Re: [PATCH v9 22/27] cxl: allow region creation by type2 drivers

Alejandro Lucero Palau
2025-01-03T08:16:31Z

On 1/2/25 15:22, Jonathan Cameron wrote:
> On Mon, 30 Dec 2024 21:44:40 +0000
> alejandro.lucero-palau@amd.com wrote:
>
>> From: Alejandro Lucero <alucerop@amd.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.
>>
>> Based on https://lore.kernel.org/linux-cxl/168592159835.1948938.1647215579839222774.stgit@dwillia2-xfh.jf.intel.com/
>>
>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>> Co-developed-by: Dan Williams <dan.j.williams@intel.com>
>> Reviewed-by: Zhi Wang <zhiw@nvidia.com>
> Trivial comment inline. Either way
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
>> ---
>> drivers/cxl/core/region.c | 145 ++++++++++++++++++++++++++++++++++----
>> drivers/cxl/cxlmem.h | 2 +
>> drivers/cxl/port.c | 5 +-
>> include/cxl/cxl.h | 4 ++
>> 4 files changed, 141 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>> index 1b1d45c44b52..a2b92162edbd 100644
>> --- a/drivers/cxl/core/region.c
>> +++ b/drivers/cxl/core/region.c
>> @@ -2270,6 +2270,18 @@ static int cxl_region_detach(struct cxl_endpoint_decoder *cxled)
>> return rc;
>> }
>>
>> +int cxl_accel_region_detach(struct cxl_endpoint_decoder *cxled)
>> +{
>> + int rc;
>> +
>> + down_write(&cxl_region_rwsem);
> Could use a guard here so you can return directly.

Interesting. Not familiar with this automatic cleanups, but I'll use as
it is already being used inside kernel cxl core.

Thanks!

>> + cxled->mode = CXL_DECODER_DEAD;
>> + rc = cxl_region_detach(cxled);
>> + up_write(&cxl_region_rwsem);
>> + return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_accel_region_detach, "CXL");
>