From 4a444b1f06d259ce938a47048840260f71a91c84 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Fri, 30 Aug 2013 10:05:22 -0400
Subject: [PATCH] rwsem: add rwsem_is_contended

Btrfs needs a simple way to know if it needs to let go of it's read lock on a
rwsem.  Introduce rwsem_is_contended to check to see if there are any waiters on
this rwsem currently.  This is just a hueristic, it is meant to be light and not
100% accurate and called by somebody already holding on to the rwsem in either
read or write.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
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Reading git-format-patch failed