tree 2c6df4c16fbe4430ea2723f2aec284105aab08db
parent ed00f64346631dff035adfb9b0240daaa8b46c4e
author Michel Lespinasse <walken@google.com> 1367934355 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1367936416 -0700

rwsem: use cmpxchg for trying to steal write lock

Using rwsem_atomic_update to try stealing the write lock forced us to
undo the adjustment in the failure path.  We can have simpler and faster
code by using cmpxchg instead.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>