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Date: Tue, 5 Dec 2017 20:54:35 -0800
From: Matthew Wilcox <willy@infradead.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Cyril Hrubis <chrubis@suse.cz>, Michal Hocko <mhocko@kernel.org>,
        Kees Cook <keescook@chromium.org>,
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        Abdul Haleem <abdhalee@linux.vnet.ibm.com>,
        Joel Stanley <joel@jms.id.au>
Subject: Re: [PATCH 0/2] mm: introduce MAP_FIXED_SAFE
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On Wed, Dec 06, 2017 at 03:51:44PM +1100, Michael Ellerman wrote:
> Cyril Hrubis <chrubis@suse.cz> writes:
> 
> > Hi!
> >> > MAP_FIXED_UNIQUE
> >> > MAP_FIXED_ONCE
> >> > MAP_FIXED_FRESH
> >> 
> >> Well, I can open a poll for the best name, but none of those you are
> >> proposing sound much better to me. Yeah, naming sucks...
> >
> > Given that MAP_FIXED replaces the previous mapping MAP_FIXED_NOREPLACE
> > would probably be a best fit.
> 
> Yeah that could work.
> 
> I prefer "no clobber" as I just suggested, because the existing
> MAP_FIXED doesn't politely "replace" a mapping, it destroys the current
> one - which you or another thread may be using - and clobbers it with
> the new one.

It's longer than MAP_FIXED_WEAK :-P

You'd have to be pretty darn strong to clobber an existing mapping.