Re: [RFC PATCH 06/12] staging: android: ion: Remove crufty cache support

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Mar 02, 2017 at 01:44:38PM -0800, Laura Abbott wrote:
> 
> 
> Now that we call dma_map in the dma_buf API callbacks there is no need
> to use the existing cache APIs. Remove the sync ioctl and the existing
> bad dma_sync calls. Explicit caching can be handled with the dma_buf
> sync API.
> 
> Signed-off-by: Laura Abbott <labbott@redhat.com>
> ---
>  drivers/staging/android/ion/ion-ioctl.c         |  5 ----
>  drivers/staging/android/ion/ion.c               | 40 -------------------------
>  drivers/staging/android/ion/ion_carveout_heap.c |  6 ----
>  drivers/staging/android/ion/ion_chunk_heap.c    |  6 ----
>  drivers/staging/android/ion/ion_page_pool.c     |  3 --
>  drivers/staging/android/ion/ion_system_heap.c   |  5 ----
>  6 files changed, 65 deletions(-)
> 
> diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
> index 5b2e93f..f820d77 100644
> --- a/drivers/staging/android/ion/ion-ioctl.c
> +++ b/drivers/staging/android/ion/ion-ioctl.c
> @@ -146,11 +146,6 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  			data.handle.handle = handle->id;
>  		break;
>  	}
> -	case ION_IOC_SYNC:
> -	{
> -		ret = ion_sync_for_device(client, data.fd.fd);
> -		break;
> -	}

You missed the case ION_IOC_SYNC: in compat_ion.c.

While at it: Should we also remove the entire custom_ioctl infrastructure?
It's entirely unused afaict, and for a pure buffer allocator I don't see
any need to have custom ioctl.

More code to remove potentially:
- The entire compat ioctl stuff - would be an abi break, but I guess if we
  pick the 32bit abi and clean up the uapi headers we'll be mostly fine.
  would allow us to remove compat_ion.c entirely.

- ION_IOC_IMPORT: With this ion is purely an allocator, so not sure we
  still need to be able to import anything. All the cache flushing/mapping
  is done through dma-buf ops/ioctls.


With the case in compat_ion.c also removed, this patch is:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

>  	case ION_IOC_CUSTOM:
>  	{
>  		if (!dev->custom_ioctl)
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 8eef1d7..c3c316f 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -815,22 +815,6 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
>  	free_duped_table(table);
>  }
>  
> -void ion_pages_sync_for_device(struct device *dev, struct page *page,
> -			       size_t size, enum dma_data_direction dir)
> -{
> -	struct scatterlist sg;
> -
> -	sg_init_table(&sg, 1);
> -	sg_set_page(&sg, page, size, 0);
> -	/*
> -	 * This is not correct - sg_dma_address needs a dma_addr_t that is valid
> -	 * for the targeted device, but this works on the currently targeted
> -	 * hardware.
> -	 */
> -	sg_dma_address(&sg) = page_to_phys(page);
> -	dma_sync_sg_for_device(dev, &sg, 1, dir);
> -}
> -
>  static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
>  {
>  	struct ion_buffer *buffer = dmabuf->priv;
> @@ -1042,30 +1026,6 @@ struct ion_handle *ion_import_dma_buf_fd(struct ion_client *client, int fd)
>  }
>  EXPORT_SYMBOL(ion_import_dma_buf_fd);
>  
> -int ion_sync_for_device(struct ion_client *client, int fd)
> -{
> -	struct dma_buf *dmabuf;
> -	struct ion_buffer *buffer;
> -
> -	dmabuf = dma_buf_get(fd);
> -	if (IS_ERR(dmabuf))
> -		return PTR_ERR(dmabuf);
> -
> -	/* if this memory came from ion */
> -	if (dmabuf->ops != &dma_buf_ops) {
> -		pr_err("%s: can not sync dmabuf from another exporter\n",
> -		       __func__);
> -		dma_buf_put(dmabuf);
> -		return -EINVAL;
> -	}
> -	buffer = dmabuf->priv;
> -
> -	dma_sync_sg_for_device(NULL, buffer->sg_table->sgl,
> -			       buffer->sg_table->nents, DMA_BIDIRECTIONAL);
> -	dma_buf_put(dmabuf);
> -	return 0;
> -}
> -
>  int ion_query_heaps(struct ion_client *client, struct ion_heap_query *query)
>  {
>  	struct ion_device *dev = client->dev;
> diff --git a/drivers/staging/android/ion/ion_carveout_heap.c b/drivers/staging/android/ion/ion_carveout_heap.c
> index 9bf8e98..e0e360f 100644
> --- a/drivers/staging/android/ion/ion_carveout_heap.c
> +++ b/drivers/staging/android/ion/ion_carveout_heap.c
> @@ -100,10 +100,6 @@ static void ion_carveout_heap_free(struct ion_buffer *buffer)
>  
>  	ion_heap_buffer_zero(buffer);
>  
> -	if (ion_buffer_cached(buffer))
> -		dma_sync_sg_for_device(NULL, table->sgl, table->nents,
> -				       DMA_BIDIRECTIONAL);
> -
>  	ion_carveout_free(heap, paddr, buffer->size);
>  	sg_free_table(table);
>  	kfree(table);
> @@ -128,8 +124,6 @@ struct ion_heap *ion_carveout_heap_create(struct ion_platform_heap *heap_data)
>  	page = pfn_to_page(PFN_DOWN(heap_data->base));
>  	size = heap_data->size;
>  
> -	ion_pages_sync_for_device(NULL, page, size, DMA_BIDIRECTIONAL);
> -
>  	ret = ion_heap_pages_zero(page, size, pgprot_writecombine(PAGE_KERNEL));
>  	if (ret)
>  		return ERR_PTR(ret);
> diff --git a/drivers/staging/android/ion/ion_chunk_heap.c b/drivers/staging/android/ion/ion_chunk_heap.c
> index 8c41889..46e13f6 100644
> --- a/drivers/staging/android/ion/ion_chunk_heap.c
> +++ b/drivers/staging/android/ion/ion_chunk_heap.c
> @@ -101,10 +101,6 @@ static void ion_chunk_heap_free(struct ion_buffer *buffer)
>  
>  	ion_heap_buffer_zero(buffer);
>  
> -	if (ion_buffer_cached(buffer))
> -		dma_sync_sg_for_device(NULL, table->sgl, table->nents,
> -				       DMA_BIDIRECTIONAL);
> -
>  	for_each_sg(table->sgl, sg, table->nents, i) {
>  		gen_pool_free(chunk_heap->pool, page_to_phys(sg_page(sg)),
>  			      sg->length);
> @@ -132,8 +128,6 @@ struct ion_heap *ion_chunk_heap_create(struct ion_platform_heap *heap_data)
>  	page = pfn_to_page(PFN_DOWN(heap_data->base));
>  	size = heap_data->size;
>  
> -	ion_pages_sync_for_device(NULL, page, size, DMA_BIDIRECTIONAL);
> -
>  	ret = ion_heap_pages_zero(page, size, pgprot_writecombine(PAGE_KERNEL));
>  	if (ret)
>  		return ERR_PTR(ret);
> diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
> index aea89c1..532eda7 100644
> --- a/drivers/staging/android/ion/ion_page_pool.c
> +++ b/drivers/staging/android/ion/ion_page_pool.c
> @@ -30,9 +30,6 @@ static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
>  
>  	if (!page)
>  		return NULL;
> -	if (!pool->cached)
> -		ion_pages_sync_for_device(NULL, page, PAGE_SIZE << pool->order,
> -					  DMA_BIDIRECTIONAL);
>  	return page;
>  }
>  
> diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
> index 6cb2fe7..a33331b 100644
> --- a/drivers/staging/android/ion/ion_system_heap.c
> +++ b/drivers/staging/android/ion/ion_system_heap.c
> @@ -75,9 +75,6 @@ static struct page *alloc_buffer_page(struct ion_system_heap *heap,
>  
>  	page = ion_page_pool_alloc(pool);
>  
> -	if (cached)
> -		ion_pages_sync_for_device(NULL, page, PAGE_SIZE << order,
> -					  DMA_BIDIRECTIONAL);
>  	return page;
>  }
>  
> @@ -401,8 +398,6 @@ static int ion_system_contig_heap_allocate(struct ion_heap *heap,
>  
>  	buffer->sg_table = table;
>  
> -	ion_pages_sync_for_device(NULL, page, len, DMA_BIDIRECTIONAL);
> -
>  	return 0;
>  
>  free_table:
> -- 
> 2.7.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch