From 743c97ca9dc989b0b08ca1fbfd134a83b37fe9ec Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Thu, 11 Feb 2021 14:40:58 -0800 Subject: drm/msm/kms: Use nested locking for crtc lock instead of custom classes We don't need to make up custom lock classes here, we can simply use mutex_lock_nested() and pass in the index of the crtc to the locking APIs instead. This helps lockdep understand that these are really different locks while avoiding having to allocate custom lockdep classes. Cc: Krishna Manikandan Suggested-by: Daniel Vetter Fixes: b3d91800d9ac ("drm/msm: Fix race condition in msm driver with async layer updates") Signed-off-by: Stephen Boyd Signed-off-by: Rob Clark --- drivers/gpu/drm/msm/msm_atomic.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/msm/msm_atomic.c') diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c index 6a326761dc4a..edcaccaa27e6 100644 --- a/drivers/gpu/drm/msm/msm_atomic.c +++ b/drivers/gpu/drm/msm/msm_atomic.c @@ -57,10 +57,13 @@ static void vblank_put(struct msm_kms *kms, unsigned crtc_mask) static void lock_crtcs(struct msm_kms *kms, unsigned int crtc_mask) { + int crtc_index; struct drm_crtc *crtc; - for_each_crtc_mask(kms->dev, crtc, crtc_mask) - mutex_lock(&kms->commit_lock[drm_crtc_index(crtc)]); + for_each_crtc_mask(kms->dev, crtc, crtc_mask) { + crtc_index = drm_crtc_index(crtc); + mutex_lock_nested(&kms->commit_lock[crtc_index], crtc_index); + } } static void unlock_crtcs(struct msm_kms *kms, unsigned int crtc_mask) -- cgit v1.2.3-59-g8ed1b