drm/i915: Assert that we have allocated the drm_mm_node upon pinning

We currently check after the slow path that the vma is bound correctly,
but we don't currently check after the fast path. This is important in
case we accidentally take the fast path and leave the vma misplaced.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170111210937.29252-27-chris@chris-wilson.co.ukReviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/i915_vma.c

@@ -476,6 +476,7 @@ int __i915_vma_do_pin(struct i915_vma *vma,
 	if ((bound ^ vma->flags) & I915_VMA_GLOBAL_BIND)
 		__i915_vma_set_map_and_fenceable(vma);
 
+	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
 	GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
 	return 0;
 

drivers/gpu/drm/i915/i915_vma.h

@@ -232,8 +232,11 @@ i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 	/* Pin early to prevent the shrinker/eviction logic from destroying
 	 * our vma as we insert and bind.
 	 */
-	if (likely(((++vma->flags ^ flags) & I915_VMA_BIND_MASK) == 0))
+	if (likely(((++vma->flags ^ flags) & I915_VMA_BIND_MASK) == 0)) {
+		GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
+		GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
 		return 0;
+	}
 
 	return __i915_vma_do_pin(vma, size, alignment, flags);
 }