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

[Upadhyay, Tejas]

> -----Original Message-----
> From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of
> Matthew Brost
> Sent: Friday, July 26, 2024 4:54 AM
> To: intel-xe at lists.freedesktop.org
> Cc: Zanoni, Paulo R <paulo.r.zanoni at intel.com>;
> maarten.lankhorst at linux.intel.com
> Subject: [PATCH] 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.

Can you please give some details why VM needed now!

Tejas
> 
> 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>
> ---
>  drivers/gpu/drm/xe/xe_lrc.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c index
> 94ff62e1d95e..9ef9b45a3596 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1634,6 +1634,8 @@ struct xe_lrc_snapshot
> *xe_lrc_snapshot_capture(struct xe_lrc *lrc)
>  	if (!snapshot)
>  		return NULL;
> 
> +	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 +1655,14 @@
> 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 +1682,7 @@ void xe_lrc_snapshot_capture_delayed(struct
> xe_lrc_snapshot *snapshot)
>  	xe_bo_unlock(bo);
>  put_bo:
>  	xe_bo_put(bo);
> +	xe_vm_put(vm);
>  }
> 
>  void xe_lrc_snapshot_print(struct xe_lrc_snapshot *snapshot, struct
> drm_printer *p)
> --
> 2.34.1