Re: [PATCH] s390/zcrypt: remove set_fs() invocation in zcrypt device driver

[Christoph Hellwig]

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.