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Date: Mon, 18 Jul 2016 17:09:39 -0600
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>, Jan Kara <jack@suse.cz>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
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        Sasha Levin <sasha.levin@oracle.com>, linux-kernel@vger.kernel.org,
        Konstantin Khlebnikov <koct9i@gmail.com>,
        Matthew Wilcox <willy@linux.intel.com>,
        Hugh Dickins <hughd@google.com>, stable@vger.kernel.org
Subject: Re: [PATCH] radix-tree: fix radix_tree_iter_retry() for tagged
 iterators.
Message-ID: <20160718230939.GA2076@linux.intel.com>
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On Fri, Jul 15, 2016 at 01:57:33PM -0700, Andrew Morton wrote:
> On Fri, 15 Jul 2016 13:00:40 -0600 Ross Zwisler <ross.zwisler@linux.intel.com> wrote:
> 
> > 
> > ...
> >
> > In looking at this more, I agree that your patch fixes this particular bug,
> > but I think that ultimately we might want something more general.
> > 
> > ...
> >
> > --- a/include/linux/radix-tree.h
> > +++ b/include/linux/radix-tree.h
> > @@ -463,6 +463,9 @@ static inline struct radix_tree_node *entry_to_node(void *ptr)
> >  static __always_inline void **
> >  radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
> >  {
> > +	if (unlikely(!slot))
> > +		return NULL;
> > +
> >  	if (flags & RADIX_TREE_ITER_TAGGED) {
> >  		void *canon = slot;
> 
> I'll hang onto Andrey's
> radix-tree-fix-radix_tree_iter_retry-for-tagged-iterators.patch for
> now, plan to send it in to Linus Wednesdayish.  If we can get the above
> settled down prior to that then I shall swap over.

Sure, that works for me.