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Date: Tue, 19 Oct 2010 10:11:58 -0600
From: Jonathan Corbet <corbet@lwn.net>
To: Kay Sievers <kay.sievers@vrfy.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, Greg KH <greg@kroah.com>
Subject: Re: [PATCH] support polling of /proc/swaps
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> From: Kay Sievers <kay.sievers@vrfy.org>
> Subject: support polling of /proc/swaps
> 
> System management wants to subscribe to changes in swap
> configuration. Make /proc/swaps pollable like /proc/mounts.

Please forgive me...I'm probably undercaffeinated and even dumber than
usual, but...

Here we have this:

> +static unsigned swaps_poll(struct file *file, poll_table *wait)
> +{
> +	struct proc_swaps *s = file->private_data;

But here I see:

>  static int swaps_open(struct inode *inode, struct file *file)
>  {
> -	return seq_open(file, &swaps_op);
> +	struct proc_swaps *s;
> +	int ret;
> +
> +	s = kmalloc(sizeof(struct proc_swaps), GFP_KERNEL);
> +	if (!s)
> +		return -ENOMEM;
> +
> +	file->private_data = &s->seq;

It sure looks to me like private_data is a struct seq_file pointer, not a
struct proc_swaps pointer.  What am I missing?

Thanks,

jon