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authorNoralf Trønnes <noralf@tronnes.org>2019-02-08 15:01:02 +0100
committerDave Airlie <airlied@redhat.com>2019-03-25 15:58:05 +1000
commit3f04e0a6cfebf48152ac64502346cdc258811f79 (patch)
tree4ccc47708c31d7198068575adf781b581eb00d91 /drivers/gpu/drm/drm_drv.c
parentb23b52b6720e4be1652a4c92819f34d91e735559 (diff)
downloadlinux-3f04e0a6cfebf48152ac64502346cdc258811f79.tar.bz2
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> Signed-off-by: Dave Airlie <airlied@redhat.com> 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 381581b01d48..05bbc2b622fc 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);