Re: fs: layered device driver to write to evdev

[Guillermo Rodriguez Garcia]

El jue, 3 nov 2022 a las 1:04, Luis Chamberlain (<mcgrof@xxxxxxxxxx>) escribió:
>
> On Wed, Nov 02, 2022 at 02:14:24PM +0100, Guillermo Rodriguez Garcia wrote:
> > I understand that device drivers should implement ->write_iter if they
> > need to be written from kernel space, but evdev does not support this.
> > What is the recommended way to have a layered device driver that can
> > talk to evdev ?
>
> Shouldn't just writing write_iter support make this work?

If I understand correctly, supporting both write and write_iter is not
allowed [1]:

"If a file has both the regular ->read/->write methods and the iter
variants those could have different semantics for messed up enough
drivers.  Also fails the kernel access to them in that case."

 [1]: https://lore.kernel.org/all/20200817073212.830069-3-hch@xxxxxx/

Thanks,

Guillermo Rodriguez Garcia
guille.rodriguez@xxxxxxxxx