b7644592bd
The size of the critical section in this function appears to be larger than necessary. The `wacom_udev_list_lock` exists to ensure that one interface cannot begin checking if a shared object exists while a second interface is doing the same (otherwise both could determine that no object exists yet and create their own independent objects rather than sharing just one). It should be safe for the critical section to end once a fresly-allocated shared object would be found by other threads (i.e., once it has been added to `wacom_udev_list`, which is looped over by `wacom_get_hdev_data`). This commit is a necessary pre-requisite for a later change to swap the use of `devm_add_action` with `devm_add_action_or_reset`, which would otherwise deadlock in its error case. Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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.