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// 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");
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