Re: linux-next: manual merge of the akpm-current tree with the tip tree

[Andrea Arcangeli]

Hello Stephen,

On Tue, Jul 28, 2015 at 04:00:15PM +1000, Stephen Rothwell wrote:
>  -359	i386	userfaultfd		sys_userfaultfd
> ++374	i386	userfaultfd		sys_userfaultfd

Do I understand correctly the syscall number of userfaultfd for x86
32bit has just changed from 359 to 374? Appreciated that you CCed me
on such a relevant change to be sure I didn't miss it.

Then the below is needed as well.

One related question: is it ok to ship kernels in production right now
with the userfaultfd syscall number 374 for x86 32bit ABI (after the
above change) and 323 for x86-64 64bit ABI, with these syscalls number
registered in linux-next or it may keep changing like it has just
happened? I refer only to userfaultfd syscalls of x86 32bit and x86-64
64bit, not all other syscalls in linux-next.

Of course, I know full well that the standard answer is no, and in
fact the above is an expected and fine change. In other words what I'm
really asking is if I wonder if I could get an agreement here that
from now on, the syscall number of userfaultfd for x86 32bit and
x86-64 64bit won't change anymore in linux-next and it's already
reserved just like if it was already upstream.

Again: I'd only seek such guarantee for the x86-64 64bit and x86 32bit
ABIs (not any other arch, and not any other syscall). If I could get
such a guarantee from you within the next week or two, that would
avoid me complications and some work, so I thought it was worth
asking. If it's not possible never mind.

Thanks,
Andrea

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