On 12/3/19 12:26 PM, 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
> Cc: Benjamin Gaignard
> Cc: Sumit Semwal
> Cc: Liam Mark
> Cc: Pratik Patel
> Cc: Brian Starkey
> Cc: Vincent Donnefort
> Cc: Sudipto Paul
> Cc: Andrew F. Davis
> Cc: Christoph Hellwig
> Cc: Chenbo Feng
> Cc: Alistair Strachan
> Cc: Hridya Valsaraju
> Cc: Sandeep Patil
> Cc: Hillf Danton
> Cc: Dave Airlie
> Cc: dri-devel@lists.freedesktop.org
> Reviewed-by: Benjamin Gaignard
> Reviewed-by: Brian Starkey
> Acked-by: Sandeep Patil
> Acked-by: Laura Abbott
> Tested-by: Ayan Kumar Halder
> Signed-off-by: John Stultz
> ---
> 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)
> v6:
> * Minor whitespace change suggested by Brian
> * Remove unused variable
> v7:
> * Use newly lower-cased init_heap_helper_buffer helper
> * Add system heap DOS avoidance suggested by Laura from ION code
> * Use new dmabuf export helper
> v8:
> * Make struct dma_heap_ops consts (suggested by Christoph)
> * Get rid of needless struct system_heap (suggested by Christoph)
> * Condense dma_heap_buffer and heap_helper_buffer (suggested by
> Christoph)
> * Add forgotten include file to fix build issue on x86
> v12:
> * Minor tweaks to prep loading heap from module
> v14:
> * Fix "redundant assignment to variable ret" issue reported
> by Colin King and fixed by Andrew Davis
> v15:
> * Drop unused heap flag from heap_helper_buffer as suggested
> by Sandeep Patil
> ---
> 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 bffa58fc3e6e..0613bb7770f5 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -53,4 +53,6 @@ menuconfig DMABUF_HEAPS
> 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 ..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 ..1aa01e98c595
> --- /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
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +#include "heap-helpers.h"
> +
> +struct dma_heap *sys_heap;
> +
> +static void system_heap_free(struct heap_helper_buffer *buffer)
> +{
> + pgoff_t pg;
> +
> + for (pg = 0; pg < buffer->pagecount; pg++)
> + __free_page(buffer->pages[pg]);
> + kfree(buffer->pages);
> + kfree(buffer);
> +}
> +
> +static
