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Date: Tue, 24 Mar 2015 15:42:56 +0100
From: Christian Borntraeger <borntraeger@de.ibm.com>
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To: Jason Low <jason.low2@hp.com>, linux-mm@kvack.org,
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CC: Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@suse.cz>,
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        Aswin Chandramouleeswaran <aswin@hp.com>, Mel Gorman <mgorman@suse.de>,
        Hugh Dickins <hughd@google.com>, Minchan Kim <minchan@kernel.org>,
        Davidlohr Bueso <dave@stgolabs.net>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH] mm: Remove usages of ACCESS_ONCE
References: <1427150680.2515.36.camel@j-VirtualBox>
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Am 23.03.2015 um 23:44 schrieb Jason Low:
> Commit 38c5ce936a08 converted ACCESS_ONCE usage in gup_pmd_range() to
> READ_ONCE, since ACCESS_ONCE doesn't work reliably on non-scalar types.
> 
> This patch removes the rest of the usages of ACCESS_ONCE, and use
> READ_ONCE for the read accesses. This also makes things cleaner,
> instead of using separate/multiple sets of APIs.
> 
> Signed-off-by: Jason Low <jason.low2@hp.com>

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

one remark or question:

> -	anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
> +	anon_mapping = (unsigned long)READ_ONCE(page->mapping);

Were the white space changes intentional? IIRC checkpatch does prefer
it your way and you have changed several places - so I assume yes.
Either way, its probably fine to change that along.

Christian