On 3/6/26 4:36 AM, Albert Esteve wrote:
> From: John Stultz <john.stultz@linaro.org>
> 
> Keep track of the heap device struct.
> 
> This will be useful for special DMA allocations
> and actions.
> 
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Reviewed-by: Maxime Ripard <mripard@kernel.org>
> Signed-off-by: Albert Esteve <aesteve@redhat.com>
> ---
>   drivers/dma-buf/dma-heap.c | 34 ++++++++++++++++++++++++++--------
>   include/linux/dma-heap.h   |  2 ++
>   2 files changed, 28 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
> index ac5f8685a6494..1124d63eb1398 100644
> --- a/drivers/dma-buf/dma-heap.c
> +++ b/drivers/dma-buf/dma-heap.c
> @@ -31,6 +31,7 @@
>    * @heap_devt:		heap device node
>    * @list:		list head connecting to list of heaps
>    * @heap_cdev:		heap char device
> + * @heap_dev:		heap device
>    *
>    * Represents a heap of memory from which buffers can be made.
>    */
> @@ -41,6 +42,7 @@ struct dma_heap {
>   	dev_t heap_devt;
>   	struct list_head list;
>   	struct cdev heap_cdev;
> +	struct device *heap_dev;
>   };
> 
>   static LIST_HEAD(heap_list);
> @@ -223,6 +225,19 @@ const char *dma_heap_get_name(struct dma_heap *heap)
>   }
>   EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP");
> 
> +/**
> + * dma_heap_get_dev() - get device struct for the heap
> + * @heap: DMA-Heap to retrieve device struct from
> + *
> + * Returns:
> + * The device struct for the heap.
> + */
> +struct device *dma_heap_get_dev(struct dma_heap *heap)
> +{
> +	return heap->heap_dev;
> +}
> +EXPORT_SYMBOL_NS_GPL(dma_heap_get_dev, "DMA_BUF_HEAP");
> +
>   /**
>    * dma_heap_add - adds a heap to dmabuf heaps
>    * @exp_info: information needed to register this heap
> @@ -230,7 +245,6 @@ EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP");
>   struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
>   {
>   	struct dma_heap *heap, *h, *err_ret;
> -	struct device *dev_ret;
>   	unsigned int minor;
>   	int ret;
> 
> @@ -272,14 +286,14 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
>   		goto err1;
>   	}
> 
> -	dev_ret = device_create(dma_heap_class,
> -				NULL,
> -				heap->heap_devt,
> -				NULL,
> -				heap->name);
> -	if (IS_ERR(dev_ret)) {
> +	heap->heap_dev = device_create(dma_heap_class,
> +				       NULL,
> +				       heap->heap_devt,
> +				       NULL,
> +				       heap->name);
> +	if (IS_ERR(heap->heap_dev)) {
>   		pr_err("dma_heap: Unable to create device\n");
> -		err_ret = ERR_CAST(dev_ret);
> +		err_ret = ERR_CAST(heap->heap_dev);
>   		goto err2;
>   	}
> 
> @@ -295,6 +309,10 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)
>   		}
>   	}
> 
> +	/* Make sure it doesn't disappear on us */
> +	heap->heap_dev = get_device(heap->heap_dev);
> +
> +

Is this actually something that matters or could happen? Seems you
just remove it in the next patch anyway.

Andrew

>   	/* Add heap to the list */
>   	list_add(&heap->list, &heap_list);
>   	mutex_unlock(&heap_list_lock);
> diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
> index 648328a64b27e..493085e69b70e 100644
> --- a/include/linux/dma-heap.h
> +++ b/include/linux/dma-heap.h
> @@ -12,6 +12,7 @@
>   #include <linux/types.h>
> 
>   struct dma_heap;
> +struct device;
> 
>   /**
>    * struct dma_heap_ops - ops to operate on a given heap
> @@ -43,6 +44,7 @@ struct dma_heap_export_info {
>   void *dma_heap_get_drvdata(struct dma_heap *heap);
> 
>   const char *dma_heap_get_name(struct dma_heap *heap);
> +struct device *dma_heap_get_dev(struct dma_heap *heap);
> 
>   struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);
> 
>