Re: [Intel-gfx] [PATCH v10 03/11] drm/ttm: Add a generic TTM memcpy move for page-based iomem

I've just been talking with Ben about nouveau having some issues since this path,

ttm_resource can be subclassed by drivers, and the code below that copies ttm_resources around pretty much seems to destroy that.

•   struct ttm_resource *src_mem = &bo->mem;
  

•   struct ttm_resource_manager *src_man =
  

•           ttm_manager_type(bdev, src_mem->mem_type);
  

•   struct ttm_resource src_copy = *src_mem;
  

This here ^^

•   union {
  

•           struct ttm_kmap_iter_tt tt;
  

•           struct ttm_kmap_iter_linear_io io;
  

•   } _dst_iter, _src_iter;
  

•   struct ttm_kmap_iter *dst_iter, *src_iter;
  

•   int ret = 0;
  
  

•   /*
  

•    * TTM might be null for moves within the same region.
  

•    */
  

•   if (ttm) {
  

•   if (ttm && ((ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) ||
  

•               dst_man->use_tt)) {
            ret = ttm_tt_populate(bdev, ttm, ctx);
            if (ret)
  

•                   goto out1;
  

•                   return ret;
    }
  
  

•   for (i = 0; i < new_mem->num_pages; ++i) {
  

•           if (old_iomap == NULL) {
  

•                   pgprot_t prot = ttm_io_prot(bo, old_mem, PAGE_KERNEL);
  

•                   ret = ttm_copy_ttm_io_page(ttm, new_iomap, i,
  

•                                              prot);
  

•           } else if (new_iomap == NULL) {
  

•                   pgprot_t prot = ttm_io_prot(bo, new_mem, PAGE_KERNEL);
  

•                   ret = ttm_copy_io_ttm_page(ttm, old_iomap, i,
  

•                                              prot);
  

•           } else {
  

•                   ret = ttm_copy_io_page(new_iomap, old_iomap, i);
  

•           }
  

•           if (ret)
  

•                   goto out1;
  

•   dst_iter = ttm_kmap_iter_linear_io_init(&_dst_iter.io, bdev, dst_mem);
  

•   if (PTR_ERR(dst_iter) == -EINVAL && dst_man->use_tt)
  

•           dst_iter = ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm);
  

•   if (IS_ERR(dst_iter))
  

•           return PTR_ERR(dst_iter);
  

•   src_iter = ttm_kmap_iter_linear_io_init(&_src_iter.io, bdev, src_mem);
  

•   if (PTR_ERR(src_iter) == -EINVAL && src_man->use_tt)
  

•           src_iter = ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm);
  

•   if (IS_ERR(src_iter)) {
  

•           ret = PTR_ERR(src_iter);
  

•           goto out_src_iter;
    }
  

•   mb();
  

-out2:

•   old_copy = *old_mem;
  
  

•   ttm_bo_assign_mem(bo, new_mem);
  

•   if (!man->use_tt)
  

•           ttm_bo_tt_destroy(bo);
  

•   ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);
  

•   src_copy = *src_mem;
  

•   ttm_bo_move_sync_cleanup(bo, dst_mem);
  
  

-out1:

•   ttm_resource_iounmap(bdev, old_mem, new_iomap);
  

-out:

•   ttm_resource_iounmap(bdev, &old_copy, old_iomap);
  

•   if (!src_iter->ops->maps_tt)
  

•           ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, &src_copy);
  

passes a copy into linear_io_fini which calls the driver io_mem_free without the subclass data.

Dave.