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 !virtio_ops->get_uuid) {
29 return ERR_PTR(-EINVAL);
30 }
31
32 if (!(IS_ENABLED(CONFIG_CFI_CLANG) && IS_ENABLED(CONFIG_MODULES)) &&
33 exp_info->ops->attach != &virtio_dma_buf_attach)
34 return ERR_PTR(-EINVAL);
35
36 return dma_buf_export(exp_info);
37 }
38 EXPORT_SYMBOL(virtio_dma_buf_export);
39
40 /**
41 * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs
42 */
virtio_dma_buf_attach(struct dma_buf * dma_buf,struct dma_buf_attachment * attach)43 int virtio_dma_buf_attach(struct dma_buf *dma_buf,
44 struct dma_buf_attachment *attach)
45 {
46 int ret;
47 const struct virtio_dma_buf_ops *ops =
48 container_of(dma_buf->ops,
49 const struct virtio_dma_buf_ops, ops);
50
51 if (ops->device_attach) {
52 ret = ops->device_attach(dma_buf, attach);
53 if (ret)
54 return ret;
55 }
56 return 0;
57 }
58 EXPORT_SYMBOL(virtio_dma_buf_attach);
59
60 /**
61 * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
62 * @dma_buf: buffer to query
63 */
is_virtio_dma_buf(struct dma_buf * dma_buf)64 bool is_virtio_dma_buf(struct dma_buf *dma_buf)
65 {
66 if (IS_ENABLED(CONFIG_CFI_CLANG) && IS_ENABLED(CONFIG_MODULES))
67 return true;
68
69 return dma_buf->ops->attach == &virtio_dma_buf_attach;
70 }
71 EXPORT_SYMBOL(is_virtio_dma_buf);
72
73 /**
74 * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
75 * @dma_buf: [in] buffer to query
76 * @uuid: [out] the uuid
77 *
78 * Returns: 0 on success, negative on failure.
79 */
virtio_dma_buf_get_uuid(struct dma_buf * dma_buf,uuid_t * uuid)80 int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
81 uuid_t *uuid)
82 {
83 const struct virtio_dma_buf_ops *ops =
84 container_of(dma_buf->ops,
85 const struct virtio_dma_buf_ops, ops);
86
87 if (!is_virtio_dma_buf(dma_buf))
88 return -EINVAL;
89
90 return ops->get_uuid(dma_buf, uuid);
91 }
92 EXPORT_SYMBOL(virtio_dma_buf_get_uuid);
93
94 MODULE_LICENSE("GPL");
95