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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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References: <1393625931-2858-1-git-send-email-quning@google.com>
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Subject: Re: [PATCH 1/1] mm: implement ->map_pages for shmem/tmpfs
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Message-Id: <20140303110747.01F2DE0098@blue.fi.intel.com>
Date: Mon,  3 Mar 2014 13:07:46 +0200 (EET)
Sender: owner-linux-mm@kvack.org
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To: Ning Qu <quning@google.com>, Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Andi Kleen <ak@linux.intel.com>, Matthew Wilcox <matthew.r.wilcox@intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, Alexander Viro <viro@zeniv.linux.org.uk>, Dave Chinner <david@fromorbit.com>, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org

Ning Qu wrote:
> Btw, should we first check if page returned by radix_tree_deref_slot is NULL?

Yes, we should. I don't know how I missed that. :(

The patch below should address both issues.