[PATCH 0/3] procfs wrt pid namespace cleanups

[Daniel Lezcano]

This patchset is a cleanup and a preparation to unshare the pid
namespace. These prerequisite prepare the next Eric's patchset
to give a file descriptor to a namespace and join an existing
namespace.

The initial authors of this patchset are Eric Biederman and Oleg
Nesterov.

Changelog:

        02/14/11 - daniel.lezcano at free.fr
        * patch 2/3 : fix return ENOMEM and put_pid_ns on error
        * removed buggy patch #4 from the initial patchset

        01/31/11 - daniel.lezcano at free.fr:
        * patch 1/4 : wrapped test in a function
        * patch 2/4 : handle proc_pid_ns_prepare_proc error
        * patch 2/4 : put parent pid_ns on error
        * other patches : refreshed against linux-next