drm/i915: Preallocate the drm_mm_node prior to manipulating the GTT drm_mm manager

As we may reap neighbouring objects in order to free up pages for
allocations, we need to be careful not to allocate in the middle of the
drm_mm manager. To accomplish this, we can simply allocate the
drm_mm_node up front and then use the combined search & insert
drm_mm routines, reducing our code footprint in the process.

Fixes (partially) i-g-t/gem_tiled_swapping

Reported-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Again fixup atomic bikeshed.]
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 c1f6919..5feda1f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2890,7 +2890,7 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 {
        struct drm_device *dev = obj->base.dev;
        drm_i915_private_t *dev_priv = dev->dev_private;
-       struct drm_mm_node *free_space;
+       struct drm_mm_node *node;
        u32 size, fence_size, fence_alignment, unfenced_alignment;
        bool mappable, fenceable;
        int ret;
@@ -2936,66 +2936,54 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 
        i915_gem_object_pin_pages(obj);
 
+       node = kzalloc(sizeof(*node), GFP_KERNEL);
+       if (node == NULL) {
+               i915_gem_object_unpin_pages(obj);
+               return -ENOMEM;
+       }
+
  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);
+               ret = drm_mm_insert_node_in_range_generic(&dev_priv->mm.gtt_space, node,
+                                                         size, alignment, obj->cache_level,
+                                                         0, dev_priv->mm.gtt_mappable_end);
        else
-               free_space = drm_mm_search_free_color(&dev_priv->mm.gtt_space,
-                                                     size, alignment, obj->cache_level,
-                                                     false);
-
-       if (free_space != NULL) {
-               if (map_and_fenceable)
-                       free_space =
-                               drm_mm_get_block_range_generic(free_space,
-                                                              size, alignment, obj->cache_level,
-                                                              0, dev_priv->mm.gtt_mappable_end,
-                                                              false);
-               else
-                       free_space =
-                               drm_mm_get_block_generic(free_space,
-                                                        size, alignment, obj->cache_level,
-                                                        false);
-       }
-       if (free_space == NULL) {
+               ret = drm_mm_insert_node_generic(&dev_priv->mm.gtt_space, node,
+                                                size, alignment, obj->cache_level);
+       if (ret) {
                ret = i915_gem_evict_something(dev, size, alignment,
                                               obj->cache_level,
                                               map_and_fenceable,
                                               nonblocking);
-               if (ret) {
-                       i915_gem_object_unpin_pages(obj);
-                       return ret;
-               }
+               if (ret == 0)
+                       goto search_free;
 
-               goto search_free;
+               i915_gem_object_unpin_pages(obj);
+               kfree(node);
+               return ret;
        }
-       if (WARN_ON(!i915_gem_valid_gtt_space(dev,
-                                             free_space,
-                                             obj->cache_level))) {
+       if (WARN_ON(!i915_gem_valid_gtt_space(dev, node, obj->cache_level))) {
                i915_gem_object_unpin_pages(obj);
-               drm_mm_put_block(free_space);
+               drm_mm_put_block(node);
                return -EINVAL;
        }
 
        ret = i915_gem_gtt_prepare_object(obj);
        if (ret) {
                i915_gem_object_unpin_pages(obj);
-               drm_mm_put_block(free_space);
+               drm_mm_put_block(node);
                return ret;
        }
 
        list_move_tail(&obj->gtt_list, &dev_priv->mm.bound_list);
        list_add_tail(&obj->mm_list, &dev_priv->mm.inactive_list);
 
-       obj->gtt_space = free_space;
-       obj->gtt_offset = free_space->start;
+       obj->gtt_space = node;
+       obj->gtt_offset = node->start;
 
        fenceable =
-               free_space->size == fence_size &&
-               (free_space->start & (fence_alignment - 1)) == 0;
+               node->size == fence_size &&
+               (node->start & (fence_alignment - 1)) == 0;
 
        mappable =
                obj->gtt_offset + obj->base.size <= dev_priv->mm.gtt_mappable_end;