linux-kernel - [PATCH] saa7164-dvb: Remove unnecessary null test

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Message-ID: <20140715212953.GA28003@himangi-Dell>
Date:	Wed, 16 Jul 2014 02:59:53 +0530
From:	Himangi Saraogi <himangi774@...il.com>
To:	Mauro Carvalho Chehab <m.chehab@...sung.com>,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	julia.lawall@...6.fr
Subject: [PATCH] saa7164-dvb: Remove unnecessary null test

This patch removes the null test on dvb. dvb is initialized at the
beginning of the function to &port->dvb. Since port is dereferenced
prior to the null test, port must be a valid pointer, and
&port->dvb cannot be null.

The following Coccinelle script is used for detecting the change:

@r@
expression e,f;
identifier g,y;
statement S1,S2;
@@

*e = &f->g
<+...
 f->y
 ...+>
*if (e != NULL || ...)
 S1 else S2

Signed-off-by: Himangi Saraogi <himangi774@...il.com>
Acked-by: Julia Lawall <julia.lawall@...6.fr>
---
 drivers/media/pci/saa7164/saa7164-dvb.c | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/media/pci/saa7164/saa7164-dvb.c b/drivers/media/pci/saa7164/saa7164-dvb.c
index 5c5cc3e..16ae715 100644
--- a/drivers/media/pci/saa7164/saa7164-dvb.c
+++ b/drivers/media/pci/saa7164/saa7164-dvb.c
@@ -242,16 +242,14 @@ static int saa7164_dvb_start_feed(struct dvb_demux_feed *feed)
 	if (!demux->dmx.frontend)
 		return -EINVAL;
 
-	if (dvb) {
-		mutex_lock(&dvb->lock);
-		if (dvb->feeding++ == 0) {
-			/* Start transport */
-			ret = saa7164_dvb_start_port(port);
-		}
-		mutex_unlock(&dvb->lock);
-		dprintk(DBGLVL_DVB, "%s(port=%d) now feeding = %d\n",
-			__func__, port->nr, dvb->feeding);
+	mutex_lock(&dvb->lock);
+	if (dvb->feeding++ == 0) {
+		/* Start transport */
+		ret = saa7164_dvb_start_port(port);
 	}
+	mutex_unlock(&dvb->lock);
+	dprintk(DBGLVL_DVB, "%s(port=%d) now feeding = %d\n",
+		__func__, port->nr, dvb->feeding);
 
 	return ret;
 }
@@ -266,16 +264,14 @@ static int saa7164_dvb_stop_feed(struct dvb_demux_feed *feed)
 
 	dprintk(DBGLVL_DVB, "%s(port=%d)\n", __func__, port->nr);
 
-	if (dvb) {
-		mutex_lock(&dvb->lock);
-		if (--dvb->feeding == 0) {
-			/* Stop transport */
-			ret = saa7164_dvb_stop_streaming(port);
-		}
-		mutex_unlock(&dvb->lock);
-		dprintk(DBGLVL_DVB, "%s(port=%d) now feeding = %d\n",
-			__func__, port->nr, dvb->feeding);
+	mutex_lock(&dvb->lock);
+	if (--dvb->feeding == 0) {
+		/* Stop transport */
+		ret = saa7164_dvb_stop_streaming(port);
 	}
+	mutex_unlock(&dvb->lock);
+	dprintk(DBGLVL_DVB, "%s(port=%d) now feeding = %d\n",
+		__func__, port->nr, dvb->feeding);
 
 	return ret;
 }
-- 
1.9.1

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