On Wed, Feb 09, 2022 at 06:25:07PM +0100, Ingo Rohloff wrote:
> This patch implements the same functionality for FunctionFS as
> commit f7d34b445abc00e979b7 ("USB: Add support for usbfs zerocopy.")
> did for USB host devio.c
>
> For FunctionFS, each "struct file *" for an endpoint (except EP0), keeps
> a list of mmapped buffers. User space might use these buffers to avoid
> copying of data by the kernel, by employing Linux native AsyncIO via
> libaio.
>
> Standard read() and write() operations will NOT be zerocopy.
> Especially for reads, the expected USB transfer length is unclear;
> whereas an AIO request clearly specifies the maximum transfer length.
No documentation of the new mount option here?
It should go somewhere, right?
thanks,
greg k-h
