5735878a7b
[ Upstream commit 6d03bbff456befeccdd4d663177c4d6c75d0c4ff ] Coretemp's platform driver is unconventional. All the real work is done globally by the initcall and CPU hotplug notifiers, while the "driver" effectively just wraps an allocation and the registration of the hwmon interface in a long-winded round-trip through the driver core. The whole logic of dynamically creating and destroying platform devices to bring the interfaces up and down is error prone, since it assumes platform_device_add() will synchronously bind the driver and set drvdata before it returns, thus results in a NULL dereference if drivers_autoprobe is turned off for the platform bus. Furthermore, the unusual approach of doing that from within a CPU hotplug notifier, already commented in the code that it deadlocks suspend, also causes lockdep issues for other drivers or subsystems which may want to legitimately register a CPU hotplug notifier from a platform bus notifier. All of these issues can be solved by ripping this unusual behaviour out completely, simply tying the platform devices to the lifetime of the module itself, and directly managing the hwmon interfaces from the hotplug notifiers. There is a slight user-visible change in that /sys/bus/platform/drivers/coretemp will no longer appear, and /sys/devices/platform/coretemp.n will remain present if package n is hotplugged off, but hwmon users should really only be looking for the presence of the hwmon interfaces, whose behaviour remains unchanged. Link: https://lore.kernel.org/lkml/20220922101036.87457-1-janusz.krzysztofik@linux.intel.com/ Link: https://gitlab.freedesktop.org/drm/intel/issues/6641 Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> Link: https://lore.kernel.org/r/20230103114620.15319-1-janusz.krzysztofik@linux.intel.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.