Re: [PATCH 09/26] cxl/region: Add Dynamic Capacity CXL region support

Jonathan Cameron
2024-04-04T10:26:31Z

On Sun, 24 Mar 2024 16:18:12 -0700
ira.weiny@intel.com wrote:

> From: Navneet Singh <navneet.singh@intel.com>
>
> CXL devices optionally support dynamic capacity. CXL Regions must be
> configured correctly to access this capacity. Similar to ram and pmem
> partitions, DC Regions, as they are called in CXL 3.1, represent
> different partitions of the DPA space.
>
> Introduce the concept of a sparse DAX region. Add the create_dc_region
> sysfs entry to create sparse DC DAX regions. Special case DC capable
> regions to create a 0 sized seed DAX device to maintain backwards
> compatibility with older software which needs a default DAX device to
> hold the region reference.
>
> Flag sparse DAX regions to indicate 0 capacity available until such time
> as DC capacity is added.
>
> Interleaving is deferred in this series. Add an early check.
>
> Signed-off-by: Navneet Singh <navneet.singh@intel.com>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
With the -EBUSY others addressed LGTM. Fan's duplication comment
might be something to tidy up later.

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