Subject: Re: [PATCH 7/8] net: Allow setting the network namespace by fd

From: Daniel Lezcano <dlezcano-NmTC/[email-masked]>
Date: Fri, 24 Sep 2010 15:46:28 +0200

On 09/23/2010 10:51 AM, Eric W. Biederman wrote:
>
> Take advantage of the new abstraction and allow network devices
> to be placed in any network namespace that we have a fd to talk
> about.
>
> Signed-off-by: Eric W. Biederman<ebiederm-aS9lmoZGLiVWk0Htik3J/[email-masked]>
> ---

[ ... ]

> +struct net *get_net_ns_by_fd(int fd)
> +{
> +	struct proc_inode *ei;
> +	struct file *file;
> +	struct net *net;
> +
> +	file = NULL;
> +	net = ERR_PTR(-EINVAL);
> +	file = proc_ns_fget(fd);
> +	if (!fd)
> +		goto out;
> +		return ERR_PTR(-EINVAL);
> +
> +	ei = PROC_I(file->f_dentry->d_inode);
> +	if (ei->ns_ops !=&netns_operations)
> +		goto out;

Is this check necessary here ? proc_ns_fget checks "file->f_op != 
&ns_file_operations", no ?