[PATCH] cbus-tahvo: Add tahvo_write_reg locking

Michael Büsch
2011-11-05T16:20:04Z

tahvo_write_reg() needs to take the mutex to avoid a race
condition with tahvo_set_clear_reg_bits:

tahvo_set_clear_reg_bits(): | tahvo_write_reg():
__tahvo_read_reg() |
| __tahvo_write_reg() <-- race here
__tahvo_write_reg() |

Signed-off-by: Michael Buesch <m@bues.ch>

---

Index: linux-3.1/drivers/cbus/tahvo.c
===================================================================
--- linux-3.1.orig/drivers/cbus/tahvo.c 2011-11-05 17:03:39.598846119 +0100
+++ linux-3.1/drivers/cbus/tahvo.c 2011-11-05 17:04:36.274768324 +0100
@@ -104,7 +104,9 @@ void tahvo_write_reg(struct device *chil
{
struct tahvo *tahvo = dev_get_drvdata(child->parent);

+ mutex_lock(&tahvo->mutex);
__tahvo_write_reg(tahvo, reg, val);
+ mutex_unlock(&tahvo->mutex);
}
EXPORT_SYMBOL(tahvo_write_reg);

--
Greetings, Michael.