Re: [PATCH] w1: Introduce a slave mutex for serializing IO.

[Evgeniy Polyakov]

On Wed, Apr 25, 2012 at 12:49:14PM +1000, NeilBrown (neilb@xxxxxxx) wrote:
> w1 devices need a mutex to serial IO.
> Most use master->mutex.
> 
> However that is used for other purposes and they can conflict.
> 
> In particular master->mutex is held while w1_attach_slave_device is
> called.
> 
> For bq27000, this registers a 'powersupply' device which tries to
> read the current status.  The attempt to read will cause a deadlock on
> master->mutex.
> 
> So create a new per-slave mutex and use that for serializing IO for
> bq27000.

How will this protect against master doing search for example?
It performs a number of read/write operations which are not allowed to
be interrupted by outside read.

-- 
	Evgeniy Polyakov
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