Re: [PATCH 2/7] cxl/region: Fix cxl_region leak, cleanup targets at region delete

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Thu, 2022-11-03 at 17:30 -0700, Dan Williams wrote:
> When a region is deleted any targets that have been previously assigned
> to that region hold references to it. Trigger those references to
> drop by detaching all targets at unregister_region() time.
> 
> Otherwise that region object will leak as userspace has lost the ability
> to detach targets once region sysfs is torn down.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: b9686e8c8e39 ("cxl/region: Enable the assignment of endpoint decoders to regions")
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/cxl/core/region.c |   11 +++++++++++
>  1 file changed, 11 insertions(+)

Looks good,

Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>

> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index d26ca7a6beae..c52465e09f26 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1557,8 +1557,19 @@ static struct cxl_region *to_cxl_region(struct device *dev)
>  static void unregister_region(void *dev)
>  {
>         struct cxl_region *cxlr = to_cxl_region(dev);
> +       struct cxl_region_params *p = &cxlr->params;
> +       int i;
>  
>         device_del(dev);
> +
> +       /*
> +        * Now that region sysfs is shutdown, the parameter block is now
> +        * read-only, so no need to hold the region rwsem to access the
> +        * region parameters.
> +        */
> +       for (i = 0; i < p->interleave_ways; i++)
> +               detach_target(cxlr, i);
> +
>         cxl_region_iomem_release(cxlr);
>         put_device(dev);
>  }
>