Sep 12 2012

[media] drivers/media/dvb-frontends/dvb_dummy_fe.c: Removes useless kfree() 

Author: Peter Senna Tschudin <peter.senna@gmail.com>

Remove useless kfree() and clean up code related to the removal.
The semantic patch that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// 
@r exists@
position p1,p2;
expression x;
@@
if (x@p1 == NULL) { ... kfree@p2(x); ... return ...; }
@unchanged exists@
position r.p1,r.p2;
expression e <= r.x,x,e1;
iterator I;
statement S;
@@
if (x@p1 == NULL) { ... when != I(x,...) S
                        when != e = e1
                        when != e += e1
                        when != e -= e1
                        when != ++e
                        when != --e
                        when != e++
                        when != e--
                        when != &e
   kfree@p2(x); ... return ...; }
@ok depends on unchanged exists@
position any r.p1;
position r.p2;
expression x;
@@
... when != true x@p1 == NULL
kfree@p2(x);
@depends on !ok && unchanged@
position r.p2;
expression x;
@@
*kfree@p2(x);
// 

Signed-off-by: Peter Senna Tschudin 
Signed-off-by: Mauro Carvalho Chehab 

---
 drivers/media/dvb-frontends/dvb_dummy_fe.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)
 
diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
index dcfc902..d5acc30 100644
--- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
+++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
@@ -121,16 +121,13 @@ struct dvb_frontend* dvb_dummy_fe_ofdm_attach(void)
 
 	/* allocate memory for the internal state */
 	state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
-	if (state == NULL) goto error;
+	if (!state)
+		return NULL;
 
 	/* create dvb_frontend */
 	memcpy(&state->frontend.ops, &dvb_dummy_fe_ofdm_ops, sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;
 	return &state->frontend;
-
-error:
-	kfree(state);
-	return NULL;
 }
 
 static struct dvb_frontend_ops dvb_dummy_fe_qpsk_ops;
@@ -141,16 +138,13 @@ struct dvb_frontend *dvb_dummy_fe_qpsk_attach(void)
 
 	/* allocate memory for the internal state */
 	state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
-	if (state == NULL) goto error;
+	if (!state)
+		return NULL;
 
 	/* create dvb_frontend */
 	memcpy(&state->frontend.ops, &dvb_dummy_fe_qpsk_ops, sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;
 	return &state->frontend;
-
-error:
-	kfree(state);
-	return NULL;
 }
 
 static struct dvb_frontend_ops dvb_dummy_fe_qam_ops;
@@ -161,16 +155,13 @@ struct dvb_frontend *dvb_dummy_fe_qam_attach(void)
 
 	/* allocate memory for the internal state */
 	state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
-	if (state == NULL) goto error;
+	if (!state)
+		return NULL;
 
 	/* create dvb_frontend */
 	memcpy(&state->frontend.ops, &dvb_dummy_fe_qam_ops, sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;
 	return &state->frontend;
-
-error:
-	kfree(state);
-	return NULL;
 }
 
 static struct dvb_frontend_ops dvb_dummy_fe_ofdm_ops = {

qlambert