Aug 09 2014

mfd: menelaus: Remove null pointer dereference 

Author: Himangi Saraogi <himangi774@gmail.com>

If vtg is NULL, it is not possible to access its mode_reg field. At all
sites where the static function menelaus_set_voltage is called, the first
argument is the address of a structure defined in the file. So, the null
test is unnecessary and is removed. Also, a label is done away with.

This problem was found using the following Coccinelle semantic match:

// 
@@
expression E, E1;
identifier f;
statement S1,S2,S3;
@@

* if (E == NULL)
{
  ... when != if (E == NULL) S1 else S2
      when != E = E1
* E->f
  ... when any
  return ...;
}
else S3
// 

Signed-off-by: Himangi Saraogi 
Acked-by: Julia Lawall 
Signed-off-by: Lee Jones 

---
 drivers/mfd/menelaus.c | 3 ---
 1 file changed, 3 deletions(-)
 
diff --git a/drivers/mfd/menelaus.c b/drivers/mfd/menelaus.c
index 5e2667a..18ff56f 100644
--- a/drivers/mfd/menelaus.c
+++ b/drivers/mfd/menelaus.c
@@ -466,8 +466,6 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
 	struct i2c_client *c = the_menelaus->client;
 
 	mutex_lock(&the_menelaus->lock);
-	if (!vtg)
-		goto set_voltage;
 
 	ret = menelaus_read_reg(vtg->vtg_reg);
 	if (ret < 0)
@@ -482,7 +480,6 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
 	ret = menelaus_write_reg(vtg->vtg_reg, val);
 	if (ret < 0)
 		goto out;
-set_voltage:
 	ret = menelaus_write_reg(vtg->mode_reg, mode);
 out:
 	mutex_unlock(&the_menelaus->lock);

qlambert