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

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/w@public.gmane.org>
---

[ ... ]

+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 ?