drm/i915: Make pin count per VMA

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -100,7 +100,7 @@ static const char *get_pin_flag(struct drm_i915_gem_object *obj)
 {
 	if (obj->user_pin_count > 0)
 		return "P";
-	else if (obj->pin_count > 0)
+	else if (i915_gem_obj_is_pinned(obj))
 		return "p";
 	else
 		return " ";
@@ -125,6 +125,8 @@ static void
 describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 {
 	struct i915_vma *vma;
+	int pin_count = 0;
+
 	seq_printf(m, "%pK: %s%s%s %8zdKiB %02x %02x %u %u %u%s%s%s",
 		   &obj->base,
 		   get_pin_flag(obj),
@@ -141,8 +143,10 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 		   obj->madv == I915_MADV_DONTNEED ? " purgeable" : "");
 	if (obj->base.name)
 		seq_printf(m, " (name: %d)", obj->base.name);
-	if (obj->pin_count)
-		seq_printf(m, " (pinned x %d)", obj->pin_count);
+	list_for_each_entry(vma, &obj->vma_list, vma_link)
+		if (vma->pin_count > 0)
+			pin_count++;
+		seq_printf(m, " (pinned x %d)", pin_count);
 	if (obj->pin_display)
 		seq_printf(m, " (display)");
 	if (obj->fence_reg != I915_FENCE_REG_NONE)
@@ -439,7 +443,7 @@ static int i915_gem_gtt_info(struct seq_file *m, void *data)
 
 	total_obj_size = total_gtt_size = count = 0;
 	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
-		if (list == PINNED_LIST && obj->pin_count == 0)
+		if (list == PINNED_LIST && !i915_gem_obj_is_pinned(obj))
 			continue;
 
 		seq_puts(m, "   ");
@@ -2843,7 +2847,7 @@ i915_drop_caches_set(void *data, u64 val)
 		list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
 			list_for_each_entry_safe(vma, x, &vm->inactive_list,
 						 mm_list) {
-				if (vma->obj->pin_count)
+				if (vma->pin_count)
 					continue;
 
 				ret = i915_vma_unbind(vma);

drivers/gpu/drm/i915/i915_drv.h

@@ -651,6 +651,19 @@ struct i915_vma {
 	unsigned long exec_handle;
 	struct drm_i915_gem_exec_object2 *exec_entry;
 
+	/**
+	 * How many users have pinned this object in GTT space. The following
+	 * users can each hold at most one reference: pwrite/pread, pin_ioctl
+	 * (via user_pin_count), execbuffer (objects are not allowed multiple
+	 * times for the same batchbuffer), and the framebuffer code. When
+	 * switching/pageflipping, the framebuffer code has at most two buffers
+	 * pinned per crtc.
+	 *
+	 * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3
+	 * bits with absolutely no headroom. So use 4 bits.
+	 */
+	unsigned int pin_count:4;
+#define DRM_I915_GEM_OBJECT_MAX_PIN_COUNT 0xf
 };
 
 struct i915_ctx_hang_stats {
@@ -1617,18 +1630,6 @@ struct drm_i915_gem_object {
 	 */
 	unsigned int fence_dirty:1;
 
-	/** How many users have pinned this object in GTT space. The following
-	 * users can each hold at most one reference: pwrite/pread, pin_ioctl
-	 * (via user_pin_count), execbuffer (objects are not allowed multiple
-	 * times for the same batchbuffer), and the framebuffer code. When
-	 * switching/pageflipping, the framebuffer code has at most two buffers
-	 * pinned per crtc.
-	 *
-	 * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3
-	 * bits with absolutely no headroom. So use 4 bits. */
-	unsigned int pin_count:4;
-#define DRM_I915_GEM_OBJECT_MAX_PIN_COUNT 0xf
-
 	/**
 	 * Is the object at the current location in the gtt mappable and
 	 * fenceable? Used to avoid costly recalculations.
@@ -2005,7 +2006,7 @@ int __must_check i915_gem_object_pin(struct drm_i915_gem_object *obj,
 				     uint32_t alignment,
 				     bool map_and_fenceable,
 				     bool nonblocking);
-void i915_gem_object_unpin(struct drm_i915_gem_object *obj);
+void i915_gem_object_ggtt_unpin(struct drm_i915_gem_object *obj);
 int __must_check i915_vma_unbind(struct i915_vma *vma);
 int __must_check i915_gem_object_ggtt_unbind(struct drm_i915_gem_object *obj);
 int i915_gem_object_put_pages(struct drm_i915_gem_object *obj);
@@ -2168,6 +2169,13 @@ i915_gem_obj_lookup_or_create_vma(struct drm_i915_gem_object *obj,
 				  struct i915_address_space *vm);
 
 struct i915_vma *i915_gem_obj_to_ggtt(struct drm_i915_gem_object *obj);
+static inline bool i915_gem_obj_is_pinned(struct drm_i915_gem_object *obj) {
+	struct i915_vma *vma;
+	list_for_each_entry(vma, &obj->vma_list, vma_link)
+		if (vma->pin_count > 0)
+			return true;
+	return false;
+}
 
 /* Some GGTT VM helpers */
 #define obj_to_ggtt(obj) \

drivers/gpu/drm/i915/i915_gem.c

@@ -204,7 +204,7 @@ i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
 	pinned = 0;
 	mutex_lock(&dev->struct_mutex);
 	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list)
-		if (obj->pin_count)
+		if (i915_gem_obj_is_pinned(obj))
 			pinned += i915_gem_obj_ggtt_size(obj);
 	mutex_unlock(&dev->struct_mutex);
 
@@ -651,7 +651,7 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev,
 	}
 
 out_unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 out:
 	return ret;
 }
@@ -1418,7 +1418,7 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	/* Finally, remap it using the new GTT offset */
 	ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
 unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 unlock:
 	mutex_unlock(&dev->struct_mutex);
 out:
@@ -2721,7 +2721,7 @@ int i915_vma_unbind(struct i915_vma *vma)
 		return 0;
 	}
 
-	if (obj->pin_count)
+	if (vma->pin_count)
 		return -EBUSY;
 
 	BUG_ON(obj->pages == NULL);
@@ -2785,7 +2785,7 @@ i915_gem_object_ggtt_unbind(struct drm_i915_gem_object *obj)
 	if (!i915_gem_obj_ggtt_bound(obj))
 		return 0;
 
-	if (obj->pin_count)
+	if (i915_gem_obj_to_ggtt(obj)->pin_count)
 		return -EBUSY;
 
 	BUG_ON(obj->pages == NULL);
@@ -3486,7 +3486,7 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
 	if (obj->cache_level == cache_level)
 		return 0;
 
-	if (obj->pin_count) {
+	if (i915_gem_obj_is_pinned(obj)) {
 		DRM_DEBUG("can not change the cache level of pinned objects\n");
 		return -EBUSY;
 	}
@@ -3646,7 +3646,7 @@ static bool is_pin_display(struct drm_i915_gem_object *obj)
 	 * subtracting the potential reference by the user, any pin_count
 	 * remains, it must be due to another use by the display engine.
 	 */
-	return obj->pin_count - !!obj->user_pin_count;
+	return i915_gem_obj_to_ggtt(obj)->pin_count - !!obj->user_pin_count;
 }
 
 /*
@@ -3720,7 +3720,7 @@ err_unpin_display:
 void
 i915_gem_object_unpin_from_display_plane(struct drm_i915_gem_object *obj)
 {
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 	obj->pin_display = is_pin_display(obj);
 }
 
@@ -3853,18 +3853,18 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 	struct i915_vma *vma;
 	int ret;
 
-	if (WARN_ON(obj->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT))
-		return -EBUSY;
-
 	WARN_ON(map_and_fenceable && !i915_is_ggtt(vm));
 
 	vma = i915_gem_obj_to_vma(obj, vm);
 
 	if (vma) {
+		if (WARN_ON(vma->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT))
+			return -EBUSY;
+
 		if ((alignment &&
 		     vma->node.start & (alignment - 1)) ||
 		    (map_and_fenceable && !obj->map_and_fenceable)) {
-			WARN(obj->pin_count,
+			WARN(vma->pin_count,
 			     "bo is already pinned with incorrect alignment:"
 			     " offset=%lx, req.alignment=%x, req.map_and_fenceable=%d,"
 			     " obj->map_and_fenceable=%d\n",
@@ -3893,19 +3893,22 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 	if (!obj->has_global_gtt_mapping && map_and_fenceable)
 		i915_gem_gtt_bind_object(obj, obj->cache_level);
 
-	obj->pin_count++;
+	i915_gem_obj_to_vma(obj, vm)->pin_count++;
 	obj->pin_mappable |= map_and_fenceable;
 
 	return 0;
 }
 
 void
-i915_gem_object_unpin(struct drm_i915_gem_object *obj)
+i915_gem_object_ggtt_unpin(struct drm_i915_gem_object *obj)
 {
-	BUG_ON(obj->pin_count == 0);
-	BUG_ON(!i915_gem_obj_bound_any(obj));
+	struct i915_vma *vma = i915_gem_obj_to_ggtt(obj);
 
-	if (--obj->pin_count == 0)
+	BUG_ON(!vma);
+	BUG_ON(vma->pin_count == 0);
+	BUG_ON(!i915_gem_obj_ggtt_bound(obj));
+
+	if (--vma->pin_count == 0)
 		obj->pin_mappable = false;
 }
 
@@ -3989,7 +3992,7 @@ i915_gem_unpin_ioctl(struct drm_device *dev, void *data,
 	obj->user_pin_count--;
 	if (obj->user_pin_count == 0) {
 		obj->pin_filp = NULL;
-		i915_gem_object_unpin(obj);
+		i915_gem_object_ggtt_unpin(obj);
 	}
 
 out:
@@ -4069,7 +4072,7 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 		goto unlock;
 	}
 
-	if (obj->pin_count) {
+	if (i915_gem_obj_is_pinned(obj)) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -4178,12 +4181,14 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 	if (obj->phys_obj)
 		i915_gem_detach_phys_object(dev, obj);
 
-	obj->pin_count = 0;
 	/* NB: 0 or 1 elements */
 	WARN_ON(!list_empty(&obj->vma_list) &&
 		!list_is_singular(&obj->vma_list));
 	list_for_each_entry_safe(vma, next, &obj->vma_list, vma_link) {
-		int ret = i915_vma_unbind(vma);
+		int ret;
+
+		vma->pin_count = 0;
+		ret = i915_vma_unbind(vma);
 		if (WARN_ON(ret == -ERESTARTSYS)) {
 			bool was_interruptible;
 
@@ -4963,7 +4968,7 @@ i915_gem_inactive_count(struct shrinker *shrinker, struct shrink_control *sc)
 		if (obj->active)
 			continue;
 
-		if (obj->pin_count == 0 && obj->pages_pin_count == 0)
+		if (!i915_gem_obj_is_pinned(obj) && obj->pages_pin_count == 0)
 			count += obj->base.size >> PAGE_SHIFT;
 	}
 

drivers/gpu/drm/i915/i915_gem_context.c

@@ -241,7 +241,7 @@ static int create_default_context(struct drm_i915_private *dev_priv)
 	return 0;
 
 err_unpin:
-	i915_gem_object_unpin(ctx->obj);
+	i915_gem_object_ggtt_unpin(ctx->obj);
 err_destroy:
 	i915_gem_context_unreference(ctx);
 	return ret;
@@ -300,11 +300,11 @@ void i915_gem_context_fini(struct drm_device *dev)
 	if (dev_priv->ring[RCS].last_context == dctx) {
 		/* Fake switch to NULL context */
 		WARN_ON(dctx->obj->active);
-		i915_gem_object_unpin(dctx->obj);
+		i915_gem_object_ggtt_unpin(dctx->obj);
 		i915_gem_context_unreference(dctx);
 	}
 
-	i915_gem_object_unpin(dctx->obj);
+	i915_gem_object_ggtt_unpin(dctx->obj);
 	i915_gem_context_unreference(dctx);
 	dev_priv->ring[RCS].default_context = NULL;
 	dev_priv->ring[RCS].last_context = NULL;
@@ -412,7 +412,7 @@ static int do_switch(struct i915_hw_context *to)
 	u32 hw_flags = 0;
 	int ret, i;
 
-	BUG_ON(from != NULL && from->obj != NULL && from->obj->pin_count == 0);
+	BUG_ON(from != NULL && from->obj != NULL && !i915_gem_obj_is_pinned(from->obj));
 
 	if (from == to && !to->remap_slice)
 		return 0;
@@ -428,7 +428,7 @@ static int do_switch(struct i915_hw_context *to)
 	 * XXX: We need a real interface to do this instead of trickery. */
 	ret = i915_gem_object_set_to_gtt_domain(to->obj, false);
 	if (ret) {
-		i915_gem_object_unpin(to->obj);
+		i915_gem_object_ggtt_unpin(to->obj);
 		return ret;
 	}
 
@@ -440,7 +440,7 @@ static int do_switch(struct i915_hw_context *to)
 
 	ret = mi_set_context(ring, to, hw_flags);
 	if (ret) {
-		i915_gem_object_unpin(to->obj);
+		i915_gem_object_ggtt_unpin(to->obj);
 		return ret;
 	}
 
@@ -476,7 +476,7 @@ static int do_switch(struct i915_hw_context *to)
 		BUG_ON(from->obj->ring != ring);
 
 		/* obj is kept alive until the next request by its active ref */
-		i915_gem_object_unpin(from->obj);
+		i915_gem_object_ggtt_unpin(from->obj);
 		i915_gem_context_unreference(from);
 	}
 

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -34,7 +34,8 @@
 static bool
 mark_free(struct i915_vma *vma, struct list_head *unwind)
 {
-	if (vma->obj->pin_count)
+	/* Freeing up memory requires no VMAs are pinned */
+	if (i915_gem_obj_is_pinned(vma->obj))
 		return false;
 
 	if (WARN_ON(!list_empty(&vma->exec_list)))
@@ -186,7 +187,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
 	}
 
 	list_for_each_entry_safe(vma, next, &vm->inactive_list, mm_list)
-		if (vma->obj->pin_count == 0)
+		if (vma->pin_count == 0)
 			WARN_ON(i915_vma_unbind(vma));
 
 	return 0;

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -566,7 +566,7 @@ i915_gem_execbuffer_unreserve_vma(struct i915_vma *vma)
 		i915_gem_object_unpin_fence(obj);
 
 	if (entry->flags & __EXEC_OBJECT_HAS_PIN)
-		i915_gem_object_unpin(obj);
+		vma->pin_count--;
 
 	entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
 }
@@ -923,7 +923,9 @@ i915_gem_execbuffer_move_to_active(struct list_head *vmas,
 		if (obj->base.write_domain) {
 			obj->dirty = 1;
 			obj->last_write_seqno = intel_ring_get_seqno(ring);
-			if (obj->pin_count) /* check for potential scanout */
+			/* check for potential scanout */
+			if (i915_gem_obj_ggtt_bound(obj) &&
+			    i915_gem_obj_to_ggtt(obj)->pin_count)
 				intel_mark_fb_busy(obj, ring);
 		}
 

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -308,7 +308,7 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 
-	if (obj->pin_count || obj->framebuffer_references) {
+	if (i915_gem_obj_is_pinned(obj) || obj->framebuffer_references) {
 		drm_gem_object_unreference_unlocked(&obj->base);
 		return -EBUSY;
 	}

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -578,7 +578,7 @@ static void capture_bo(struct drm_i915_error_buffer *err,
 	err->write_domain = obj->base.write_domain;
 	err->fence_reg = obj->fence_reg;
 	err->pinned = 0;
-	if (obj->pin_count > 0)
+	if (i915_gem_obj_is_pinned(obj))
 		err->pinned = 1;
 	if (obj->user_pin_count > 0)
 		err->pinned = -1;
@@ -611,7 +611,7 @@ static u32 capture_pinned_bo(struct drm_i915_error_buffer *err,
 	int i = 0;
 
 	list_for_each_entry(obj, head, global_list) {
-		if (obj->pin_count == 0)
+		if (!i915_gem_obj_is_pinned(obj))
 			continue;
 
 		capture_bo(err++, obj);
@@ -875,7 +875,7 @@ static void i915_gem_capture_vm(struct drm_i915_private *dev_priv,
 		i++;
 	error->active_bo_count[ndx] = i;
 	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list)
-		if (obj->pin_count)
+		if (i915_gem_obj_is_pinned(obj))
 			i++;
 	error->pinned_bo_count[ndx] = i - error->active_bo_count[ndx];
 

drivers/gpu/drm/i915/intel_fbdev.c

@@ -104,7 +104,7 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 	return 0;
 
 out_unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 out_unref:
 	drm_gem_object_unreference(&obj->base);
 out:
@@ -208,7 +208,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	return 0;
 
 out_unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 	drm_gem_object_unreference(&obj->base);
 out_unlock:
 	mutex_unlock(&dev->struct_mutex);

drivers/gpu/drm/i915/intel_overlay.c

@@ -293,7 +293,7 @@ static void intel_overlay_release_old_vid_tail(struct intel_overlay *overlay)
 {
 	struct drm_i915_gem_object *obj = overlay->old_vid_bo;
 
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 	drm_gem_object_unreference(&obj->base);
 
 	overlay->old_vid_bo = NULL;
@@ -306,7 +306,7 @@ static void intel_overlay_off_tail(struct intel_overlay *overlay)
 	/* never have the overlay hw on without showing a frame */
 	BUG_ON(!overlay->vid_bo);
 
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 	drm_gem_object_unreference(&obj->base);
 	overlay->vid_bo = NULL;
 
@@ -782,7 +782,7 @@ static int intel_overlay_do_put_image(struct intel_overlay *overlay,
 	return 0;
 
 out_unpin:
-	i915_gem_object_unpin(new_bo);
+	i915_gem_object_ggtt_unpin(new_bo);
 	return ret;
 }
 
@@ -1386,7 +1386,7 @@ void intel_setup_overlay(struct drm_device *dev)
 
 out_unpin_bo:
 	if (!OVERLAY_NEEDS_PHYSICAL(dev))
-		i915_gem_object_unpin(reg_bo);
+		i915_gem_object_ggtt_unpin(reg_bo);
 out_free_bo:
 	drm_gem_object_unreference(&reg_bo->base);
 out_free:

drivers/gpu/drm/i915/intel_pm.c

@@ -3298,7 +3298,7 @@ intel_alloc_context_page(struct drm_device *dev)
 	return ctx;
 
 err_unpin:
-	i915_gem_object_unpin(ctx);
+	i915_gem_object_ggtt_unpin(ctx);
 err_unref:
 	drm_gem_object_unreference(&ctx->base);
 	return NULL;
@@ -4166,13 +4166,13 @@ void ironlake_teardown_rc6(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	if (dev_priv->ips.renderctx) {
-		i915_gem_object_unpin(dev_priv->ips.renderctx);
+		i915_gem_object_ggtt_unpin(dev_priv->ips.renderctx);
 		drm_gem_object_unreference(&dev_priv->ips.renderctx->base);
 		dev_priv->ips.renderctx = NULL;
 	}
 
 	if (dev_priv->ips.pwrctx) {
-		i915_gem_object_unpin(dev_priv->ips.pwrctx);
+		i915_gem_object_ggtt_unpin(dev_priv->ips.pwrctx);
 		drm_gem_object_unreference(&dev_priv->ips.pwrctx->base);
 		dev_priv->ips.pwrctx = NULL;
 	}

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -549,7 +549,7 @@ init_pipe_control(struct intel_ring_buffer *ring)
 	return 0;
 
 err_unpin:
-	i915_gem_object_unpin(ring->scratch.obj);
+	i915_gem_object_ggtt_unpin(ring->scratch.obj);
 err_unref:
 	drm_gem_object_unreference(&ring->scratch.obj->base);
 err:
@@ -625,7 +625,7 @@ static void render_ring_cleanup(struct intel_ring_buffer *ring)
 
 	if (INTEL_INFO(dev)->gen >= 5) {
 		kunmap(sg_page(ring->scratch.obj->pages->sgl));
-		i915_gem_object_unpin(ring->scratch.obj);
+		i915_gem_object_ggtt_unpin(ring->scratch.obj);
 	}
 
 	drm_gem_object_unreference(&ring->scratch.obj->base);
@@ -1250,7 +1250,7 @@ static void cleanup_status_page(struct intel_ring_buffer *ring)
 		return;
 
 	kunmap(sg_page(obj->pages->sgl));
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 	drm_gem_object_unreference(&obj->base);
 	ring->status_page.obj = NULL;
 }
@@ -1290,7 +1290,7 @@ static int init_status_page(struct intel_ring_buffer *ring)
 	return 0;
 
 err_unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 err_unref:
 	drm_gem_object_unreference(&obj->base);
 err:
@@ -1387,7 +1387,7 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 err_unmap:
 	iounmap(ring->virtual_start);
 err_unpin:
-	i915_gem_object_unpin(obj);
+	i915_gem_object_ggtt_unpin(obj);
 err_unref:
 	drm_gem_object_unreference(&obj->base);
 	ring->obj = NULL;
@@ -1415,7 +1415,7 @@ void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring)
 
 	iounmap(ring->virtual_start);
 
-	i915_gem_object_unpin(ring->obj);
+	i915_gem_object_ggtt_unpin(ring->obj);
 	drm_gem_object_unreference(&ring->obj->base);
 	ring->obj = NULL;
 	ring->preallocated_lazy_request = NULL;