Re: [PATCH 3/6] dax/hmem, cxl: Tighten dependencies on DEV_DAX_CXL and dax_hmem

["Koralahalli Channabasappa, Smita" <skoralah@amd.com>]

On 8/31/2025 8:28 PM, Zhijian Li (Fujitsu) wrote:
> 
> 
> On 22/08/2025 11:41, Smita Koralahalli wrote:
>> Update Kconfig and runtime checks to better coordinate dax_cxl and dax_hmem
>> registration.
>>
>> Add explicit Kconfig ordering so that CXL_ACPI and CXL_PCI must be
>> initialized before DEV_DAX_HMEM.
> 
> Is this dependency statement fully accurate? To clarify, another prerequisite for
> this ordering to work correctly is that dax_hmem must explicitly call
> `request_module("cxl_acpi")` and `request_module("cxl_pci")` during its initialization.
>    
> Therefore, I recommend consolidating the following patches into a single commit
> to ensure atomic handling of the initialization order:
> - [PATCH 2/6] dax/hmem: Request cxl_acpi and cxl_pci before walking Soft Reserved ranges
> - [PATCH 3/6] dax/hmem, cxl: Tighten dependencies on DEV_DAX_CXL and dax_hmem
> 
> Thanks
> Zhijian

I have merged 2/6 and 3/6 in v2.

Thanks
Smita

>> This prevents dax_hmem from consuming
>> Soft Reserved ranges before CXL drivers have had a chance to claim them.
>>
>> Replace IS_ENABLED(CONFIG_CXL_REGION) with IS_ENABLED(CONFIG_DEV_DAX_CXL)
>> so the code more precisely reflects when CXL-specific DAX coordination is
>> expected.
>>
>> This ensures that ownership of Soft Reserved ranges is consistently
>> handed off to the CXL stack when DEV_DAX_CXL is configured.