drm/i915: Defer assignment of obj->gtt_space until after all possible mallocs

As we may invoke the shrinker whilst trying to allocate memory to hold
the gtt_space for this object, we need to be careful not to mark the
drm_mm_node as activated (by assigning it to this object) before we
have finished our sequence of allocations.

Note: We also need to move the binding of the object into the actual
pagetables down a bit. The best way seems to be to move it out into
the callsites.

Reported-by: Imre Deak <imre.deak@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Added small note to commit message to summarize review
discussion.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 19 insertions, 20 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e9c80065805b..71b5129947ba 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2918,11 +2918,10 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 
  search_free:
         if (map_and_fenceable)
-                free_space =
-                        drm_mm_search_free_in_range_color(&dev_priv->mm.gtt_space,
-                                                          size, alignment, obj->cache_level,
-                                                          0, dev_priv->mm.gtt_mappable_end,
-                                                          false);
+                free_space = drm_mm_search_free_in_range_color(&dev_priv->mm.gtt_space,
+                                                               size, alignment, obj->cache_level,
+                                                               0, dev_priv->mm.gtt_mappable_end,
+                                                               false);
         else
                 free_space = drm_mm_search_free_color(&dev_priv->mm.gtt_space,
                                                       size, alignment, obj->cache_level,
@@ -2930,18 +2929,18 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 
         if (free_space != NULL) {
                 if (map_and_fenceable)
-                        obj->gtt_space =
+                        free_space =
                                 drm_mm_get_block_range_generic(free_space,
                                                                size, alignment, obj->cache_level,
                                                                0, dev_priv->mm.gtt_mappable_end,
                                                                false);
                 else
-                        obj->gtt_space =
+                        free_space =
                                 drm_mm_get_block_generic(free_space,
                                                          size, alignment, obj->cache_level,
                                                          false);
         }
-        if (obj->gtt_space == NULL) {
+        if (free_space == NULL) {
                 ret = i915_gem_evict_something(dev, size, alignment,
                                                obj->cache_level,
                                                map_and_fenceable,
@@ -2954,34 +2953,29 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
                 goto search_free;
         }
         if (WARN_ON(!i915_gem_valid_gtt_space(dev,
-                                              obj->gtt_space,
+                                              free_space,
                                               obj->cache_level))) {
                 i915_gem_object_unpin_pages(obj);
-                drm_mm_put_block(obj->gtt_space);
-                obj->gtt_space = NULL;
+                drm_mm_put_block(free_space);
                 return -EINVAL;
         }
 
-
         ret = i915_gem_gtt_prepare_object(obj);
         if (ret) {
                 i915_gem_object_unpin_pages(obj);
-                drm_mm_put_block(obj->gtt_space);
-                obj->gtt_space = NULL;
+                drm_mm_put_block(free_space);
                 return ret;
         }
 
-        if (!dev_priv->mm.aliasing_ppgtt)
-                i915_gem_gtt_bind_object(obj, obj->cache_level);
-
         list_move_tail(&obj->gtt_list, &dev_priv->mm.bound_list);
         list_add_tail(&obj->mm_list, &dev_priv->mm.inactive_list);
 
-        obj->gtt_offset = obj->gtt_space->start;
+        obj->gtt_space = free_space;
+        obj->gtt_offset = free_space->start;
 
         fenceable =
-                obj->gtt_space->size == fence_size &&
-                (obj->gtt_space->start & (fence_alignment - 1)) == 0;
+                free_space->size == fence_size &&
+                (free_space->start & (fence_alignment - 1)) == 0;
 
         mappable =
                 obj->gtt_offset + obj->base.size <= dev_priv->mm.gtt_mappable_end;
@@ -3452,11 +3446,16 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
         }
 
         if (obj->gtt_space == NULL) {
+                struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
+
                 ret = i915_gem_object_bind_to_gtt(obj, alignment,
                                                   map_and_fenceable,
                                                   nonblocking);
                 if (ret)
                         return ret;
+
+                if (!dev_priv->mm.aliasing_ppgtt)
+                        i915_gem_gtt_bind_object(obj, obj->cache_level);
         }
 
         if (!obj->has_global_gtt_mapping && map_and_fenceable)