[PATCH v6] drm/xe: Add a null pointer check

[Michal Wajdeczko]

On 25.03.2024 15:12, Karthik Poosa wrote:
> Add a missing null pointer check.
> 
> v2: Release resources before returning error. (Riana)
> 
> v3: Update commit message. (Badal)
> 
> v4: Change drm_err to XE_WARN_ON. (Anshuman)
> 
> v5: Fix XE_WARN_ON check. (Riana)
> 
> v6: Update commit message. (Jani)
> 
> Fixes: 09d88e3beb64 ("drm/xe/pm: Init pcode and restore vram on power lost")
> Signed-off-by: Karthik Poosa <karthik.poosa at intel.com>
> Reviewed-by: Riana Tauro <riana.tauro at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_pm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index cc650a92c2fc..f6837bd6f9a3 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -383,6 +383,11 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>  	 * really lost power. Detecting primary Gt power is sufficient.
>  	 */
>  	gt = xe_device_get_gt(xe, 0);

maybe easier way to silence the tool is to use:

	gt = xe_root_mmio_gt(xe);

that don't have a path with NULL as return

> +	if (XE_WARN_ON(!gt)) {

but if you still want to add the WARN for the impossible case then as we
have xe it is better to use drm_WARN_ON()

> +		err = -ENXIO;
> +		goto out;
> +	}
> +
>  	xe->d3cold.power_lost = xe_guc_in_reset(&gt->uc.guc);
>  
>  	if (xe->d3cold.allowed && xe->d3cold.power_lost) {