Li Ming fdc9be9092 cxl/edac: Fix the min_scrub_cycle of a region miscalculation
When trying to update the scrub_cycle value of a cxl region, which means
updating the scrub_cycle value of each memdev under a cxl region. cxl
driver needs to guarantee the new scrub_cycle value is greater than the
min_scrub_cycle value of a memdev, otherwise the updating operation will
fail(Per Table 8-223 in CXL r3.2 section 8.2.10.9.11.1).

Current implementation logic of getting the min_scrub_cycle value of a
cxl region is that getting the min_scrub_cycle value of each memdevs
under the cxl region, then using the minimum min_scrub_cycle value as
the region's min_scrub_cycle. Checking if the new scrub_cycle value is
greater than this value. If yes, updating the new scrub_cycle value to
each memdevs. The issue is that the new scrub_cycle value is possibly
greater than the minimum min_scrub_cycle value of all memdevs but less
than the maximum min_scrub_cycle value of all memdevs if memdevs have
a different min_scrub_cycle value. The updating operation will always
fail on these memdevs which have a greater min_scrub_cycle than the new
scrub_cycle.

The correct implementation logic is to get the maximum value of these
memdevs' min_scrub_cycle, check if the new scrub_cycle value is greater
than the value. If yes, the new scrub_cycle value is fit for the region.

The change also impacts the result of
cxl_patrol_scrub_get_min_scrub_cycle(), the interface returned the
minimum min_scrub_cycle value among all memdevs under the region before
the change. The interface will return the maximum min_scrub_cycle value
among all memdevs under the region with the change.

Signed-off-by: Li Ming <ming.li@zohomail.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Shiju Jose <shiju.jose@huawei.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Link: https://patch.msgid.link/20250603104314.25569-1-ming.li@zohomail.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-06-10 13:54:15 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-06-08 13:44:43 -07:00
2024-03-18 03:36:32 -06:00

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 reStructuredText 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.
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