From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH 0/2] mm: introduce MAP_FIXED_SAFE Date: Thu, 7 Dec 2017 11:57:27 -0800 Message-ID: <20171207195727.GA26792@bombadil.infradead.org> References: <20171129144219.22867-1-mhocko@kernel.org> <20171130065835.dbw4ajh5q5whikhf@dhcp22.suse.cz> <20171201152640.GA3765@rei> <87wp20e9wf.fsf@concordia.ellerman.id.au> <20171206045433.GQ26021@bombadil.infradead.org> <20171206070355.GA32044@bombadil.infradead.org> <87bmjbks4c.fsf@concordia.ellerman.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kees Cook Cc: Michael Ellerman , Cyril Hrubis , Michal Hocko , Linux API , Khalid Aziz , Andrew Morton , Russell King - ARM Linux , Andrea Arcangeli , Linux-MM , LKML , linux-arch , Florian Weimer , John Hubbard , Abdul Haleem , Joel Stanley , Pavel Machek List-Id: linux-api@vger.kernel.org On Thu, Dec 07, 2017 at 11:14:27AM -0800, Kees Cook wrote: > On Wed, Dec 6, 2017 at 9:46 PM, Michael Ellerman wrote: > > Matthew Wilcox writes: > >> So, just like we currently say "exactly one of MAP_SHARED or MAP_PRIVATE", > >> we could add a new paragraph saying "at most one of MAP_FIXED or > >> MAP_REQUIRED" and "any of the following values". > > > > MAP_REQUIRED doesn't immediately grab me, but I don't actively dislike > > it either :) > > > > What about MAP_AT_ADDR ? > > > > It's short, and says what it does on the tin. The first argument to mmap > > is actually called "addr" too. > > "FIXED" is supposed to do this too. > > Pavel suggested: > > MAP_ADD_FIXED > > (which is different from "use fixed", and describes why it would fail: > can't add since it already exists.) > > Perhaps "MAP_FIXED_NEW"? > > There has been a request to drop "FIXED" from the name, so these: > > MAP_FIXED_NOCLOBBER > MAP_FIXED_NOREPLACE > MAP_FIXED_ADD > MAP_FIXED_NEW > > Could be: > > MAP_NOCLOBBER > MAP_NOREPLACE > MAP_ADD > MAP_NEW > > and we still have the unloved, but acceptable: > > MAP_REQUIRED > > My vote is still for "NOREPLACE" or "NOCLOBBER" since it's very > specific, though "NEW" is pretty clear too. How about MAP_NOFORCE?