Two fixes for TTM, one for a NULL pointer dereference and one to make sure

the buffer is pinned prior to a bulk move, and a fix for a spurious
 compiler warning.
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Merge tag 'drm-misc-fixes-2022-06-16' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes

Two fixes for TTM, one for a NULL pointer dereference and one to make sure
the buffer is pinned prior to a bulk move, and a fix for a spurious
compiler warning.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220616072519.qwrsefsemejefowu@houat

drivers/gpu/drm/ttm/ttm_bo.c

@@ -109,11 +109,11 @@ void ttm_bo_set_bulk_move(struct ttm_buffer_object *bo,
 		return;
 
 	spin_lock(&bo->bdev->lru_lock);
-	if (bo->bulk_move && bo->resource)
+	if (bo->resource)
-		ttm_lru_bulk_move_del(bo->bulk_move, bo->resource);
+		ttm_resource_del_bulk_move(bo->resource, bo);
 	bo->bulk_move = bulk;
-	if (bo->bulk_move && bo->resource)
+	if (bo->resource)
-		ttm_lru_bulk_move_add(bo->bulk_move, bo->resource);
+		ttm_resource_add_bulk_move(bo->resource, bo);
 	spin_unlock(&bo->bdev->lru_lock);
 }
 EXPORT_SYMBOL(ttm_bo_set_bulk_move);
@@ -689,8 +689,11 @@ void ttm_bo_pin(struct ttm_buffer_object *bo)
 {
 	dma_resv_assert_held(bo->base.resv);
 	WARN_ON_ONCE(!kref_read(&bo->kref));
-	if (!(bo->pin_count++) && bo->bulk_move && bo->resource)
+	spin_lock(&bo->bdev->lru_lock);
-		ttm_lru_bulk_move_del(bo->bulk_move, bo->resource);
+	if (bo->resource)
+		ttm_resource_del_bulk_move(bo->resource, bo);
+	++bo->pin_count;
+	spin_unlock(&bo->bdev->lru_lock);
 }
 EXPORT_SYMBOL(ttm_bo_pin);
 
@@ -707,8 +710,11 @@ void ttm_bo_unpin(struct ttm_buffer_object *bo)
 	if (WARN_ON_ONCE(!bo->pin_count))
 		return;
 
-	if (!(--bo->pin_count) && bo->bulk_move && bo->resource)
+	spin_lock(&bo->bdev->lru_lock);
-		ttm_lru_bulk_move_add(bo->bulk_move, bo->resource);
+	--bo->pin_count;
+	if (bo->resource)
+		ttm_resource_add_bulk_move(bo->resource, bo);
+	spin_unlock(&bo->bdev->lru_lock);
 }
 EXPORT_SYMBOL(ttm_bo_unpin);
 

drivers/gpu/drm/ttm/ttm_device.c

@@ -156,8 +156,12 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 
 		ttm_resource_manager_for_each_res(man, &cursor, res) {
 			struct ttm_buffer_object *bo = res->bo;
-			uint32_t num_pages = PFN_UP(bo->base.size);
+			uint32_t num_pages;
 
+			if (!bo)
+				continue;
+
+			num_pages = PFN_UP(bo->base.size);
 			ret = ttm_bo_swapout(bo, ctx, gfp_flags);
 			/* ttm_bo_swapout has dropped the lru_lock */
 			if (!ret)

drivers/gpu/drm/ttm/ttm_resource.c

@@ -91,8 +91,8 @@ static void ttm_lru_bulk_move_pos_tail(struct ttm_lru_bulk_move_pos *pos,
 }
 
 /* Add the resource to a bulk_move cursor */
-void ttm_lru_bulk_move_add(struct ttm_lru_bulk_move *bulk,
+static void ttm_lru_bulk_move_add(struct ttm_lru_bulk_move *bulk,
-			   struct ttm_resource *res)
+				  struct ttm_resource *res)
 {
 	struct ttm_lru_bulk_move_pos *pos = ttm_lru_bulk_move_pos(bulk, res);
 
@@ -105,8 +105,8 @@ void ttm_lru_bulk_move_add(struct ttm_lru_bulk_move *bulk,
 }
 
 /* Remove the resource from a bulk_move range */
-void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk,
+static void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk,
-			   struct ttm_resource *res)
+				  struct ttm_resource *res)
 {
 	struct ttm_lru_bulk_move_pos *pos = ttm_lru_bulk_move_pos(bulk, res);
 
@@ -122,6 +122,22 @@ void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk,
 	}
 }
 
+/* Add the resource to a bulk move if the BO is configured for it */
+void ttm_resource_add_bulk_move(struct ttm_resource *res,
+				struct ttm_buffer_object *bo)
+{
+	if (bo->bulk_move && !bo->pin_count)
+		ttm_lru_bulk_move_add(bo->bulk_move, res);
+}
+
+/* Remove the resource from a bulk move if the BO is configured for it */
+void ttm_resource_del_bulk_move(struct ttm_resource *res,
+				struct ttm_buffer_object *bo)
+{
+	if (bo->bulk_move && !bo->pin_count)
+		ttm_lru_bulk_move_del(bo->bulk_move, res);
+}
+
 /* Move a resource to the LRU or bulk tail */
 void ttm_resource_move_to_lru_tail(struct ttm_resource *res)
 {
@@ -169,15 +185,14 @@ void ttm_resource_init(struct ttm_buffer_object *bo,
 	res->bus.is_iomem = false;
 	res->bus.caching = ttm_cached;
 	res->bo = bo;
-	INIT_LIST_HEAD(&res->lru);
 
 	man = ttm_manager_type(bo->bdev, place->mem_type);
 	spin_lock(&bo->bdev->lru_lock);
-	man->usage += res->num_pages << PAGE_SHIFT;
+	if (bo->pin_count)
-	if (bo->bulk_move)
+		list_add_tail(&res->lru, &bo->bdev->pinned);
-		ttm_lru_bulk_move_add(bo->bulk_move, res);
 	else
-		ttm_resource_move_to_lru_tail(res);
+		list_add_tail(&res->lru, &man->lru[bo->priority]);
+	man->usage += res->num_pages << PAGE_SHIFT;
 	spin_unlock(&bo->bdev->lru_lock);
 }
 EXPORT_SYMBOL(ttm_resource_init);
@@ -210,8 +225,16 @@ int ttm_resource_alloc(struct ttm_buffer_object *bo,
 {
 	struct ttm_resource_manager *man =
 		ttm_manager_type(bo->bdev, place->mem_type);
+	int ret;
 
-	return man->func->alloc(man, bo, place, res_ptr);
+	ret = man->func->alloc(man, bo, place, res_ptr);
+	if (ret)
+		return ret;
+
+	spin_lock(&bo->bdev->lru_lock);
+	ttm_resource_add_bulk_move(*res_ptr, bo);
+	spin_unlock(&bo->bdev->lru_lock);
+	return 0;
 }
 
 void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res)
@@ -221,12 +244,9 @@ void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res)
 	if (!*res)
 		return;
 
-	if (bo->bulk_move) {
+	spin_lock(&bo->bdev->lru_lock);
-		spin_lock(&bo->bdev->lru_lock);
+	ttm_resource_del_bulk_move(*res, bo);
-		ttm_lru_bulk_move_del(bo->bulk_move, *res);
+	spin_unlock(&bo->bdev->lru_lock);
-		spin_unlock(&bo->bdev->lru_lock);
-	}
-
 	man = ttm_manager_type(bo->bdev, (*res)->mem_type);
 	man->func->free(man, *res);
 	*res = NULL;

include/drm/drm_atomic.h

@@ -1022,6 +1022,7 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	for ((__i) = 0; \
 	     (__i) < (__state)->num_private_objs && \
 		     ((obj) = (__state)->private_objs[__i].ptr, \
+		      (void)(obj) /* Only to avoid unused-but-set-variable warning */, \
 		      (new_obj_state) = (__state)->private_objs[__i].new_state, 1); \
 	     (__i)++)
 

include/drm/ttm/ttm_resource.h

@@ -311,12 +311,12 @@ ttm_resource_manager_cleanup(struct ttm_resource_manager *man)
 }
 
 void ttm_lru_bulk_move_init(struct ttm_lru_bulk_move *bulk);
-void ttm_lru_bulk_move_add(struct ttm_lru_bulk_move *bulk,
-			   struct ttm_resource *res);
-void ttm_lru_bulk_move_del(struct ttm_lru_bulk_move *bulk,
-			   struct ttm_resource *res);
 void ttm_lru_bulk_move_tail(struct ttm_lru_bulk_move *bulk);
 
+void ttm_resource_add_bulk_move(struct ttm_resource *res,
+				struct ttm_buffer_object *bo);
+void ttm_resource_del_bulk_move(struct ttm_resource *res,
+				struct ttm_buffer_object *bo);
 void ttm_resource_move_to_lru_tail(struct ttm_resource *res);
 
 void ttm_resource_init(struct ttm_buffer_object *bo,