   a8c7687bf216 ("caif_virtio: Check that vringh_config is not null")
>   b2273be8d2df ("caif_virtio: Use vringh_notify_enable correctly")
>   0d2e1a2926b1 ("caif_virtio: Introduce caif over virtio")
> 
> Not-so-coincidentally, according to "the Internet" ST-Ericsson officially
> shut down its modem joint venture in Aug 2013.
> 
> If anyone is using this code please yell!
> 
> In the 13 years since, the code has accumulated 200 non-merge commits,
> of which 71 were cross-tree API changes, 21 carried Fixes: tags, and
> the remaining ~110 were cleanups, doc conversions, treewide refactors,
> and one partial removal (caif_hsi, ca75bcf0a83b).
> 
> We are still getting fixes to this code, in the last 10 days there were
> 3 reports on security@ about CAIF that I have been CCed on.
> 
> UAPI constants (AF_CAIF, ARPHRD_CAIF, N_CAIF, VIRTIO_ID_CAIF) and the
> SELinux classmap entry are intentionally kept for ABI stability.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> I think we should accumulate such patches over the coming days on a separate
> branch. CAIF is a no-brainer IMO but other removals may be more controversial.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>