On 2020-10-20 15:26, Rob Clark wrote:

From: Rob Clark robdclark@chromium.org

lockdep dislikes seeing locks unwound in a non-nested fashion.

Fixes: 37c2016e3608 ("drm/msm: Fix race condition in msm driver with async layer updates") Signed-off-by: Rob Clark robdclark@chromium.org

Reviewed-by: Abhinav Kumar abhinavk@codeaurora.org

---

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 b03d6ab6b19b..6a326761dc4a 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 8d3e626c9fee..d8151a89e163 100644 --- a/drivers/gpu/drm/msm/msm_kms.h +++ b/drivers/gpu/drm/msm/msm_kms.h @@ -211,4 +211,8 @@ 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 dfdb04619b0d..25f5958f2882 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -1274,4 +1274,14 @@ 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__ */