drm: use the lookup lock in drm_is_current_master

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Inside drm_is_current_master, using the outer drm_device.master_mutex
to protect reads of drm_file.master makes the function prone to creating
lock hierarchy inversions. Instead, we can use the
drm_file.master_lookup_lock that sits at the bottom of the lock
hierarchy.

Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210724111824.59266-2-desmondcheongzx@gmail.com

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Desmond Cheong Zhi Xi 2021-07-24 19:18:22 +08:00 • committed by Daniel Vetter

parent c29758cdc7

commit 28be2405fb

1 changed files with 5 additions and 4 deletions

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drivers/gpu/drm/drm_auth.c

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