V4L/DVB: drivers/media/video: move dereference after NULL test

In quickcam_messenger.c, if the NULL test on uvd is needed, then the
dereference should be after the NULL test.

In vpif_display.c, std_info is initialized to the address of a structure
field.  This seems unlikely to be NULL.  Test std_info->stdid instead.

In saa7134-alsa.c, the function is only called from one place, where the
chip argument has already been dereferenced.  On the other hand, if it
should be kept, then card should be initialized after it.

A simplified version of the semantic match that detects this problem is as
follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Muralidharan Karicheri <m-karicheri2@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 3 insertions, 4 deletions

diff --git a/drivers/media/video/davinci/vpif_display.c b/drivers/media/video/davinci/vpif_display.c
index 13c3a1b97760..e5bab3d0d53f 100644
--- a/drivers/media/video/davinci/vpif_display.c
+++ b/drivers/media/video/davinci/vpif_display.c
@@ -384,7 +384,7 @@ static int vpif_get_std_info(struct channel_obj *ch)
         int index;
 
         std_info->stdid = vid_ch->stdid;
-        if (!std_info)
+        if (!std_info->stdid)
                 return -1;
 
         for (index = 0; index < ARRAY_SIZE(ch_params); index++) {
diff --git a/drivers/media/video/saa7134/saa7134-alsa.c b/drivers/media/video/saa7134/saa7134-alsa.c
index d48c450ed77c..d3bd82ad010a 100644
--- a/drivers/media/video/saa7134/saa7134-alsa.c
+++ b/drivers/media/video/saa7134/saa7134-alsa.c
@@ -1011,8 +1011,6 @@ static int snd_card_saa7134_new_mixer(snd_card_saa7134_t * chip)
         unsigned int idx;
         int err, addr;
 
-        if (snd_BUG_ON(!chip))
-                return -EINVAL;
         strcpy(card->mixername, "SAA7134 Mixer");
 
         for (idx = 0; idx < ARRAY_SIZE(snd_saa7134_volume_controls); idx++) {
diff --git a/drivers/media/video/usbvideo/quickcam_messenger.c b/drivers/media/video/usbvideo/quickcam_messenger.c
index fab48ec6c0ea..fbd665fa1979 100644
--- a/drivers/media/video/usbvideo/quickcam_messenger.c
+++ b/drivers/media/video/usbvideo/quickcam_messenger.c
@@ -693,12 +693,13 @@ static int qcm_start_data(struct uvd *uvd)
 
 static void qcm_stop_data(struct uvd *uvd)
 {
-        struct qcm *cam = (struct qcm *) uvd->user_data;
+        struct qcm *cam;
         int i, j;
         int ret;
 
         if ((uvd == NULL) || (!uvd->streaming) || (uvd->dev == NULL))
                 return;
+        cam = (struct qcm *) uvd->user_data;
 
         ret = qcm_camera_off(uvd);
         if (ret)