drm/i915: BUG_ON put_pages later

With multiple VMs, the eviction code benefits from being able to blindly
put pages without needing to know if there are any entities still
holding on to those pages. As such it's preferable to return the -EBUSY
before the BUG.

Eviction code is the only user for now, but overall it makes sense
anyway, IMO.

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

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 56c300f8f9b1a084dbfbf8bd57f64c6d8083ec99..f02d9234bd9105bd6cd0c0cb7485e7745b2b4208 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1668,11 +1668,11 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
        if (obj->pages == NULL)
                return 0;
 
-       BUG_ON(i915_gem_obj_ggtt_bound(obj));
-
        if (obj->pages_pin_count)
                return -EBUSY;
 
+       BUG_ON(i915_gem_obj_ggtt_bound(obj));
+
        /* ->put_pages might need to allocate memory for the bit17 swizzle
         * array, hence protect them from being reaped by removing them from gtt
         * lists early. */