[RFC v2 01/11] file: add callback for pre-mapping dmabuf

[Pavel Begunkov]

On 12/4/25 10:42, Christoph Hellwig wrote:
> On Sun, Nov 23, 2025 at 10:51:21PM +0000, Pavel Begunkov wrote:
>> +static inline struct dma_token *
>> +dma_token_create(struct file *file, struct dma_token_params *params)
>> +{
>> +	struct dma_token *res;
>> +
>> +	if (!file->f_op->dma_map)
>> +		return ERR_PTR(-EOPNOTSUPP);
>> +	res = file->f_op->dma_map(file, params);
> 
> Calling the file operation ->dmap_map feels really misleading.

agreed

> create_token as in the function name is already much better, but
> it really is not just dma, but dmabuf related, and that should really
> be encoded in the name.
> 
> Also why not pass the dmabuf and direction directly instead of wrapping
> it in the odd params struct making the whole thing hard to follow?

I added it after I forgot about the direction and had to plumb
it through all the layers. In a draft of v3 I had I already
removed it as dmabuf is passed with the token to drivers.

-- 
Pavel Begunkov