[Intel-gfx] [PATCH] drm/i915: Add ww context to intel_dpt_pin, v2.

[Thomas Hellström (Intel)]

On 9/29/21 10:59, Maarten Lankhorst wrote:
> Ensure i915_vma_pin_iomap and vma_unpin are done with dpt->obj lock held.
>
> I don't think there's much of a point in merging intel_dpt_pin() with
> intel_pin_fb_obj_dpt(), they touch different objects.
>
> Changes since v1:
> - Fix using the wrong pointer to retrieve error code (Julia)
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Reported-by: kernel test robot <lkp at intel.com>
> Reported-by: Julia Lawall <julia.lawall at lip6.fr>

LGTM.

Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>

> ---
>   drivers/gpu/drm/i915/display/intel_dpt.c | 40 +++++++++++++++---------
>   1 file changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dpt.c b/drivers/gpu/drm/i915/display/intel_dpt.c
> index de62bd77b15e..8f7b1f7534a4 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpt.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpt.c
> @@ -121,32 +121,42 @@ struct i915_vma *intel_dpt_pin(struct i915_address_space *vm)
>   	intel_wakeref_t wakeref;
>   	struct i915_vma *vma;
>   	void __iomem *iomem;
> +	struct i915_gem_ww_ctx ww;
> +	int err;
>   
>   	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
>   	atomic_inc(&i915->gpu_error.pending_fb_pin);
>   
> -	vma = i915_gem_object_ggtt_pin(dpt->obj, NULL, 0, 4096,
> -				       HAS_LMEM(i915) ? 0 : PIN_MAPPABLE);
> -	if (IS_ERR(vma))
> -		goto err;
> +	for_i915_gem_ww(&ww, err, true) {
> +		err = i915_gem_object_lock(dpt->obj, &ww);
> +		if (err)
> +			continue;
>   
> -	iomem = i915_vma_pin_iomap(vma);
> -	i915_vma_unpin(vma);
> -	if (IS_ERR(iomem)) {
> -		vma = ERR_CAST(iomem);
> -		goto err;
> -	}
> +		vma = i915_gem_object_ggtt_pin_ww(dpt->obj, &ww, NULL, 0, 4096,
> +						  HAS_LMEM(i915) ? 0 : PIN_MAPPABLE);
> +		if (IS_ERR(vma)) {
> +			err = PTR_ERR(vma);
> +			continue;
> +		}
> +
> +		iomem = i915_vma_pin_iomap(vma);
> +		i915_vma_unpin(vma);
>   
> -	dpt->vma = vma;
> -	dpt->iomem = iomem;
> +		if (IS_ERR(iomem)) {
> +			err = PTR_ERR(iomem);
> +			continue;
> +		}
>   
> -	i915_vma_get(vma);
> +		dpt->vma = vma;
> +		dpt->iomem = iomem;
> +
> +		i915_vma_get(vma);
> +	}
>   
> -err:
>   	atomic_dec(&i915->gpu_error.pending_fb_pin);
>   	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
>   
> -	return vma;
> +	return err ? ERR_PTR(err) : vma;
>   }
>   
>   void intel_dpt_unpin(struct i915_address_space *vm)