Re: [PATCH] drm/exynos: fix cancel page flip code

Hi Andrzej,

On 24 March 2016 at 10:52, Andrzej Hajda a.hajda@samsung.com wrote:

@@ -229,24 +229,12 @@ void exynos_drm_crtc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file) { struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);

•   struct drm_pending_vblank_event *e;
  

•   unsigned long flags;
  

•   struct drm_pending_vblank_event *e = exynos_crtc->event;
  
  

•   spin_lock_irqsave(&crtc->dev->event_lock, flags);
  

•   e = exynos_crtc->event;
  

•   if (e && e->base.file_priv == file) {
  

•           exynos_crtc->event = NULL;
  

•           /*
  

•            * event will be destroyed by core part
  

•            * so below line should be removed later with core changes
  

•            */
  

•           e->base.destroy(&e->base);
  

•           /*
  

•            * event_space will be increased by core part
  

•            * so below line should be removed later with core changes.
  

•            */
  

•           file->event_space += sizeof(e->event);
  

•           atomic_dec(&exynos_crtc->pending_update);
  

•   }
  

•   spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
  

•   if (!e || e->base.file_priv != file)
  

•           return;
  

•   exynos_crtc->event = NULL;
  

•   atomic_dec(&exynos_crtc->pending_update);
  

•   drm_event_cancel_free(crtc->dev, &e->base);
  

Accessing and manipulating exynos_crtc->event should still be done under event_lock, to avoid racing with the IRQ handler.

Cheers, Daniel