Re: [PATCH 01/13] powerpc: Add rcu_read_lock() to gup_fast()implementation

From: James Bottomley
Date: Sat Apr 17 2010 - 23:07:06 EST


On Fri, 2010-04-16 at 09:45 -0700, Paul E. McKenney wrote:
> o mutex_lock(): Critical sections need not guarantee
> forward progress, as general blocking is permitted.

This isn't quite right. mutex critical sections must guarantee eventual
forward progress against the class of other potential acquirers of the
mutex otherwise the system will become either deadlocked or livelocked.

James


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