[PATCH] media: dvb-frontends/cxd2099: report errors

From: trix
Date: Wed Jul 22 2020 - 09:41:57 EST


From: Tom Rix <trix@xxxxxxxxxx>

Clang static analysis reports this error

drivers/media/dvb-frontends/cxd2099.c:420:2: warning: Undefined
or garbage value returned to caller
return val;
^~~~~~~~~~

In read_cam_control, the call to read_io can fail.
When it fails val is not set.

The failure status should be returned to the caller,
not the unset val.

Similar problem with read_attribute_mem

Fixes: 0f0b270f905b ("[media] ngene: CXD2099AR Common Interface driver")

Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
drivers/media/dvb-frontends/cxd2099.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/media/dvb-frontends/cxd2099.c b/drivers/media/dvb-frontends/cxd2099.c
index f88b5355493e..9dfaf18fc4b4 100644
--- a/drivers/media/dvb-frontends/cxd2099.c
+++ b/drivers/media/dvb-frontends/cxd2099.c
@@ -387,12 +387,15 @@ static int read_attribute_mem(struct dvb_ca_en50221 *ca,
{
struct cxd *ci = ca->data;
u8 val;
+ int ret;

mutex_lock(&ci->lock);
set_mode(ci, 1);
- read_pccard(ci, address, &val, 1);
+ ret = read_pccard(ci, address, &val, 1);
+ if (!ret)
+ ret = val;
mutex_unlock(&ci->lock);
- return val;
+ return ret;
}

static int write_attribute_mem(struct dvb_ca_en50221 *ca, int slot,
@@ -412,12 +415,15 @@ static int read_cam_control(struct dvb_ca_en50221 *ca,
{
struct cxd *ci = ca->data;
unsigned int val;
+ int ret;

mutex_lock(&ci->lock);
set_mode(ci, 0);
- read_io(ci, address, &val);
+ ret = read_io(ci, address, &val);
+ if (!ret)
+ ret = val;
mutex_unlock(&ci->lock);
- return val;
+ return ret;
}

static int write_cam_control(struct dvb_ca_en50221 *ca, int slot,
--
2.18.1