Re: [PATCH v3 1/3] drm/i915: pass a pointer for tlb seqno at vma_invalidate_tlb()

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

On 04/08/2022 08:37, Mauro Carvalho Chehab wrote:
> WRITE_ONCE() should happen at the original var, not on a local
> copy of it.
>
> Fixes: 5d36acb7198b ("drm/i915/gt: Batch TLB invalidations")

Cc: stable I think, since the above one was. So both hit 5.21 (or 6.1) 
together.

Regards,

Tvrtko

> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> ---
>
> To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover.
> See [PATCH v3 0/3] at: https://lore.kernel.org/all/cover.1659598090.git.mchehab@xxxxxxxxxx/
>
>   drivers/gpu/drm/i915/gt/intel_ppgtt.c | 2 +-
>   drivers/gpu/drm/i915/i915_vma.c       | 6 +++---
>   drivers/gpu/drm/i915/i915_vma.h       | 2 +-
>   3 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_ppgtt.c b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> index 2da6c82a8bd2..6ee8d1127016 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> @@ -211,7 +211,7 @@ void ppgtt_unbind_vma(struct i915_address_space *vm,
>   
>   	vm->clear_range(vm, vma_res->start, vma_res->vma_size);
>   	if (vma_res->tlb)
> -		vma_invalidate_tlb(vm, *vma_res->tlb);
> +		vma_invalidate_tlb(vm, vma_res->tlb);
>   }
>   
>   static unsigned long pd_count(u64 size, int shift)
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index 84a9ccbc5fc5..260371716490 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1308,7 +1308,7 @@ I915_SELFTEST_EXPORT int i915_vma_get_pages(struct i915_vma *vma)
>   	return err;
>   }
>   
> -void vma_invalidate_tlb(struct i915_address_space *vm, u32 tlb)
> +void vma_invalidate_tlb(struct i915_address_space *vm, u32 *tlb)
>   {
>   	/*
>   	 * Before we release the pages that were bound by this vma, we
> @@ -1318,7 +1318,7 @@ void vma_invalidate_tlb(struct i915_address_space *vm, u32 tlb)
>   	 * the most recent TLB invalidation seqno, and if we have not yet
>   	 * flushed the TLBs upon release, perform a full invalidation.
>   	 */
> -	WRITE_ONCE(tlb, intel_gt_next_invalidate_tlb_full(vm->gt));
> +	WRITE_ONCE(*tlb, intel_gt_next_invalidate_tlb_full(vm->gt));
>   }
>   
>   static void __vma_put_pages(struct i915_vma *vma, unsigned int count)
> @@ -1971,7 +1971,7 @@ struct dma_fence *__i915_vma_evict(struct i915_vma *vma, bool async)
>   			dma_fence_put(unbind_fence);
>   			unbind_fence = NULL;
>   		}
> -		vma_invalidate_tlb(vma->vm, vma->obj->mm.tlb);
> +		vma_invalidate_tlb(vma->vm, &vma->obj->mm.tlb);
>   	}
>   
>   	/*
> diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> index 5048eed536da..33a58f605d75 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -213,7 +213,7 @@ bool i915_vma_misplaced(const struct i915_vma *vma,
>   			u64 size, u64 alignment, u64 flags);
>   void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);
>   void i915_vma_revoke_mmap(struct i915_vma *vma);
> -void vma_invalidate_tlb(struct i915_address_space *vm, u32 tlb);
> +void vma_invalidate_tlb(struct i915_address_space *vm, u32 *tlb);
>   struct dma_fence *__i915_vma_evict(struct i915_vma *vma, bool async);
>   int __i915_vma_unbind(struct i915_vma *vma);
>   int __must_check i915_vma_unbind(struct i915_vma *vma);