Re: [PATCH 3/5] cxl/region: Prevent device_find_child() from modifying caller's match data

[Przemek Kitszel]

On 8/11/24 02:18, Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
>
> It does not make sense for match_free_decoder() as device_find_child()'s
> match function to modify caller's match data, 

match_free_decoder() is just doing that, treating caller's match data as
a piece of memory to store their int.
(So it is hard to tell it does not make sense "for [it] ... to").

> fixed by using
> constify_device_find_child_helper() instead of device_find_child().

I don't like the constify... name, I would go with something like
device_find_child_mut() or similar.

> Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
> ---
>   drivers/cxl/core/region.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 21ad5f242875..266231d69dff 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -849,7 +849,8 @@ cxl_region_find_decoder(struct cxl_port *port,
>   		dev = device_find_child(&port->dev, &cxlr->params,
>   					match_auto_decoder);
>   	else
> -		dev = device_find_child(&port->dev, &id, match_free_decoder);
> +		dev = constify_device_find_child_helper(&port->dev, &id,
> +							match_free_decoder);
>   	if (!dev)
>   		return NULL;
>   	/*