V4L/DVB (7398): Adds an error if priv argument of tuner_callback is NULL

Adds a consistency check to avoid OOPS, if tuner_callback priv argument is
NULL. Also, simplifies callback codes on cx88.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/media/video/saa7134/saa7134-cards.c b/drivers/media/video/saa7134/saa7134-cards.c
index b622d979e634..c323ca005f72 100644
--- a/drivers/media/video/saa7134/saa7134-cards.c
+++ b/drivers/media/video/saa7134/saa7134-cards.c
@@ -5266,6 +5266,9 @@ int saa7134_tuner_callback(void *priv, int command, int arg)
                 case TUNER_XC2028:
                         return saa7134_xc2028_callback(dev, command, arg);
                 }
+        } else {
+                printk(KERN_ERR "saa7134: Error - device struct undefined.\n");
+                return -EINVAL;
         }
         return -EINVAL;
 }