[RESEND][PATCH v16 3/5] dma-buf: heaps: Add system heap to dmabuf heaps

John Stultz
2019-12-03T17:27:01Z

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@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Vincent Donnefort <Vincent.Donnefort@arm.com>
Cc: Sudipto Paul <Sudipto.Paul@arm.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chenbo Feng <fengc@google.com>
Cc: Alistair Strachan <astrachan@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Acked-by: Sandeep Patil <sspatil@android.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Tested-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
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 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..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 <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/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <asm/page.h>
+
+#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 int system_heap_allocate(struct dma_heap *heap,
+ unsigned long len,
+ unsigned long fd_flags,
+ unsigned long heap_flags)
+{
+ struct heap_helper_buffer *helper_buffer;
+ struct dma_buf *dmabuf;
+ int ret = -ENOMEM;
+ pgoff_t pg;
+
+ 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 = heap;
+ helper_buffer->size = len;
+
+ helper_buffer->pagecount = len / PAGE_SIZE;
+ helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
+ sizeof(*helper_buffer->pages),
+ GFP_KERNEL);
+ if (!helper_buffer->pages) {
+ ret = -ENOMEM;
+ goto err0;
+ }
+
+ for (pg = 0; pg < helper_buffer->pagecount; pg++) {
+ /*
+ * Avoid trying to allocate memory if the process
+ * has been killed by by SIGKILL
+ */
+ if (fatal_signal_pending(current))
+ goto err1;
+
+ helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!helper_buffer->pages[pg])
+ goto err1;
+ }
+
+ /* create the dmabuf */
+ dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+ if (IS_ERR(dmabuf)) {
+ ret = PTR_ERR(dmabuf);
+ goto err1;
+ }
+
+ helper_buffer->dmabuf = dmabuf;
+
+ ret = dma_buf_fd(dmabuf, fd_flags);
+ if (ret < 0) {
+ dma_buf_put(dmabuf);
+ /* just return, as put will call release and that will free */
+ return ret;
+ }
+
+ return ret;
+
+err1:
+ while (pg > 0)
+ __free_page(helper_buffer->pages[--pg]);
+ kfree(helper_buffer->pages);
+err0:
+ kfree(helper_buffer);
+
+ return ret;
+}
+
+static const struct dma_heap_ops system_heap_ops = {
+ .allocate = system_heap_allocate,
+};
+
+static int system_heap_create(void)
+{
+ struct dma_heap_export_info exp_info;
+ int ret = 0;
+
+ exp_info.name = "system_heap";
+ exp_info.ops = &system_heap_ops;
+ exp_info.priv = NULL;
+
+ sys_heap = dma_heap_add(&exp_info);
+ if (IS_ERR(sys_heap))
+ ret = PTR_ERR(sys_heap);
+
+ return ret;
+}
+module_init(system_heap_create);
+MODULE_LICENSE("GPL v2");
--
2.17.1