drm: Introduce drm_mm_create_block()

To be used later by i915 to preallocate exact blocks of space from the
range manager.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Airlie <airlied@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 0761a03cdbb2..bd203b61a72b 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -161,6 +161,56 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
         }
 }
 
+struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
+                                        unsigned long start,
+                                        unsigned long size,
+                                        bool atomic)
+{
+        struct drm_mm_node *hole, *node;
+        unsigned long end = start + size;
+
+        list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
+                unsigned long hole_start;
+                unsigned long hole_end;
+
+                BUG_ON(!hole->hole_follows);
+                hole_start = drm_mm_hole_node_start(hole);
+                hole_end = drm_mm_hole_node_end(hole);
+
+                if (hole_start > start || hole_end < end)
+                        continue;
+
+                node = drm_mm_kmalloc(mm, atomic);
+                if (unlikely(node == NULL))
+                        return NULL;
+
+                node->start = start;
+                node->size = size;
+                node->mm = mm;
+                node->allocated = 1;
+
+                INIT_LIST_HEAD(&node->hole_stack);
+                list_add(&node->node_list, &hole->node_list);
+
+                if (start == hole_start) {
+                        hole->hole_follows = 0;
+                        list_del_init(&hole->hole_stack);
+                }
+
+                node->hole_follows = 0;
+                if (end != hole_end) {
+                        list_add(&node->hole_stack, &mm->hole_stack);
+                        node->hole_follows = 1;
+                }
+
+                return node;
+        }
+
+        WARN(1, "no hole found for block 0x%lx + 0x%lx\n", start, size);
+        return NULL;
+}
+EXPORT_SYMBOL(drm_mm_create_block);
+
 struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *hole_node,
                                              unsigned long size,
                                              unsigned alignment,