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authorNoralf Trønnes <noralf@tronnes.org>2019-02-08 15:01:02 +0100
committerNoralf Trønnes <noralf@tronnes.org>2019-02-21 12:11:32 +0100
commit1ee57d4d75fbc74bb2ae601c8f334219165ef276 (patch)
treec1147055afbfad120a467bd7210108743d0fd9ad /drivers/gpu/drm/drm_drv.c
parent1fdafbd023793e754aa6ca73c877a375e83b8239 (diff)
drm: Fix drm_release() and device unplug
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> Link: https://patchwork.freedesktop.org/patch/msgid/20190208140103.28919-2-noralf@tronnes.org
Diffstat (limited to 'drivers/gpu/drm/drm_drv.c')
-rw-r--r--drivers/gpu/drm/drm_drv.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 4fec551eb781..f2d5a41b61f7 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -376,11 +376,7 @@ void drm_dev_unplug(struct drm_device *dev)
synchronize_srcu(&drm_unplug_srcu);
drm_dev_unregister(dev);
-
- mutex_lock(&drm_global_mutex);
- if (dev->open_count == 0)
- drm_dev_put(dev);
- mutex_unlock(&drm_global_mutex);
+ drm_dev_put(dev);
}
EXPORT_SYMBOL(drm_dev_unplug);