Re: [PATCH v2 1/3] cxl/mem: Quiet port walking warnings

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Wed, 25 Jan 2023 14:11:17 -0800
Dan Williams <dan.j.williams@intel.com> wrote:

> The cxl_mem driver attempts to establish, or revalidate, the cxl_port
> hierarcy to attach a cxl_memdev to a CXL platform topology. There is a
> natural race (on ACPI platforms) between when the cxl_mem driver
> attempts to attach and when the cxl_acpi driver establishes the root of
> the topology.
> 
> If cxl_mem_probe() runs first it will iterate to the top of the device
> topology without finding the CXL platform root. That situation is benign
> / expected, so stop warning about it. The cxl_acpi driver will poke
> cxl_mem_probe() to try again once the CXL platform root is established.
> 
> Suppress any upper level errors by making it clear that this is merely a
> probe deferral event, not a hard error.
> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> Changes since v1:
> * Use dev_err_probe() (Jonathan)
> 
>  drivers/cxl/core/port.c |    7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index b631a0520456..feb8f84a9281 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1397,9 +1397,10 @@ int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd)
>  
>  		uport_dev = dport_dev->parent;
>  		if (!uport_dev) {
> -			dev_warn(dev, "at %s no parent for dport: %s\n",
> -				 dev_name(iter), dev_name(dport_dev));
> -			return -ENXIO;
> +			dev_err_probe(dev, -EPROBE_DEFER,
> +				      "at %s no parent for dport: %s\n",
> +				      dev_name(iter), dev_name(dport_dev));
> +			return -EPROBE_DEFER;
>  		}
>  
>  		dev_dbg(dev, "scan: iter: %s dport_dev: %s parent: %s\n",
>