Date: Wed, 8 Mar 2017 11:39:00 -0800
From: Andi Kleen <ak@linux.intel.com>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: akpm@linux-foundation.org, mhocko@suse.com, mtk.manpages@gmail.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH] mm,hugetlb: compute page_size_log properly
Message-ID: <20170308193900.GC32070@tassilo.jf.intel.com>
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> One example of the problems with extra layers what this patch fixes:
> mmap_pgoff() should never be using SHM_HUGE_* logic. This was
> introduced by:
> 
>    091d0d55b28 (shm: fix null pointer deref when userspace specifies invalid hugepage size)
> 
> It is obviously harmless but lets just rip out the whole thing --
> the shmget.2 manpage will need updating, as it should not be
> describing kernel internals.

The SHM_* defines were supposed to be exported to user space,
but somehow they didn't make it into uapi.

But something like this is useful, it's a much nicer 
interface for users than to hard code the bit position

So I would rather if you move it to uapi instead of 
removing. What the kernel uses internally doesn't
really matter.

-Andi