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authorDaniel Vetter <daniel.vetter@ffwll.ch>2020-10-28 12:31:20 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2020-11-27 16:43:54 +0100
commit57fcd550eb15bce14a7154736379dfd4ed60ae81 (patch)
treec7744650575016e8e7bc2d94ecb4fafd0ed2ef1b
parentfbdev: aty: SPARC64 requires FB_ATY_CT (diff)
downloadlinux-dev-57fcd550eb15bce14a7154736379dfd4ed60ae81.tar.xz
linux-dev-57fcd550eb15bce14a7154736379dfd4ed60ae81.zip
drm/ttm: Warn on pinning without holding a reference
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). Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Christian Koenig <christian.koenig@amd.com> Cc: Huang Rui <ray.huang@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201028113120.3641237-1-daniel.vetter@ffwll.ch
-rw-r--r--drivers/gpu/drm/ttm/ttm_bo.c2
-rw-r--r--include/drm/ttm/ttm_bo_api.h2
2 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 9a03c7834b1e..fc6b619c0329 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -514,7 +514,7 @@ 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 2564e66e67d7..79b9367e0ffd 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -600,6 +600,7 @@ 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;
}
@@ -613,6 +614,7 @@ 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;
}