2013-02-05 15:53:42

by Johannes Berg

Subject: [PATCH] cfg80211: remove scan ies NULL check

From: Johannes Berg <[email protected]>

There's no way scan BSS IEs can be NULL as even
if the allocation fails the frame is discarded.
Remove some code checking for this and document
that it is always non-NULL.

Signed-off-by: Johannes Berg <[email protected]>
---
drivers/net/wireless/mwifiex/sta_ioctl.c | 5 -----
include/net/cfg80211.h | 8 ++++----
net/wireless/scan.c | 11 +++--------
3 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/mwifiex/sta_ioctl.c b/drivers/net/wireless/mwifiex/sta_ioctl.c
index ee85b41..8866a2b 100644
--- a/drivers/net/wireless/mwifiex/sta_ioctl.c
+++ b/drivers/net/wireless/mwifiex/sta_ioctl.c
@@ -162,11 +162,6 @@ int mwifiex_fill_new_bss_desc(struct mwifiex_private *priv,

rcu_read_lock();
ies = rcu_dereference(bss->ies);
- if (WARN_ON(!ies)) {
- /* should never happen */
- rcu_read_unlock();
- return -EINVAL;
- }
beacon_ie = kmemdup(ies->data, ies->len, GFP_ATOMIC);
beacon_ie_len = ies->len;
rcu_read_unlock();
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 2907cec..7b73267 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1299,10 +1299,10 @@ struct cfg80211_bss_ies {
* @tsf: timestamp of last received update
* @beacon_interval: the beacon interval as from the frame
* @capability: the capability field in host byte order
- * @ies: the information elements (Note that there
- * is no guarantee that these are well-formed!); this is a pointer to
- * either the beacon_ies or proberesp_ies depending on whether Probe
- * Response frame has been received
+ * @ies: the information elements (Note that there is no guarantee that these
+ * are well-formed!); this is a pointer to either the beacon_ies or
+ * proberesp_ies depending on whether Probe Response frame has been
+ * received. It is always non-%NULL.
* @beacon_ies: the information elements from the last Beacon frame
* (implementation note: if @hidden_beacon_bss is set this struct doesn't
* own the beacon_ies, but they're just pointers to the ones from the
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 5e0983d..02a2383 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1293,15 +1293,10 @@ ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,

rcu_read_lock();
ies = rcu_dereference(bss->pub.ies);
- if (ies) {
- rem = ies->len;
- ie = ies->data;
- } else {
- rem = 0;
- ie = NULL;
- }
+ rem = ies->len;
+ ie = ies->data;

- while (ies && rem >= 2) {
+ while (rem >= 2) {
/* invalid data */
if (ie[1] > rem - 2)
break;
--
1.8.0

2013-02-11 11:49:27

by Johannes Berg

Subject: Re: [PATCH] cfg80211: remove scan ies NULL check

On Tue, 2013-02-05 at 16:54 +0100, Johannes Berg wrote:
> From: Johannes Berg <[email protected]>
>
> There's no way scan BSS IEs can be NULL as even
> if the allocation fails the frame is discarded.
> Remove some code checking for this and document
> that it is always non-NULL.

Applied.

johannes