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/slaves | |
| parent | bdd4034df8b37841eeaf7b05f86e732ab8e0b08a (diff) | |
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/slaves')
| -rw-r--r-- | drivers/w1/slaves/w1_bq27000.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/w1/slaves/w1_bq27000.c b/drivers/w1/slaves/w1_bq27000.c index 52ad812fa1e7..87554788fa32 100644 --- a/drivers/w1/slaves/w1_bq27000.c +++ b/drivers/w1/slaves/w1_bq27000.c @@ -31,10 +31,10 @@ static int w1_bq27000_read(struct device *dev, unsigned int reg) u8 val; struct w1_slave *sl = container_of(dev->parent, struct w1_slave, dev); - mutex_lock(&sl->master->mutex); + mutex_lock(&sl->mutex); w1_write_8(sl->master, HDQ_CMD_READ | reg); val = w1_read_8(sl->master); - mutex_unlock(&sl->master->mutex); + mutex_unlock(&sl->mutex); return val; } |