[PATCH] drm/i915: Add locking around framebuffer_references--

[PATCH] drm/i915: Add locking around framebuffer_references--

[ville.syrjala]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

obj->framebuffer_references isn't an atomic_t so the decrement needs to
be protected by some lock. struct_mutex seems like the appropriate lock
here, and we may already take it for the obj unref anyway.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b5cbb28..5762726 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11504,11 +11504,14 @@ static void intel_setup_outputs(struct drm_device *dev)
 
 static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
+	struct drm_device *dev = fb->dev;
 	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
 
 	drm_framebuffer_cleanup(fb);
+	mutex_lock(&dev->struct_mutex);
 	WARN_ON(!intel_fb->obj->framebuffer_references--);
-	drm_gem_object_unreference_unlocked(&intel_fb->obj->base);
+	drm_gem_object_unreference(&intel_fb->obj->base);
+	mutex_unlock(&dev->struct_mutex);
 	kfree(intel_fb);
 }
 
-- 
1.8.5.5

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Re: [PATCH] drm/i915: Add locking around framebuffer_references--

[Daniel Vetter]

On Fri, Jun 13, 2014 at 11:10:53AM +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> obj->framebuffer_references isn't an atomic_t so the decrement needs to
> be protected by some lock. struct_mutex seems like the appropriate lock
> here, and we may already take it for the obj unref anyway.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_display.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index b5cbb28..5762726 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -11504,11 +11504,14 @@ static void intel_setup_outputs(struct drm_device *dev)
>  
>  static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
>  {
> +	struct drm_device *dev = fb->dev;
>  	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
>  
>  	drm_framebuffer_cleanup(fb);
> +	mutex_lock(&dev->struct_mutex);
>  	WARN_ON(!intel_fb->obj->framebuffer_references--);
> -	drm_gem_object_unreference_unlocked(&intel_fb->obj->base);
> +	drm_gem_object_unreference(&intel_fb->obj->base);
> +	mutex_unlock(&dev->struct_mutex);
>  	kfree(intel_fb);
>  }
>  
> -- 
> 1.8.5.5
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch