[PATCH v4 2/2] drm/amdgpu: SDMA update use unlocked iterator

[Christian König]

Am 13.09.22 um 22:05 schrieb Philip Yang:
> SDMA update page table may be called from unlocked context, this
> generate below warning. Use unlocked iterator to handle this case.
>
> WARNING: CPU: 0 PID: 1475 at
> drivers/dma-buf/dma-resv.c:483 dma_resv_iter_next
> Call Trace:
>   dma_resv_iter_first+0x43/0xa0
>   amdgpu_vm_sdma_update+0x69/0x2d0 [amdgpu]
>   amdgpu_vm_ptes_update+0x29c/0x870 [amdgpu]
>   amdgpu_vm_update_range+0x2f6/0x6c0 [amdgpu]
>   svm_range_unmap_from_gpus+0x115/0x300 [amdgpu]
>   svm_range_cpu_invalidate_pagetables+0x510/0x5e0 [amdgpu]
>   __mmu_notifier_invalidate_range_start+0x1d3/0x230
>   unmap_vmas+0x140/0x150
>   unmap_region+0xa8/0x110
>
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> index 1fd3cbca20a2..718db7d98e5a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> @@ -211,12 +211,15 @@ static int amdgpu_vm_sdma_update(struct amdgpu_vm_update_params *p,
>   	int r;
>   
>   	/* Wait for PD/PT moves to be completed */
> -	dma_resv_for_each_fence(&cursor, bo->tbo.base.resv,
> -				DMA_RESV_USAGE_KERNEL, fence) {
> +	dma_resv_iter_begin(&cursor, bo->tbo.base.resv, DMA_RESV_USAGE_KERNEL);
> +	dma_resv_for_each_fence_unlocked(&cursor, fence) {
>   		r = amdgpu_sync_fence(&p->job->sync, fence);
> -		if (r)
> +		if (r) {
> +			dma_resv_iter_end(&cursor);
>   			return r;
> +		}
>   	}
> +	dma_resv_iter_end(&cursor);
>   
>   	do {
>   		ndw = p->num_dw_left;