Re: [PATCH 08/20] drm/armada: use xchg() to atomically update dplane->old_fb

Hi Russell,

On 29 September 2015 at 19:10, Russell King rmk+kernel@arm.linux.org.uk wrote:

Rather than using a spinlock, use xchg() to atomically update dplane->old_fb. This allows us to eliminate dplane->lock.

Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk

[...]

@@ -76,13 +75,10 @@ static void armada_ovl_retire_fb(struct armada_ovl_plane *dplane, { struct drm_framebuffer *old_fb;

•   spin_lock(&dplane->lock);
  

•   old_fb = dplane->old_fb;
  

•   dplane->old_fb = fb;
  

•   spin_unlock(&dplane->lock);
  

•   old_fb = xchg(&dplane->old_fb, fb);
  
    if (old_fb)
  

•           armada_drm_queue_unref_work(dplane->base.dev, old_fb);
  

•           armada_drm_queue_unref_work(dplane->base.base.dev, old_fb);
  

Shouldn't this be part of another patch ?

-Emil