From cb21f3f882ad12811331c1067b9acfc4dd359d3f Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Tue, 20 Oct 2020 15:26:00 -0700 Subject: [PATCH] drm/msm/atomic: Drop per-CRTC locks in reverse order lockdep dislikes seeing locks unwound in a non-nested fashion. Fixes: b3d91800d9ac ("drm/msm: Fix race condition in msm driver with async layer updates") Signed-off-by: Rob Clark Reviewed-by: Abhinav Kumar --- drivers/gpu/drm/msm/msm_atomic.c | 2 +- drivers/gpu/drm/msm/msm_kms.h | 4 ++++ include/drm/drm_crtc.h | 10 ++++++++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c index 575e9af9b6fc9..93d39608a0739 100644 --- a/drivers/gpu/drm/msm/msm_atomic.c +++ b/drivers/gpu/drm/msm/msm_atomic.c @@ -67,7 +67,7 @@ static void unlock_crtcs(struct msm_kms *kms, unsigned int crtc_mask) { struct drm_crtc *crtc; - for_each_crtc_mask(kms->dev, crtc, crtc_mask) + for_each_crtc_mask_reverse(kms->dev, crtc, crtc_mask) mutex_unlock(&kms->commit_lock[drm_crtc_index(crtc)]); } diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h index 2049847b66428..977ea96e383bb 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -196,4 +196,8 @@ int dpu_mdss_init(struct drm_device *dev); drm_for_each_crtc(crtc, dev) \ for_each_if (drm_crtc_mask(crtc) & (crtc_mask)) +#define for_each_crtc_mask_reverse(dev, crtc, crtc_mask) \ + drm_for_each_crtc_reverse(crtc, dev) \ + for_each_if (drm_crtc_mask(crtc) & (crtc_mask)) + #endif /* __MSM_KMS_H__ */ diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 59b51a09cae6b..cd42f79b28909 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1266,4 +1266,14 @@ static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev, #define drm_for_each_crtc(crtc, dev) \ list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head) +/** + * drm_for_each_crtc_reverse - iterate over all CRTCs in reverse order + * @crtc: a &struct drm_crtc as the loop cursor + * @dev: the &struct drm_device + * + * Iterate over all CRTCs of @dev. + */ +#define drm_for_each_crtc_reverse(crtc, dev) \ + list_for_each_entry_reverse(crtc, &(dev)->mode_config.crtc_list, head) + #endif /* __DRM_CRTC_H__ */ -- 2.30.2