Re: [PATCH V6 10/18] cxl/mem: Refactor cxl pmem region auto-assembling

Neeraj Kumar
2026-03-06T10:23:05Z

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On 27/01/26 04:45PM, Dave Jiang wrote:
>
>
>On 1/26/26 3:48 PM, Dave Jiang wrote:
>>
>>
>> On 1/23/26 4:31 AM, Neeraj Kumar wrote:
>>> In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
>>> before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
>>> used to get called at last in cxl_endpoint_port_probe(), which requires
>>> cxl_nvd presence.
>>>
>>> For cxl region persistency, region creation happens during nvdimm_probe
>>> which need the completion of endpoint probe.
>>>
>>> In order to accommodate both cxl pmem region auto-assembly and cxl region
>>> persistency, refactored following
>>>
>>> 1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
>>> will be called only after successful completion of endpoint probe.
>>>
>>> 2. Create cxl_region_discovery() which performs pmem region
>>> auto-assembly and remove cxl pmem region auto-assembly from
>>> cxl_endpoint_port_probe()
>>>
>>> 3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
>>> called during cxl_pci_probe() in context of cxl_mem_probe()
>>>
>>> 4. As cxlmd->attach->probe() calls registered cxl_region_discovery(), so
>>> move devm_cxl_add_nvdimm() before cxlmd->attach->probe(). It guarantees
>>> both the completion of endpoint probe and cxl_nvd presence before
>>> calling cxlmd->attach->probe().
>>>
>>> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
>>> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>>> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>
>>
>> Hi Neeraj,
>> Just FYI this is the patch that breaks the auto-region assemble in cxl_test.
>
>So it's missing this part in cxl_test. cxl_test auto region is now showing up. But now I'm hitting some lockdep issues.
>
>---
>diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
>index cb87e8c0e63c..03af15edd988 100644
>--- a/tools/testing/cxl/test/mem.c
>+++ b/tools/testing/cxl/test/mem.c
>@@ -1686,6 +1686,7 @@ static void cxl_mock_test_feat_init(struct cxl_mockmem_data *mdata)
>
> static int cxl_mock_mem_probe(struct platform_device *pdev)
> {
>+ struct cxl_memdev_attach memdev_attach = { 0 };
> struct device *dev = &pdev->dev;
> struct cxl_memdev *cxlmd;
> struct cxl_memdev_state *mds;
>@@ -1767,7 +1768,8 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
>
> cxl_mock_add_event_logs(&mdata->mes);
>
>- cxlmd = devm_cxl_add_memdev(cxlds, NULL);
>+ memdev_attach.probe = cxl_region_discovery;
>+ cxlmd = devm_cxl_add_memdev(cxlds, &memdev_attach);
> if (IS_ERR(cxlmd))
> return PTR_ERR(cxlmd);
>
>---
>
>
>>
>> DJ

Hi Dave,

Yes using the above snippet auto region failure is getting fixed.
But still with above fix cxl-topology.sh is failing.

Actually we have a test case in cxl-topology.sh where we disable
mem device and check its availability after enabling it. And this
test case is failing in this case.

I am working on multi interleave support. I will test this with
next series and fix it accordingly.

Regards,
Neeraj

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