1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2022 Advanced Micro Devices, Inc.
4 * Authors:
5 * Christian König <christian.koenig@amd.com>
6 */
7
8#ifndef __LINUX_DMA_FENCE_UNWRAP_H
9#define __LINUX_DMA_FENCE_UNWRAP_H
10
11struct dma_fence;
12
13/**
14 * struct dma_fence_unwrap - cursor into the container structure
15 *
16 * Should be used with dma_fence_unwrap_for_each() iterator macro.
17 */
18struct dma_fence_unwrap {
19 /**
20 * @chain: potential dma_fence_chain, but can be other fence as well
21 */
22 struct dma_fence *chain;
23 /**
24 * @array: potential dma_fence_array, but can be other fence as well
25 */
26 struct dma_fence *array;
27 /**
28 * @index: last returned index if @array is really a dma_fence_array
29 */
30 unsigned int index;
31};
32
33struct dma_fence *dma_fence_unwrap_first(struct dma_fence *head,
34 struct dma_fence_unwrap *cursor);
35struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor);
36
37/**
38 * dma_fence_unwrap_for_each - iterate over all fences in containers
39 * @fence: current fence
40 * @cursor: current position inside the containers
41 * @head: starting point for the iterator
42 *
43 * Unwrap dma_fence_chain and dma_fence_array containers and deep dive into all
44 * potential fences in them. If @head is just a normal fence only that one is
45 * returned.
46 */
47#define dma_fence_unwrap_for_each(fence, cursor, head) \
48 for (fence = dma_fence_unwrap_first(head, cursor); fence; \
49 fence = dma_fence_unwrap_next(cursor))
50
51struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
52 struct dma_fence **fences,
53 struct dma_fence_unwrap *cursors);
54
55int dma_fence_dedup_array(struct dma_fence **array, int num_fences);
56
57/**
58 * dma_fence_unwrap_merge - unwrap and merge fences
59 *
60 * All fences given as parameters are unwrapped and merged back together as flat
61 * dma_fence_array. Useful if multiple containers need to be merged together.
62 *
63 * Implemented as a macro to allocate the necessary arrays on the stack and
64 * account the stack frame size to the caller.
65 *
66 * Returns NULL on memory allocation failure, a dma_fence object representing
67 * all the given fences otherwise.
68 */
69#define dma_fence_unwrap_merge(...) \
70 ({ \
71 struct dma_fence *__f[] = { __VA_ARGS__ }; \
72 struct dma_fence_unwrap __c[ARRAY_SIZE(__f)]; \
73 \
74 __dma_fence_unwrap_merge(ARRAY_SIZE(__f), __f, __c); \
75 })
76
77#endif
78

source code of linux/include/linux/dma-fence-unwrap.h