From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 04 Jun 2019 07:26:10 +0000
Subject: Re: [PATCH 03/16] mm: simplify gup_fast_permitted
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>, Paul Burton <paul.burton@mips.com>, James Hogan <jhogan@kernel.org>, Yoshinori Sato <ysato@users.sourceforge.jp>, Rich Felker <dalias@libc.org>, "David S. Miller" <davem@davemloft.net>, Nicholas Piggin <npiggin@gmail.com>, Khalid Aziz <khalid.aziz@oracle.com>, Andrey Konovalov <andreyknvl@google.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>, linux-mips@vger.kernel.org, Linux-sh list <linux-sh@vger.kernel.org>, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Linux-MM <linux-mm@kvack.org>, the arch/x86 maintainers <x86@kernel.org>, Linux List Kernel Mailing <linux-kernel@vger.kernel.org>

On Mon, Jun 03, 2019 at 10:02:10AM -0700, Linus Torvalds wrote:
> On Mon, Jun 3, 2019 at 9:08 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > The new code has no test at all for "nr_pages = 0", afaik.
> 
> Note that it really is important to check for that, because right now we do

True.  The 0 check got lost.  I'll make sure we do the right thing for
the next version.