* [PATCH] drm/ttm: Warn on pinning without holding a reference
@ 2020-10-28 11:31 Daniel Vetter
2020-10-28 11:52 ` Huang Rui
2020-10-28 12:11 ` Christian König
0 siblings, 2 replies; 4+ messages in thread
From: Daniel Vetter @ 2020-10-28 11:31 UTC (permalink / raw)
To: DRI Development; +Cc: Daniel Vetter, Huang Rui, Christian Koenig, Daniel Vetter
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@intel.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
---
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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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] drm/ttm: Warn on pinning without holding a reference
2020-10-28 11:31 [PATCH] drm/ttm: Warn on pinning without holding a reference Daniel Vetter
@ 2020-10-28 11:52 ` Huang Rui
2020-10-28 12:11 ` Christian König
1 sibling, 0 replies; 4+ messages in thread
From: Huang Rui @ 2020-10-28 11:52 UTC (permalink / raw)
To: Daniel Vetter; +Cc: Daniel Vetter, Koenig, Christian, DRI Development
On Wed, Oct 28, 2020 at 07:31:20PM +0800, Daniel Vetter wrote:
> 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@intel.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
> Cc: Christian Koenig <christian.koenig@amd.com>
> Cc: Huang Rui <ray.huang@amd.com>
> ---
> 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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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/ttm: Warn on pinning without holding a reference
2020-10-28 11:31 [PATCH] drm/ttm: Warn on pinning without holding a reference Daniel Vetter
2020-10-28 11:52 ` Huang Rui
@ 2020-10-28 12:11 ` Christian König
2020-11-27 15:44 ` Daniel Vetter
1 sibling, 1 reply; 4+ messages in thread
From: Christian König @ 2020-10-28 12:11 UTC (permalink / raw)
To: Daniel Vetter, DRI Development; +Cc: Daniel Vetter, Huang Rui
Am 28.10.20 um 12:31 schrieb Daniel Vetter:
> 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@intel.com>
> Cc: Christian Koenig <christian.koenig@amd.com>
> Cc: Huang Rui <ray.huang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
> ---
> 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;
> }
>
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/ttm: Warn on pinning without holding a reference
2020-10-28 12:11 ` Christian König
@ 2020-11-27 15:44 ` Daniel Vetter
0 siblings, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2020-11-27 15:44 UTC (permalink / raw)
To: Christian König
Cc: Daniel Vetter, Huang Rui, DRI Development, Daniel Vetter
On Wed, Oct 28, 2020 at 01:11:51PM +0100, Christian König wrote:
> Am 28.10.20 um 12:31 schrieb Daniel Vetter:
> > 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@intel.com>
> > Cc: Christian Koenig <christian.koenig@amd.com>
> > Cc: Huang Rui <ray.huang@amd.com>
>
> Reviewed-by: Christian König <christian.koenig@amd.com>
Remembered this patch, pushed it. Thanks to you both for the reviews.
-Daniel
>
> > ---
> > 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;
> > }
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-10-28 11:31 [PATCH] drm/ttm: Warn on pinning without holding a reference Daniel Vetter
2020-10-28 11:52 ` Huang Rui
2020-10-28 12:11 ` Christian König
2020-11-27 15:44 ` Daniel Vetter
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