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authorNeilBrown <neilb@suse.de>2012-05-01 11:49:24 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-12 15:27:32 -0700
commit59d4467be405316916a4087d5b02d99196eeef04 (patch)
treec6f42a454b2d3e3818c84bb0050a2f920993b1df /drivers/w1/w1.c
parentbdd4034df8b37841eeaf7b05f86e732ab8e0b08a (diff)
downloadop-kernel-dev-59d4467be405316916a4087d5b02d99196eeef04.zip
op-kernel-dev-59d4467be405316916a4087d5b02d99196eeef04.tar.gz
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.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 2f2e894..69075c3 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);
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