drm/ttm: introduce utility function to free an allocated memory node

Existing core code/drivers call drm_mm_put_block on ttm_mem_reg.mm_node
directly.  Future patches will modify TTM behaviour in such a way that
ttm_mem_reg.mm_node doesn't necessarily belong to drm_mm.

Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Acked-by: Thomas Hellström <thellstrom@vmware.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -693,12 +693,7 @@ nouveau_bo_move_flipd(struct ttm_buffer_object *bo, bool evict, bool intr,
 
 	ret = ttm_bo_move_ttm(bo, evict, no_wait_reserve, no_wait_gpu, new_mem);
 out:
-	if (tmp_mem.mm_node) {
+	ttm_bo_mem_put(bo, &tmp_mem);
-		spin_lock(&bo->bdev->glob->lru_lock);
-		drm_mm_put_block(tmp_mem.mm_node);
-		spin_unlock(&bo->bdev->glob->lru_lock);
-	}
-
 	return ret;
 }
 
@@ -731,12 +726,7 @@ nouveau_bo_move_flips(struct ttm_buffer_object *bo, bool evict, bool intr,
 		goto out;
 
 out:
-	if (tmp_mem.mm_node) {
+	ttm_bo_mem_put(bo, &tmp_mem);
-		spin_lock(&bo->bdev->glob->lru_lock);
-		drm_mm_put_block(tmp_mem.mm_node);
-		spin_unlock(&bo->bdev->glob->lru_lock);
-	}
-
 	return ret;
 }
 

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -326,14 +326,7 @@ static int radeon_move_vram_ram(struct ttm_buffer_object *bo,
 	}
 	r = ttm_bo_move_ttm(bo, true, no_wait_reserve, no_wait_gpu, new_mem);
 out_cleanup:
-	if (tmp_mem.mm_node) {
+	ttm_bo_mem_put(bo, &tmp_mem);
-		struct ttm_bo_global *glob = rdev->mman.bdev.glob;
-
-		spin_lock(&glob->lru_lock);
-		drm_mm_put_block(tmp_mem.mm_node);
-		spin_unlock(&glob->lru_lock);
-		return r;
-	}
 	return r;
 }
 
@@ -372,14 +365,7 @@ static int radeon_move_ram_vram(struct ttm_buffer_object *bo,
 		goto out_cleanup;
 	}
 out_cleanup:
-	if (tmp_mem.mm_node) {
+	ttm_bo_mem_put(bo, &tmp_mem);
-		struct ttm_bo_global *glob = rdev->mman.bdev.glob;
-
-		spin_lock(&glob->lru_lock);
-		drm_mm_put_block(tmp_mem.mm_node);
-		spin_unlock(&glob->lru_lock);
-		return r;
-	}
 	return r;
 }
 

drivers/gpu/drm/ttm/ttm_bo.c

@@ -475,11 +475,8 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
 			list_del_init(&bo->ddestroy);
 			++put_count;
 		}
-		if (bo->mem.mm_node) {
-			drm_mm_put_block(bo->mem.mm_node);
-			bo->mem.mm_node = NULL;
-		}
 		spin_unlock(&glob->lru_lock);
+		ttm_bo_mem_put(bo, &bo->mem);
 
 		atomic_set(&bo->reserved, 0);
 
@@ -621,7 +618,6 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible,
 			bool no_wait_reserve, bool no_wait_gpu)
 {
 	struct ttm_bo_device *bdev = bo->bdev;
-	struct ttm_bo_global *glob = bo->glob;
 	struct ttm_mem_reg evict_mem;
 	struct ttm_placement placement;
 	int ret = 0;
@@ -667,12 +663,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible,
 	if (ret) {
 		if (ret != -ERESTARTSYS)
 			printk(KERN_ERR TTM_PFX "Buffer eviction failed\n");
-		spin_lock(&glob->lru_lock);
+		ttm_bo_mem_put(bo, &evict_mem);
-		if (evict_mem.mm_node) {
-			drm_mm_put_block(evict_mem.mm_node);
-			evict_mem.mm_node = NULL;
-		}
-		spin_unlock(&glob->lru_lock);
 		goto out;
 	}
 	bo->evicted = true;
@@ -769,6 +760,19 @@ static int ttm_bo_man_get_node(struct ttm_buffer_object *bo,
 	return 0;
 }
 
+void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem)
+{
+	struct ttm_bo_global *glob = bo->glob;
+
+	if (mem->mm_node) {
+		spin_lock(&glob->lru_lock);
+		drm_mm_put_block(mem->mm_node);
+		spin_unlock(&glob->lru_lock);
+		mem->mm_node = NULL;
+	}
+}
+EXPORT_SYMBOL(ttm_bo_mem_put);
+
 /**
  * Repeatedly evict memory from the LRU for @mem_type until we create enough
  * space, or we've evicted everything and there isn't enough space.

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -39,14 +39,7 @@
 
 void ttm_bo_free_old_node(struct ttm_buffer_object *bo)
 {
-	struct ttm_mem_reg *old_mem = &bo->mem;
+	ttm_bo_mem_put(bo, &bo->mem);
-
-	if (old_mem->mm_node) {
-		spin_lock(&bo->glob->lru_lock);
-		drm_mm_put_block(old_mem->mm_node);
-		spin_unlock(&bo->glob->lru_lock);
-	}
-	old_mem->mm_node = NULL;
 }
 
 int ttm_bo_move_ttm(struct ttm_buffer_object *bo,

include/drm/ttm/ttm_bo_driver.h

@@ -649,6 +649,10 @@ extern int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 				struct ttm_mem_reg *mem,
 				bool interruptible,
 				bool no_wait_reserve, bool no_wait_gpu);
+
+extern void ttm_bo_mem_put(struct ttm_buffer_object *bo,
+			   struct ttm_mem_reg *mem);
+
 /**
  * ttm_bo_wait_for_cpu
  *