netdev - Re: [PATCH v18 16/20] cxl: Allow region creation by type2 drivers

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Message-ID: <5860ea5f-3a49-4c54-aff9-4be0801eefa5@amd.com>
Date: Fri, 26 Sep 2025 10:01:16 +0100
From: Alejandro Lucero Palau <alucerop@....com>
To: "Cheatham, Benjamin" <benjamin.cheatham@....com>,
 alejandro.lucero-palau@....com
Cc: linux-cxl@...r.kernel.org, netdev@...r.kernel.org,
 dan.j.williams@...el.com, edward.cree@....com, davem@...emloft.net,
 kuba@...nel.org, pabeni@...hat.com, edumazet@...gle.com, dave.jiang@...el.com
Subject: Re: [PATCH v18 16/20] cxl: Allow region creation by type2 drivers


On 9/22/25 22:09, Cheatham, Benjamin wrote:
> On 9/18/2025 4:17 AM, alejandro.lucero-palau@....com wrote:
>> From: Alejandro Lucero <alucerop@....com>
>>
>> Creating a CXL region requires userspace intervention through the cxl
>> sysfs files. Type2 support should allow accelerator drivers to create
>> such cxl region from kernel code.
>>
>> Adding that functionality and integrating it with current support for
>> memory expanders.
>>
>> Support an action by the type2 driver to be linked to the created region
>> for unwinding the resources allocated properly.
>>
>> Based on https://lore.kernel.org/linux-cxl/168592159835.1948938.1647215579839222774.stgit@dwillia2-xfh.jf.intel.com/
>>
>> Signed-off-by: Alejandro Lucero <alucerop@....com>
>> ---
> [snip]
>
>> +static struct cxl_region *
>> +__construct_new_region(struct cxl_root_decoder *cxlrd,
>> +		       struct cxl_endpoint_decoder **cxled, int ways)
>> +{
>> +	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled[0]);
>> +	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
>> +	struct cxl_region_params *p;
>> +	resource_size_t size = 0;
>> +	struct cxl_region *cxlr;
>> +	int rc, i;
>> +
>> +	cxlr = construct_region_begin(cxlrd, cxled[0]);
>> +	if (IS_ERR(cxlr))
>> +		return cxlr;
> I think you can use a cleanup helper here and get rid of the gotos. If you return a return_ptr(cxlr) (or whatever
> it's called) you can still return the error without doing the drop_region() cleanup action.
>

I like the idea which should imply cleaner code. I'll try to do so for v19.


Thanks!