From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH RFC] netpoll: convert mutex into a semaphore
Date: Wed, 01 May 2013 15:00:59 -0400 (EDT)
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References: <20130429181322.GA27119@hmsreliant.think-freely.org>
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Cc: netdev@vger.kernel.org, bvanassche@acm.org
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From: Neil Horman <nhorman@tuxdriver.com>
Date: Tue, 30 Apr 2013 11:35:05 -0400

> Bart Van Assche recently reported a warning to me:
 ...
> This resulted from my commit ca99ca14c which introduced a mutex_trylock
> operation in a path that could execute in interrupt context.  When mutex
> debugging is enabled, the above warns the user when we are in fact
> exectuting in interrupt context
> interrupt context.
> 
> After some discussion, It seems that a semaphore is the proper mechanism to use
> here.  While mutexes are defined to be unusable in interrupt context, no such
> condition exists for semaphores (save for the fact that the non blocking api
> calls, like up and down_trylock must be used when in irq context).
> 
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> Reported-by: Bart Van Assche <bvanassche@acm.org>

Neil this looks good to me so I'm going to toss it into my tree and queue
it up for -stable too, thanks!