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>

1 files changed, 25 insertions, 37 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c1f691958f8..5feda1f6704 100644
--- 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;