userns: Make seq_file's user namespace accessible

struct file already has a user namespace associated with it
in file->f_cred->user_ns, unfortunately because struct
seq_file has no struct file backpointer associated with
it, it is difficult to get at the user namespace in seq_file
context.  Therefore add a helper function seq_user_ns to return
the associated user namespace and a user_ns field to struct
seq_file to be used in implementing seq_user_ns.

Cc: Al Viro <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Acked-by: David S. Miller <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>

0 files changed, 0 insertions, 0 deletions