Re: New subsystem for acceleration devices

[Christoph Hellwig]

On Tue, Aug 09, 2022 at 08:23:27AM +0200, Greg Kroah-Hartman wrote:
> Based on the number of drivers that I see submitted weekly that try to
> restrict their open call to just one user by using atomic variables or
> other tricks, I think my interpretation of this stands :)

I think they really want what Jason described most of the time.  They
just don't know about the pitfalls of dup yet.

> > This is different from the number of FDs pointing at the struct file.
> > Userpsace can open a HW state and point a lot of FDs at it, that is
> > userspace's problem. From a kernel view they all share one struct file
> > and thus one HW state.
> 
> Yes, that's fine, if that is what is happening here, I have no
> objection.

It would be great if we could actually life that into a common
layer (chardev or vfs) given just how common this, and drivers tend
to get it wrong, do it suboptimal so often.