Dan Williams d35b495ddf cxl/port: Fix find_cxl_root() for RCDs and simplify it
The find_cxl_root() helper is used to lookup root decoders and other CXL
platform topology information for a given endpoint. It turns out that
for RCDs it has never worked. The result of find_cxl_root(&cxlmd->dev)
is always NULL for the RCH topology case because it expects to find a
cxl_port at the host-bridge. RCH topologies only have the root cxl_port
object with the host-bridge as a dport. While there are no reports of
this being a problem to date, by inspection region enumeration should
crash as a result of this problem, and it does in a local unit test for
this scenario.

However, an observation that ever since:

commit f17b558d66 ("cxl/pmem: Refactor nvdimm device registration, delete the workqueue")

...all callers of find_cxl_root() occur after the memdev connection to
the port topology has been established. That means that find_cxl_root()
can be simplified to a walk of the endpoint port topology to the root.
Switch to that arrangement which also fixes the RCD bug.

Fixes: a32320b71f ("cxl/region: Add region autodiscovery")
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/168002857715.50647.344876437247313909.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-04-04 15:34:34 -07:00
2023-03-05 10:49:37 -08:00
2022-09-28 09:02:20 +02:00
2023-03-12 16:36:44 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 3.4 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%