Re: [PATCH v2 3/4] drm/xe: Allow freeing of a managed bo

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 8/5/2025 4:42 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> If a bo is created via xe_managed_bo_create_pin_map() then it cannot be
> freed by the driver using xe_bo_unpin_map_no_vm(), or indeed any other
> existing function. The DRM layer will still have a pointer stashed
> away for later freeing, causing a invalid memory access on driver
> unload. So add a helper for releasing the DRM action as well.
>
> v2: Drop 'xe' parameter (review feedbak from Michal W)
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>   drivers/gpu/drm/xe/xe_bo.c | 5 +++++
>   drivers/gpu/drm/xe/xe_bo.h | 1 +
>   2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index ffca1cea5585..87aa0f5b2b2a 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -2222,6 +2222,11 @@ struct xe_bo *xe_managed_bo_create_pin_map(struct xe_device *xe, struct xe_tile
>   	return bo;
>   }
>   
> +void xe_managed_bo_unpin_map_no_vm(struct xe_bo *bo)

Not sure if the "_no_vm" postfix is the best choice here, because all 
managed_bo operations are without vm. But maybe better to keep it for 
future-proofing, in case we have a vm-enabled version later?
Since I'm undecided myself I won't block on it.

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

> +{
> +	devm_release_action(xe_bo_device(bo)->drm.dev, __xe_bo_unpin_map_no_vm, bo);
> +}
> +
>   struct xe_bo *xe_managed_bo_create_from_data(struct xe_device *xe, struct xe_tile *tile,
>   					     const void *data, size_t size, u32 flags)
>   {
> diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> index 8cce413b5235..298eef403505 100644
> --- a/drivers/gpu/drm/xe/xe_bo.h
> +++ b/drivers/gpu/drm/xe/xe_bo.h
> @@ -122,6 +122,7 @@ struct xe_bo *xe_bo_create_pin_map_at_aligned(struct xe_device *xe,
>   					      u64 alignment);
>   struct xe_bo *xe_managed_bo_create_pin_map(struct xe_device *xe, struct xe_tile *tile,
>   					   size_t size, u32 flags);
> +void xe_managed_bo_unpin_map_no_vm(struct xe_bo *bo);
>   struct xe_bo *xe_managed_bo_create_from_data(struct xe_device *xe, struct xe_tile *tile,
>   					     const void *data, size_t size, u32 flags);
>   int xe_managed_bo_reinit_in_vram(struct xe_device *xe, struct xe_tile *tile, struct xe_bo **src);