124 строки
2.6 KiB
C
124 строки
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* DMABUF System heap exporter
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*
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* Copyright (C) 2011 Google, Inc.
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* Copyright (C) 2019 Linaro Ltd.
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*/
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#include <linux/dma-buf.h>
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#include <linux/dma-mapping.h>
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#include <linux/dma-heap.h>
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#include <linux/err.h>
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#include <linux/highmem.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/slab.h>
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#include <linux/sched/signal.h>
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#include <asm/page.h>
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#include "heap-helpers.h"
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struct dma_heap *sys_heap;
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static void system_heap_free(struct heap_helper_buffer *buffer)
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{
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pgoff_t pg;
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for (pg = 0; pg < buffer->pagecount; pg++)
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__free_page(buffer->pages[pg]);
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kfree(buffer->pages);
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kfree(buffer);
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}
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static int system_heap_allocate(struct dma_heap *heap,
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unsigned long len,
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unsigned long fd_flags,
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unsigned long heap_flags)
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{
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struct heap_helper_buffer *helper_buffer;
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struct dma_buf *dmabuf;
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int ret = -ENOMEM;
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pgoff_t pg;
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helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
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if (!helper_buffer)
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return -ENOMEM;
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init_heap_helper_buffer(helper_buffer, system_heap_free);
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helper_buffer->heap = heap;
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helper_buffer->size = len;
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helper_buffer->pagecount = len / PAGE_SIZE;
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helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
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sizeof(*helper_buffer->pages),
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GFP_KERNEL);
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if (!helper_buffer->pages) {
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ret = -ENOMEM;
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goto err0;
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}
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for (pg = 0; pg < helper_buffer->pagecount; pg++) {
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/*
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* Avoid trying to allocate memory if the process
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* has been killed by by SIGKILL
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*/
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if (fatal_signal_pending(current))
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goto err1;
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helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
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if (!helper_buffer->pages[pg])
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goto err1;
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}
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/* create the dmabuf */
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dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
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if (IS_ERR(dmabuf)) {
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ret = PTR_ERR(dmabuf);
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goto err1;
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}
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helper_buffer->dmabuf = dmabuf;
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ret = dma_buf_fd(dmabuf, fd_flags);
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if (ret < 0) {
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dma_buf_put(dmabuf);
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/* just return, as put will call release and that will free */
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return ret;
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}
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return ret;
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err1:
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while (pg > 0)
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__free_page(helper_buffer->pages[--pg]);
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kfree(helper_buffer->pages);
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err0:
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kfree(helper_buffer);
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return ret;
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}
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static const struct dma_heap_ops system_heap_ops = {
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.allocate = system_heap_allocate,
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};
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static int system_heap_create(void)
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{
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struct dma_heap_export_info exp_info;
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int ret = 0;
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exp_info.name = "system";
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exp_info.ops = &system_heap_ops;
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exp_info.priv = NULL;
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sys_heap = dma_heap_add(&exp_info);
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if (IS_ERR(sys_heap))
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ret = PTR_ERR(sys_heap);
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return ret;
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}
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module_init(system_heap_create);
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MODULE_LICENSE("GPL v2");
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