dma-buf: heaps: Add system heap to dmabuf heaps

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: Hillf Danton <hdanton@sina.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: Laura Abbott <labbott@redhat.com>
Tested-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021190310.85221-4-john.stultz@linaro.org

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index bffa58fc3e6e0838f2297bdd4d27bec274e1f501..0613bb7770f52db969da6d8d65644d9002d62760 100644 (file)
--- 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 (file)
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 de49898112db852e91330b4ba9b776ede518c40a..d1808eca258109c7529ac4b9ec225aad5b70bfff 100644 (file)
--- 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 (file)
index 0000000..455782e
--- /dev/null
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -0,0 +1,124 @@
+// 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->flags = heap_flags;
+       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 -ENOMEM;
+}
+
+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");