Am 20.11.20 um 11:05 schrieb Daniel Vetter:
On Fri, Nov 20, 2020 at 11:04 AM Christian König
<christian.koenig@xxxxxxx> wrote:
Am 20.11.20 um 10:54 schrieb Daniel Vetter:
Random observation while trying to review Christian's patch series to
stop looking at struct page for dma-buf imports.
This was originally added in
commit 58aa6622d32af7d2c08d45085f44c54554a16ed7
Author: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Date: Fri Jan 3 11:47:23 2014 +0100
drm/ttm: Correctly set page mapping and -index members
Needed for some vm operations; most notably unmap_mapping_range() with
even_cows = 0.
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Brian Paul <brianp@xxxxxxxxxx>
but we do not have a single caller of unmap_mapping_range with
even_cows == 0. And all the gem drivers don't do this, so another
small thing we could standardize between drm and ttm drivers.
Plus I don't really see a need for unamp_mapping_range where we don't
want to indiscriminately shoot down all ptes.
Cc: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Cc: Brian Paul <brianp@xxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Christian Koenig <christian.koenig@xxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
This is still a NAK as long as we can't come up with a better way to
track TTMs page allocations.
Additional to that page_mapping() is used quite extensively in the mm
code and I'm not sure if that isn't needed for other stuff as well.
Apologies, I'm honestly not quite sure how this lone patch here ended
up in this submission. I didn't want to send it out.
No problem.
But looking a bit deeper into the mm code that other drm drivers don't
set this correctly and still use unmap_mapping_range() sounds like quite
a bug to me.
Going to track down what exactly that is used for.
Christian.
-Daniel
Regards,
Christian.
---
drivers/gpu/drm/ttm/ttm_tt.c | 12 ------------
1 file changed, 12 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index da9eeffe0c6d..5b2eb6d58bb7 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -284,17 +284,6 @@ int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm)
return ret;
}
-static void ttm_tt_add_mapping(struct ttm_bo_device *bdev, struct ttm_tt *ttm)
-{
- pgoff_t i;
-
- if (ttm->page_flags & TTM_PAGE_FLAG_SG)
- return;
-
- for (i = 0; i < ttm->num_pages; ++i)
- ttm->pages[i]->mapping = bdev->dev_mapping;
-}
-
int ttm_tt_populate(struct ttm_bo_device *bdev,
struct ttm_tt *ttm, struct ttm_operation_ctx *ctx)
{
@@ -313,7 +302,6 @@ int ttm_tt_populate(struct ttm_bo_device *bdev,
if (ret)
return ret;
- ttm_tt_add_mapping(bdev, ttm);
ttm->page_flags |= TTM_PAGE_FLAG_PRIV_POPULATED;
if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
ret = ttm_tt_swapin(ttm);
