usb: typec: unlock dp->lock on error exit path, and also zero ret if successful

One of the error handling paths forgets to unlock dp->lock on the error
exit path leading to a potential lock-up.  Also the return path for a
successful call to the function configuration_store can return an
uninitialized error return code if dp->alt->active is false, so ensure
ret is zeroed on the successful exit path to avoid garbage being returned.

Detected by CoverityScan, CID#1471597 ("Unitialized scalar variable")

Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index ef12b15..3f06e94 100644 (file)
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -333,7 +333,7 @@ configuration_store(struct device *dev, struct device_attribute *attr,
        u32 conf;
        u32 cap;
        int con;
-       int ret;
+       int ret = 0;
 
        con = sysfs_match_string(configurations, buf);
        if (con < 0)
@@ -349,8 +349,10 @@ configuration_store(struct device *dev, struct device_attribute *attr,
        cap = DP_CAP_CAPABILITY(dp->alt->vdo);
 
        if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
-           (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D)))
-               return -EINVAL;
+           (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
+               ret = -EINVAL;
+               goto err_unlock;
+       }
 
        conf = dp->data.conf & ~DP_CONF_DUAL_D;
        conf |= con;