With the use of RCU in files structure, the look-up of files using fds can now
be lock-free.  The lookup is protected by rcu_read_lock()/rcu_read_unlock().
This patch changes the readers to use lock-free lookup.
Signed-off-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NRavikiran Thirumalai <kiran_th@gmail.com>
Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>