Re: [PATCH] drm/amdgpu: amdgpu_fence: remove ops->release()

[Alex Deucher]

Applied.  thanks!

On Tue, Oct 27, 2026 at 4:16 PM Christian König
<christian.koenig@xxxxxxx> wrote:
>
> On 10/27/26 14:37, Philipp Stanner wrote:
> > amdgpu's fence implements the deprecated fence_ops->release() callback
> > which prevents the driver from ever unloading robustly.
> >
> > amdgpu's implementation merely uses a call_rcu() that performs a kfree()
> > on the fence - this functionality is already centrally implemented by
> > the dma_fence backend.
> >
> > The dma_fence backend invokes a kfree_rcu() on the dma_fence, which is
> > fine since this is always the first member of a struct amdgpu_fence.
> > Thus, amdgpu's implementation is redundant.
> >
> > Remove fence_ops->release().
> >
> > Signed-off-by: Philipp Stanner <phasta@xxxxxxxxxx>
>
> I have exactly the same patch in my pipeline as well.
>
> Reviewed-by: Christian König <christian.koenig@xxxxxxx>
>
> > ---
> > Just saw that this should be unnecessary? Don't have a setup for amdgpu
> > testing right now, so please take a close look, just compile-tested.
> >
> > P.
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 29 -----------------------
> >  1 file changed, 29 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > index 3043ad041bb4..3f8b2571d74a 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > @@ -892,39 +892,10 @@ static bool amdgpu_fence_enable_signaling(struct dma_fence *f)
> >       return true;
> >  }
> >
> > -/**
> > - * amdgpu_fence_free - free up the fence memory
> > - *
> > - * @rcu: RCU callback head
> > - *
> > - * Free up the fence memory after the RCU grace period.
> > - */
> > -static void amdgpu_fence_free(struct rcu_head *rcu)
> > -{
> > -     struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
> > -
> > -     /* free fence_slab if it's separated fence*/
> > -     kfree(to_amdgpu_fence(f));
> > -}
> > -
> > -/**
> > - * amdgpu_fence_release - callback that fence can be freed
> > - *
> > - * @f: fence
> > - *
> > - * This function is called when the reference count becomes zero.
> > - * It just RCU schedules freeing up the fence.
> > - */
> > -static void amdgpu_fence_release(struct dma_fence *f)
> > -{
> > -     call_rcu(&f->rcu, amdgpu_fence_free);
> > -}
> > -
> >  static const struct dma_fence_ops amdgpu_fence_ops = {
> >       .get_driver_name = amdgpu_fence_get_driver_name,
> >       .get_timeline_name = amdgpu_fence_get_timeline_name,
> >       .enable_signaling = amdgpu_fence_enable_signaling,
> > -     .release = amdgpu_fence_release,
> >  };
> >
> >  /*
> >
> > base-commit: 731ba09867520c047c7de53f92e384808e0b638e
>