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 * @dma_buf: [in] buffer to attach
40 * @attach: [in] attachment structure
41 */
virtio_dma_buf_attach(struct dma_buf * dma_buf,struct dma_buf_attachment * attach)42 int virtio_dma_buf_attach(struct dma_buf *dma_buf,
43 struct dma_buf_attachment *attach)
44 {
45 int ret;
46 const struct virtio_dma_buf_ops *ops =
47 container_of(dma_buf->ops,
48 const struct virtio_dma_buf_ops, ops);
49
50 if (ops->device_attach) {
51 ret = ops->device_attach(dma_buf, attach);
52 if (ret)
53 return ret;
54 }
55 return 0;
56 }
57 EXPORT_SYMBOL(virtio_dma_buf_attach);
58
59 /**
60 * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
61 * @dma_buf: buffer to query
62 */
is_virtio_dma_buf(struct dma_buf * dma_buf)63 bool is_virtio_dma_buf(struct dma_buf *dma_buf)
64 {
65 return dma_buf->ops->attach == &virtio_dma_buf_attach;
66 }
67 EXPORT_SYMBOL(is_virtio_dma_buf);
68
69 /**
70 * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
71 * @dma_buf: [in] buffer to query
72 * @uuid: [out] the uuid
73 *
74 * Returns: 0 on success, negative on failure.
75 */
virtio_dma_buf_get_uuid(struct dma_buf * dma_buf,uuid_t * uuid)76 int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
77 uuid_t *uuid)
78 {
79 const struct virtio_dma_buf_ops *ops =
80 container_of(dma_buf->ops,
81 const struct virtio_dma_buf_ops, ops);
82
83 if (!is_virtio_dma_buf(dma_buf))
84 return -EINVAL;
85
86 return ops->get_uuid(dma_buf, uuid);
87 }
88 EXPORT_SYMBOL(virtio_dma_buf_get_uuid);
89
90 MODULE_DESCRIPTION("dma-bufs for virtio exported objects");
91 MODULE_LICENSE("GPL");
92 MODULE_IMPORT_NS("DMA_BUF");
93