V4L/DVB (4311): Fix possible dvb-pll oops

Supplying a NULL i2c adapter to dvb_pll_attach is allowed, for example with
mt352 demods. However, the pll i2c probe will segfault because it does not
check for this.

Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 10 insertions, 8 deletions

diff --git a/drivers/media/dvb/frontends/dvb-pll.c b/drivers/media/dvb/frontends/dvb-pll.c
index fce5c4252252..4c8a506479b4 100644
--- a/drivers/media/dvb/frontends/dvb-pll.c
+++ b/drivers/media/dvb/frontends/dvb-pll.c
@@ -619,14 +619,16 @@ int dvb_pll_attach(struct dvb_frontend *fe, int pll_addr, struct i2c_adapter *i2
         struct dvb_pll_priv *priv = NULL;
         int ret;
 
-        if (fe->ops.i2c_gate_ctrl)
-                fe->ops.i2c_gate_ctrl(fe, 1);
-
-        ret = i2c_transfer (i2c, msg, 2);
-        if (ret != 2)
-                return -1;
-        if (fe->ops.i2c_gate_ctrl)
-                     fe->ops.i2c_gate_ctrl(fe, 0);
+        if (i2c != NULL) {
+                if (fe->ops.i2c_gate_ctrl)
+                        fe->ops.i2c_gate_ctrl(fe, 1);
+
+                ret = i2c_transfer (i2c, msg, 2);
+                if (ret != 2)
+                        return -1;
+                if (fe->ops.i2c_gate_ctrl)
+                             fe->ops.i2c_gate_ctrl(fe, 0);
+        }
 
         priv = kzalloc(sizeof(struct dvb_pll_priv), GFP_KERNEL);
         if (priv == NULL)