Re: [PATCH 10/18] cxl/region: Fix passthrough-decoder detection

[Dave Jiang <dave.jiang@intel.com>]

On 2/5/23 6:03 PM, Dan Williams wrote:
> A passthrough decoder is a decoder that maps only 1 target. It is a
> special case because it does not impose any constraints on the
> interleave-math as compared to a decoder with multiple targets. Extend
> the passthrough case to multi-target-capable decoders that only have one
> target selected. I.e. the current code was only considering passthrough
> *ports* which are only a subset of the potential passthrough decoder
> scenarios.
> 
> Fixes: e4f6dfa9ef75 ("cxl/region: Fix 'distance' calculation with passthrough ports")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>   drivers/cxl/core/region.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index c82d3b6f3d1f..34cf95217901 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1019,10 +1019,10 @@ static int cxl_port_setup_targets(struct cxl_port *port,
>   		int i, distance;
>   
>   		/*
> -		 * Passthrough ports impose no distance requirements between
> +		 * Passthrough decoders impose no distance requirements between
>   		 * peers
>   		 */
> -		if (port->nr_dports == 1)
> +		if (cxl_rr->nr_targets == 1)
>   			distance = 0;
>   		else
>   			distance = p->nr_targets / cxl_rr->nr_targets;
>