How to replace set_fs(KERNEL_DS) for a kernel 5.10.x module driver version

[Jorge Fernandez Monteagudo]

>Patents have almost nothing to do with licenses, we have many things in
>the Linux kernel that are under a GPLv2 license that have patents issued
>for (and are actively enforced.)  The GPL can, and does, work with the
>patent system, so if that's a reason that any company tries to give for
>not releasing kernel code, it's very misinformed.

Well, I think the only the reason not to publish the code was because it's a driver for a custom hardware with no interest outside our department...
 
> Anyway, off-topic but I figured I would try to clear that up.

I was wondering that with the current limitation, there is no way to call functions in a driver as the cdc-acm from other drivers as the dummy I sent. Maybe our driver was designed the way is to avoid latencies from context switching if the code were in userspace... It's only a guess...

Thanks,
Jorge