diff options
Diffstat (limited to 'drivers/virtio/virtio_dma_buf.c')
-rw-r--r-- | drivers/virtio/virtio_dma_buf.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_dma_buf.c b/drivers/virtio/virtio_dma_buf.c new file mode 100644 index 0000000000..2521a75009 --- /dev/null +++ b/drivers/virtio/virtio_dma_buf.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * dma-bufs for virtio exported objects + * + * Copyright (C) 2020 Google, Inc. + */ + +#include <linux/module.h> +#include <linux/virtio_dma_buf.h> + +/** + * virtio_dma_buf_export - Creates a new dma-buf for a virtio exported object + * @exp_info: [in] see dma_buf_export(). ops MUST refer to a dma_buf_ops + * struct embedded in a virtio_dma_buf_ops. + * + * This wraps dma_buf_export() to allow virtio drivers to create a dma-buf + * for an virtio exported object that can be queried by other virtio drivers + * for the object's UUID. + */ +struct dma_buf *virtio_dma_buf_export + (const struct dma_buf_export_info *exp_info) +{ + const struct virtio_dma_buf_ops *virtio_ops = + container_of(exp_info->ops, + const struct virtio_dma_buf_ops, ops); + + if (!exp_info->ops || + exp_info->ops->attach != &virtio_dma_buf_attach || + !virtio_ops->get_uuid) { + return ERR_PTR(-EINVAL); + } + + return dma_buf_export(exp_info); +} +EXPORT_SYMBOL(virtio_dma_buf_export); + +/** + * virtio_dma_buf_attach - mandatory attach callback for virtio dma-bufs + */ +int virtio_dma_buf_attach(struct dma_buf *dma_buf, + struct dma_buf_attachment *attach) +{ + int ret; + const struct virtio_dma_buf_ops *ops = + container_of(dma_buf->ops, + const struct virtio_dma_buf_ops, ops); + + if (ops->device_attach) { + ret = ops->device_attach(dma_buf, attach); + if (ret) + return ret; + } + return 0; +} +EXPORT_SYMBOL(virtio_dma_buf_attach); + +/** + * is_virtio_dma_buf - returns true if the given dma-buf is a virtio dma-buf + * @dma_buf: buffer to query + */ +bool is_virtio_dma_buf(struct dma_buf *dma_buf) +{ + return dma_buf->ops->attach == &virtio_dma_buf_attach; +} +EXPORT_SYMBOL(is_virtio_dma_buf); + +/** + * virtio_dma_buf_get_uuid - gets a virtio dma-buf's exported object's uuid + * @dma_buf: [in] buffer to query + * @uuid: [out] the uuid + * + * Returns: 0 on success, negative on failure. + */ +int virtio_dma_buf_get_uuid(struct dma_buf *dma_buf, + uuid_t *uuid) +{ + const struct virtio_dma_buf_ops *ops = + container_of(dma_buf->ops, + const struct virtio_dma_buf_ops, ops); + + if (!is_virtio_dma_buf(dma_buf)) + return -EINVAL; + + return ops->get_uuid(dma_buf, uuid); +} +EXPORT_SYMBOL(virtio_dma_buf_get_uuid); + +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS(DMA_BUF); |