Re: [PATCH v2 0/2] firewire: Simplify storing pointers in device id struct

[Takashi Sakamoto <o-takashi@sakamocchi.jp>]

Hi,

On Mon, May 11, 2026 at 12:45:01PM +0200, Uwe Kleine-König (The Capable Hub) wrote:
> Hello,
> 
> v1 of this series can be found at
> https://lore.kernel.org/all/cover.1776579304.git.u.kleine-koenig@baylibre.com
> .
> 
> The changes introduced here are the same as before, but the commit log
> of the first patch is (hopefully) improved to better point out the
> advantage of the approach for mainline. The second patch demonstrates
> the explicit casts can be dropped after the first patch.
> 
> The patch series intends to not change the runtime behaviour, however
> the 2nd patch introduces a few changes to the generated code. Looking at
> these for an arm64 build they only affected register allocation (so
> where x0 was used before it's x1 after the patch). I'm not proficient in
> x86 assembly enough to understand the changes there, but I guess they
> also don't affect the runtime behaviour.
> 
> My motivation for this patch set is to reduce the patch stack for Linux
> CHERI support. This affects firewire because with CHERI you cannot store
> a pointer in an unsigned long variable. But I hope these changes qualify
> as cleanup worth to be applied even without considering CHERI.
> 
> For merging I suggest to take the whole series via the ALSA tree during
> the next merge window, as there are no modified files that are specific
> to firewire only and the second patch depends on the first.
> 
> Best regards
> Uwe
> 
> Uwe Kleine-König (The Capable Hub) (2):
>   firewire: Simplify storing pointers in device id struct
>   ALSA: firewire: Make use of ieee1394's .driver_data_ptr
> 
>  include/linux/mod_devicetable.h |  5 ++++-
>  sound/firewire/dice/dice.c      | 34 ++++++++++++++++-----------------
>  sound/firewire/fireface/ff.c    | 12 ++++++------
>  sound/firewire/motu/motu.c      |  6 +++---
>  sound/firewire/oxfw/oxfw.c      |  4 ++--
>  5 files changed, 32 insertions(+), 29 deletions(-)

These two patches are applied to for-next branch.

We can't predict the future, but setting aside the comment about the CHERI
extension, the actual benefit of these changes in the current Linux
kernel is simply to avoid casting between long and pointer and enable
constant pointer for the existing code.


Thanks

Takashi Sakamoto