Noralf Trønnes
c5eb9a424e
[ Upstream commit 3f04e0a6cf ]
If userspace has open fd(s) when drm_dev_unplug() is run, it will result
in drm_dev_unregister() being called twice. First in drm_dev_unplug() and
then later in drm_release() through the call to drm_put_dev().
Since userspace already holds a ref on drm_device through the drm_minor,
it's not necessary to add extra ref counting based on no open file
handles. Instead just drm_dev_put() unconditionally in drm_dev_unplug().
We now have this:
- Userpace holds a ref on drm_device as long as there's open fd(s)
- The driver holds a ref on drm_device as long as it's bound to the
struct device
When both sides are done with drm_device, it is released.
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190208140103.28919-2-noralf@tronnes.org
Signed-off-by: Sasha Levin (Microsoft) <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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.