1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * dma-bufs for virtio exported objects
 4 *
 5 * Copyright (C) 2020 Google, Inc.
 6 */
 7
 8#include <linux/module.h>
 9#include <linux/virtio_dma_buf.h>
10
11/**
12 * virtio_dma_buf_export - Creates a new dma-buf for a virtio exported object
13 * @exp_info: [in] see dma_buf_export(). ops MUST refer to a dma_buf_ops
14 *	struct embedded in a virtio_dma_buf_ops.
15 *
16 * This wraps dma_buf_export() to allow virtio drivers to create a dma-buf
17 * for an virtio exported object that can be queried by other virtio drivers
18 * for the object's UUID.
19 */
20struct dma_buf *virtio_dma_buf_export
21	(const struct dma_buf_export_info *exp_info)
22{
23	const struct virtio_dma_buf_ops *virtio_ops =
24		container_of(exp_info->ops,
25			     const struct virtio_dma_buf_ops, ops);
26
27	if (!exp_info->ops ||
28	    exp_info->ops->attach != &virtio_dma_buf_attach ||
29	    !virtio_ops->get_uuid) {
30		return ERR_PTR(-EINVAL);
31	}
32
33	return dma_buf_export(exp_info);
34}
35EXPORT_SYMBOL(virtio_dma_buf_export);
36
37/**
38 * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs
39 */
40int virtio_dma_buf_attach(struct dma_buf *dma_buf,
41			  struct dma_buf_attachment *attach)
42{
43	int ret;
44	const struct virtio_dma_buf_ops *ops =
45		container_of(dma_buf->ops,
46			     const struct virtio_dma_buf_ops, ops);
47
48	if (ops->device_attach) {
49		ret = ops->device_attach(dma_buf, attach);
50		if (ret)
51			return ret;
52	}
53	return 0;
54}
55EXPORT_SYMBOL(virtio_dma_buf_attach);
56
57/**
58 * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
59 * @dma_buf: buffer to query
60 */
61bool is_virtio_dma_buf(struct dma_buf *dma_buf)
62{
63	return dma_buf->ops->attach == &virtio_dma_buf_attach;
64}
65EXPORT_SYMBOL(is_virtio_dma_buf);
66
67/**
68 * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
69 * @dma_buf: [in] buffer to query
70 * @uuid: [out] the uuid
71 *
72 * Returns: 0 on success, negative on failure.
73 */
74int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
75			    uuid_t *uuid)
76{
77	const struct virtio_dma_buf_ops *ops =
78		container_of(dma_buf->ops,
79			     const struct virtio_dma_buf_ops, ops);
80
81	if (!is_virtio_dma_buf(dma_buf))
82		return -EINVAL;
83
84	return ops->get_uuid(dma_buf, uuid);
85}
86EXPORT_SYMBOL(virtio_dma_buf_get_uuid);
87
88MODULE_LICENSE("GPL");
89MODULE_IMPORT_NS(DMA_BUF);