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From: Sven Eckelmann <sven@narfation.org>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org
Cc: simon.wunderlich@s2003.tu-chemnitz.de,
	Marek Lindner <lindner_marek@yahoo.de>
Subject: Using nested locking for spin_lock_bh
Date: Wed, 28 Mar 2012 18:36:39 +0200	[thread overview]
Message-ID: <2108147.Aqyix6xDmB@bentobox> (raw)

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Hi,

I started to run some experimental batman-adv code inside some virtual 
machines with different debugging functions enabled. One of them was lockdep. 
There we noticed a false positive for a lock class that is actually used in 
two different data structures. Therefore, lockdep noticed that there could be 
a deadlock for this class in a function that locks the two different data 
structures.

To resolve this problem, I wanted to define two different subclasses and 
replace the spin_lock_bh with its nested version. The only problem now is the 
absence of spin_lock_bh_nested. I could only find spin_lock_bh and 
spin_lock_irqsave_nested.

Is there another way how this should be done or is there a general problem why 
there is no nested support for this incarnation of spin_lock?

Kind regards,
	Sven

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             reply	other threads:[~2012-03-28 16:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-28 16:36 Sven Eckelmann [this message]
2012-03-29  3:11 ` Using nested locking for spin_lock_bh Yong Zhang
2012-03-29 10:41   ` Sven Eckelmann
2012-04-15 11:18 ` Peter Zijlstra

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