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Date: Tue, 27 Nov 2007 01:02:54 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Michael Kerrisk <mtk-manpages@gmx.net>,
       Thomas Gleixner <tglx@linutronix.de>,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [patch 2/4] Timerfd v3 - new timerfd API
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On Sun, 25 Nov 2007 14:14:19 -0800 Davide Libenzi <davidel@xmailserver.org> wrote:

> +static struct file *timerfd_fget(int fd)
> +{
> +	struct file *file;
> +
> +	file = fget(fd);
> +	if (!file)
> +		return ERR_PTR(-EBADF);
> +	if (file->f_op != &timerfd_fops) {
> +		fput(file);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	return file;
> +}

I suppose we could use fget_light() in here sometime.  It is significantly
quicker in microbenchmarks.  Or it was - nobody has checked that in a few
years afaik.