[PATCH v4 1/3] drm/xe: Take ref to VM in delayed snapshot

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Matthew Brost
Sent: Wednesday, July 31, 2024 2:32 PM
To: intel-xe at lists.freedesktop.org; dri-devel at lists.freedesktop.org
Cc: maarten.lankhorst at linux.intel.com; Vivi, Rodrigo <rodrigo.vivi at intel.com>
Subject: [PATCH v4 1/3] drm/xe: Take ref to VM in delayed snapshot
> 
> Kernel BO's don't take a ref to the VM, we need to the VM for the
> delayed snapshot, so take a ref to the VM in delayed snapshot.
> 
> v2:
>  - Check for lrc_bo before taking a VM ref (CI)
>  - Check lrc_bo->vm before taking / dropping a VM ref (CI)
>  - Drop VM in xe_lrc_snapshot_free
> 
> 47058633d9c5 ("drm/xe: Move lrc snapshot capturing to xe_lrc.c")
> Cc: Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>

s/need to the VM/need to get the VM
Otherwise:
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  drivers/gpu/drm/xe/xe_lrc.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index 94ff62e1d95e..58121821f081 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1634,6 +1634,9 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
>  	if (!snapshot)
>  		return NULL;
>  
> +	if (lrc->bo && lrc->bo->vm)
> +		xe_vm_get(lrc->bo->vm);
> +
>  	snapshot->context_desc = xe_lrc_ggtt_addr(lrc);
>  	snapshot->indirect_context_desc = xe_lrc_indirect_ring_ggtt_addr(lrc);
>  	snapshot->head = xe_lrc_ring_head(lrc);
> @@ -1653,12 +1656,14 @@ struct xe_lrc_snapshot *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
>  void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot)
>  {
>  	struct xe_bo *bo;
> +	struct xe_vm *vm;
>  	struct iosys_map src;
>  
>  	if (!snapshot)
>  		return;
>  
>  	bo = snapshot->lrc_bo;
> +	vm = bo->vm;
>  	snapshot->lrc_bo = NULL;
>  
>  	snapshot->lrc_snapshot = kvmalloc(snapshot->lrc_size, GFP_KERNEL);
> @@ -1678,6 +1683,8 @@ void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot)
>  	xe_bo_unlock(bo);
>  put_bo:
>  	xe_bo_put(bo);
> +	if (vm)
> +		xe_vm_put(vm);
>  }
>  
>  void xe_lrc_snapshot_print(struct xe_lrc_snapshot *snapshot, struct drm_printer *p)
> @@ -1727,8 +1734,14 @@ void xe_lrc_snapshot_free(struct xe_lrc_snapshot *snapshot)
>  		return;
>  
>  	kvfree(snapshot->lrc_snapshot);
> -	if (snapshot->lrc_bo)
> +	if (snapshot->lrc_bo) {
> +		struct xe_vm *vm;
> +
> +		vm = snapshot->lrc_bo->vm;
>  		xe_bo_put(snapshot->lrc_bo);
> +		if (vm)
> +			xe_vm_put(vm);
> +	}
>  	kfree(snapshot);
>  }
>  
> -- 
> 2.34.1
> 
>