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Date: Wed, 16 Apr 2014 13:50:37 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Yogesh Gaur <yogeshgaur.83@gmail.com>
Cc: "torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Dead code removal in madvise_willneed
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On Wed, 16 Apr 2014 13:16:18 +0530 Yogesh Gaur <yogeshgaur.83@gmail.com> wrote:

> Dead code removal in func madvise_willneed().
> When file is NULL i.e. !file true
> 	case CONFIG_SWAP returns 0.
> 	else returns -EBADF.
> Signed-off-by: Yogesh Gaur <yogeshgaur.83@gmail.com>
> ---
>  mm/madvise.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 7055883..be24987 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -231,10 +231,10 @@ static long madvise_willneed(struct vm_area_struct * vma,
>  						file->f_mapping);
>  		return 0;
>  	}
> -#endif
> -
> +#else
>  	if (!file)
>  		return -EBADF;
> +#endif

The compiler should have no trouble making this optimisation for us.  I
don't see that it is necessary to add more ugly-looking ifdefs for
this.