On Fri, 28 Sep 2018, Andy Lutomirski wrote: > On Fri, Sep 28, 2018 at 7:53 AM Martin Schwidefsky <schwidefsky@xxxxxxxxxx> wrote: > > On Fri, 28 Sep 2018 07:11:44 -0700 Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > > > > > There’s another way to skin this cat: keep KERNEL_DS but pass a valid pointer. > > > I don’t suppose you remember why you didn’t do that? > > > > No, I don't remember. To use a valid kernel pointer with KERNEL_DS and > > then test for == 0 (vs -ENOSYS) imho should work. > > > > There may be a much nicer solution. Unless I missed something, only > mips and xtensa even have the possibility of cmpxchg being missing. > We could just make those arches supply a futex-detecting helper. That makes sense. Thanks, tglx
