linux-4.4.1/dma_buf_export() の履歴(No.1)

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linux-4.4.1/dma_buf_export() へ行く。
- 1 (2016-02-08 (月) 19:38:40)

参照元†

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説明†

パス: linux-4.4.1/drivers/dma-buf/dma-buf.c

FIXME: これは何？
- 説明

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引数†

const struct dma_buf_export_info *exp_info
- linux-4.4.1/dma_buf_export_info

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返り値†

struct dma_buf *
- linux-4.4.1/dma_buf

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参考†

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実装†

/**
 * dma_buf_export - Creates a new dma_buf, and associates an anon file
 * with this buffer, so it can be exported.
 * Also connect the allocator specific data and ops to the buffer.
 * Additionally, provide a name string for exporter; useful in debugging.
 *
 * @exp_info:   [in]    holds all the export related information provided
 *                      by the exporter. see struct dma_buf_export_info
 *                      for further details.
 *
 * Returns, on success, a newly created dma_buf object, which wraps the
 * supplied private data and operations for dma_buf_ops. On either missing
 * ops, or error in allocating struct dma_buf, will return negative error.
 *
 */
struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
{
        struct dma_buf *dmabuf;
        struct reservation_object *resv = exp_info->resv;
        struct file *file;
        size_t alloc_size = sizeof(struct dma_buf);

        if (!exp_info->resv)
                alloc_size += sizeof(struct reservation_object);
        else
                /* prevent &dma_buf[1] == dma_buf->resv */
                alloc_size += 1;

        if (WARN_ON(!exp_info->priv
                          || !exp_info->ops
                          || !exp_info->ops->map_dma_buf
                          || !exp_info->ops->unmap_dma_buf
                          || !exp_info->ops->release
                          || !exp_info->ops->kmap_atomic
                          || !exp_info->ops->kmap
                          || !exp_info->ops->mmap)) {
                return ERR_PTR(-EINVAL);
        }

        if (!try_module_get(exp_info->owner))
                return ERR_PTR(-ENOENT);

- linux-4.4.1/try_module_get()

        dmabuf = kzalloc(alloc_size, GFP_KERNEL);
        if (!dmabuf) {
                module_put(exp_info->owner);
                return ERR_PTR(-ENOMEM);
        }

- linux-4.4.1/kzalloc()
- linux-4.4.1/module_put()

        dmabuf->priv = exp_info->priv;
        dmabuf->ops = exp_info->ops;
        dmabuf->size = exp_info->size;
        dmabuf->exp_name = exp_info->exp_name;
        dmabuf->owner = exp_info->owner;
        init_waitqueue_head(&dmabuf->poll);
        dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
        dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;

- linux-4.4.1/init_waitqueue_head()
- dmabuf->cb_excl は struct dma_buf_poll_cb_t 型
- linux-4.4.1/dma_buf_poll_cb_t

        if (!resv) {
                resv = (struct reservation_object *)&dmabuf[1];
                reservation_object_init(resv);
        }
        dmabuf->resv = resv;

- linux-4.4.1/reservation_object_init()

        file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
                                        exp_info->flags);
        if (IS_ERR(file)) {
                kfree(dmabuf);
                return ERR_CAST(file);
        }

        file->f_mode |= FMODE_LSEEK;
        dmabuf->file = file;

        mutex_init(&dmabuf->lock);
        INIT_LIST_HEAD(&dmabuf->attachments);

- linux-4.4.1/mutex_init()
- linux-4.4.1/INIT_LIST_HEAD()

        mutex_lock(&db_list.lock);
        list_add(&dmabuf->list_node, &db_list.head);
        mutex_unlock(&db_list.lock);

        return dmabuf;
}
EXPORT_SYMBOL_GPL(dma_buf_export);

- linux-4.4.1/EXPORT_SYMBOL_GPL()

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linux-4.4.1/dma_buf_export() の履歴(No.1)

参照元†

説明†

引数†

返り値†

参考†

実装†

コメント†