From: NeilBrown <neilb@suse.de>
Date: Tue, 1 May 2012 18:49:24 +0000 (-0700)
Subject: w1: introduce a slave mutex for serializing IO
X-Git-Tag: v3.6-rc1~99^2~14^2~23
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59d4467be405316916a4087d5b02d99196eeef04;p=pandora-kernel.git

w1: introduce a slave mutex for serializing IO

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.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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