Re: [NDCTL PATCH v2] cxl: Add helper function to verify port is in memdev hierarchy

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Fri, 2025-07-11 at 15:33 -0700, Dave Jiang wrote:
> 'cxl enable-port -m' uses cxl_port_get_dport_by_memdev() to find the
> memdevs that are associated with a port in order to enable those
> associated memdevs. When the kernel switch to delayed dport
> initialization by enumerating the dports during memdev probe, the
> dports are no longer valid until the memdev is probed. This means
> that cxl_port_get_dport_by_memdev() will not find any memdevs under
> the port.
> 
> Add a new helper function cxl_port_is_memdev_hierarchy() that checks if a

Stale commit message - since the actual helper is called
cxl_memdev_is_port_ancestor() ?

> port is in the memdev hierarchy via the memdev->host_path where the sysfs
> path contains all the devices in the hierarchy. This call is also backward
> compatible with the old behavior.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
> v2:
> - Remove usages of cxl_port_get_dport_by_memdev() and add documentation to explain
>   when cxl_port_get_dport_by_memdev() should be used. (Alison)
> ---
>  Documentation/cxl/lib/libcxl.txt |  5 +++++
>  cxl/filter.c                     |  2 +-
>  cxl/lib/libcxl.c                 | 31 +++++++++++++++++++++++++++++++
>  cxl/lib/libcxl.sym               |  5 +++++
>  cxl/libcxl.h                     |  3 +++
>  cxl/port.c                       |  4 ++--
>  6 files changed, 47 insertions(+), 3 deletions(-)