Re: [PATCH 2/4] dma-buf/dma-fence: remove unnecessary callbacks

[Simona Vetter <simona.vetter@ffwll.ch>]

On Tue, Feb 11, 2025 at 05:31:07PM +0100, Christian König wrote:
> The fence_value_str and timeline_value_str callbacks were just an
> unnecessary abstraction in the SW sync implementation.
> 
> The only caller of those callbacks already knew that the fence in
> questions is a timeline_fence. So print the values directly instead
> of using a redirection.
> 
> Additional to that remove the implementations from virtgpu and vgem.
> As far as I can see those were never used in the first place.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Ok I got really confused here for a moment, but checks all out.

Reviewed-by: Simona Vetter <simona.vetter@ffwll.ch>

> ---
>  drivers/dma-buf/sw_sync.c              | 16 ----------------
>  drivers/dma-buf/sync_debug.c           | 21 ++-------------------
>  drivers/gpu/drm/vgem/vgem_fence.c      | 15 ---------------
>  drivers/gpu/drm/virtio/virtgpu_fence.c | 16 ----------------
>  include/linux/dma-fence.h              | 21 ---------------------
>  5 files changed, 2 insertions(+), 87 deletions(-)
> 
> diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
> index f5905d67dedb..849280ae79a9 100644
> --- a/drivers/dma-buf/sw_sync.c
> +++ b/drivers/dma-buf/sw_sync.c
> @@ -173,20 +173,6 @@ static bool timeline_fence_signaled(struct dma_fence *fence)
>  	return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops);
>  }
>  
> -static void timeline_fence_value_str(struct dma_fence *fence,
> -				    char *str, int size)
> -{
> -	snprintf(str, size, "%lld", fence->seqno);
> -}
> -
> -static void timeline_fence_timeline_value_str(struct dma_fence *fence,
> -					     char *str, int size)
> -{
> -	struct sync_timeline *parent = dma_fence_parent(fence);
> -
> -	snprintf(str, size, "%d", parent->value);
> -}
> -
>  static void timeline_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
>  {
>  	struct sync_pt *pt = dma_fence_to_sync_pt(fence);
> @@ -208,8 +194,6 @@ static const struct dma_fence_ops timeline_fence_ops = {
>  	.get_timeline_name = timeline_fence_get_timeline_name,
>  	.signaled = timeline_fence_signaled,
>  	.release = timeline_fence_release,
> -	.fence_value_str = timeline_fence_value_str,
> -	.timeline_value_str = timeline_fence_timeline_value_str,
>  	.set_deadline = timeline_fence_set_deadline,
>  };
>  
> diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
> index 237bce21d1e7..270daae7d89a 100644
> --- a/drivers/dma-buf/sync_debug.c
> +++ b/drivers/dma-buf/sync_debug.c
> @@ -82,25 +82,8 @@ static void sync_print_fence(struct seq_file *s,
>  		seq_printf(s, "@%lld.%09ld", (s64)ts64.tv_sec, ts64.tv_nsec);
>  	}
>  
> -	if (fence->ops->timeline_value_str &&
> -		fence->ops->fence_value_str) {
> -		char value[64];
> -		bool success;
> -
> -		fence->ops->fence_value_str(fence, value, sizeof(value));
> -		success = strlen(value);
> -
> -		if (success) {
> -			seq_printf(s, ": %s", value);
> -
> -			fence->ops->timeline_value_str(fence, value,
> -						       sizeof(value));
> -
> -			if (strlen(value))
> -				seq_printf(s, " / %s", value);
> -		}
> -	}
> -
> +	seq_printf(s, ": %lld", fence->seqno);
> +	seq_printf(s, " / %d", parent->value);
>  	seq_putc(s, '\n');
>  }
>  
> diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
> index e15754178395..5298d995faa7 100644
> --- a/drivers/gpu/drm/vgem/vgem_fence.c
> +++ b/drivers/gpu/drm/vgem/vgem_fence.c
> @@ -53,25 +53,10 @@ static void vgem_fence_release(struct dma_fence *base)
>  	dma_fence_free(&fence->base);
>  }
>  
> -static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size)
> -{
> -	snprintf(str, size, "%llu", fence->seqno);
> -}
> -
> -static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str,
> -					  int size)
> -{
> -	snprintf(str, size, "%llu",
> -		 dma_fence_is_signaled(fence) ? fence->seqno : 0);
> -}
> -
>  static const struct dma_fence_ops vgem_fence_ops = {
>  	.get_driver_name = vgem_fence_get_driver_name,
>  	.get_timeline_name = vgem_fence_get_timeline_name,
>  	.release = vgem_fence_release,
> -
> -	.fence_value_str = vgem_fence_value_str,
> -	.timeline_value_str = vgem_fence_timeline_value_str,
>  };
>  
>  static void vgem_fence_timeout(struct timer_list *t)
> diff --git a/drivers/gpu/drm/virtio/virtgpu_fence.c b/drivers/gpu/drm/virtio/virtgpu_fence.c
> index f28357dbde35..44c1d8ef3c4d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_fence.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_fence.c
> @@ -49,26 +49,10 @@ static bool virtio_gpu_fence_signaled(struct dma_fence *f)
>  	return false;
>  }
>  
> -static void virtio_gpu_fence_value_str(struct dma_fence *f, char *str, int size)
> -{
> -	snprintf(str, size, "[%llu, %llu]", f->context, f->seqno);
> -}
> -
> -static void virtio_gpu_timeline_value_str(struct dma_fence *f, char *str,
> -					  int size)
> -{
> -	struct virtio_gpu_fence *fence = to_virtio_gpu_fence(f);
> -
> -	snprintf(str, size, "%llu",
> -		 (u64)atomic64_read(&fence->drv->last_fence_id));
> -}
> -
>  static const struct dma_fence_ops virtio_gpu_fence_ops = {
>  	.get_driver_name     = virtio_gpu_get_driver_name,
>  	.get_timeline_name   = virtio_gpu_get_timeline_name,
>  	.signaled            = virtio_gpu_fence_signaled,
> -	.fence_value_str     = virtio_gpu_fence_value_str,
> -	.timeline_value_str  = virtio_gpu_timeline_value_str,
>  };
>  
>  struct virtio_gpu_fence *virtio_gpu_fence_alloc(struct virtio_gpu_device *vgdev,
> diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
> index e230af0d123f..8778e2d758da 100644
> --- a/include/linux/dma-fence.h
> +++ b/include/linux/dma-fence.h
> @@ -238,27 +238,6 @@ struct dma_fence_ops {
>  	 */
>  	void (*release)(struct dma_fence *fence);
>  
> -	/**
> -	 * @fence_value_str:
> -	 *
> -	 * Callback to fill in free-form debug info specific to this fence, like
> -	 * the sequence number.
> -	 *
> -	 * This callback is optional.
> -	 */
> -	void (*fence_value_str)(struct dma_fence *fence, char *str, int size);
> -
> -	/**
> -	 * @timeline_value_str:
> -	 *
> -	 * Fills in the current value of the timeline as a string, like the
> -	 * sequence number. Note that the specific fence passed to this function
> -	 * should not matter, drivers should only use it to look up the
> -	 * corresponding timeline structures.
> -	 */
> -	void (*timeline_value_str)(struct dma_fence *fence,
> -				   char *str, int size);
> -
>  	/**
>  	 * @set_deadline:
>  	 *
> -- 
> 2.34.1
> 

-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch