May 26 2010

drivers/isdn/hardware/mISDN: Add missing spin_unlock 

Author: Julia Lawall <julia@diku.dk>

Add a spin_unlock missing on the error path.  The return value of write_reg
seems to be completely ignored, so it seems that the lock should be
released in every case.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
expression E1;
@@

* spin_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* spin_unlock(E1,...);
// 

Signed-off-by: Julia Lawall 
Signed-off-by: David S. Miller 

---
 drivers/isdn/hardware/mISDN/hfcsusb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
 
diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
index b3b7e28..8700474 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -97,8 +97,10 @@ static int write_reg(struct hfcsusb *hw, __u8 reg, __u8 val)
 			hw->name, __func__, reg, val);
 
 	spin_lock(&hw->ctrl_lock);
-	if (hw->ctrl_cnt >= HFC_CTRL_BUFSIZE)
+	if (hw->ctrl_cnt >= HFC_CTRL_BUFSIZE) {
+		spin_unlock(&hw->ctrl_lock);
 		return 1;
+	}
 	buf = &hw->ctrl_buff[hw->ctrl_in_idx];
 	buf->hfcs_reg = reg;
 	buf->reg_val = val;

qlambert