Not technically a problem for ttm, but very likely a driver bug and
pretty big time confusing for reviewing code.
So warn about it, both at cleanup time (so we catch these for sure)
and at pin/unpin time (so we know who's the culprit).
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Christian Koenig <christian.koenig@xxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
include/drm/ttm/ttm_bo_api.h | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index f51b5e20fa17..a011072ab61d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -509,7 +509,7 @@ static void ttm_bo_release(struct kref *kref)
* shrinkers, now that they are queued for
* destruction.
*/
- if (bo->pin_count) {
+ if (WARN_ON(bo->pin_count)) {
bo->pin_count = 0;
ttm_bo_del_from_lru(bo);
ttm_bo_add_mem_to_lru(bo, &bo->mem);
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 37102e45e496..b45aee23d7d0 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -571,6 +571,7 @@ static inline bool ttm_bo_uses_embedded_gem_object(struct ttm_buffer_object *bo)
static inline void ttm_bo_pin(struct ttm_buffer_object *bo)
{
dma_resv_assert_held(bo->base.resv);
+ WARN_ON_ONCE(!kref_read(&bo->kref));
++bo->pin_count;
}
@@ -584,6 +585,7 @@ static inline void ttm_bo_unpin(struct ttm_buffer_object *bo)
{
dma_resv_assert_held(bo->base.resv);
WARN_ON_ONCE(!bo->pin_count);
+ WARN_ON_ONCE(!kref_read(&bo->kref));
--bo->pin_count;
}
--
2.28.0
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