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Date:   Thu, 5 Jul 2018 14:00:07 -0700
From:   Matthew Wilcox <willy@infradead.org>
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>
Subject: Re: [PATCH 13/13] libnvdimm, namespace: Publish page structure init
 state / control
Message-ID: <20180705210007.GC28447@bombadil.infradead.org>
References: <153077334130.40830.2714147692560185329.stgit@dwillia2-desk3.amr.corp.intel.com>
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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.