[PATCH] drm/amdgpu: grab the id mgr lock while accessing passid_mapping

[Christian König]

Ping!

Am 09.09.19 um 13:59 schrieb Christian König:
> Need to make sure that we actually dropping the right fence.
> Could be done with RCU as well, but to complicated for a fix.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index b285ab25146d..e11764164cbf 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1036,10 +1036,8 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
>   		id->oa_base != job->oa_base ||
>   		id->oa_size != job->oa_size);
>   	bool vm_flush_needed = job->vm_needs_flush;
> -	bool pasid_mapping_needed = id->pasid != job->pasid ||
> -		!id->pasid_mapping ||
> -		!dma_fence_is_signaled(id->pasid_mapping);
>   	struct dma_fence *fence = NULL;
> +	bool pasid_mapping_needed;
>   	unsigned patch_offset = 0;
>   	int r;
>   
> @@ -1049,6 +1047,12 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
>   		pasid_mapping_needed = true;
>   	}
>   
> +	mutex_lock(&id_mgr->lock);
> +	if (id->pasid != job->pasid || !id->pasid_mapping ||
> +	    !dma_fence_is_signaled(id->pasid_mapping))
> +		pasid_mapping_needed = true;
> +	mutex_unlock(&id_mgr->lock);
> +
>   	gds_switch_needed &= !!ring->funcs->emit_gds_switch;
>   	vm_flush_needed &= !!ring->funcs->emit_vm_flush  &&
>   			job->vm_pd_addr != AMDGPU_BO_INVALID_OFFSET;
> @@ -1088,9 +1092,11 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
>   	}
>   
>   	if (pasid_mapping_needed) {
> +		mutex_lock(&id_mgr->lock);
>   		id->pasid = job->pasid;
>   		dma_fence_put(id->pasid_mapping);
>   		id->pasid_mapping = dma_fence_get(fence);
> +		mutex_unlock(&id_mgr->lock);
>   	}
>   	dma_fence_put(fence);
>