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.

v2: separate out new list_bulk_move_tail helper

Signed-off-by: Christian König christian.koenig@amd.com --- drivers/gpu/drm/ttm/ttm_bo.c | 46 +++++++++++++++++++------------------------- 1 file changed, 20 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 138c98902033..26b889f86670 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -247,47 +247,38 @@ 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) -{ - struct list_head *list; - LIST_HEAD(entries); - LIST_HEAD(before); - - reservation_object_assert_held(pos->last->resv); - list = is_swap ? &pos->last->swap : &pos->last->lru; - list_cut_position(&entries, lru, list); - - 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); -} - 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]; + list_bulk_move_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]; + list_bulk_move_tail(&man->lru[i], &pos->first->lru, + &pos->last->lru); }

for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { @@ -297,8 +288,11 @@ 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); + list_bulk_move_tail(lru, &pos->first->swap, &pos->last->swap); } } EXPORT_SYMBOL(ttm_bo_bulk_move_lru_tail);

On Thu, Sep 13, 2018 at 01:22:07PM +0200, Christian König wrote:

Move all entries between @first and including @last before @head.

This is useful for LRU lists where a whole block of entries should be moved to the end of an list.

Signed-off-by: Christian König christian.koenig@amd.com

Bulk move helper is useful for TTM driver to improve the LRU moving efficiency. Please go on with my RB.

Series are Reviewed-and-Tested-by: Huang Rui ray.huang@amd.com

---

include/linux/list.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)

diff --git a/include/linux/list.h b/include/linux/list.h index de04cc5ed536..edb7628e46ed 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -183,6 +183,29 @@ static inline void list_move_tail(struct list_head *list, list_add_tail(list, head); }

+/**

• • list_bulk_move_tail - move a subsection of a list to its tail
• • @head: the head that will follow our entry
• • @first: first entry to move
• • @last: last entry to move, can be the same as first
• • Move all entries between @first and including @last before @head.
• • All three entries must belong to the same linked list.
• */

+static inline void list_bulk_move_tail(struct list_head *head,

• 		       struct list_head *first,
  

• 		       struct list_head *last)
  

+{

• first->prev->next = last->next;
• last->next->prev = first->prev;
• head->prev->next = first;
• first->prev = head->prev;
• last->next = head;
• head->prev = last;

+}

/**

• list_is_last - tests whether @list is the last entry in list @head
• @list: the entry to test

-- 2.14.1

---

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