On Wed, May 10, 2017 at 04:39:12AM +0100, Al Viro wrote:

fcntl stuff: I've decided not to put something similar into work.compat
since I couldn't decide what to do with compat stuff - word-by-word copy
from userland converting to struct flock + conversion to posix_lock +
actual work + conversion to flock + word-by-word copy to userland...  Smells
like we might be better off with compat_flock_to_posix_lock() et.al.
I'm still not sure; played a bit one way and another and dediced to drop
it for now.  Hell knows...

My version already is an improvement in lines of code alone.  Between
that and stopping to mess with the address limit I think it's a clear
winner.  But it's pretty independent of the rest, and I'll just run
it through Jeff and Bruce and ask them what they think.