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 */
virtio_dma_buf_export(const struct dma_buf_export_info * exp_info)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(-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 */
virtio_dma_buf_attach(struct dma_buf * dma_buf,struct dma_buf_attachment * attach)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 */
is_virtio_dma_buf(struct dma_buf * dma_buf)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 */
virtio_dma_buf_get_uuid(struct dma_buf * dma_buf,uuid_t * uuid)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