Re: [PATCH] mm: Remove usages of ACCESS_ONCE

From: Christian Borntraeger
Date: Tue Mar 24 2015 - 10:43:17 EST


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@xxxxxx>

Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>

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

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