Re: [PATCH v5 3/5] dma-buf: heaps: Add system heap to dmabuf heaps

[Brian Starkey]

Hi,

On Fri, Jun 07, 2019 at 03:07:17AM +0000, John Stultz wrote:
> This patch adds system heap to the dma-buf heaps framework.
> 
> This allows applications to get a page-allocator backed dma-buf
> for non-contiguous memory.
> 
> This code is an evolution of the Android ION implementation, so
> thanks to its original authors and maintainters:
>   Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
> 
> Cc: Laura Abbott <labbott@xxxxxxxxxx>
> Cc: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
> Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> Cc: Liam Mark <lmark@xxxxxxxxxxxxxx>
> Cc: Pratik Patel <pratikp@xxxxxxxxxxxxxx>
> Cc: Brian Starkey <Brian.Starkey@xxxxxxx>
> Cc: Vincent Donnefort <Vincent.Donnefort@xxxxxxx>
> Cc: Sudipto Paul <Sudipto.Paul@xxxxxxx>
> Cc: Andrew F. Davis <afd@xxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: Chenbo Feng <fengc@xxxxxxxxxx>
> Cc: Alistair Strachan <astrachan@xxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> Change-Id: I4dc5ff54ccb1f7ca3ac8675661114ca33813654b
> ---
> v2:
> * Switch allocate to return dmabuf fd
> * Simplify init code
> * Checkpatch fixups
> * Droped dead system-contig code
> v3:
> * Whitespace fixups from Benjamin
> * Make sure we're zeroing the allocated pages (from Liam)
> * Use PAGE_ALIGN() consistently (suggested by Brian)
> * Fold in new registration style from Andrew
> * Avoid needless dynamic allocation of sys_heap (suggested by
>   Christoph)
> * Minor cleanups
> * Folded in changes from Andrew to use simplified page list
>   from the heap helpers
> v4:
> * Optimization to allocate pages in chunks, similar to old
>   pagepool code
> * Use fd_flags when creating dmabuf fd (Suggested by Benjamin)
> v5:
> * Back out large order page allocations (was leaking memory,
>   as the page array didn't properly track order size)
> ---
>  drivers/dma-buf/Kconfig             |   2 +
>  drivers/dma-buf/heaps/Kconfig       |   6 ++
>  drivers/dma-buf/heaps/Makefile      |   1 +
>  drivers/dma-buf/heaps/system_heap.c | 123 ++++++++++++++++++++++++++++
>  4 files changed, 132 insertions(+)
>  create mode 100644 drivers/dma-buf/heaps/Kconfig
>  create mode 100644 drivers/dma-buf/heaps/system_heap.c
> 
> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index 9b93f86f597c..434cfe646dad 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -47,4 +47,6 @@ menuconfig DMABUF_HEAPS
>  	  this allows userspace to allocate dma-bufs that can be shared between
>  	  drivers.
>  
> +source "drivers/dma-buf/heaps/Kconfig"
> +
>  endmenu
> diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
> new file mode 100644
> index 000000000000..205052744169
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/Kconfig
> @@ -0,0 +1,6 @@
> +config DMABUF_HEAPS_SYSTEM
> +	bool "DMA-BUF System Heap"
> +	depends on DMABUF_HEAPS
> +	help
> +	  Choose this option to enable the system dmabuf heap. The system heap
> +	  is backed by pages from the buddy allocator. If in doubt, say Y.
> diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
> index de49898112db..d1808eca2581 100644
> --- a/drivers/dma-buf/heaps/Makefile
> +++ b/drivers/dma-buf/heaps/Makefile
> @@ -1,2 +1,3 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-y					+= heap-helpers.o
> +obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)	+= system_heap.o
> diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
> new file mode 100644
> index 000000000000..863834499ce1
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/system_heap.c
> @@ -0,0 +1,123 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DMABUF System heap exporter
> + *
> + * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2019 Linaro Ltd.
> + */
> +
> +#include <asm/page.h>
> +#include <linux/dma-buf.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dma-heap.h>
> +#include <linux/err.h>
> +#include <linux/highmem.h>
> +#include <linux/mm.h>
> +#include <linux/scatterlist.h>
> +#include <linux/slab.h>
> +
> +#include "heap-helpers.h"
> +
> +struct system_heap {
> +	struct dma_heap *heap;
> +} sys_heap;
> +
> +

extra newline. Otherwise, LGTM:

Reviewed-by: Brian Starkey <brian.starkey@xxxxxxx>