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 | */ |
20 | struct 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(error: -EINVAL); |
31 | } |
32 | |
33 | return dma_buf_export(exp_info); |
34 | } |
35 | EXPORT_SYMBOL(virtio_dma_buf_export); |
36 | |
37 | /** |
38 | * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs |
39 | */ |
40 | int 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 | } |
55 | EXPORT_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 | */ |
61 | bool is_virtio_dma_buf(struct dma_buf *dma_buf) |
62 | { |
63 | return dma_buf->ops->attach == &virtio_dma_buf_attach; |
64 | } |
65 | EXPORT_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 | */ |
74 | int 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 | } |
86 | EXPORT_SYMBOL(virtio_dma_buf_get_uuid); |
87 | |
88 | MODULE_LICENSE("GPL" ); |
89 | MODULE_IMPORT_NS(DMA_BUF); |
90 | |