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Date:   Mon, 16 Nov 2020 20:00:09 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc:     David Laight <David.Laight@aculab.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
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        Soheil Hassas Yeganeh <soheil.kdev@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>, Shuo Chen <shuochen@google.com>
Subject: Re: [PATCH v2] epoll: add nsec timeout support
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On Mon, Nov 16, 2020 at 02:54:17PM -0500, Willem de Bruijn wrote:
> > You could also add a compile assert to check that the flag is reserved.
> 
> Like this?
> 
>         /* Check the EPOLL_* constant for consistency.  */
>         BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
> +        BUILD_BUG_ON(EPOLL_NSTIMEO & EPOLL_RESERVED_FLAGS);

i think you got the sense of that test wrong.  but yes.