1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * dma-bufs for virtio exported objects
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2020 Google, Inc.
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/module.h>
9*4882a593Smuzhiyun #include <linux/virtio_dma_buf.h>
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun /**
12*4882a593Smuzhiyun * virtio_dma_buf_export - Creates a new dma-buf for a virtio exported object
13*4882a593Smuzhiyun * @exp_info: [in] see dma_buf_export(). ops MUST refer to a dma_buf_ops
14*4882a593Smuzhiyun * struct embedded in a virtio_dma_buf_ops.
15*4882a593Smuzhiyun *
16*4882a593Smuzhiyun * This wraps dma_buf_export() to allow virtio drivers to create a dma-buf
17*4882a593Smuzhiyun * for an virtio exported object that can be queried by other virtio drivers
18*4882a593Smuzhiyun * for the object's UUID.
19*4882a593Smuzhiyun */
virtio_dma_buf_export(const struct dma_buf_export_info * exp_info)20*4882a593Smuzhiyun struct dma_buf *virtio_dma_buf_export
21*4882a593Smuzhiyun (const struct dma_buf_export_info *exp_info)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun const struct virtio_dma_buf_ops *virtio_ops =
24*4882a593Smuzhiyun container_of(exp_info->ops,
25*4882a593Smuzhiyun const struct virtio_dma_buf_ops, ops);
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun if (!exp_info->ops ||
28*4882a593Smuzhiyun !virtio_ops->get_uuid) {
29*4882a593Smuzhiyun return ERR_PTR(-EINVAL);
30*4882a593Smuzhiyun }
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun if (!(IS_ENABLED(CONFIG_CFI_CLANG) && IS_ENABLED(CONFIG_MODULES)) &&
33*4882a593Smuzhiyun exp_info->ops->attach != &virtio_dma_buf_attach)
34*4882a593Smuzhiyun return ERR_PTR(-EINVAL);
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun return dma_buf_export(exp_info);
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun EXPORT_SYMBOL(virtio_dma_buf_export);
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /**
41*4882a593Smuzhiyun * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs
42*4882a593Smuzhiyun */
virtio_dma_buf_attach(struct dma_buf * dma_buf,struct dma_buf_attachment * attach)43*4882a593Smuzhiyun int virtio_dma_buf_attach(struct dma_buf *dma_buf,
44*4882a593Smuzhiyun struct dma_buf_attachment *attach)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun int ret;
47*4882a593Smuzhiyun const struct virtio_dma_buf_ops *ops =
48*4882a593Smuzhiyun container_of(dma_buf->ops,
49*4882a593Smuzhiyun const struct virtio_dma_buf_ops, ops);
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun if (ops->device_attach) {
52*4882a593Smuzhiyun ret = ops->device_attach(dma_buf, attach);
53*4882a593Smuzhiyun if (ret)
54*4882a593Smuzhiyun return ret;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun return 0;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun EXPORT_SYMBOL(virtio_dma_buf_attach);
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun /**
61*4882a593Smuzhiyun * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf
62*4882a593Smuzhiyun * @dma_buf: buffer to query
63*4882a593Smuzhiyun */
is_virtio_dma_buf(struct dma_buf * dma_buf)64*4882a593Smuzhiyun bool is_virtio_dma_buf(struct dma_buf *dma_buf)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun if (IS_ENABLED(CONFIG_CFI_CLANG) && IS_ENABLED(CONFIG_MODULES))
67*4882a593Smuzhiyun return true;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun return dma_buf->ops->attach == &virtio_dma_buf_attach;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun EXPORT_SYMBOL(is_virtio_dma_buf);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun /**
74*4882a593Smuzhiyun * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid
75*4882a593Smuzhiyun * @dma_buf: [in] buffer to query
76*4882a593Smuzhiyun * @uuid: [out] the uuid
77*4882a593Smuzhiyun *
78*4882a593Smuzhiyun * Returns: 0 on success, negative on failure.
79*4882a593Smuzhiyun */
virtio_dma_buf_get_uuid(struct dma_buf * dma_buf,uuid_t * uuid)80*4882a593Smuzhiyun int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf,
81*4882a593Smuzhiyun uuid_t *uuid)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun const struct virtio_dma_buf_ops *ops =
84*4882a593Smuzhiyun container_of(dma_buf->ops,
85*4882a593Smuzhiyun const struct virtio_dma_buf_ops, ops);
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun if (!is_virtio_dma_buf(dma_buf))
88*4882a593Smuzhiyun return -EINVAL;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun return ops->get_uuid(dma_buf, uuid);
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun EXPORT_SYMBOL(virtio_dma_buf_get_uuid);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun MODULE_LICENSE("GPL");
95