Re: [RFC][PATCH 2/6] staging: android: ion: Switch to using an idr to manage heaps

[Liviu Dudau <Liviu.Dudau@arm.com>]

On Mon, Jun 06, 2016 at 11:23:29AM -0700, Laura Abbott wrote:
> From: Laura Abbott <labbott@fedoraproject.org>
> 
> 
> In anticipation of dynamic registration of heaps, switch to using
> an idr for heaps. The idr makes it easier to control the assignment
> and management + lookup of heap numbers.
> 
> Signed-off-by: Laura Abbott <labbott@redhat.com>
> ---
>  drivers/staging/android/ion/ion.c | 83 +++++++++++++++++++++++++--------------
>  1 file changed, 53 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 306340a..739060f 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -55,13 +55,14 @@ struct ion_device {
>  	struct rb_root buffers;
>  	struct mutex buffer_lock;
>  	struct rw_semaphore lock;
> -	struct plist_head heaps;
>  	long (*custom_ioctl)(struct ion_client *client, unsigned int cmd,
>  			     unsigned long arg);
>  	struct rb_root clients;
>  	struct dentry *debug_root;
>  	struct dentry *heaps_debug_root;
>  	struct dentry *clients_debug_root;
> +	struct idr idr;
> +	int heap_cnt;
>  };
>  
>  /**
> @@ -488,39 +489,22 @@ static int ion_handle_add(struct ion_client *client, struct ion_handle *handle)
>  	return 0;
>  }
>  
> -struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
> -			     size_t align, unsigned int heap_id_mask,
> +static struct ion_handle *__ion_alloc(struct ion_client *client, size_t len,
> +			     size_t align, struct ion_heap *heap,
>  			     unsigned int flags)
>  {
>  	struct ion_handle *handle;
>  	struct ion_device *dev = client->dev;
>  	struct ion_buffer *buffer = NULL;
> -	struct ion_heap *heap;
>  	int ret;
>  
> -	pr_debug("%s: len %zu align %zu heap_id_mask %u flags %x\n", __func__,
> -		 len, align, heap_id_mask, flags);
> -	/*
> -	 * traverse the list of heaps available in this system in priority
> -	 * order.  If the heap type is supported by the client, and matches the
> -	 * request of the caller allocate from it.  Repeat until allocate has
> -	 * succeeded or all heaps have been tried
> -	 */
> +

Drop the (second) empty line here.

>  	len = PAGE_ALIGN(len);
>  
>  	if (!len)
>  		return ERR_PTR(-EINVAL);
>  
> -	down_read(&dev->lock);
> -	plist_for_each_entry(heap, &dev->heaps, node) {
> -		/* if the caller didn't specify this heap id */
> -		if (!((1 << heap->id) & heap_id_mask))
> -			continue;
> -		buffer = ion_buffer_create(heap, dev, len, align, flags);
> -		if (!IS_ERR(buffer))
> -			break;
> -	}
> -	up_read(&dev->lock);
> +	buffer = ion_buffer_create(heap, dev, len, align, flags);
>  
>  	if (buffer == NULL)
>  		return ERR_PTR(-ENODEV);
> @@ -549,6 +533,41 @@ struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
>  
>  	return handle;
>  }
> +
> +struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
> +				size_t align, unsigned int heap_mask,
> +				unsigned int flags)
> +{
> +	int bit;
> +	struct ion_handle *handle = ERR_PTR(-ENODEV);
> +
> +	pr_debug("%s: len %zu align %zu heap_id_mask %u flags %x\n", __func__,
> +		 len, align, heap_mask, flags);
> +
> +	down_read(&client->dev->lock);
> +	/*
> +	 * traverse the list of heaps available in this system in priority
> +	 * order.  If the heap type is supported by the client, and matches the
> +	 * request of the caller allocate from it.  Repeat until allocate has
> +	 * succeeded or all heaps have been tried
> +	 */
> +	for_each_set_bit(bit, (unsigned long *)&heap_mask, 32) {
> +		struct ion_heap *heap;
> +
> +		heap = idr_find(&client->dev->idr, bit);
> +		if (!heap)
> +			continue;
> +
> +		handle = __ion_alloc(client, len, align, heap, flags);
> +		if (IS_ERR(handle))
> +			continue;
> +		else
> +			break;
> +	}
> +
> +	up_read(&client->dev->lock);
> +	return handle;
> +}
>  EXPORT_SYMBOL(ion_alloc);
>  
>  static void ion_free_nolock(struct ion_client *client, struct ion_handle *handle)
> @@ -1587,6 +1606,7 @@ DEFINE_SIMPLE_ATTRIBUTE(debug_shrink_fops, debug_shrink_get,
>  int ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
>  {
>  	struct dentry *debug_file;
> +	int ret;
>  
>  	if (!heap->ops->allocate || !heap->ops->free || !heap->ops->map_dma ||
>  	    !heap->ops->unmap_dma) {
> @@ -1606,12 +1626,15 @@ int ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
>  
>  	heap->dev = dev;
>  	down_write(&dev->lock);
> -	/*
> -	 * use negative heap->id to reverse the priority -- when traversing
> -	 * the list later attempt higher id numbers first
> -	 */
> -	plist_node_init(&heap->node, -heap->id);
> -	plist_add(&heap->node, &dev->heaps);
> +
> +	ret = idr_alloc(&dev->idr, heap, heap->id, heap->id + 1, GFP_KERNEL);
> +	if (ret < 0 || ret != heap->id) {
> +		pr_info("%s: Failed to add heap id, expected %d got %d\n",
> +			__func__, heap->id, ret);
> +		up_write(&dev->lock);
> +		return ret < 0 ? ret : -EINVAL;
> +	}
> +
>  	debug_file = debugfs_create_file(heap->name, 0664,
>  					dev->heaps_debug_root, heap,
>  					&debug_heap_fops);
> @@ -1639,7 +1662,7 @@ int ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
>  				path, debug_name);
>  		}
>  	}
> -
> +	dev->heap_cnt++;
>  	up_write(&dev->lock);
>  	return 0;
>  }
> @@ -1689,7 +1712,7 @@ debugfs_done:
>  	idev->buffers = RB_ROOT;
>  	mutex_init(&idev->buffer_lock);
>  	init_rwsem(&idev->lock);
> -	plist_head_init(&idev->heaps);
> +	idr_init(&idev->idr);
>  	idev->clients = RB_ROOT;
>  	ion_root_client = &idev->clients;
>  	mutex_init(&debugfs_mutex);
> -- 
> 2.5.5
> 

Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com>

-- 
====================
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