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