diff options
author | NeilBrown <neilb@suse.de> | 2012-05-01 11:49:24 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-12 15:27:32 -0700 |
commit | 59d4467be405316916a4087d5b02d99196eeef04 (patch) | |
tree | c6f42a454b2d3e3818c84bb0050a2f920993b1df /drivers/w1/w1.c | |
parent | bdd4034df8b37841eeaf7b05f86e732ab8e0b08a (diff) | |
download | linux-3.10-59d4467be405316916a4087d5b02d99196eeef04.tar.gz linux-3.10-59d4467be405316916a4087d5b02d99196eeef04.tar.bz2 linux-3.10-59d4467be405316916a4087d5b02d99196eeef04.zip |
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>
Diffstat (limited to 'drivers/w1/w1.c')
-rw-r--r-- | drivers/w1/w1.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 2f2e894ea0c..69075c3dfc7 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -688,6 +688,7 @@ static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn) memcpy(&sl->reg_num, rn, sizeof(sl->reg_num)); atomic_set(&sl->refcnt, 0); init_completion(&sl->released); + mutex_init(&sl->mutex); spin_lock(&w1_flock); f = w1_family_registered(rn->family); |