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Subject: Re: [PATCH 02/33] mm: overload get_user_pages() functions
To: Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20160212210152.9CAD15B0@viggo.jf.intel.com>
 <20160212210155.73222EE1@viggo.jf.intel.com>
 <20160216083606.GB3335@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
        dave.hansen@linux.intel.com, srikar@linux.vnet.ibm.com, vbabka@suse.cz,
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From: Dave Hansen <dave@sr71.net>
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Date: Wed, 17 Feb 2016 10:15:57 -0800
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On 02/16/2016 12:36 AM, Ingo Molnar wrote:
>> > From: Dave Hansen <dave.hansen@linux.intel.com>
>> > 
>> > The concept here was a suggestion from Ingo.  The implementation
>> > horrors are all mine.
>> > 
>> > This allows get_user_pages(), get_user_pages_unlocked(), and
>> > get_user_pages_locked() to be called with or without the
>> > leading tsk/mm arguments.  We will give a compile-time warning
>> > about the old style being __deprecated and we will also
>> > WARN_ON() if the non-remote version is used for a remote-style
>> > access.
> So at minimum this should be WARN_ON_ONCE(), to make it easier to recover some 
> meaningful kernel log from such incidents.

I went to go fix this in the code but realized that I coded it up as
WARN_ONCE().  The description was just imprecise.  So I won't be sending
a code fix for this.