linux-kernel - Re: [RFC PATCH v2 7/9] drm: atomic: factor out common out-fence operations

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Message-ID: <20161026213055.GF12629@joana>
Date:   Wed, 26 Oct 2016 19:30:55 -0200
From:   Gustavo Padovan <gustavo@...ovan.org>
To:     Brian Starkey <brian.starkey@....com>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: Re: [RFC PATCH v2 7/9] drm: atomic: factor out common out-fence
 operations

2016-10-26 Brian Starkey <brian.starkey@....com>:

> Some parts of setting up the CRTC out-fence can be re-used for
> writeback out-fences. Factor this out into a separate function.
> 
> Signed-off-by: Brian Starkey <brian.starkey@....com>
> ---
>  drivers/gpu/drm/drm_atomic.c |   64 +++++++++++++++++++++++++++---------------
>  1 file changed, 42 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index f434f34..3f8fc97 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1693,37 +1693,46 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_atomic_clean_old_fb);
>  
> -static int crtc_setup_out_fence(struct drm_crtc *crtc,
> -				struct drm_crtc_state *crtc_state,
> -				struct drm_out_fence_state *fence_state)
> +static struct fence *get_crtc_fence(struct drm_crtc *crtc,
> +				    struct drm_crtc_state *crtc_state)
>  {
>  	struct fence *fence;
>  
> -	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
> -	if (fence_state->fd < 0) {
> -		return fence_state->fd;
> -	}
> -
> -	fence_state->out_fence_ptr = crtc_state->out_fence_ptr;
> -	crtc_state->out_fence_ptr = NULL;
> -
> -	if (put_user(fence_state->fd, fence_state->out_fence_ptr))
> -		return -EFAULT;
> -
>  	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>  	if (!fence)
> -		return -ENOMEM;
> +		return NULL;
>  
>  	fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
>  		   crtc->fence_context, ++crtc->fence_seqno);
>  
> +	crtc_state->event->base.fence = fence_get(fence);
> +
> +	return fence;
> +}
> +
> +static int setup_out_fence(struct drm_out_fence_state *fence_state,
> +			   u64 __user *out_fence_ptr,
> +			   struct fence *fence)
> +{
> +	int ret;
> +
> +	DRM_DEBUG_ATOMIC("Putting out-fence %p into user ptr: %p\n",
> +			 fence, out_fence_ptr);
> +
> +	fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
> +	if (fence_state->fd < 0)
> +		return fence_state->fd;
> +
> +	ret = put_user(fence_state->fd, out_fence_ptr);
> +	if (ret)
> +		return ret;
> +
> +	fence_state->out_fence_ptr = out_fence_ptr;
> +
>  	fence_state->sync_file = sync_file_create(fence);
> -	if(!fence_state->sync_file) {
> -		fence_put(fence);
> +	if (!fence_state->sync_file)
>  		return -ENOMEM;
> -	}
>  
> -	crtc_state->event->base.fence = fence_get(fence);
>  	return 0;
>  }
>  
> @@ -1896,10 +1905,21 @@ retry:
>  		}
>  
>  		if (crtc_state->out_fence_ptr) {
> -			ret = crtc_setup_out_fence(crtc, crtc_state,
> -						   &fence_state[fence_idx++]);
> -			if (ret)
> +			struct fence *fence = get_crtc_fence(crtc, crtc_state);
> +			if (!fence) {
> +				ret = -ENOMEM;
> +				goto out;
> +			}
> +
> +			ret = setup_out_fence(&fence_state[fence_idx++],
> +					      crtc_state->out_fence_ptr,
> +					      fence);
> +			if (ret) {
> +				fence_put(fence);
>  				goto out;
> +			}
> +
> +			crtc_state->out_fence_ptr = NULL;

Yes, this split makes sense. I can break crtc_setup_out_fence() in
my out_fence patch already.

Gustavo