Commit 023d43c7 authored Jul 21, 2009 by Peter Zijlstra Committed by Peter Zijlstra Jul 22, 2009

lockdep: Fix lockdep annotation for pipe_double_lock()



The presumed use of the pipe_double_lock() routine is to lock 2 locks in
a deadlock free way by ordering the locks by their address. However it
fails to keep the specified lock classes in order and explicitly
annotates a deadlock.

Rectify this.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Miklos Szeredi <mszeredi@suse.cz>
LKML-Reference: <1248163763.15751.11098.camel@twins>

parent aea1f796

fs/pipe.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -68,8 +68,8 @@ void pipe_double_lock(struct pipe_inode_info *pipe1,
		pipe_lock_nested(pipe1, I_MUTEX_PARENT);
		pipe_lock_nested(pipe2, I_MUTEX_CHILD);
		} else {
		pipe_lock_nested(pipe2, I_MUTEX_CHILD);
		pipe_lock_nested(pipe1, I_MUTEX_PARENT);
		pipe_lock_nested(pipe2, I_MUTEX_PARENT);
		pipe_lock_nested(pipe1, I_MUTEX_CHILD);
		}
		}

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