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Message-ID: <CA+M3ks6ga2-c2GRWDMdDnPDEFQ+0+QdxAUbSc--fKVHJNR6R6Q@mail.gmail.com>
Date: Wed, 6 Mar 2019 17:01:08 +0100
From: Benjamin Gaignard <benjamin.gaignard@...aro.org>
To: John Stultz <john.stultz@...aro.org>
Cc: lkml <linux-kernel@...r.kernel.org>,
Laura Abbott <labbott@...hat.com>,
Greg KH <gregkh@...uxfoundation.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
Liam Mark <lmark@...eaurora.org>,
Brian Starkey <Brian.Starkey@....com>,
"Andrew F . Davis" <afd@...com>, Chenbo Feng <fengc@...gle.com>,
Alistair Strachan <astrachan@...gle.com>,
ML dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [RFC][PATCH 3/5 v2] dma-buf: heaps: Add system heap to dmabuf heaps
Le mar. 5 mars 2019 à 21:54, John Stultz <john.stultz@...aro.org> a écrit :
>
> 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@...hat.com>
> Cc: Benjamin Gaignard <benjamin.gaignard@...aro.org>
> Cc: Greg KH <gregkh@...uxfoundation.org>
> Cc: Sumit Semwal <sumit.semwal@...aro.org>
> Cc: Liam Mark <lmark@...eaurora.org>
> Cc: Brian Starkey <Brian.Starkey@....com>
> Cc: Andrew F. Davis <afd@...com>
> Cc: Chenbo Feng <fengc@...gle.com>
> Cc: Alistair Strachan <astrachan@...gle.com>
> Cc: dri-devel@...ts.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@...aro.org>
> ---
> v2:
> * Switch allocate to return dmabuf fd
> * Simplify init code
> * Checkpatch fixups
> * Droped dead system-contig code
just few blank lines to remove.
Reveiwed-by: Benjamin Gaignard <benjamin.gaignard@...aro.org>
> ---
> drivers/dma-buf/Kconfig | 2 +
> drivers/dma-buf/heaps/Kconfig | 6 ++
> drivers/dma-buf/heaps/Makefile | 1 +
> drivers/dma-buf/heaps/system_heap.c | 132 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 141 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 09c61db..63c139d 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 0000000..2050527
> --- /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 de49898..d1808ec 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 0000000..e001661
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/system_heap.c
> @@ -0,0 +1,132 @@
> +// 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"
> +
> +
remove blank line
> +struct system_heap {
> + struct dma_heap heap;
> +};
> +
> +
remove blank line
> +static void system_heap_free(struct heap_helper_buffer *buffer)
> +{
> + int i;
> + struct scatterlist *sg;
> + struct sg_table *table = buffer->sg_table;
> +
> + for_each_sg(table->sgl, sg, table->nents, i)
> + __free_page(sg_page(sg));
> +
> + sg_free_table(table);
> + kfree(table);
> + kfree(buffer);
> +}
> +
> +static int system_heap_allocate(struct dma_heap *heap,
> + unsigned long len,
> + unsigned long flags)
> +{
> + struct heap_helper_buffer *helper_buffer;
> + struct sg_table *table;
> + struct scatterlist *sg;
> + int i, j;
> + int npages = PAGE_ALIGN(len) / PAGE_SIZE;
> + DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> + struct dma_buf *dmabuf;
> + int ret = -ENOMEM;
> +
> + helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
> + if (!helper_buffer)
> + return -ENOMEM;
> +
> + INIT_HEAP_HELPER_BUFFER(helper_buffer, system_heap_free);
> + helper_buffer->heap_buffer.flags = flags;
> + helper_buffer->heap_buffer.heap = heap;
> + helper_buffer->heap_buffer.size = len;
> +
> + table = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
> + if (!table)
> + goto err0;
> +
> + i = sg_alloc_table(table, npages, GFP_KERNEL);
> + if (i)
> + goto err1;
> + for_each_sg(table->sgl, sg, table->nents, i) {
> + struct page *page;
> +
> + page = alloc_page(GFP_KERNEL);
> + if (!page)
> + goto err2;
> + sg_set_page(sg, page, PAGE_SIZE, 0);
> + }
> +
> + /* create the dmabuf */
> + exp_info.ops = &heap_helper_ops;
> + exp_info.size = len;
> + exp_info.flags = O_RDWR;
> + exp_info.priv = &helper_buffer->heap_buffer;
> + dmabuf = dma_buf_export(&exp_info);
> + if (IS_ERR(dmabuf)) {
> + ret = PTR_ERR(dmabuf);
> + goto err2;
> + }
> +
> + helper_buffer->heap_buffer.dmabuf = dmabuf;
> + helper_buffer->sg_table = table;
> +
> + ret = dma_buf_fd(dmabuf, O_CLOEXEC);
> + if (ret < 0) {
> + dma_buf_put(dmabuf);
> + /* just return, as put will call release and that will free */
> + return ret;
> + }
> +
> + return ret;
> +
> +err2:
> + for_each_sg(table->sgl, sg, i, j)
> + __free_page(sg_page(sg));
> + sg_free_table(table);
> +err1:
> + kfree(table);
> +err0:
> + kfree(helper_buffer);
> + return -ENOMEM;
> +}
> +
> +
remove blank line
> +static struct dma_heap_ops system_heap_ops = {
> + .allocate = system_heap_allocate,
> +};
> +
> +static int system_heap_create(void)
> +{
> + struct system_heap *sys_heap;
> +
> + sys_heap = kzalloc(sizeof(*sys_heap), GFP_KERNEL);
> + if (!sys_heap)
> + return -ENOMEM;
> + sys_heap->heap.name = "system_heap";
> + sys_heap->heap.ops = &system_heap_ops;
> +
> + dma_heap_add(&sys_heap->heap);
> +
> + return 0;
> +}
> +device_initcall(system_heap_create);
> --
> 2.7.4
>
--
Benjamin Gaignard
Graphic Study Group
Linaro.org │ Open source software for ARM SoCs
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