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

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Hi!

On 8/30/21 8:16 AM, Christian König wrote:
> Am 30.08.21 um 03:54 schrieb Dave Airlie:
>> 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 ^^
>
> Mhm, that's most likely a rebase/merge conflict between my change to 
> subclass ttm_resource which came in through the drm-misc-next tree and 
> Thomas change here.
>
> Thomas can you take a look?


Sure.

/Thomas




>
> Thanks,
> Christian.
>
>>
>>> +       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.
>