On Mon, Sep 14, 2020 at 09:36:07AM +0200, Harald Freudenberger wrote: > Christoph, maybe you have a greater idea on how to solve this. So don't hesitate and tell me. > Otherwise how to we provide this fix then ? My recommendation would be to go the 'usual' way: > Commit this s390 internal and then let this go out with the next kernel merge window when > next time Linus is pulling patches from the s390 subsystem for the 5.10 kernel development cycle. What I did for the networking code is to add a new structure that contains a union of the kernel and userspace pointer and a flag for which one to use. That is pretty much the same as what you did, just a little more structured and type safe. The other alternative would be to use the iov_iter infrastructure, but that has some overhead.
