Re: [PATCH v2 2/2] cxl/region: Use __free(put_device) in find_pos_and_ways()

On Wed, Jul 22, 2026 at 12:56:48AM +0100, Jonathan Cameron wrote:
> On Tue, 21 Jul 2026 10:37:04 -0700
> Alison Schofield <[email protected]> wrote:
> 
> > Use __free(put_device) for the switch decoder reference returned by
> > device_find_child() instead of releasing it with an open-coded
> > put_device().
> > 
> > This matches the scoped device reference handling used elsewhere in
> > the file.
> > 
> > Suggested-by: Li Ming <[email protected]>
> > Signed-off-by: Alison Schofield <[email protected]>
> > ---
> > 
> > This is a new patch added in series after the UAF fixup in patch 1/2.
> > 
> > 
> >  drivers/cxl/core/region.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> > index c86dd9d55e93..4d7d96d03ece 100644
> > --- a/drivers/cxl/core/region.c
> > +++ b/drivers/cxl/core/region.c
> > @@ -1911,9 +1911,9 @@ static int match_switch_decoder_by_range(struct device *dev,
> >  static int find_pos_and_ways(struct cxl_port *port, struct range *range,
> >  			     int *pos, int *ways)
> >  {
> > +	struct device *dev __free(put_device) = NULL;
> 
> No to this.  See rules in cleanup.h.
> This is the path to grumpy Linus if he happens to spot it.
> 
> Short story is declaration and destructor must be in same statement
> as the constructor.  Here that means 
> 
> 	struct device *dev __free(put_device) =
> 		device_find_child(&parent->dev, range, match_switch_decoder_by_range);
> 
> I would go long on that second line given it's only a bit beyond 80 chars
> and the two lines are horrible enough to read without becoming 3.

Thanks for the cleanup.h pointer.
In v3 dev is declared and assigned in a single statement after the
!parent check, formatted as you suggested above.

-- Alison