2012-09-10 04:46:47

by Wei Yongjun

Subject: [PATCH] rndis_wlan: move the dereference below the NULL test

From: Wei Yongjun <[email protected]>

The dereference should be moved below the NULL test.

spatch with a semantic match is used to found this.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <[email protected]>
---
drivers/net/wireless/rndis_wlan.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c
index 7a4ae9e..de2a673 100644
--- a/drivers/net/wireless/rndis_wlan.c
+++ b/drivers/net/wireless/rndis_wlan.c
@@ -1946,12 +1946,19 @@ static int rndis_get_tx_power(struct wiphy *wiphy, int *dbm)
static int rndis_scan(struct wiphy *wiphy,
struct cfg80211_scan_request *request)
{
- struct net_device *dev = request->wdev->netdev;
- struct usbnet *usbdev = netdev_priv(dev);
- struct rndis_wlan_private *priv = get_rndis_wlan_priv(usbdev);
+ struct net_device *dev;
+ struct usbnet *usbdev;
+ struct rndis_wlan_private *priv;
int ret;
int delay = SCAN_DELAY_JIFFIES;

+ if (!request)
+ return -EINVAL;
+
+ dev = request->wdev->netdev;
+ usbdev = netdev_priv(dev);
+ priv = get_rndis_wlan_priv(usbdev);
+
netdev_dbg(usbdev->net, "cfg80211.scan\n");

/* Get current bssid list from device before new scan, as new scan
@@ -1959,9 +1966,6 @@ static int rndis_scan(struct wiphy *wiphy,
*/
rndis_check_bssid_list(usbdev, NULL, NULL);

- if (!request)
- return -EINVAL;
-
if (priv->scan_request && priv->scan_request != request)
return -EBUSY;

2012-09-10 06:29:57

by Jussi Kivilinna

Subject: Re: [PATCH] rndis_wlan: move the dereference below the NULL test

Quoting Wei Yongjun <[email protected]>:

> From: Wei Yongjun <[email protected]>
>
> The dereference should be moved below the NULL test.
>
> spatch with a semantic match is used to found this.
> (http://coccinelle.lip6.fr/)
>
> Signed-off-by: Wei Yongjun <[email protected]>
> ---
> drivers/net/wireless/rndis_wlan.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/wireless/rndis_wlan.c
> b/drivers/net/wireless/rndis_wlan.c
> index 7a4ae9e..de2a673 100644
> --- a/drivers/net/wireless/rndis_wlan.c
> +++ b/drivers/net/wireless/rndis_wlan.c
> @@ -1946,12 +1946,19 @@ static int rndis_get_tx_power(struct wiphy
> *wiphy, int *dbm)
> static int rndis_scan(struct wiphy *wiphy,
> struct cfg80211_scan_request *request)
> {
> - struct net_device *dev = request->wdev->netdev;
> - struct usbnet *usbdev = netdev_priv(dev);
> - struct rndis_wlan_private *priv = get_rndis_wlan_priv(usbdev);
> + struct net_device *dev;
> + struct usbnet *usbdev;
> + struct rndis_wlan_private *priv;
> int ret;
> int delay = SCAN_DELAY_JIFFIES;
>
> + if (!request)
> + return -EINVAL;
> +
> + dev = request->wdev->netdev;
> + usbdev = netdev_priv(dev);
> + priv = get_rndis_wlan_priv(usbdev);
> +

'request' is actually always valid pointer and the !request check is
unneeded. Correct fix is to remove the check.

> netdev_dbg(usbdev->net, "cfg80211.scan\n");
>
> /* Get current bssid list from device before new scan, as new scan
> @@ -1959,9 +1966,6 @@ static int rndis_scan(struct wiphy *wiphy,
> */
> rndis_check_bssid_list(usbdev, NULL, NULL);
>
> - if (!request)
> - return -EINVAL;
> -

Only this part is needed.

-Jussi

> if (priv->scan_request && priv->scan_request != request)
> return -EBUSY;
>