[PATCH 3/9] drm/xe/xe_reg_sr: Always call xe_force_wake_put/get in pairs

[Michal Wajdeczko]

On 04.06.2024 13:02, Nirmoy Das wrote:
> xe_force_wake_get() increments the domain ref regardless of success
> or failure so call xe_force_wake_put() even on failure to keep ref
> count accurate.
> 
> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_reg_sr.c | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_reg_sr.c b/drivers/gpu/drm/xe/xe_reg_sr.c
> index 440ac572f6e5..8fcc08658d89 100644
> --- a/drivers/gpu/drm/xe/xe_reg_sr.c
> +++ b/drivers/gpu/drm/xe/xe_reg_sr.c
> @@ -201,13 +201,11 @@ void xe_reg_sr_apply_mmio(struct xe_reg_sr *sr, struct xe_gt *gt)
>  	xa_for_each(&sr->xa, reg, entry)
>  		apply_one_mmio(gt, entry);
>  
> -	err = xe_force_wake_put(&gt->mmio.fw, XE_FORCEWAKE_ALL);
> -	XE_WARN_ON(err);
> -
> -	return;
> -
>  err_force_wake:
> -	xe_gt_err(gt, "Failed to apply, err=%d\n", err);
> +	if (err)
> +		xe_gt_err(gt, "Failed to whitelist %s registers, err=%d\n",
> +			  sr->name, err);
> +	XE_WARN_ON(xe_force_wake_put(&gt->mmio.fw, XE_FORCEWAKE_ALL));

what's the rule whether to WARN about the failed xe_force_wake_put() or
not ? should we also WARN when xe_force_wake_get() failed ? does it make
sense to WARN about put() if get() already failed ?

maybe simpler solution would be make function xe_force_wake_put() void
as it almost nothing that caller can do and move WARN there if needed ?

what about making the flow more intuitive like this:

bool xe_force_wake_get(fw, d);
void xe_force_wake_put(fw, d);

	if (xe_force_wake_get(fw, d)) {
		...
		xe_force_wake_put(fw, d);
	}

>  }
>  
>  void xe_reg_sr_apply_whitelist(struct xe_hw_engine *hwe)
> @@ -253,13 +251,11 @@ void xe_reg_sr_apply_whitelist(struct xe_hw_engine *hwe)
>  		xe_mmio_write32(gt, RING_FORCE_TO_NONPRIV(mmio_base, slot), addr);
>  	}
>  
> -	err = xe_force_wake_put(&gt->mmio.fw, XE_FORCEWAKE_ALL);
> -	XE_WARN_ON(err);
> -
> -	return;
> -
>  err_force_wake:
> -	drm_err(&xe->drm, "Failed to apply, err=%d\n", err);
> +	if (err)
> +		xe_gt_err(gt, "Failed to whitelist %s registers, err=%d\n",
> +			  sr->name, err);
> +	XE_WARN_ON(xe_force_wake_put(&gt->mmio.fw, XE_FORCEWAKE_ALL));
>  }
>  
>  /**