[Nouveau] [PATCH 4/6] drm/ttm: audit bo->resource usage v2

[Christian König]

Allow BOs to exist without backing store.

v2: handle ttm_bo_move_memcpy as well.

Signed-off-by: Christian König <christian.koe...@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c      | 16 ++++++++--------
 drivers/gpu/drm/ttm/ttm_bo_util.c |  7 +++++--
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 984535d6a2d0..a2f49bdda8a1 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -117,12 +117,13 @@ static int ttm_bo_handle_move_mem(struct 
ttm_buffer_object *bo,
                                  struct ttm_operation_ctx *ctx,
                                  struct ttm_place *hop)
 {
-       struct ttm_resource_manager *old_man, *new_man;
        struct ttm_device *bdev = bo->bdev;
+       bool old_use_tt, new_use_tt;
        int ret;
 
-       old_man = ttm_manager_type(bdev, bo->resource->mem_type);
-       new_man = ttm_manager_type(bdev, mem->mem_type);
+       old_use_tt = bo->resource &&
+               ttm_manager_type(bdev, bo->resource->mem_type)->use_tt;
+       new_use_tt = ttm_manager_type(bdev, mem->mem_type)->use_tt;
 
        ttm_bo_unmap_virtual(bo);
 
@@ -130,11 +131,11 @@ static int ttm_bo_handle_move_mem(struct 
ttm_buffer_object *bo,
         * Create and bind a ttm if required.
         */
 
-       if (new_man->use_tt) {
+       if (new_use_tt) {
                /* Zero init the new TTM structure if the old location should
                 * have used one as well.
                 */
-               ret = ttm_tt_create(bo, old_man->use_tt);
+               ret = ttm_tt_create(bo, old_use_tt);
                if (ret)
                        goto out_err;
 
@@ -160,8 +161,7 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object 
*bo,
        return 0;
 
 out_err:
-       new_man = ttm_manager_type(bdev, bo->resource->mem_type);
-       if (!new_man->use_tt)
+       if (!old_use_tt)
                ttm_bo_tt_destroy(bo);
 
        return ret;
@@ -904,7 +904,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
        /*
         * Check whether we need to move buffer.
         */
-       if (!ttm_resource_compat(bo->resource, placement)) {
+       if (!bo->resource || !ttm_resource_compat(bo->resource, placement)) {
                ret = ttm_bo_move_buffer(bo, placement, ctx);
                if (ret)
                        return ret;
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c 
b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 1cbfb00c1d65..1530982338e9 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -137,8 +137,7 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
                ttm_manager_type(bo->bdev, dst_mem->mem_type);
        struct ttm_tt *ttm = bo->ttm;
        struct ttm_resource *src_mem = bo->resource;
-       struct ttm_resource_manager *src_man =
-               ttm_manager_type(bdev, src_mem->mem_type);
+       struct ttm_resource_manager *src_man;
        union {
                struct ttm_kmap_iter_tt tt;
                struct ttm_kmap_iter_linear_io io;
@@ -147,6 +146,10 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
        bool clear;
        int ret = 0;
 
+       if (!src_mem)
+               return 0;
+
+       src_man = ttm_manager_type(bdev, src_mem->mem_type);
        if (ttm && ((ttm->page_flags & TTM_TT_FLAG_SWAPPED) ||
                    dst_man->use_tt)) {
                ret = ttm_tt_populate(bdev, ttm, ctx);
-- 
2.25.1