[PATCH 4/7] drm/xe/oa: Signal output fences

[Dixit, Ashutosh]

On Fri, 30 Aug 2024 15:16:15 -0700, Ashutosh Dixit wrote:
>
> Introduce 'struct xe_oa_fence' which includes the dma_fence used to signal
> output fences in the xe_sync array. The fences are signaled
> asynchronously. When there are no output fences to signal, the OA
> configuration wait is synchronously re-introduced into the ioctl.
>
> v2: Don't wait in the work, use callback + delayed work (Matt B)
>     Use a single, not a per-fence spinlock (Matt Brost)
> v3: Move ofence alloc before job submission (Matt)
>     Assert, don't fail, from dma_fence_add_callback (Matt)
>     Additional dma_fence_get for dma_fence_wait (Matt)
>     Change dma_fence_wait to non-interruptible (Matt)
> v4: Introduce last_fence to prevent uaf if stream is closed with
>     pending OA config jobs

I made a small change to this patch to prevent a potential uaf. Since the
change is small and I have tested them, I have retained previous R-b's on
the patch. If you want to review again, please grep for 'last_fence' in the
patch.

Thanks.
--
Ashutosh

> Suggested-by: Matthew Brost <matthew.brost at intel.com>
> Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
> Reviewed-by: Matthew Brost <matthew.brost at intel.com>