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Date: Thu, 5 Jul 2018 14:00:07 -0700
From: Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH 13/13] libnvdimm, namespace: Publish page structure init
 state / control
Message-ID: <20180705210007.GC28447@bombadil.infradead.org>
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To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Thumshirn <jthumshirn@suse.de>, Dan Williams <dan.j.williams@intel.com>, Ross Zwisler <ross.zwisler@linux.intel.com>, Vishal Verma <vishal.l.verma@intel.com>, Dave Jiang <dave.jiang@intel.com>, Jeff Moyer <jmoyer@redhat.com>, Christoph Hellwig <hch@lst.de>, linux-nvdimm <linux-nvdimm@lists.01.org>, Linux MM <linux-mm@kvack.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>

On Thu, Jul 05, 2018 at 01:24:55PM -0700, Andrew Morton wrote:
> On Thu, 5 Jul 2018 16:49:41 +0200 Johannes Thumshirn <jthumshirn@suse.de> wrote:
> 
> > On Thu, Jul 05, 2018 at 07:46:05AM -0700, Dan Williams wrote:
> > > ...but that also allows 'echo "syncAndThenSomeGarbage" >
> > > /sys/.../memmap_state' to succeed.
> > 
> > Yep it does :-(.
> > 
> > Damn
> 
> sysfs_streq()

Thanks!  I didn't know that one existed.

It's kind of a shame that we realised this was a problem and decided
to solve it this way back in 2008 instead of realising that no driver
actually cares whether there's a \n or not and stripping off the \n
before the driver gets to see it.  Probably too late to fix that now.