[PATCH] drm/prime: drop reference on imported dma-buf come from gem

Rob Clark rob.clark at linaro.org
Thu Sep 27 00:38:33 PDT 2012


On Thu, Sep 27, 2012 at 9:14 AM, 김승우 <sw0312.kim at samsung.com> wrote:
> Hi Rob,
>
> On 2012년 09월 27일 15:52, Rob Clark wrote:
>> fwiw, I had a similar patch:
>>
>> https://patchwork.kernel.org/patch/1229161/
>
> Yes, I already check your patch and even my patch's title is a bit from
> your patch.
>
> I thought locking issue blocks your patch, so I sent simple fixes on
> current state. How do you think merging bug-fixes at first?

well, the lack of locking is a real problem too.. although I didn't
see quite what the locking changes could have to do with the crash
that Dave had seen. But I don't know if anyone has looked at it more,
and I only re-import my own buffers in omapdrm so I don't think I can
trigger the same scenario myself.

I guess if no one else has a chance to take at least a quick look at
the locking crash, maybe we should take this patch.  But I would be
interested get the locking patch too.  We are needing both patches on
our product kernels to fix some issues.

BR,
-R

> Best Regards,
> - Seung-Woo Kim
>
>>
>> although it was on top of some locking fixes from Daniel (which I
>> think are also needed):
>>
>> https://patchwork.kernel.org/patch/1227251/
>>
>> although that seemed to cause/trigger some explosions which I think
>> still need to be debugged..
>>
>> BR,
>> -R
>>
>> On Thu, Sep 27, 2012 at 8:30 AM, Seung-Woo Kim <sw0312.kim at samsung.com> wrote:
>>> Increasing ref counts of both dma-buf and gem for imported dma-buf come from gem
>>> makes memory leak. release function of dma-buf cannot be called because f_count
>>> of dma-buf increased by importing gem and gem ref count cannot be decrease
>>> because of exported dma-buf.
>>>
>>> So I add dma_buf_put() for imported gem come from its own gem into each drivers
>>> having prime_import and prime_export capabilities. With this, only gem ref
>>> count is increased if importing gem exported from gem of same driver.
>>>
>>> Signed-off-by: Seung-Woo Kim <sw0312.kim at samsung.com>
>>> Signed-off-by: Kyungmin.park <kyungmin.park at samsung.com>
>>> Cc: Inki Dae <inki.dae at samsung.com>
>>> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
>>> Cc: Rob Clark <rob.clark at linaro.org>
>>> Cc: Alex Deucher <alexander.deucher at amd.com>
>>> ---
>>>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c |    5 +++++
>>>  drivers/gpu/drm/i915/i915_gem_dmabuf.c     |    5 +++++
>>>  drivers/gpu/drm/nouveau/nouveau_prime.c    |    1 +
>>>  drivers/gpu/drm/radeon/radeon_prime.c      |    1 +
>>>  drivers/staging/omapdrm/omap_gem_dmabuf.c  |    5 +++++
>>>  5 files changed, 17 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
>>> index ae13feb..b0897c9 100644
>>> --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
>>> @@ -211,7 +211,12 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
>>>
>>>                 /* is it from our device? */
>>>                 if (obj->dev == drm_dev) {
>>> +                       /*
>>> +                        * Importing dmabuf exported from out own gem increases
>>> +                        * refcount on gem itself instead of f_count of dmabuf.
>>> +                        */
>>>                         drm_gem_object_reference(obj);
>>> +                       dma_buf_put(dma_buf);
>>>                         return obj;
>>>                 }
>>>         }
>>> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
>>> index aa308e1..32e6287 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
>>> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
>>> @@ -188,7 +188,12 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
>>>                 obj = dma_buf->priv;
>>>                 /* is it from our device? */
>>>                 if (obj->base.dev == dev) {
>>> +                       /*
>>> +                        * Importing dmabuf exported from out own gem increases
>>> +                        * refcount on gem itself instead of f_count of dmabuf.
>>> +                        */
>>>                         drm_gem_object_reference(&obj->base);
>>> +                       dma_buf_put(dma_buf);
>>>                         return &obj->base;
>>>                 }
>>>         }
>>> diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c
>>> index a25cf2c..bb653c6 100644
>>> --- a/drivers/gpu/drm/nouveau/nouveau_prime.c
>>> +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
>>> @@ -199,6 +199,7 @@ struct drm_gem_object *nouveau_gem_prime_import(struct drm_device *dev,
>>>                 if (nvbo->gem) {
>>>                         if (nvbo->gem->dev == dev) {
>>>                                 drm_gem_object_reference(nvbo->gem);
>>> +                               dma_buf_put(dma_buf);
>>>                                 return nvbo->gem;
>>>                         }
>>>                 }
>>> diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c
>>> index 6bef46a..d344a3be 100644
>>> --- a/drivers/gpu/drm/radeon/radeon_prime.c
>>> +++ b/drivers/gpu/drm/radeon/radeon_prime.c
>>> @@ -195,6 +195,7 @@ struct drm_gem_object *radeon_gem_prime_import(struct drm_device *dev,
>>>                 bo = dma_buf->priv;
>>>                 if (bo->gem_base.dev == dev) {
>>>                         drm_gem_object_reference(&bo->gem_base);
>>> +                       dma_buf_put(dma_buf);
>>>                         return &bo->gem_base;
>>>                 }
>>>         }
>>> diff --git a/drivers/staging/omapdrm/omap_gem_dmabuf.c b/drivers/staging/omapdrm/omap_gem_dmabuf.c
>>> index 42728e0..5b50eb6 100644
>>> --- a/drivers/staging/omapdrm/omap_gem_dmabuf.c
>>> +++ b/drivers/staging/omapdrm/omap_gem_dmabuf.c
>>> @@ -207,7 +207,12 @@ struct drm_gem_object * omap_gem_prime_import(struct drm_device *dev,
>>>                 obj = buffer->priv;
>>>                 /* is it from our device? */
>>>                 if (obj->dev == dev) {
>>> +                       /*
>>> +                        * Importing dmabuf exported from out own gem increases
>>> +                        * refcount on gem itself instead of f_count of dmabuf.
>>> +                        */
>>>                         drm_gem_object_reference(obj);
>>> +                       dma_buf_put(buffer);
>>>                         return obj;
>>>                 }
>>>         }
>>> --
>>> 1.7.4.1
>>>
>>> _______________________________________________
>>> dri-devel mailing list
>>> dri-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>>
>
> --
> Seung-Woo Kim
> Samsung Software R&D Center
> --
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel


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