[ Moving to dri-devel, where TTM patches are reviewed ]
On 2018-09-12 9:23 p.m., Christian König wrote:
> While cutting the lists we sometimes accidentally added a list_head from
> the stack to the LRUs, effectively corrupting the list.
>
> Remove the list cutting and use explicit list manipulation instead.
>
> Signed-off-by: Christian König <christian.koe...@amd.com>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 51
> ++++++++++++++++++++++++++------------------
> 1 file changed, 30 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 138c98902033..b2a33bf1ef10 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -247,23 +247,18 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object
> *bo,
> }
> EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>
> -static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> - struct list_head *lru, bool is_swap)
> +static void ttm_list_move_bulk_tail(struct list_head *list,
> + struct list_head *first,
> + struct list_head *last)
> {
> - struct list_head *list;
> - LIST_HEAD(entries);
> - LIST_HEAD(before);
> + first->prev->next = last->next;
> + last->next->prev = first->prev;
>
> - reservation_object_assert_held(pos->last->resv);
> - list = is_swap ? &pos->last->swap : &pos->last->lru;
> - list_cut_position(&entries, lru, list);
> + list->prev->next = first;
> + first->prev = list->prev;
>
> - reservation_object_assert_held(pos->first->resv);
> - list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> - list_cut_position(&before, &entries, list);
> -
> - list_splice(&before, lru);
> - list_splice_tail(&entries, lru);
> + last->next = list;
> + list->prev = last;
> }
>
> void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move *bulk)
> @@ -271,23 +266,33 @@ void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move
> *bulk)
> unsigned i;
>
> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> + struct ttm_lru_bulk_move_pos *pos = &bulk->tt[i];
> struct ttm_mem_type_manager *man;
>
> - if (!bulk->tt[i].first)
> + if (!pos->first)
> continue;
>
> - man = &bulk->tt[i].first->bdev->man[TTM_PL_TT];
> - ttm_bo_bulk_move_helper(&bulk->tt[i], &man->lru[i], false);
> + reservation_object_assert_held(pos->first->resv);
> + reservation_object_assert_held(pos->last->resv);
> +
> + man = &pos->first->bdev->man[TTM_PL_TT];
> + ttm_list_move_bulk_tail(&man->lru[i], &pos->first->lru,
> + &pos->last->lru);
> }
>
> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> + struct ttm_lru_bulk_move_pos *pos = &bulk->vram[i];
> struct ttm_mem_type_manager *man;
>
> - if (!bulk->vram[i].first)
> + if (!pos->first)
> continue;
>
> - man = &bulk->vram[i].first->bdev->man[TTM_PL_VRAM];
> - ttm_bo_bulk_move_helper(&bulk->vram[i], &man->lru[i], false);
> + reservation_object_assert_held(pos->first->resv);
> + reservation_object_assert_held(pos->last->resv);
> +
> + man = &pos->first->bdev->man[TTM_PL_VRAM];
> + ttm_list_move_bulk_tail(&man->lru[i], &pos->first->lru,
> + &pos->last->lru);
> }
>
> for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
> @@ -297,8 +302,12 @@ void ttm_bo_bulk_move_lru_tail(struct ttm_lru_bulk_move
> *bulk)
> if (!pos->first)
> continue;
>
> + reservation_object_assert_held(pos->first->resv);
> + reservation_object_assert_held(pos->last->resv);
> +
> lru = &pos->first->bdev->glob->swap_lru[i];
> - ttm_bo_bulk_move_helper(&bulk->swap[i], lru, true);
> + ttm_list_move_bulk_tail(lru, &pos->first->swap,
> + &pos->last->swap);
> }
> }
> EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);
>
Seems like more code could be kept in / moved into the shared helper
function. That would keep the ttm_bo_bulk_move_lru_tail code leaner, and
might make the helper function changes easier to review as well.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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